生態(tài)環(huán)境與農(nóng)業(yè)氣象

生態(tài)環(huán)境與農(nóng)業(yè)氣象研究進(jìn)展

1 農(nóng)業(yè)氣候資源與農(nóng)業(yè)氣象災(zāi)害監(jiān)測(cè)預(yù)測(cè)

1.1 洪澇災(zāi)害監(jiān)測(cè)預(yù)警與防控關(guān)鍵技術(shù)研究

揭示了全國及研究區(qū)域農(nóng)業(yè)、玉米、水稻洪澇災(zāi)害的時(shí)空、風(fēng)險(xiǎn)分布特征，建立玉米、水稻洪澇災(zāi)害等級(jí)指標(biāo)11套，分省農(nóng)業(yè)洪澇災(zāi)害等級(jí)指標(biāo)10套，玉米、水稻抗?jié)衬脱托螒B(tài)生理指標(biāo)3套；研發(fā)防洪避災(zāi)種植模式3套，制定災(zāi)害防控技術(shù)規(guī)程3項(xiàng)。成果已在湖南、江西、浙江、安徽、廣西、重慶、陜西7?。▍^(qū)、市）進(jìn)行了氣象業(yè)務(wù)應(yīng)用，制作發(fā)布洪澇災(zāi)害農(nóng)業(yè)氣象專題服務(wù)產(chǎn)品、決策服務(wù)報(bào)告40多期，洪澇預(yù)警與減災(zāi)服務(wù)取得了顯著的減災(zāi)增產(chǎn)效果。提出了基于災(zāi)害風(fēng)險(xiǎn)逆過程分析的等級(jí)指標(biāo)構(gòu)建方法，突破了基于降水過程的農(nóng)業(yè)、玉米、水稻洪澇災(zāi)害等級(jí)閾值確定、分省指標(biāo)可比性等關(guān)鍵技術(shù)，為農(nóng)業(yè)災(zāi)害實(shí)時(shí)監(jiān)測(cè)預(yù)警評(píng)估的業(yè)務(wù)發(fā)展提供了指標(biāo)支撐。（霍治國）

1.2 重大農(nóng)業(yè)氣象災(zāi)害立體監(jiān)測(cè)與動(dòng)態(tài)評(píng)估技術(shù)研究

通過對(duì)西南玉米和水稻干旱、南方雙季稻低溫、黃淮海小麥干熱風(fēng)不同災(zāi)害的立體監(jiān)測(cè)與動(dòng)態(tài)評(píng)估技術(shù)的研究，提出不同農(nóng)業(yè)氣象災(zāi)害的致災(zāi)氣象指標(biāo)和災(zāi)害分級(jí)指標(biāo)體系，研發(fā)了可在氣象業(yè)務(wù)中應(yīng)用的基于地面觀測(cè)、衛(wèi)星遙感和作物模式相結(jié)合的不同災(zāi)害的立體監(jiān)測(cè)技術(shù)和動(dòng)態(tài)評(píng)估的技術(shù)方法。上述工作在以下幾個(gè)方面有所創(chuàng)新：在信息耦合上，集成了地面氣象、農(nóng)業(yè)氣象、田間小氣候觀測(cè)以及農(nóng)情、災(zāi)情和地理信息等多源信息，向多源信息方向發(fā)展；在立體監(jiān)測(cè)和動(dòng)態(tài)評(píng)估技術(shù)研發(fā)上，向模型化、動(dòng)態(tài)化和精細(xì)化方向發(fā)展；在多源觀測(cè)資料信息的使用過程中，注重了尺度轉(zhuǎn)換技術(shù)。該項(xiàng)目研究解決的農(nóng)業(yè)氣象災(zāi)害監(jiān)測(cè)與評(píng)估中的關(guān)鍵技術(shù)是完全針對(duì)我國農(nóng)業(yè)生產(chǎn)模式和災(zāi)害對(duì)象，具有明顯的地域性和現(xiàn)實(shí)性等特點(diǎn)；同時(shí)該研究也是針對(duì)氣象和農(nóng)業(yè)部門的業(yè)務(wù)需求和決策服務(wù)需求而展開的。因此，本項(xiàng)目的實(shí)施可顯著地提高我國農(nóng)業(yè)氣象災(zāi)害的監(jiān)測(cè)和評(píng)估能力。（趙艷霞）

1.3 重大農(nóng)業(yè)氣象災(zāi)害預(yù)測(cè)預(yù)警關(guān)鍵技術(shù)研究

揭示了氣候變暖背景下南方雙季稻低溫災(zāi)害突變、發(fā)生趨勢(shì)、等級(jí)風(fēng)險(xiǎn)、綜合風(fēng)險(xiǎn)的地理分布特征，提出了預(yù)測(cè)預(yù)警的風(fēng)險(xiǎn)分區(qū)方法；建立了南方雙季稻低溫災(zāi)害預(yù)測(cè)預(yù)警指標(biāo)與技術(shù)體系，≥5天預(yù)警、≥1個(gè)月預(yù)測(cè)的準(zhǔn)確率在80%以上；開發(fā)了精細(xì)化土壤墑情預(yù)報(bào)系統(tǒng)，實(shí)現(xiàn)了自動(dòng)調(diào)用資料、自動(dòng)運(yùn)行、自動(dòng)生成產(chǎn)品等功能；利用改進(jìn)后的作物模擬模型對(duì)區(qū)域農(nóng)業(yè)干旱進(jìn)行模擬驗(yàn)證，將模型分別采用鏈接遙感技術(shù)和不鏈接遙感技術(shù)2種方式模擬區(qū)域農(nóng)業(yè)干旱，并將其模擬結(jié)果與基準(zhǔn)值進(jìn)行對(duì)比。結(jié)果表明，引入遙感信息后，作物干旱模型對(duì)區(qū)域農(nóng)業(yè)干旱的模擬能力明顯提高。研究成果已在相關(guān)省級(jí)農(nóng)業(yè)氣象業(yè)務(wù)服務(wù)中推廣應(yīng)用，提升了農(nóng)業(yè)氣象災(zāi)害預(yù)測(cè)預(yù)警的時(shí)效性、準(zhǔn)確率。（劉建棟）

1.4 重大農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)評(píng)價(jià)與管理關(guān)鍵技術(shù)研究

針對(duì)我國典型地區(qū)農(nóng)業(yè)干旱、洪澇、低溫冷害等農(nóng)業(yè)氣象災(zāi)害發(fā)生頻繁、影響嚴(yán)重且目前尚無有效風(fēng)險(xiǎn)評(píng)價(jià)技術(shù)的狀況，選擇東北、華北和長(zhǎng)江中下游地區(qū)主要糧食產(chǎn)區(qū)的主要農(nóng)作物為研究對(duì)象，基于多種技術(shù)集成的風(fēng)險(xiǎn)分析方法，從農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)研究入手，以農(nóng)作物為中心，從土壤-作物-大氣連續(xù)體出發(fā)，提出了基于災(zāi)害形成機(jī)理的農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)綜合評(píng)價(jià)理論；構(gòu)建了農(nóng)業(yè)氣象災(zāi)害靜態(tài)和動(dòng)態(tài)風(fēng)險(xiǎn)相耦合的評(píng)價(jià)與風(fēng)險(xiǎn)圖繪制技術(shù)、多種農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)綜合評(píng)價(jià)與區(qū)劃技術(shù)及農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)預(yù)警技術(shù)；編制了主要糧食產(chǎn)區(qū)的農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)圖譜；研制了農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)分析與評(píng)價(jià)系統(tǒng)；提出了農(nóng)業(yè)氣象災(zāi)害綜合風(fēng)險(xiǎn)管理技術(shù)對(duì)策體系。主要研究成果在吉林、河北等省的氣象、農(nóng)業(yè)等相關(guān)部門推廣應(yīng)用，取得了良好效果，為農(nóng)業(yè)防災(zāi)減災(zāi)提供了必要的理論依據(jù)和技術(shù)支撐。（王春乙）

1.5 基于遙感信息與氣溫的夏玉米土壤水分估算模型

土壤水分是土壤-植被-大氣連續(xù)體的一個(gè)重要組分，是決定陸地生態(tài)系統(tǒng)水分狀況的關(guān)鍵因子，也是作物的水分供應(yīng)庫。為估算站點(diǎn)尺度不同深度的土壤水分，基于能量平衡方程和水分虧缺指數(shù)（WDI），提出了基于地面遙感信息（植被指數(shù)NDVI和下墊面溫度）和氣溫估算土壤相對(duì)濕度（WR）方法。利用2014年中國氣象局固城生態(tài)與農(nóng)業(yè)氣象試驗(yàn)站夏玉米水分控制試驗(yàn)資料驗(yàn)證表明，該方法可以有效估算不同深度的土壤相對(duì)濕度，其中對(duì)0～10 cm土壤水分估算精度最高，決定系數(shù)達(dá)90%；對(duì)0～20 cm到0～50 cm土壤水分估算的平均相對(duì)誤差均在15%以內(nèi)，相對(duì)均方根誤差均在20%以內(nèi)。（周廣勝）

1.6 玉米干旱致災(zāi)臨界氣象條件及其監(jiān)測(cè)預(yù)警技術(shù)

基于試驗(yàn)資料和相關(guān)研究資料的綜合分析，初步闡明了作物在干旱和其他氣候變化關(guān)鍵因子相互作用下，葉片氣孔導(dǎo)度、水分利用率和生長(zhǎng)相互協(xié)調(diào)的響應(yīng)和適應(yīng)機(jī)制?；陧?xiàng)目觀測(cè)試驗(yàn)資料分析了在不同生育期干旱發(fā)生發(fā)展過程中玉米的光合生理和葉綠素?zé)晒鈪?shù)變化特征以及復(fù)水的影響。拔節(jié)期開始水分控制的玉米，控水2周后SPAD、gs、E顯著下降，但葉綠素?zé)晒鈪?shù)（ΦPSII、Fv'/Fm'）無顯著下降；抽雄期開始水分控制的玉米，控水1周后光合特征參數(shù)就發(fā)生顯著下降，且抽雄期干旱導(dǎo)致的光合速率下降速度大于拔節(jié)期；在復(fù)水干旱解除后，光合能力雖有一定程度的恢復(fù)，但仍沒有達(dá)到其對(duì)照的水平。對(duì)同一葉片全生育期的觀測(cè)資料分析表明，Asat、gs、E隨著生育期（即葉片的葉齡）的進(jìn)展呈下降趨勢(shì)、SPAD呈先升后降趨勢(shì)，且干旱處理的玉米各參數(shù)的下降比對(duì)照大；而同一葉片的葉綠素?zé)晒鈪?shù)（ΦPSII、Fv'/Fm'）在水分充分條件（對(duì)照）下呈現(xiàn)較為平穩(wěn)的波動(dòng)，4種干旱處理沒有導(dǎo)致熒光參數(shù)的顯著下降，并在干旱后復(fù)水的情況下比對(duì)照有明顯升高。這表明，隨著葉片生長(zhǎng)發(fā)育的進(jìn)程，其光合系統(tǒng)II（PSII）的耐旱性可能有所增加。

利用土壤濕度觀測(cè)資料對(duì)氣象干旱指標(biāo)等級(jí)重新劃分。首先采用線性內(nèi)插法得到站點(diǎn)逐日土壤相對(duì)濕度序列（1992—2010年）；分別分析玉米生長(zhǎng)季內(nèi)水分脅迫下（各發(fā)育階段土壤相對(duì)濕度低于對(duì)應(yīng)階段玉米發(fā)生干旱時(shí)的土壤相對(duì)濕度上限值）的逐日平均土壤相對(duì)濕度與平均MCI指數(shù)之間的關(guān)系，建立MCI指數(shù)與土壤相對(duì)濕度的關(guān)系模型；根據(jù)觀測(cè)資料確定了玉米不同生育期氣象干旱指數(shù)的上限。將以上結(jié)果初步在業(yè)務(wù)系統(tǒng)中實(shí)現(xiàn)，在氣象災(zāi)害風(fēng)險(xiǎn)管理系統(tǒng)中建設(shè)了玉米影響評(píng)估模塊，該系統(tǒng)可以實(shí)時(shí)計(jì)算玉米干旱累計(jì)指數(shù)：同一發(fā)育階段期間各干旱過程逐日值的累加，即當(dāng)MCI小于上限時(shí)，干旱指數(shù)開始累加；不同發(fā)育階段及全生育期干旱累積指數(shù)計(jì)算方法為各發(fā)育階段累加值與歷史上該時(shí)段干旱對(duì)產(chǎn)量影響的影響系數(shù)乘積之和。該系統(tǒng)2016年9月30日全國玉米干旱累積指數(shù)的分析結(jié)果顯示，玉米氣象干旱主要分布在東北的西部、內(nèi)蒙古東部以及湖北、安徽、江蘇、四川等地（圖1）。（周莉）

1.7 植物適應(yīng)未來氣候變化的自我防御機(jī)制

對(duì)貝加爾針茅進(jìn)行相對(duì)長(zhǎng)期（42 d）的增溫（正常、增溫4 ℃）和水分變化（降水增加15%、正常、降水減少15%）模擬試驗(yàn)結(jié)果表明，在相對(duì)長(zhǎng)的暖干氣候條件下，貝加爾針茅的光合作用主要受非氣孔限制調(diào)控，盡管光能利用效率和光合作用速率減弱，但自我防御機(jī)制使貝加爾針茅有能力維持正常的生長(zhǎng)活動(dòng)。（周廣勝）

1.8 北方冬小麥精細(xì)化土壤墑情和灌溉預(yù)報(bào)技術(shù)及其應(yīng)用

完善了農(nóng)田土壤水分和灌溉預(yù)報(bào)數(shù)據(jù)集，其中北方冬小麥區(qū)的逐日氣象資料和自動(dòng)土壤水分資料擴(kuò)展到2016年7月31日。進(jìn)一步深入研究了遙感作物水分虧缺指數(shù)反演方法。分析了?ngstr?m-Prescott公式中a、b系數(shù)的年代際變化，確定了研究區(qū)域以及中國各大區(qū)域1961—2010年各年代逐月a、b系數(shù)參考值。以冬小麥生長(zhǎng)機(jī)理、農(nóng)田土壤水分平衡方程為根據(jù)，以本項(xiàng)目各種試驗(yàn)資料為依托，在前期冬小麥農(nóng)田水量平衡簡(jiǎn)化模型和精細(xì)化逐日多層土壤墑情和灌溉預(yù)報(bào)模型研究和3個(gè)省級(jí)冬小麥精細(xì)化土壤墑情和灌溉預(yù)報(bào)系統(tǒng)本地化試用基礎(chǔ)上，初步構(gòu)建了國家級(jí)冬小麥精細(xì)化土壤墑情和灌溉預(yù)報(bào)系統(tǒng)程序。利用項(xiàng)目科研成果和3個(gè)省級(jí)冬小麥精細(xì)化土壤墑情和灌溉預(yù)報(bào)系統(tǒng)業(yè)務(wù)平臺(tái)，分別在河北、山東、河南省發(fā)布了一些服務(wù)產(chǎn)品，為農(nóng)業(yè)等部門灌溉決策提供了有價(jià)值的參考信息（圖2）。（毛飛）

1.9 海南冬季瓜菜氣象災(zāi)害風(fēng)險(xiǎn)區(qū)劃

基于海南省各市縣1971—2010年3—5月不同持續(xù)少雨日數(shù)的發(fā)生頻率及其過程降水量，開展了辣椒春季干旱人工控制試驗(yàn)。試驗(yàn)采用均勻組合設(shè)計(jì)，設(shè)置持續(xù)干旱日數(shù)（10、15、20、25、30、35、40、45、50d）和補(bǔ)水量（0、2、4、6、8、10、12、14、16 mm）2因素9水平處理，測(cè)定不同處理下的不同深度（10、20、30、50、100 cm）土壤濕度，分析不同處理對(duì)辣椒死苗率、生理特性和產(chǎn)量的影響。試驗(yàn)結(jié)果表明，辣椒死苗率與20 cm土壤相對(duì)濕度和持續(xù)干旱日數(shù)顯著相關(guān)，與補(bǔ)水量相關(guān)性不大。隨著持續(xù)干旱日數(shù)的增加，辣椒凈光合速率、蒸騰速率和氣孔導(dǎo)度均呈下降趨勢(shì)，辣椒相對(duì)產(chǎn)量損失呈明顯加重趨勢(shì)。構(gòu)建了基于持續(xù)干旱日數(shù)的辣椒春季干旱等級(jí)指標(biāo)，經(jīng)歷史災(zāi)情驗(yàn)證，與實(shí)際發(fā)生情況相吻合。為開展辣椒春季干旱監(jiān)測(cè)預(yù)警業(yè)務(wù)服務(wù)提供了指標(biāo)和方法支持。（霍治國）

1.10 1961—2015年中國潛在蒸散時(shí)空變化特征與成因

基于全國552個(gè)氣象站點(diǎn)1961—2015年逐日氣象數(shù)據(jù)，利用Penman-Monteith公式得到各站點(diǎn)逐日蒸散量（ET0），以全國和各干濕氣候區(qū)為研究單元，從年、季節(jié)和年代際尺度分析ET0的時(shí)空分布特征及其變化成因。結(jié)果表明：我國年平均ET0為621～1733 mm，在年、年代際尺度表現(xiàn)為干旱區(qū)ET0最高、半干旱區(qū)和濕潤(rùn)區(qū)次之、半濕潤(rùn)區(qū)最低；季節(jié)尺度上，ET0的空間分布存在明顯差異，且夏季ET0最高、春秋季次之、冬季最低。我國年平均ET0以-0.52 mm/a的速率遞減，該下降趨勢(shì)在1972年存在突變現(xiàn)象；干旱區(qū)和濕潤(rùn)區(qū)大部分站點(diǎn)ET0呈減小趨勢(shì)，且干旱區(qū)減小速率較大；而在半干旱區(qū)和半濕潤(rùn)區(qū)，ET0呈增加和減小趨勢(shì)的站點(diǎn)數(shù)大致相當(dāng)。研究表明，近55年我國ET0呈減少趨勢(shì)主要是由風(fēng)速減小、日照時(shí)數(shù)降低和水汽壓微弱增加共同導(dǎo)致的。（王培娟）

1.11 基于冬小麥水分脅迫試驗(yàn)的干旱監(jiān)測(cè)指數(shù)構(gòu)建

借助中國氣象科學(xué)研究院大型人工水分控制試驗(yàn)場(chǎng)，于2013—2014年和2014—2015年的冬小麥生長(zhǎng)期內(nèi)，分別種植當(dāng)?shù)囟←溨髟云贩N“河農(nóng)6425”和“郯麥98”，對(duì)其進(jìn)行3個(gè)水分脅迫處理，同時(shí)設(shè)置1個(gè)對(duì)照，研究不同水分脅迫條件對(duì)冬小麥生長(zhǎng)發(fā)育的影響。根據(jù)水量平衡方程，計(jì)算不同水分脅迫和對(duì)照條件下冬小麥全生育期的實(shí)際蒸散量（ETa），以對(duì)照條件下的實(shí)際蒸散作為作物標(biāo)準(zhǔn)蒸散（ETc），構(gòu)建冬小麥全生育期干旱監(jiān)測(cè)指數(shù)（CDMI=1-ETa/ETc），并結(jié)合不同水分脅迫條件下冬小麥減產(chǎn)率和CDMI的關(guān)系，劃分干旱等級(jí)。本研究建立的干旱監(jiān)測(cè)指數(shù)以標(biāo)準(zhǔn)蒸散為參照，與基于潛在蒸散的干旱監(jiān)測(cè)指數(shù)相比，能夠真正地反映農(nóng)作物的干旱程度，可為我國華北冬麥區(qū)干旱監(jiān)測(cè)提供客觀依據(jù)。（王培娟）

1.12 西南地區(qū)水稻洪澇等級(jí)指標(biāo)構(gòu)建及風(fēng)險(xiǎn)分析

為全面評(píng)估水稻洪澇的綜合風(fēng)險(xiǎn)，基于自然災(zāi)害系統(tǒng)理論和農(nóng)業(yè)氣象災(zāi)害風(fēng)險(xiǎn)評(píng)估方法，利用西南地區(qū)（重慶、四川、貴州和云南）193個(gè)氣象站1961—2012年逐日降水資料、396個(gè)縣（市）1981—2012年水稻產(chǎn)量、面積資料和17個(gè)農(nóng)氣站點(diǎn)水稻生育期數(shù)據(jù)，以及西南地區(qū)數(shù)字高程（DEM）數(shù)據(jù)，構(gòu)建區(qū)域水稻洪澇災(zāi)害致災(zāi)因子危險(xiǎn)性、承災(zāi)體暴露性、孕災(zāi)環(huán)境敏感性和區(qū)域抗災(zāi)能力指數(shù)，以及綜合風(fēng)險(xiǎn)評(píng)價(jià)模型，對(duì)西南地區(qū)水稻洪澇進(jìn)行風(fēng)險(xiǎn)分析與區(qū)劃。結(jié)果表明：（1）水稻不同生育階段洪澇等級(jí)風(fēng)險(xiǎn)概率分布存在明顯的地區(qū)差異，洪澇危險(xiǎn)性表現(xiàn)為移栽分蘗期＞拔節(jié)孕穗期＞抽穗成熟期；全生育期高、次高危險(xiǎn)區(qū)主要分布于云南南部和東北部、貴州南部，以及四川的成都、眉山和德陽地區(qū)。（2）基于不同時(shí)間序列的水稻相對(duì)暴露率明顯波動(dòng)，水稻生產(chǎn)承災(zāi)體高、次高暴露區(qū)主要集中在四川東北部和重慶地區(qū)；孕災(zāi)環(huán)境高、次高敏感區(qū)主要位于云南北部、四川南部和貴州東南部地區(qū)；水稻洪澇低抗災(zāi)能力區(qū)主要位于貴州。（3）西南地區(qū)水稻洪澇綜合風(fēng)險(xiǎn)呈由中部向四周遞增的趨勢(shì)，高、次高風(fēng)險(xiǎn)區(qū)主要位于貴州南部、云南南部和四川東北部地區(qū)，低風(fēng)險(xiǎn)區(qū)位于重慶南部和云南北部地區(qū)（圖3）。（楊建瑩）

1.13 冬前和春季灌溉對(duì)華北冬小麥影響的研究

通過在灌溉越冬水（80/150 mm）和不灌溉越冬水條件下，春季氣溫分別穩(wěn)定通過0 ℃、3 ℃、7 ℃和10 ℃時(shí)進(jìn)行春季第1水灌溉的多年田間模擬試驗(yàn)，探討了冬前和春季灌溉對(duì)華北冬小麥生長(zhǎng)發(fā)育和籽粒產(chǎn)量的影響，以揭示華北冬小麥適宜的灌溉方式和灌溉時(shí)間。結(jié)果表明，無越冬水灌溉條件下，冬后氣溫穩(wěn)定通過0 ℃時(shí)進(jìn)行春季第1水灌溉能夠緩解冬季干旱，使冬小麥春季有效莖數(shù)增加，對(duì)有效穗數(shù)和產(chǎn)量增加作用顯著；越冬水灌溉條件下，春季氣溫穩(wěn)定通過7 ℃時(shí)進(jìn)行春季第1水灌溉能夠減少關(guān)鍵生育期的連續(xù)干旱時(shí)間，有利于冬小麥產(chǎn)量增加。越冬水量的大小（80 mm和150 mm）對(duì)冬小麥產(chǎn)量的影響不顯著。春季第1水對(duì)冬小麥的生長(zhǎng)發(fā)育至關(guān)重要，無春季第1水灌溉條件下，冬小麥減產(chǎn)平均達(dá)32.2%。因此，為達(dá)到冬小麥的穩(wěn)產(chǎn)高產(chǎn)和節(jié)水灌溉目的，無越冬水灌溉條件時(shí)，應(yīng)選擇在春季氣溫穩(wěn)定通過0 ℃時(shí)進(jìn)行春季第1水灌溉；有越冬水灌溉條件時(shí)應(yīng)適量灌溉，并選擇春季第1水在氣溫穩(wěn)定通過7 ℃時(shí)灌溉。（劉濤）

1.14 荒漠草原土壤呼吸對(duì)水熱變化的響應(yīng)機(jī)制

利用開路式土壤碳通量測(cè)量系統(tǒng)，基于2011—2012年野外觀測(cè)資料，針對(duì)陸地碳源匯評(píng)估中的土壤呼吸，在荒漠草原開展不同水熱條件下土壤呼吸的變化研究及其控制機(jī)制研究。結(jié)果發(fā)現(xiàn)，荒漠草原生長(zhǎng)季的土壤呼吸顯著大于非生長(zhǎng)季。非生長(zhǎng)季，土壤呼吸的差異主要是由增溫處理引起的，土壤呼吸與土壤溫度呈顯著的指數(shù)相關(guān)（R2= 0.74,p＜ 0.01）。在生長(zhǎng)季，根系呼吸（21.9%）對(duì)荒漠草原土壤呼吸的貢獻(xiàn)率遠(yuǎn)低于異氧呼吸（78.1%），土壤有機(jī)碳、土壤含水量、根系生物量、微生物量是影響土壤呼吸的主要因素，其中，0～10 cm土壤有機(jī)碳是土壤呼吸最重要的影響因子，土壤含水量對(duì)土壤呼吸的間接貢獻(xiàn)率最高。基于生長(zhǎng)季不同水熱條件下荒漠草原土壤呼吸對(duì)其影響最大的4個(gè)因子的響應(yīng)關(guān)系，建立了土壤呼吸的響應(yīng)模型（R2= 0.67,p＜ 0.01）。（劉濤）

1.15 基于遙感方法的黃淮海平原冬小麥耗水特征及用水結(jié)構(gòu)研究

利用2011—2012年氣象數(shù)據(jù)、遙感影像（MODIS）、地表能量平衡方程模型 （SEBA）和地面農(nóng)作物信息，結(jié)合農(nóng)田水分平衡方程，對(duì)2011—2012年冬小麥生長(zhǎng)季內(nèi)有效降水量、農(nóng)田灌溉量、實(shí)際耗水量和農(nóng)田水分損失進(jìn)行了估算，并采用調(diào)研的灌溉量數(shù)據(jù)對(duì)估算結(jié)果進(jìn)行對(duì)比驗(yàn)證。結(jié)果表明，灌溉量估算值與實(shí)際值間有較好的相關(guān)性（R2= 0.79）；冬小麥生長(zhǎng)前期，降水能滿足70%以上的農(nóng)田耗水；＞90%冬小麥灌漿期耗水依靠灌溉；黃淮海區(qū)域灌溉量高值區(qū)域位于西部山前平原水澆地區(qū)，灌溉均值為412.76 mm；區(qū)域冬小麥耗水量與灌溉量成正相關(guān)（R2= 0.68，p＜ 0.01） 。（楊建瑩）

2 農(nóng)業(yè)對(duì)氣候變化的響應(yīng)與適應(yīng)

2.1 1961年以來中國農(nóng)業(yè)氣象災(zāi)害演變規(guī)律及其災(zāi)損評(píng)估

氣候變暖背景下中國極端氣候事件呈增加趨勢(shì)，氣候?qū)⒆兊门瘯r(shí)更暖、旱時(shí)更旱、澇時(shí)更澇。農(nóng)業(yè)干旱災(zāi)害發(fā)展呈面積增大和頻率加快趨勢(shì)，且北方旱災(zāi)影響明顯高于南方；冬小麥澇漬呈增加趨勢(shì)且生育后期災(zāi)害強(qiáng)度增加更明顯；水稻高溫?zé)岷υ黾于厔?shì)明顯且重度災(zāi)害顯著增加，低溫冷害總體呈減少態(tài)勢(shì)，但近30年低溫陰雨呈增加趨勢(shì)；霜凍害總體呈減少趨勢(shì)但局部地區(qū)有加重趨勢(shì)。農(nóng)業(yè)氣象災(zāi)害的演變趨勢(shì)、強(qiáng)度和類型已經(jīng)發(fā)生顯著變化，使得當(dāng)前針對(duì)農(nóng)業(yè)氣象災(zāi)害開展種植制度調(diào)整的避災(zāi)農(nóng)業(yè)面臨二次避災(zāi)風(fēng)險(xiǎn)，嚴(yán)重威脅到國家糧食安全、生態(tài)文明建設(shè)和精準(zhǔn)扶貧。（周廣勝）

2.2 中國草地生態(tài)系統(tǒng)固碳現(xiàn)狀、速率、機(jī)制和潛力研究

基于野外4000多個(gè)調(diào)查點(diǎn)和TEM模型，利用氣候、海拔、土壤和植被數(shù)據(jù)，以月為時(shí)間步長(zhǎng)對(duì)中國草地生態(tài)系統(tǒng)的碳密度、儲(chǔ)量空間分布及動(dòng)態(tài)變化進(jìn)行了模擬；估算了全國草地生態(tài)系統(tǒng)的碳儲(chǔ)量；繪制了中國草地土壤和植被碳密度的空間分布圖，揭示了其空間分布特征；定量描述了氣候和人類共同作用下，1960年代以來中國草地碳密度的時(shí)空變化幅度及區(qū)域差異；模擬了未來氣候情景下中國草地碳收支動(dòng)態(tài)。主要?jiǎng)?chuàng)新點(diǎn)是針對(duì)一套參數(shù)TEM模型空間模擬精度不高的問題，提出了基于草地生態(tài)型的“分區(qū)域參數(shù)化率定方案”，建立了適合中國草地的TEM模型參數(shù)系列，為準(zhǔn)確監(jiān)測(cè)和評(píng)估全國草地生態(tài)系統(tǒng)碳收支、NPP、GPP等提供了基礎(chǔ)。（汲玉河）

2.3 氣候變化背景下青稞安全氣象保障關(guān)鍵技術(shù)研究

在A2和B2氣候情景下，西藏太陽能資源雖然有略微降低的趨勢(shì)，但其仍為世界上太陽能資源最豐富的地區(qū)之一。無論A2還是B2氣候情景下，西藏地區(qū)的太陽能資源總體的時(shí)間分布格局沒有發(fā)生明顯改變，均表現(xiàn)為冬季最小、夏季最大；但是其變化幅度在各月份上差異明顯，總體表現(xiàn)為夏季增加，而其他季節(jié)則相對(duì)降低。氣候變化背景下西藏全年降水總體上表現(xiàn)為增加趨勢(shì)，但其仍為世界上降水量較少的地區(qū)之一。降水的年內(nèi)分布仍相當(dāng)不均，冬季最小、夏季最大，且夏季降水增加明顯；空間上自東向西逐漸減小的分布格局亦沒有發(fā)生改變，但西部降水較東部降水增加更為明顯。氣候變化背景下的增溫效應(yīng)有益于青稞產(chǎn)量提高，但產(chǎn)量的空間分布特征基本保持不變。目前青稞產(chǎn)量高值區(qū)在未來氣候變化背景下增值更大，換言之，目前適宜區(qū)更加適宜青稞產(chǎn)量提高。（劉建棟）

2.4 基于APSIM模型識(shí)別氣候變化對(duì)北方地區(qū)主要旱地作物產(chǎn)量的影響

通過優(yōu)化常用的農(nóng)作物模擬模型（APSIM），識(shí)別北方春小麥和春玉米關(guān)鍵發(fā)育期和產(chǎn)量對(duì)氣候變化的響應(yīng)。研究表明，APSIM模型在內(nèi)蒙古、甘肅、黑龍江、吉林、遼寧等北方地區(qū)有較好的適用性。1961—2010年內(nèi)蒙古春小麥潛在產(chǎn)量總體呈降低的變化趨勢(shì)，平均值為3561 kg/hm2，其中20世紀(jì)80年代潛在產(chǎn)量最高，達(dá)3681 kg/hm2，21世紀(jì)初最低，為3433 kg/hm2。區(qū)域間差異明顯：近50年內(nèi)蒙春小麥潛在產(chǎn)量分布由中間向東部和西部呈條帶狀逐漸增加，且在3個(gè)區(qū)域中，西部麥區(qū)潛在產(chǎn)量最大，中部麥區(qū)最小。影響內(nèi)蒙春玉米生育期的主要?dú)庀笠蜃邮亲罡邷囟龋浯问亲畹蜏囟?，太陽輻射、降水和潛在蒸散?duì)春玉米生育期的影響效果一樣。影響春玉米產(chǎn)量的主要?dú)庀笠蜃右来螢樽罡邷囟?、最低溫度、降水、太陽輻射和潛在蒸散（圖4）。（趙俊芳）

2.5 不同積溫模型對(duì)東北春玉米不同階段積溫的穩(wěn)定性評(píng)價(jià)

基于東北地區(qū)春玉米品種“丹玉13”“龍單13”“東農(nóng)248”和“四單19”生長(zhǎng)發(fā)育資料和氣象觀測(cè)資料，分別擬合了沈國權(quán)、高亮之和殷新佑非線性積溫模型參數(shù)，對(duì)3種積溫模型模擬結(jié)果進(jìn)行比較和穩(wěn)定性評(píng)價(jià)，并與常用積溫法計(jì)算的結(jié)果對(duì)比。對(duì)常用積溫法、沈國權(quán)非線性積溫模型、高亮之非線性積溫模型、殷新佑非線性積溫模型4種方法進(jìn)行穩(wěn)定性分析的結(jié)果表明，自出苗到成熟的全生育期，3種非線性積溫模型均優(yōu)于常用積溫法，表現(xiàn)出更好的穩(wěn)定性。在出苗-拔節(jié)階段，4種方法在“丹玉13”品種的穩(wěn)定性一致，而“龍單13”“東農(nóng)248”和“四單19”3個(gè)品種的常用積溫法略遜于3種非線性積溫模型；拔節(jié)-抽雄階段是穩(wěn)定性最差的階段，無論哪個(gè)品種，在此階段的變異系數(shù)均最大；在抽雄-成熟階段，4種方法的穩(wěn)定性差別不大。研究結(jié)果可為東北春玉米發(fā)育期預(yù)報(bào)和產(chǎn)量預(yù)報(bào)等工作提供理論依據(jù)和技術(shù)支持。（郭建平）

2.6 氣候變化對(duì)東北區(qū)農(nóng)業(yè)氣候資源的影響

系統(tǒng)分析了氣候變化情景下東北主要農(nóng)業(yè)氣候資源的時(shí)空特征。1961—2099年期間，熱量資源整體為南高北低，未來熱量資源明顯增加，東北地區(qū)年均溫度呈升高趨勢(shì)，中排放情景（RCP4.5）和高排放情景（RCP8.5）下分別升溫約2 ℃和3 ℃，≥10 ℃初日提早3～4 d，初霜日推遲2～6 d，導(dǎo)致可能生長(zhǎng)季延長(zhǎng)4～10 d；溫度的升高與生長(zhǎng)季的延長(zhǎng)使得積溫大幅增加，截至21世紀(jì)末，增幅分別達(dá)400 ℃·d和700 ℃·d。水資源呈增加趨勢(shì)，但變化較少。熱量資源變化速率有明顯變化，高排放情景下增溫速率更快，東北地區(qū)未來有暖濕趨勢(shì)。以溫度升高為代表的氣候變化在東北地區(qū)對(duì)農(nóng)業(yè)生產(chǎn)具有一定的積極影響，生長(zhǎng)季的延長(zhǎng)和積溫的增加使得農(nóng)作物可利用熱量資源更加豐富，原有因受到熱量資源限制的不可種植區(qū)域?qū)?huì)減少，可種植區(qū)域擴(kuò)大；種植品種得到改善，原來種植早熟品種區(qū)域可由中晚熟品種代替，晚熟品種種植面積進(jìn)一步擴(kuò)大，如晚熟玉米積溫需要達(dá)到3000 ℃·d，由原有松嫩平原北擴(kuò)至大興安嶺附近，甚至在遼寧的部分地區(qū)可種植一年兩熟制作物。（郭建平）

2.7 大氣CO2濃度升高和增溫影響作物需水量變化機(jī)理研究

在2013—2015年試驗(yàn)基礎(chǔ)上，2016年分析了增溫和CO2濃度升高環(huán)境下小麥水分利用效率變化及其與需水量和產(chǎn)量的耦合變化機(jī)理。分析結(jié)果表明，增溫和CO2濃度升高對(duì)于項(xiàng)目需水量變化具有疊加復(fù)合影響效應(yīng)。增溫提高了小麥群落和冠層溫度，促進(jìn)能量流動(dòng)和水分循環(huán)，增加了小麥植株蒸騰和株間蒸發(fā)量，增加了小麥日需水量。CO2濃度升高導(dǎo)致葉片氣孔導(dǎo)度降低、減少葉片蒸騰速率，有助于提高水分利用效率。另外，CO2濃度升高的肥效作用有利于提高小麥產(chǎn)量。綜合來看，增溫和CO2濃度升高增加了小麥需水量，提高了水分利用效率。需水量增加有助于提高小麥產(chǎn)量。在未來增溫和CO2濃度升高環(huán)境下，通過熱量資源和CO2的不斷增加和轉(zhuǎn)入，小麥需水量、水分利用效率和產(chǎn)量三者是處于正反饋耦合機(jī)制中。（俄有浩）

2.8 北方農(nóng)牧交錯(cuò)區(qū)退耕地植被演替調(diào)控機(jī)制研究

以空間代替時(shí)間的樣帶調(diào)查方法，研究北方農(nóng)牧交錯(cuò)區(qū)退耕地植被演替過程，從相對(duì)宏觀的角度揭示自然環(huán)境因子對(duì)退耕地植被演替的調(diào)控機(jī)制。針對(duì)項(xiàng)目設(shè)定的研究目標(biāo)，在山西-寧夏農(nóng)牧交錯(cuò)帶進(jìn)行了野外樣帶調(diào)查工作。重點(diǎn)收集了農(nóng)牧交錯(cuò)區(qū)典型生態(tài)系統(tǒng)0～500 cm土壤深度的土壤濕度、質(zhì)地、養(yǎng)分含量，以及植被蓋度、生物量、物種等信息。鑒于降水、氣溫等氣象因素具有較大的時(shí)空波動(dòng)性，擬從更穩(wěn)定的土壤干層、土壤質(zhì)地、地貌等環(huán)境信息，結(jié)合氣候因素識(shí)別出制約中國北方生態(tài)系統(tǒng)空間分布、群落演替的關(guān)鍵因素，研究生態(tài)系統(tǒng)的環(huán)境適應(yīng)性及耐受氣候變化的彈性。此外，采集了樹木年輪數(shù)據(jù)，以配合研究北方生態(tài)系統(tǒng)對(duì)氣候變化響應(yīng)與適應(yīng)。（汲玉河）

2.9 增溫與CO2濃度升高對(duì)冬小麥處理和品質(zhì)的影響

2015/2016年生長(zhǎng)季試驗(yàn)觀測(cè)到的發(fā)育期、株高、單株生物量和密度的影響結(jié)果與前2年基本一致，穗粒數(shù)減少仍然是導(dǎo)致減產(chǎn)的根本原因，不同的是該試驗(yàn)季復(fù)合處理的小穗數(shù)減少達(dá)到顯著水平，穗粒數(shù)減少主要?dú)w因于小穗數(shù)下降。對(duì)連續(xù)3年試驗(yàn)的籽粒粗蛋白、粗脂肪、粗纖維和粗淀粉測(cè)定結(jié)果進(jìn)行了統(tǒng)計(jì)分析，在復(fù)合處理?xiàng)l件下，冬小麥籽粒的蛋白質(zhì)含量均有增加，其中2年表現(xiàn)為顯著增加，而淀粉、脂肪和纖維含量均沒有規(guī)律性的變化。冬小麥葉片全氮含量從拔節(jié)期至開花期有逐漸減少的趨勢(shì)，但在各發(fā)育階段對(duì)照與復(fù)合處理的葉片全氮含量沒有顯示出顯著性差異，在各發(fā)育階段對(duì)照與復(fù)合處理的葉片有機(jī)碳含量也沒有顯著性的差異。（譚凱炎）

2.10 我國小麥品種改良對(duì)物候的影響

利用農(nóng)業(yè)氣象觀測(cè)數(shù)據(jù)分析了我國小麥品種改良對(duì)物候的影響。結(jié)果表明，春小麥品種變化造成不同發(fā)育階段間的熱量單位有所增加，出苗-成熟期每年增加3.5 ℃的熱量單位。對(duì)不同地區(qū)的比較發(fā)現(xiàn)，西藏、內(nèi)蒙古和新疆地區(qū)春小麥品種變化對(duì)物候的影響較大，對(duì)不同發(fā)育期間的熱量單位多為正效應(yīng)。我國冬小麥品種變化對(duì)播種到出苗、出苗到停止生長(zhǎng)、停止生長(zhǎng)到返青、拔節(jié)到抽穗、乳熟到成熟期間熱量單位的影響趨勢(shì)不明顯，而對(duì)返青到拔節(jié)、抽穗到乳熟期間熱量單位有正效應(yīng)。其中，青海、西藏、福建和新疆地區(qū)冬小麥品種變化對(duì)物候的影響仍較大，對(duì)不同發(fā)育階段的熱量單位多為正效應(yīng)（圖5）。（馬玉平）

2.11 冬小麥發(fā)育期主要影響因子作用的量化及對(duì)產(chǎn)量影響的模擬

收集了華北平原47個(gè)農(nóng)業(yè)氣象觀測(cè)站1986—2010年冬小麥的發(fā)育期資料和同期的逐日平均氣溫?cái)?shù)據(jù)，利用基于3基點(diǎn)溫度（Tb為0 ℃，Topt為22 ℃，Tmax為32 ℃）的雙線性發(fā)育期模型，以1986—1988年的平均品種狀態(tài)對(duì)發(fā)育期模型進(jìn)行參數(shù)化，隨后模擬1986—2010年間的返青-抽穗期與抽穗-成熟期，并計(jì)算模擬誤差隨時(shí)間的變化趨勢(shì)。品種更替使冬小麥返青-抽穗日數(shù)總體呈增加趨勢(shì)，但趨勢(shì)不明顯，且存在顯著的區(qū)域差異，其中平原南部、北部日數(shù)略有縮短，而中部及山東東部增加較明顯。品種變化使抽穗-成熟期日數(shù)呈顯著增加趨勢(shì)，平原南部增加尤其明顯，平原中部和東西北部增加不明顯，有些區(qū)域甚至還略有縮短。本研究表明，品種變化對(duì)發(fā)育期的影響，隨發(fā)育期的不同而不同，在不同的區(qū)域也有不同的表現(xiàn)。在研究未來氣候變化對(duì)發(fā)育期的影響時(shí)，如果能考慮到這種區(qū)域差異，將有助于降低模擬的不確定性（圖6）。（鄔定榮）

2.12 應(yīng)用統(tǒng)計(jì)模型模擬氣候變化對(duì)玉米產(chǎn)量的影響及不確定性研究

多模式的集合是處理不確定性的有效方法。研究考慮由IPCC第5次評(píng)估報(bào)告的8個(gè)全球氣候模式和3個(gè)排放情景（RCP2.6/4.5/8.5）組成的24個(gè)氣候模式數(shù)據(jù)代表氣候輸出不確定性，與應(yīng)用Bootstrap方法產(chǎn)生100組參數(shù)的2個(gè)統(tǒng)計(jì)模型代表的作物模型內(nèi)部參數(shù)不確定性相結(jié)合，以遼寧省本溪、吉林省長(zhǎng)嶺、黑龍江省海倫農(nóng)氣站為研究地點(diǎn)，量化評(píng)估了2個(gè)未來時(shí)段（2010—2039年和2040—2069年）相對(duì)于1976—2005年基準(zhǔn)時(shí)段玉米產(chǎn)量的影響及不確定性。研究結(jié)果表明，未來2個(gè)時(shí)段玉米產(chǎn)量降低均不足5%。應(yīng)用方差分析法，量化了單一不確定性來源對(duì)最終集合產(chǎn)量綜合不確定性結(jié)果的影響，如氣候模式結(jié)構(gòu)和排放情景的不確定性、作物模型參數(shù)的不確定性。研究結(jié)果表明，氣候情景的不確定性對(duì)最終結(jié)果的不確定性影響，要大于作物模型參數(shù)不確定性所帶來的影響；增加的集合產(chǎn)量方差表明未來氣候變化背景下產(chǎn)量模擬的不確定性增加。（張祎）

圖1 玉米氣象干旱業(yè)務(wù)系統(tǒng)界面Fig. 1 The operational system of maize meteorological drought

圖2 2016年河北省冬小麥開花、灌漿期灌溉量（m3/畝，1畝 = 0.0667 hm2）預(yù)報(bào)Fig. 2 Irrigation forecast of winter wheat flowering and f lling stage in Hebei Province in 2016

圖3 西南地區(qū)水稻洪澇綜合風(fēng)險(xiǎn)等級(jí)空間分布Fig. 3 Spatial distribution of integrative risk of rice flood in Southwest China

圖4 1961—2010年內(nèi)蒙古春小麥產(chǎn)量平均分布Fig. 4 Average distribution of spring wheat yield in Inner Mongolia from 1961 to 2010

圖5 我國不同地區(qū)冬小麥品種變化影響不同發(fā)育階段間熱量單位的傾向率Fig. 5 The tendency rate of the heat unit in different developmental periods affected by the variation of winter wheat varieties in different regions (Xinjiang, Qinghai, Shanganning, North China, Central and East China, Southwest China, Xizang and Fujian) in China

圖6 1986—2010年冬小麥抽穗期、成熟期模擬誤差趨勢(shì)空間分布(Error(H)為抽穗期模擬誤差；Error(M)為成熟期模擬誤差；Sig表示在0.05水平上差異顯著；No_Sig表示在0.05水平上差異不顯著）Fig. 6 The spatial distribution of the simulation error trends in heading (H) and maturity (M) stages during 1986–2010. Sig denotes significant at 0.05 significance level and No_Sig means not significant at 0.05 significance level

Progress in Ecological Environment and Agrometeorology Research

1 Agroclimatic resources and agrometeorological disasters forecasting and early warning

1.1 Research on flood disaster monitoring and early warning and prevention and control key technology

The results of this project revealed the temporal and spatial distribution characteristics of agriculture,corn, and rice flood disasters in the whole country and in the study area. Eleven sets of corn and rice flood disaster level indicators and ten sets of provincial agricultureflood disaster level indicators were built. Three sets of waterlogging and flood tolerance physiological indicators were established. Three sets of flood control and disaster prevention in cropping model farming and cultivation integrated technology were developed.Three sets of disaster prevention and control of technological processes were constructed. The results have been used for meteorological business applications in Hunan, Jiangxi, Zhejiang, Anhui, Guangxi, Chongqing,Shaanxi seven provinces (district and city). It made and published more than forty special service products and decision-making service reports of floods and agricultural weather. Flood warning and disaster reduction service achieved a significant efficiency of disaster reduction and production increase. This project put forward the construction method of level indicators based on the inverse risk analysis of disaster risk, resolved the key technologies of the flooding level threshold of agricultural flooding, maize and rice flooding, and the comparability of provincial indicators which are based on precipitation process, and provided indicators to support the development of real-time monitoring and forecasting of agricultural disaster. (Huo Zhiguo)

1.2 Techniques of the 3D monitoring and the dynamic assessment of key agrometeorological disasters

To study the 3D monitoring and the dynamic assessment of the dry-hot wind for winter wheat in Huanghuai-hai areas, cold damage for double cropping rice in southern China and agricultural drought in Southwest China, we established meteorological indicators and a grading system for the above agrometeorological disasters, and developed the 3D monitoring and the dynamic assessment techniques which are based on ground observations, remote sensing and crop models and are applied to meteorological operation. The work has some innovations in the following aspects: (1) information coupling is developed into a diversif ed development,which integrated ground meteorological, agrometeorological, farmland small-scale, agricultural situation and disasters, and geographic data; (2) the 3D monitoring and the dynamic assessment have been oriented to modeling, dynamic and refined analysis; (3) the transformation technology of spatial scale is emphasized in the process of multi-source information use. The key monitoring and assessment techniques, which are totally tailored to Chinese agricultural production and disasters, are highly regional and practical, taking into account the operational service needs of the meteorological and agricultural sectors. The implementation of the research findings can significantly improve the monitoring and assessment of agrometeorological disasters in China.(Zhao Yanxia)

1.3 Prediction of the key agro meteorological disasters in China

Impacts of the low temperature stress on double-rice growth in southern China, including its abruptchange, trends, grade risk and the characteristics of the spatial distribution of the integrated risk, were revealed in the study, based on which methods on the risk zoning for prediction was presented. Prediction index and systematic technology were also established to forecast low temperature impacts on double rice growth in southern China, with the prediction accuracy as high as 80% at the temporal scales of either 5 days or one month. Detailed soil moisture can also be obtained by a successfully established prediction system,with functions such as automatic data input, operation and product-generation. The improved crop growth model was used to simulate the regional agro-drought in North China Plain. Coupled with the remote sensing technology, the calibrated crop model showed obvious advantage in regional agro-drought prediction, which was identif ed by the comparison between the simulation results and the base line values. All of the relevant achievements have been applied in the provincial agrometeorological services, leading to an improved prediction of the agrometeorological disaster with higher accuracy. (Liu Jiandong)

1.4 Risk assessment and management technology for major agrometeorological disasters

According to the situation of the frequent agrometeorological disasters such as drought, flood and chilling disasters happened in typical areas in China with severe effects, and the lacks of effective risk assessment technology, the main crops of the major agricultural regions in Northeast China, North China, and the Middle and Lower Reaches of the Yangtze River were selected, based on multi-technology integrated risk analysis methods and the risk study of agrometeorological disasters, centered on crops and started from the continuum of the soil-plant-atmosphere, finally the integrated assessment theory of agrometeorological disaster risk based on the formation mechanism of disaster was proposed. The technologies of assessment coupling static and dynamic risk of agrometeorology disasters, risk mapping, integrated assessment and regional assessment of multi-disasters and early warning were formed. Besides, risk maps of agrometeorological disasters in major crops producing area were made. Agrometeorological disaster risk analysis and evaluation system was developed. Moreover, a countermeasure system of agrometeorological disasters integrated risk management technology was proposed. The extension and application of our main research achievements had good effects on relevant departments of Jilin, Hebei and other provinces which provided the necessary theoretical basis and technical supports for agricultural disaster prevention and mitigation. (Wang Chunyi)

1.5 Soil moisture estimation method based on both remote sensing and air temperature in a summer maize ecosystem

Soil moisture is an important component of the soil-vegetation-atmosphere continuum (SPAC), which is a key factor determining the water status of terrestrial ecosystems, and is also the main sources of water supply for crops. In order to estimate soil moisture at different soil depths at a station level, based on the energy balance equation on the earth and the water deficit index (WDI), a soil moisture estimation model was established on the hypothesis that evapotranspiration deficit ratio (i.e., WDI) depends linearly on soil relative humidity. Thus, the soil moisture could be estimated in terms of the remote sensing data (the normalized difference vegetation index (NDVI) and surface temperature (Ts)) and the ground observations (air temperatureTa). The soil water estimation model was validated based on the data from the drought process experiment on summer maize (Zea maysL.) in response to different irrigation treatments carried out during 2014 at Gucheng Eco-agrometeorological experimental station (39°08'N, 115°40'E) of China Meteorological Administration.The model was used to estimate soil relative humidity at different soil depths (0–50 cm) in terms of the parameters from the genetic algorithm and nonlinear programming algorithm. The results indicate that the soil water estimation model developed in this study is able to evaluate soil relative humidity at different soil depths in the summer maize, and the hypothesis is reasonable that evapotranspiration deficit ratio (i.e., WDI) depends linearly on soil relative humidity. It was shown that the estimation accuracy of 0–10 cm surface soil moisturewas the highest (R2= 0.90). The correlation of the estimated and measured soil relative humidity in deeper soil layers (up to 50 cm) could pass the significance test at the level of 0.0001 with the RMAEs less than 15%and the PRMSEs less than 20%. Results from this study could provide a reference for drought monitoring and irrigation management. (Zhou Guangsheng)

1.6 Critical meteorological conditions in maize response to drought disaster and the monitoring and pre-warning technology

Based on the integrations on the experimental data and relevant studies, the response and adaptive mechanism under the combinations of drought and other key factors oficlimatic change were elucidated preliminarily in terms of the coordinative changes between leaf stomatal conductance (gs), water use efficiency(WUE), and plant/leaf growth. Based on the measurement and experimental data of the present project,the changes in photosynthetically physiological process and chlorophyll fluorescence and their responses to drought and rewatering were examined in maize plants subjected to drought at different growth and development stages. Leaf relative chlorophyll concentration (SPAD meter readings),gs, and transpiration rate(E) significantly decreased in two weeks after withholding water at jointing, but the chlorophyll fluorescence parameters including actual quantum yield of PSII primary photochemistry in the light-adapted state (ΦPSII),maximum quantum yield of PSII primary photochemistry in the light-adapted state (Fv′/Fm′) remained stable.The photosynthetic capacity traits significantly decreased in one week after withholding water at tasseling,and the leafinet photosynthetic rate decreased more due to drought stress during tasseling than during jointing.Based on the measurements on the same leaves during their entire growth periods, the photosynthetic capacity was restored to some extent, but not reaching the level of the control treatment. Light-saturated photosynthetic rate (Asat),gs, andEtrended to decrease; SPAD values increased first, then decreased. In addition, there were greater declines in various parameters under drought relative to the control treatment. The changes in chlorophyll fluorescence parameters (ΦPSII,Fv′/Fm′) of the same leaves remained relatively stable with the leaf growth at amply watering condition. Meanwhile the chlorophyll fluorescence parameters did not decrease significantly under the four drought treatments, even obvious increases in the corresponding parameters occurred after rewatering when the maize plants experienced the drought stress. It is indicated that the drought tolerance of the photosystem II (PSII) may be enhanced with maize leaf growth and development.

Based on the soil moisture observational data, a new criterion of drought intensity for Drought Index,MCI, was given. Firstly, the daily relative humidity time-series (1992–2010) at a certain site was obtained by linear interpolation. Secondly, a statistic model was established based on the relationship between MCI index and soil relative humidity. Then, based on the observed data, the upper limit of meteorological drought index of maize at different growth stages was determined. A “drought impact on maize assessment module”was constructed in the operational system of “meteorological disaster risk management system” based on the above results. The system can be used to evaluate the drought effects on maize. Figure 1 shows the results of the maize drought accumulation index on September 30, 2016. The maize meteorological drought was mainly distributed in the western part of Northeast China, eastern Inner Mongolia and Hubei, Anhui, Jiangsu and Sichuan (Fig.1). (Zhou Li)

1.7 New finding on self-photoprotection mechanism of plant adapting to future climate change

We examined the photosynthetic responses ofStipa baicalensisto relatively long-term exposure (42 days) to the predicted elevated temperature and water availability changes to determine the mechanisms through which the plant would acclimate to future climate change. Two thermal regimes (ambient and +4 °C)and three irrigation levels (partial, normal and excess) were used in environmental control chambers. The gas exchange parameters, light response curves andA/Cicurves were determined. The elevated temperatureand partial irrigation reduced the net photosynthetic rate due to a limitation in the photosynthetic capacity instead of the intercellular CO2concentration. Partial irrigation decreased Rubisco activation and limited RuBP regeneration. The reduction inVcmaxincreased with increasing temperature. Excess irrigation offset the negative effect of drought and led to a partial recovery of the photosynthetic capacity. Although its light use efficiency was restricted, the use of light and dark respiration byStipa baicalensiswas unchanged. We concluded that nonstomatal limitation was the primary reason for photosynthesis regulation inStipa baicalensisunder relatively long-term climate change conditions. Although climate change caused reductions in the light use efficiency and photosynthetic rate, a self-photoprotection mechanism inStipa baicalensisresulted in its high ability to maintain normal live activities. (Zhou Guangsheng)

1.8 Fine soil moisture and irrigation forecasting technologies for winter wheat in northern China and their application

The data set of soil moisture and irrigation forecast was improved. The daily meteorological data and automatic soil moisture data in northern winter wheat region in the data set extended to July 31, 2016. The remote sensing inversion methods of crop water deficit indices were studied further. The decadal changes of theaandbcoefficients in ?ngstr?m-Prescott formula were analyzed. Theaandbcoefficients of month by month for different ages from 1961 to 2010 in the study area and major regions of China were given. Based on growth mechanism of winter wheat, soil water balance equation, various test data, the previous research of the simplif ed models of water balance in winter wheat field and the fine daily multi-layer soil moisture and irrigation forecast models and the localization trial of three provincial fine soil moisture and irrigation forecasting systems of winter wheat, a national fine soil moisture and irrigation forecasting system software was constructed initially. Using the project research results and three provincial fine soil moisture and irrigation forecasting system service platforms, a number of service products were released and provided valuable reference information for agriculture and other departments in Hebei, Shandong and Henan provinces (Fig. 2).(Mao Fei)

1.9 Meteorological disaster risk zoning of melon & vegetables in Hainan Province

Based on the occurrence frequency and process precipitation of different dry or less rainy days in March to May from 1971 to 2010 in Hainan cities and counties, the spring drought artificial control experiment was carried out. The experiment was conducted with uniform combination design of continuous drought days (10,15, 20, 25, 30, 35, 40, 45, 50 days) and the amount of water supply (0, 2, 4, 6, 8, 10, 12, 14, 16 mm): 2 factors 9 level treatments, the determination of different treatments under different depth of soil (10, 20, 30, 50, 100 cm), the effects of different treatments on the seedling death rate, physiological characteristics and yield of pepper were analyzed. The results show that the rate of dead paprika seedlings was significantly correlated with soil relative moisture at depth 20 cm and continuous drought days, and little correlated with irrigations.With the increase oficontinuous drought day duration, net photosynthetic rate, transpiration rate and stomatal conductance of paprika decreased and relative yield loss increased significantly. Grades index of spring drought disaster for paprika was constructed, the drought disaster index for paprika fitted well the actual drought disaster situation and could help provide strategies for monitoring and precaution against drought disaster for paprika. (Huo Zhiguo)

1.10 Temporal and spatial variation characteristics of potential evapotranspiration in China during 1961—2015

The spatio-temporal distribution characteristics of evapotranspiration (ETo) on the national and four climatic regional scales were analyzed at annual, seasonal and decadal scales, respectively, and the reasons ofthe spatio-temporal pattern for ETowere analyzed based on Penman-Monteith method and daily meteorological data at 552 meteorological station in China from 1961 to 2015. Results show that the average annual ETois about 621–1733 mm in China. The regions with the highest ETomainly distribute in the arid region, while the areas with lower EToconcentrate in the semi-arid, humid and semi-humid regions at both 55-year average and different decadal scales. The spatial distributions of EToare different in the seasonal scale. ETois the highest in summer, followed by spring and autumn, and the lowest in winter. Temporally, the average annual ETodecreases at a rate of – 0.52 mm/a from 1961 to 2015, and the decreasing trend has a mutation phenomenon in 1972. Although there is an increasing trend since the last decade of the twentieth, the mutation year was not detected with the M-K method. The change trend of ETois different in different climate regions. EToin most sites showed a decreasing trend in arid region and humid region, and the number of meteorological stations with decreasing rate in arid region is more than that in humid region. In semi-arid and semi-humid regions, the number of sites is roughly equivalent to the increasing or decreasing trend for ETo. EToat more than 85% of the sites in China was mainly affected by wind speed and sunshine time. Studies have shown that the decreasing trend of EToin nearly 55 years was mainly caused by the decrease of the wind speed, the reduction of sunshine time and the slight increase of vapor pressure. (Wang Peijuan)

1.11 Construction of drought monitoring index based on the winter wheat water stress experiment

Aiming to study the effects of different irrigation treatments on the growth and development of winter wheat, the field experiment was conducted with local predominant variety to simulate three water stresses,i.e., persistent severe drought, moderate drought, and mild drought, during the whole growth period of winter wheat over 2013–2014 (variety: Henong 6425) and 2014–2015 (variety: Yanmai 98) using the large-scale artificial water control field at the Gucheng ecological-meteorological experimental station in North China Plain. Based on water balance equation, the actual evapotranspiration of winter wheat under different water stresses (ETa) and CK conditions (ETc) were computed. Furthermore, a crop drought monitoring index (CDMI)which can reflect the degrees of water demands and deficits was built based on ETaand ETc. The thresholds of CDMI were determined referring to the yield reduction of winter wheat under different persistent water stresses, and further constructed a drought monitoring index system of winter wheat during the whole growth period. Compared to the traditional drought monitoring index based on potential evapotranspiration, the CDMI based on ETccan reflect drought degree more objectively and reasonably, which can be served as a method to monitor the drought of winter wheat in North China Plain. (Wang Peijuan)

1.12 Flood risk assessment and zoning for rice in Southwest China

As the main crop in Southwest China (Sichuan, Chongqing, Guizhou and Yunnan provinces), rice is widely accepted to be seriously threatened by the flood disaster. Agro-flood risk analysis is helpful for improving the ability of regional disaster management and reducing potential flood risk. In this study, the rice flood risk was analyzed and zoned using the integrated rice flood risk assessment model including hazard, exposure, sensitivity, and flood prevention and mitigation, and based on the daily rainfall data in 193 meteorological stations from 1961 to 2012, rice production data in 396 counties including plant and yield data from 1981 to 2012, the phenophase data of rice from 17 agrometeorological stations and geographic data in Southwest China. The results indicate that flood hazard risk probabilities variated with phenophase and hazard level. High flood hazard risk happened in transplanting-tillering stage, followed by jointing-booting and tasselling-maturity stages. High-risk areas of flood hazard in the whole rice growth stage was detected to be located in southern and northeastern Yunnan, southern Guizhou, and Chengdu, Meishan and Deyang in Sichuan Province. High and sub-high exposure zones were mainly located in the northeastern part of Sichuan Province and Chongqing. Subsequently, high and sub-high sensitive zones were mainly found in the northernYunnan Province, southern Sichuan Province and southeastern Guizhou Province. Low flood prevention and mitigation zones were located in parts of Guizhou. Finally, the high and sub-high zones for the integrated rice flood risk were detected in the northeastern Sichuan Province, southern Guizhou Province and southern part of Yunnan Province, while southern Chongqing and northern Yunnan were recognized with low rice flood risk (Fig. 3). (Yang Jianying)

1.13 Effects of winter and spring irrigation on winter wheat in North China

A field simulation experiment about irrigation of the first springing water (FSW) at different air temperatures (0, 3, 7, and 10 °C) in 3 years was designed under the preconditions of the irrigation of overwintering water (OWW) (80/150 mm) and no OWW. We explored the effects of OWW and FSW irrigation on growth and grain yield, and tried to find appropriate irrigation patterns and schemes of winter wheat in the North China Plan (NCP). The results show that FSW irrigation could relieve winter drought in air temperature stability through 0 °C under no OWW irrigation, which increased effective stalk number in spring, effective panicle number and grain yield significantly. The time of continuous drought in key growth stages could be reduced by FSW irrigation in air temperature stability through 7 °C under OWW irrigation, which increased grain yield significantly. We found no significant relationship between the amount (80 mm and 150 mm) of OWW irrigation and grain yield. Meanwhile, FSW was essential to the growth of winter wheat: there was an average reduction of 32.2% on grain yield under no FSW irrigation. Therefore, in order to ensure a stable and high yield of winter wheat and water-saving irrigation in the NCP, we should irrigate FSW in air temperature stability through 0 °C under no OWW irrigation and irrigate FSW in air temperature stability through 7 °C under proper amount of OWW irrigation. (Liu Tao)

1.14 The response mechanism of soil respiration on grassland desert hydrothermal change

A warming treatment and a control, and three watering levels were applied using a free air temperature increase facility with open soil carbon flux measurement system.Rswas measured throughout the year, and soil nutrition properties and microbial biomass carbon were determined over the growing season.Rsrates were significantly higher during the growing season than during the non-growing season. However, the warming treatment led to a marked increase inRsin winter. Soil temperature andRswere described by an exponential function with aQ10of 1.92 (R2= 0.74,p＜ 0.01); and root respiration (21.9%) was lower than heterotrophic respiration (78.1%). Soil organic carbon, soil moisture, root biomass, and soil ammonium-N were determined to be drivingRsduring the growing season. The most important factor was soil organic carbon content in the 0–10 cm soil layer, with soil moisture showing little direct effect onRs. Using the four most critical factors of soil respiration under hydrothermal conditions in the growing season, we established a model describing the responses ofRsto environmental change (R2= 0.67,p＜ 0.01). Soil environmental variables including temperature, moisture, nutrition status, root growth, and soil microbial activity might co-regulate soil carbon emission, which would be considered critical in assessing the carbon balance under climatic change in arid areas. (Liu Tao)

1.15 Estimating water use patterns in winter wheat using remote sensing in Huang-Huai-Hai Plain

Each water use component of winter wheat in Huang-Huai-Hai (3H) Plain from 2011 to 2012, including effective precipitation (PPeff), irrigation water applied (IWA), actual evapotranspiration (ETa) and on-farm water losses (F), was calculated at both temporal and spatial scales, integrating meteorological data, MODIS,SEBAL (Surface Energy Balance Algorithm for Land) model and the water balance equation. There was a clear relationship between survey- and model-values of IWA (R2= 0.79), indicating the applicability of the model-based method in IWA estimation.Precipitation in the 3H Plain provided ＞70% of total water use at theearly stage of winter wheat. However, over 90% of crop water use depended on IWA at the grain f lling stage.A high-IWA belt for the whole growing stage in winter wheat was mainly observed in basin-irrigable land and dry land, with average IWA = 412.76 mm. Water consumption in the winter wheat period represented a significant relationship with irrigation (p＜ 0.01) in 3H Plain, withR2of 0.68. (Yang Jianying)

2 Response and adaptation of agriculture to climate change

2.1 Assessment of agrometeorological disasters and yield losses in China since 1961

Since 1961, the extreme climate events in the whole nation showed an increasing trend. China,s climate exhibited warm becomes warmer and dry becomes drier, together with more floods under the climate change. Both the area and occurrence frequency of the national agricultural drought disaster also showed an increasing trend, and the drought showed an increasing trend from south to north. The occurrence frequency of waterlogging in winter wheat showed an increasing trend, and the intensity of the disaster increased more obviously in the late growth stage. The high temperature heat damage of paddy rice showed a significant increasing trend, and the severe disasters increased significantly. The chilling damage showed a decreasing trend, but in the recent 30 years, low temperature and rainy injury showed an increasing trend. The frost damage generally decreased, but the local area has aggravated the trend. The changes in evolution trend,intensity and types of agro meteorological disasters have taken place. As a result, the agricultural layout at present, together with the countermeasures for the food security and the ecological civilization construction as well as poverty alleviation, should be adjusted in order to adapt to the changing agrometeorological disasters.(Zhou Guangsheng)

2.2 Research on status quo, rate, mechanism and potential of carbon sequestration in grassland ecosystem in China

Based on more than 4 thousand survey points and TEM model, the carbon density, spatial distribution and dynamic change of grassland ecosystem in China were simulated with monthly time step, using climate,elevation, soil and vegetation data. The carbon storage of grassland ecosystem in China was estimated. The spatial distribution pattern of soil carbon density in Chinese grassland was drawn, and its spatial distribution characteristics were revealed. The spatial and temporal variation of carbon density of grassland in China and its regional differences since 1960s were quantitatively described. Carbon budget in China under the future climate scenarios was simulated. The main innovation is to solve the problem that the spatial precision of TEM is not high based on a set of parameters. A parameterization scheme was presented according to grassland ecology zone, and a series of TEM model parameters suitable for Chinese grassland were established, which could provide a basis for monitoring and evaluating carbon budget, NPP, GPP, etc. (Ji Yuhe)

2.3 Key technology on the agrometeorological service for highland barley production under climate change scenarios

The solar radiation resource will reduce slightly under both A2 and B2 climate change scenarios over the Tibetan Plateau, while it would still be/retain the region with the most abundant solar resource in the world. Temporal distribution pattern of the solar radiation will have no obvious change under both A2 and B2 scenarios, with the minimum in winter and maximum in summer. However, the monthly variation in the solar radiation will change clearly, increasing in summer and decreasing in other seasons. Trends in the total annual precipitation will increase under climate change scenarios, yet it will still be referred to as the lessprecipitation area in the world. Seasonal precipitation will become even more inhomogeneous, with minimumin winter and maximum in summer, revealing an increase in precipitation simultaneously. The general spatial distribution pattern of precipitation, with precipitation decreasing from east to west spatially, will witness no marked change under climate change scenarios, but increase in precipitation will become more obvious in the western than in the eastern part of the Tibetan Plateau. Increase in temperature will have positive impacts on the enhancement of highland barley yields under climate change scenarios, but the main features in the spatial distribution of highland barley yields will basically remain unchanged. Higher enhancement of the highland barley yield will occur in the current high-yield regions. In other words, under climate change conditions in the future, the greater enhancement of the highland barley can be expected/envisaged in the current optimum regions for highland barley growth. (Liu Jiandong)

2.4 Identifying the effects of climate change on the yield of main dryland crops in the northern China based on APSIM crop model

The responses of key growth stages and yield of spring wheat and spring maize to climate change in the northern China were identif ed based on the optimized APSIM crop simulation model. The results show that the APSIM model had a good applicability in Inner Mongolia, Gansu, Heilongjiang, Jilin, Liaoning and other northern regions. The potential yield of spring wheat in Inner Mongolia decreased from 1961 to 2010, with an average of 3561 kg/hm2. In particular, the potential yield of spring wheat was the highest in the 1980s (3681 kg/hm2) and the lowest in the 2010s (3433 kg/hm2). There were significant differences among regions. Over the past 50 years, the potential yield of spring wheat in Inner Mongolia increased gradually from the middle region to the east and the west regions. Among the three regions, the potential yield of spring wheat was the highest in the western region and was the smallest in the middle wheat region.

The main meteorological factors in fluencing the key growth stages of spring maize in Inner Mongolia were the maximum temperature, followed by the minimum temperature. The effects of solar radiation,precipitation and potential evapotranspiration on the growth stages of spring maize were the same. The key meteorological factors affecting the spring maize yield were the maximum temperature, the minimum temperature, precipitation, solar radiation and potential evapotranspiration (Fig. 4). (Zhao Junfang)

2.5 The stability assessment of different accumulated temperature model on accumulated temperature in different stages of spring maize in Northeast China

Based on the growth data of 4 spring maize varieties “Danyu 13” “Longdan 13” “Dongnong 248” “Sidan 19” and the meteorological data in Northeast China, the model parameters of Shen Guoquan’s, Gao Liangzhi’s and Yin Xinyou’s nonlinear accumulated temperature models were fitted, respectively. The stability of accumulated temperature of simulated results from different nonlinear models were compared and evaluated.They were also compared with the results of the commonly accumulated temperature model. The results of Shen Guoquan’s, Yin Xinyou’s, Gao Liangzhi’s nonlinear accumulated models and the commonly accumulated temperature model showed that the stability of accumulated temperature from the three nonlinear models are better than the commonly accumulated temperature model from emergence to maturity. From seedling to jointing stage, the stability of accumulated temperature from the four models are uniform for “Danyu 13”, but the three nonlinear models are slightly better than the commonly accumulated temperature model for “Longdan 13” “Dongnong 248” “Sidan 19”. The stability of the accumulated temperature from the jointing to tasseling stage is the worst stage, because the coefficient of variation in this stage is the biggest for each of varieties.From the tasseling to maturity stage, the stability of the accumulated temperature is almost not different in the four models. The results provide a theoretical basis and technical support for the development of spring maize in Northeast China. ( Guo Jianping)

2.6 Effects oficlimate change on agricultural climate resources in the northeast region of China

The temporal and spatial characteristics of major agroclimatic resources in the northeast region of China were systematically analyzed. During the period of 1961–2099, the heat resource is more abundant in the southern region than in the northern region, and the heat resource shows a significant increasing trend in the future. The average annual temperature in the northeast region of China will rise by about 2 °C and 3 °C in median emission scenarios (RCP4.5) and high emission scenarios (RCP8.5), respectively. The first day of over 10 °C will appear 3–4 days earlier. The first frost date will delay by 2–6 days. Therefore, the potential growth season may increase by 4–10 days. The accumulated temperature will be enriched because of temperature rising and growth season extending. By the end of this century, the accumulated temperature will increase by 400 °C.d and 700 °C.d in median emission scenarios and high emission scenarios, respectively. Water resource shows a weaker increasing trend. There are significant changes in the heat resource change rate,and high emission scenario corresponds to a faster warming. There is a warming trend in the future in the northeast region of China. The temperature rising in the northeast region of China has a positive impact on agricultural production. The heat resource that can be used by crop will be more abundant because of growth season extending and accumulated temperature increasing. The original no-planting area due to heat resource restrictions will be reduced, and the planting area will be expanded. The planting varieties will be improved,the region planting early maturing varieties can be replaced by late maturing varieties, and the late maturing varieties planting area will be further expanded. As such, the late maturing maize needs the accumulated temperature to reach 3000 °C.d, the planting area will extend from the original Songnen Plain to the Greater Khingan Range. Even double crops a year may occur in some areas in Liaoning. (Guo Jianping)

2.7 On the effects of CO2concentration elevation and temperature rising on crop water requirement

Based on the experiments during 2013–2015, the changes in wheat water use efficiency and the coupling mechanism correlation with water requirement and yield under the background of elevation in atmospheric carbon dioxide concentration and increase in air temperature in future were analyzed. The results show that the individual effects of increase in air temperature and elevation in atmospheric carbon dioxide concentration on wheat water requirement and wheat growth are additive. The increased air temperature lifted the temperature in wheat canopy and communities, eventually accelerated energy flow and hydrological cycle within the wheat field. As a result, the daily water requirement has rose through increase in transpiration from wheat plant and evaporation between plants. The elevated CO2also led to reduced leaf stomatal conductance and net photosynthetic rate, resulting in higher water use efficiency. In addition, the CO2fertilization effect has promoted wheat yield increase. On the integrative view, the elevation in atmospheric carbon dioxide concentration and increase in air temperature have increased the wheat water requirement, resulting in higher water use efficiency. The increased water requirement in turn has contributed to wheat yield increase. In the future, the more agricultural thermal resources and atmospheric CO2imported in the wheat eco-system will induce increased wheat water requirement, and further the higher yield and WUE, leading to a positive feedback circulatory eco-system. (E Youhao)

2.8 Study on the regulation mechanism of vegetation succession of abandoned farmland in farming pastoral zone in northern China

In this work, the vegetation succession process of abandoned farmland in farming-pastoral zone in northern China was studied using a space-for-time substitution method by transect sampling. The regulation mechanism of natural environmental factors on vegetation succession in abandoned farmland was revealed from a relatively macro perspective.

According to the research objectives of the project, the field transect survey was carried out in Shanxi-Ningxia agro-pastoral ecotone. Soil moisture content, soil texture and nutrient content at soil depth of 0–500 cm, as well as vegetation coverage, biomass, species and other information in the typical ecosystem of agropastoral ecotone were collected. In view of the greater temporal and spatial variability of rainfall, temperature and other meteorological factors, the more stable environmental information such as soil dry layer, soil texture, geomorphology as well as climatic factors will be used to select the key factors restricting the spatial distribution and community succession of ecosystem to explore the environmental adaptability and tolerance to climate change in northern China. In addition, tree ring data were also collected and will be used to study the response and adaptation to climate change of the northern ecosystem. (Ji Yuhe)

2.9 The impact of elevated temperature and CO2concentration on winter wheat yield and grain quality

During 2015–2016 winter wheat growing season, the third year of the manipulative experiment under elevated temperature and CO2concentration using OTC and infrared heaters was conducted. The data for phenology, plant height, stem density and dry biomass per plant obtained in this year produced results essentially in agreement with those in previous two years. The root cause of yield decline was still the reduction of grain number per ear, which was mainly attributed to the significant reduction of spikelet number in this year. Meanwhile the data of grain quality and leaficarbon and nitrogen contents measured in the 3 consecutive years were analyzed. The results show that crude protein in winter wheat grain under the combined treatment slightly increased, but the contents of fat, f ber and starch in grain were not significantly in fluenced.No significant differences in nitrogen and organic carbon contents in winter wheat leaves were found between the combined treatment and control over growing stages, although a tendency of decline of nitrogen content in winter wheat leaves from jointing stage to flowering stage likely existed. (Tan Kaiyan)

2.10 Effects of wheat varieties improvement on phenology in China

The effects of wheat varieties improvement on phenology were analyzed using the agrometeorological observation data in China. The results show that there is an increase in heat units at different developmental stages caused by varieties change. The heat unit from emergence to maturity increased by 3.5 °C/a. A comparison of different regions indicates that the variation of spring wheat varieties in Tibet, Inner Mongolia and Xinjiang has a great in fluence on the phenology. Most of them are positive effects on heat unit in different developmental periods. The change of winter wheat varieties has no obvious effect on heat unit during sowing to emergence, emergence to stop growth, stop growth to turn green, jointing to heading and milk to maturity while positive effect on heat unit during turning green to jointing and heading to milky. The effect of winter wheat variety on phenology is still large in Qinghai, Tibet, Fujian and Xinjiang. The effects are mostly positive on heat unit in different developmental periods (Fig. 5). (Ma Yuping)

2.11 Quanti fication of impacts of the main in fluencing factors in the growing period of winter wheat and simulation of the impact on production

Winter wheat phenological observation and daily average temperature data were collected from 47 agricultural meteorological observation stations in the North China Plain (NCP) during 1986–2010. A bilinear phenology model, which is based on three-base-point temperature (Tbwas set to 0 °C;Topt, 22 °C;Tmax, 32 °C), was used to detect the impact of cultivar shift on phenology. Parameters of the phenology model were calculated and validated by the state of average varieties during 1986–1988. The durations from turning green to heading(T-H) and heading to maturity (H-M) during 1986 to 2010 were simulated and the trends of the simulation errors over years were calculated. Generally, duration of T-H increased by cultivar shift, but few of the trendsare statistically significant. The trends are varied substantially at different stations. The days of T-H in the southern and northern plain were slightly shortened, while in central area and eastern Shandong, it increased significantly. Cultivar shift increased the duration of H-M significantly, especially in the southern plain, but no so obvious in the other areas, though it was slightly shortened in some areas. This study shows that the effects of cultivar shift on phenology were different in different development stages and regions. In the studies regarding the effects of future climate change on phenology, the uncertainties of the results will be reduced if this spatio-temporal difference of the impacts was considered (Fig. 6). (Wu Dingrong)

2.12 Using statistical model to simulate the impact of climate change on maize yield with uncertainties

The multi-model ensemble method is an effective way to deal with uncertainties. 24 climate projections consisting of the combinations of eight GCMs and three emission scenarios representing the climate projections uncertainty, and two crop statistical models with 100 sets of parameters in each model representing parameter uncertainty within the crop models, were employed to evaluate the impact of climate change on maize yield at three locations (Benxi, Changling, and Hailun) across Northeast China (NEC) in the periods 2010–2039 and 2040–2069, taking 1976–2005 as the baseline period. The results of ensemble simulations showed that maize yield reductions were less than 5% in both future periods relative to the baseline. To further understand the contributions of individual sources of uncertainty, such as climate projections and crop model parameters in ensemble yield simulations, variance decomposition was performed. The results indicate that the uncertainty from climate projections was much larger than that contributed by crop model parameters. The increased ensemble yield variance revealed the increasing uncertainty in the yield simulation in the future periods.(Zhang Yi)