徐新朋， 周 衛(wèi)*， 梁國(guó)慶， 孫靜文， 王秀斌，何 萍， 徐芳森， 余喜初

(1中國(guó)農(nóng)業(yè)科學(xué)院農(nóng)業(yè)資源與農(nóng)業(yè)區(qū)劃研究所， 北京 100081； 2 華中農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院，湖北武漢 430070； 3 江西省紅壤研究所， 江西進(jìn)賢 331717)

氮肥用量和密度對(duì)雙季稻產(chǎn)量及氮肥利用率的影響

徐新朋1， 周 衛(wèi)1*， 梁國(guó)慶1， 孫靜文1， 王秀斌1，何 萍1， 徐芳森2， 余喜初3

(1中國(guó)農(nóng)業(yè)科學(xué)院農(nóng)業(yè)資源與農(nóng)業(yè)區(qū)劃研究所， 北京 100081； 2 華中農(nóng)業(yè)大學(xué)資源與環(huán)境學(xué)院，湖北武漢 430070； 3 江西省紅壤研究所， 江西進(jìn)賢 331717)

【目的】高量化肥投入不僅不能使作物產(chǎn)量進(jìn)一步增加，相反還會(huì)造成肥料資源的浪費(fèi)并威脅到生態(tài)環(huán)境安全，同時(shí)導(dǎo)致肥料吸收利用率、農(nóng)學(xué)效率等不斷降低。為了明確氮肥用量和移栽密度的相互作用，在田間試驗(yàn)條件下研究了不同氮肥用量和移栽密度組合對(duì)江西雙季稻產(chǎn)量、產(chǎn)量構(gòu)成要素及氮肥利用率的影響，以期為雙季稻的高產(chǎn)高效栽培技術(shù)提供理論基礎(chǔ)?！痉椒ā坎捎昧褏^(qū)試驗(yàn)設(shè)計(jì)，以氮肥施用量為主區(qū)，密度為副區(qū)，設(shè)4個(gè)施氮水平(N 0、135、180和225 kg/hm2，以N0、N135、N180和N225表示)和4種移栽密度(21×104、27×104、33×104、39×104hole/hm2，以D21、D27、D33和D39表示)組合，在水稻成熟期對(duì)產(chǎn)量以及產(chǎn)量構(gòu)成要素進(jìn)行測(cè)定，并分析其吸氮量和氮肥利用率、氮收獲指數(shù)等指標(biāo)?！窘Y(jié)果】施氮水平和移栽密度對(duì)水稻產(chǎn)量具有顯著影響；增加移栽密度有助于提高單位面積水稻的有效穗數(shù)、稻谷產(chǎn)量和地上部吸氮量；在高施氮量下，水稻氮素積累總量增加，而氮素吸收利用率(REN)、氮素偏生產(chǎn)力(PFPN)、氮素生理利用率(PEN)、氮素內(nèi)在養(yǎng)分效率(IEN)和氮素收獲指數(shù)(NHI)降低；氮素農(nóng)學(xué)效率(AEN)則是先升高后降低，而產(chǎn)量并未增加。與其它處理組合相比，施氮量為180 kg/hm2和39×104hole/hm2密度的組合產(chǎn)量最高，早稻和晚稻分別為9823.0和11354.7 kg/hm2，此時(shí)早稻和晚稻的氮素吸收率分別為42.4%和47.5%。當(dāng)施氮量超過(guò)180 kg/hm2時(shí)產(chǎn)量則不再增加，但產(chǎn)量隨著移栽密度的增加而顯著增加。【結(jié)論】合理氮肥用量和移栽密度可以顯著增加水稻單位面積的有效穗數(shù)和氮累積量，進(jìn)而增加水稻產(chǎn)量和氮肥利用率，建議在江西雙季稻栽培中采用施氮量為N 180 kg/hm2，栽培密度39×104hole/hm2的組合。

水稻； 氮肥用量； 移栽密度； 產(chǎn)量； 氮肥利用率

水稻作為我國(guó)主要糧食作物之一，對(duì)我國(guó)糧食安全起著至關(guān)重要的作用。在“高投入、高回報(bào)”的傳統(tǒng)耕作理念的驅(qū)使下，化肥的施用量不斷增加，導(dǎo)致過(guò)量施肥和不合理施肥的嚴(yán)重問(wèn)題。然而，高量的化肥投入不僅不能帶來(lái)作物產(chǎn)量的進(jìn)一步增加，相反還會(huì)威脅到生態(tài)環(huán)境的安全[1-5]，造成地表水或地下水體硝酸鹽含量超標(biāo)，同時(shí)導(dǎo)致肥料利用率以及農(nóng)學(xué)效率等不斷降低。因此在水稻栽培的生產(chǎn)實(shí)踐中提高肥料利用率和產(chǎn)量已成為重要的目標(biāo)之一。要同時(shí)兼顧產(chǎn)量、經(jīng)濟(jì)、環(huán)境及農(nóng)學(xué)效益，則需要重點(diǎn)對(duì)氮肥施用量和移栽密度進(jìn)行重點(diǎn)研究。隨著水稻品種的不斷更新和生產(chǎn)基礎(chǔ)條件的不斷改進(jìn)，合理的氮肥施用量及管理方式不僅能促進(jìn)作物生長(zhǎng)、提高產(chǎn)量，而且能夠提高氮肥利用率[6-8]?？茖W(xué)的移栽密度能夠保證水稻個(gè)體及群體有效的發(fā)揮潛能，從而獲得高產(chǎn)。研究表明，合理的氮肥用量、施用時(shí)期和密度對(duì)水稻分蘗及產(chǎn)量有顯著影響[9]，同時(shí)可以增強(qiáng)水稻的抗倒伏性能[10]，最終達(dá)到提高產(chǎn)量和氮肥利用率的效果[11]，施氮量和移栽密度也影響著水稻的氮素吸收、轉(zhuǎn)運(yùn)及利用。在施氮量和栽培密度方面以往的研究多集中在單季水稻上，對(duì)雙季稻的研究還比較少，為此，本試驗(yàn)在綜合前人研究的基礎(chǔ)上，系統(tǒng)研究了施氮量和移栽密度對(duì)雙季稻產(chǎn)量、經(jīng)濟(jì)性狀、氮肥吸收轉(zhuǎn)運(yùn)及氮素利用率的影響，以期為雙季稻的高產(chǎn)高效栽培技術(shù)提供理論依據(jù)。

1 材料與方法

1.1 試驗(yàn)設(shè)計(jì)

試驗(yàn)于2013年在江西省南昌市進(jìn)賢縣張公鎮(zhèn)江西省紅壤研究所試驗(yàn)基地的紅壤性水稻田塊上進(jìn)行(東經(jīng)116°20′24″，北緯28°15′30″)。供試土壤為水稻土，耕層土壤(0—20 cm)有機(jī)質(zhì)含量22.82 g/kg、全氮1.50 g/kg、全磷0.63 g/kg、全鉀16.80 g/kg、有效磷 15.96 mg/kg、速效鉀 167.73 mg/kg、pH 5.15。供試的早稻品種為贛早秈54號(hào)，晚稻品種為正成456，試驗(yàn)采用裂區(qū)設(shè)計(jì)，以施氮量為主區(qū)(面積120 m2)，密度為副區(qū)(面積為30 m2)，早稻和晚稻施氮量和密度設(shè)置相同，施氮量設(shè)N0、135、180和225 kg/hm24個(gè)水平，以N0、N135、N180和N225表示。移栽密度設(shè)每公項(xiàng)21×104穴(20 cm × 23.8 cm)、27×104穴(20 cm × 18.5 cm)、33×104穴(20 cm × 15.2 cm)和39×104穴(20 cm × 12.8 cm)4種，以D21、D27、D33和D39表示。每處理3次重復(fù)，隨機(jī)區(qū)組排列。

早稻于3月28日播種，4月25日移栽，7月16日收獲；晚稻6月25日播種， 7月26日移栽， 10月27日收獲。 氮肥用尿素(含N 46%)，分基肥、分蘗肥、穗肥3次施用，基肥 ∶分蘗肥 ∶穗肥為4 ∶3 ∶3。磷肥用鈣鎂磷肥(含P2O512.5%)，全部作基肥；鉀肥用氯化鉀(含K2O 60%)，基肥 ∶穗肥為5 ∶5。各處理磷肥施用量為450 kg/hm2，鉀肥用量225 kg/hm2。試驗(yàn)小區(qū)間作埂隔離，并用塑料膜覆蓋埂體，以保證各小區(qū)單獨(dú)排灌并防止水肥滲出。

圖1 不同處理對(duì)產(chǎn)量的影響Fig.1 Effects of different treatments on grain yields of rice[注(Note)： N—氮肥 N fertilizer；D—種植密度 Planting density；柱上不同字母表示處理間差異達(dá)5%顯著水平 Different letters above the bars for different treatments are significantly different at the 5% probability level.]

1.2 測(cè)定項(xiàng)目及方法

水稻成熟后，每個(gè)小區(qū)單獨(dú)收割測(cè)定子粒產(chǎn)量，采集有代表性的植株5兜，對(duì)水稻產(chǎn)量構(gòu)成要素進(jìn)行考察，包括株高、穗數(shù)、穗長(zhǎng)、穗粒數(shù)、結(jié)實(shí)率、千粒重，并分別稱(chēng)量莖、葉和籽粒的重量。

用凱氏定氮法測(cè)定莖鞘、葉片和子粒氮含量。

相關(guān)計(jì)算方法：

氮素吸收利用率(N recovery efficiency，REN)=(施氮區(qū)植株地上部氮累積量-空白區(qū)地上部植株氮累積量)/施氮量×100%；

氮素農(nóng)學(xué)利用率(agronomic efficiency of applied N，AEN)=(施氮區(qū)產(chǎn)量-空白區(qū)產(chǎn)量)/施氮量；

氮素偏生產(chǎn)力(partial factor productivity of applied N，PFPN)=施氮區(qū)產(chǎn)量/施氮量；

氮素生理利用率(physiological efficiency of applied N，PEN)=(施氮區(qū)產(chǎn)量-空白區(qū)產(chǎn)量)/(施氮區(qū)地上部氮累積量-空白區(qū)地上部氮累積量)；

氮素內(nèi)在養(yǎng)分效率(internal efficiency of applied N，IEN)=施氮區(qū)產(chǎn)量/施氮區(qū)地上部氮累積量；

氮素收獲指數(shù)(N harvest index，NHI) = 子粒氮累積量/植株地上部氮累積量。

試驗(yàn)數(shù)據(jù)采用Excel 2007 和SAS進(jìn)行處理和分析。

2 結(jié)果與分析

2.1 氮肥和密度對(duì)水稻產(chǎn)量的影響

試驗(yàn)結(jié)果表明，氮肥用量及移栽密度對(duì)水稻產(chǎn)量具有顯著的影響(圖1)。無(wú)論是早稻還是晚稻均以N180D39處理組合的產(chǎn)量最高，分別為9823.0和11354.7 kg/hm2(表1和表2)。從密度看，增加水稻的移栽密度可以顯著增加水稻產(chǎn)量，所有處理中都以D39的產(chǎn)量最高，N180與N0、N135 和N225相比，早稻產(chǎn)量分別提高了40.0%、15.6%和4.1%，晚稻產(chǎn)量分別提高了57.3%、5.3%和6.5%。而從施氮水平看，在施氮水平達(dá)到180 kg/hm2時(shí)，早稻和晚稻的產(chǎn)量達(dá)到最大，施氮量與水稻產(chǎn)量呈拋物線關(guān)系，移栽密度與水稻產(chǎn)量在本試驗(yàn)設(shè)置中呈線性關(guān)系。

施氮水平和移栽密度對(duì)一些產(chǎn)量構(gòu)成要素的影響達(dá)到了顯著水平。施氮水平和移栽密度對(duì)早稻和晚稻穗粒數(shù)的影響達(dá)到了顯著水平，而氮肥水平對(duì)晚稻結(jié)實(shí)率的影響也達(dá)到了顯著水平，而對(duì)早稻的結(jié)實(shí)率則無(wú)影響。在同一施氮水平下有效穗數(shù)隨著移栽密度的增加而增加，均以D39的有效穗數(shù)最高，而單個(gè)穗子的穗粒數(shù)卻相反，穗粒數(shù)與施氮量間呈拋物線關(guān)系，在相同氮水平中均以D21的穗粒數(shù)最多，在本研究中當(dāng)施氮量超過(guò)180 kg/hm2時(shí)，穗粒數(shù)則開(kāi)始降低。因此，增加施氮量和移栽密度主要通過(guò)增加有效分蘗而提高水稻有效穗數(shù)及總穗粒數(shù)增加水稻產(chǎn)量。除此之外，施氮對(duì)水稻的株高和穗長(zhǎng)具有顯著影響。移栽密度對(duì)早稻穗長(zhǎng)的影響達(dá)到了顯著水平，同施氮量水平下早稻穗長(zhǎng)隨移栽密度增加而降低。

2.2 氮肥和密度對(duì)水稻氮素利用效率的影響

表1 不同處理下早稻產(chǎn)量及其構(gòu)成因子

注(Note): N—N fertilizer; D—Planting density. 數(shù)值后不同字母表示處理間差異達(dá)5%顯著水平 Values followed by different letters for different treatments are significantly different at the 5% probability level. ns 表示不顯著Indicates no significant; *和**分別表示達(dá)到5%和1%顯著水平 Mean significant at the 5% and 1% levels, respectively.

表2 不同處理下晚稻產(chǎn)量及其構(gòu)成因子

注(Note): N—N fertilizer; D—Planting density. 數(shù)值后不同字母表示處理間差異達(dá)5%顯著水平 Values followed by different letters for different treatments are significantly different at the 5% probability level. ns 表示不顯著Indicates no significant; *和**分別表示達(dá)到5%和1%顯著水平 Mean significant at the 5% and 1% levels, respectively.

表3 早稻不同處理的氮素利用效率

注(Note): N—N fertilizer; D—Planting density. REN—N recovery efficiency; AEN—Agronomic efficiency of applied N; PFP —Partial factor productivity of applied N; PEN—Physiological efficiency of applied N; IEN—Internal efficiency of applied N; NHI—N harvest index. 數(shù)值后不同字母表示處理間差異達(dá)5%顯著水平 Values followed by different letters for different treatments are significantly different at the 5% probability level. ns 表示不顯著Indicates no significant; *和**分別表示達(dá)到5%和1%顯著水平 Mean significant at the 5% and 1% levels, respectively.

圖2 不同處理對(duì)氮素累積的影響Fig.2 Effects of different treatments on N accumulation[注(Note)： N—氮肥 N fertilizer; D—種植密度 Planting density. 柱上不同字母表示處理間差異達(dá)5%顯著水平 Different letters above the bars for different treatments are significantly different at the 5% probability level.]

處理Treatment氮素吸收利用率REN(%)氮素農(nóng)學(xué)效率AEN(kg/kg)氮素偏生產(chǎn)力PFPN(kg/kg)氮素生理利用率PEN(kg/kg)氮素內(nèi)在養(yǎng)分效率IEN(kg/kg)氮收獲指數(shù)NHIN135D2142.8abc16.5bc57.3bc38.5bcd66.0bcd0.72aN135D2743.7abc16.7bc62.7b38.2bcd67.5bc0.72aN135D3343.2abc14.9c62.3b34.0cd65.2cd0.72aN135D3950.8a29.8a79.9a58.8a75.2a0.72aN180D2138.1c14.5c45.1efg37.1bcd63.2de0.72aN180D2741.2bc16.3bc50.8cde39.5bcd65.1cd0.70abN180D3342.1bc18.2bc53.8cd43.2bc66.2bc0.70abN180D3947.5ab22.6b63.1b47.2b68.6b0.70abN225D2136.0c14.3c38.8g39.0bcd62.2e0.72aN225D2737.8c11.7c39.3g30.9d58.4f0.68bN225D3340.0bc15.1c43.5fg36.9bcd60.9ef0.70abN225D3943.2abc13.6c47.4def29.5d59.0f0.68b氮肥N**********密度D********nsN×Dns*ns****ns

注(Note): N—N fertilizer; D—Planting density. REN—N recovery efficiency; AEN—Agronomic efficiency of applied N; PFP —Partial factor productivity of applied N; PEN—Physiological efficiency of applied N; IEN—Internal efficiency of applied N; NHI—N harvest index. 數(shù)值后不同字母表示處理間差異達(dá)5%顯著水平 Values followed by different letters for different treatments are significantly different at the 5% probability level. ns 表示不顯著Indicates no significant; *和**分別表示達(dá)到5%和1%顯著水平 Mean significant at the 5% and 1% levels, respectively.

3 討論

3.1 施氮水平和移栽密度與水稻產(chǎn)量的關(guān)系

3.2 施氮水平和移栽密度與氮素利用效率的關(guān)系

3.3 氮肥用量和密度的協(xié)同優(yōu)化

移栽密度和氮肥施用量對(duì)水稻的群體動(dòng)態(tài)和產(chǎn)量構(gòu)成具有顯著的影響[29]，同時(shí)影響水稻的葉面積指數(shù)、凈光合速率及葉綠素含量等[30]，進(jìn)而影響水稻產(chǎn)量。在本研究中，早稻N180D39處理組合具有最高的產(chǎn)量、氮素吸收率和農(nóng)學(xué)效率，對(duì)于晚稻而言， N180D39處理組合的氮素吸收率(47.5%)略低于N135D39處理組合(50.8%)且無(wú)顯著差異，但前者具有較高的產(chǎn)量，增加了5.3%。在水稻栽培中不能一味地追求高氮素吸收率，同時(shí)要考慮產(chǎn)量及經(jīng)濟(jì)效益等因素。施氮有助于提高產(chǎn)量和養(yǎng)分吸收，增加移栽密度通過(guò)提高有效分蘗數(shù)而提高產(chǎn)量，但也增加了葉片和莖鞘中的氮累積量，當(dāng)施氮量達(dá)到一定水平時(shí)(本試驗(yàn)條件下為180 kg/hm2)，雖然能夠繼續(xù)促進(jìn)作物對(duì)氮素的吸收，但并不利于氮素向子粒中轉(zhuǎn)移。因此，協(xié)調(diào)施氮量和移栽密度是實(shí)現(xiàn)高產(chǎn)及高氮肥利用率的關(guān)鍵。統(tǒng)計(jì)分析結(jié)果表明，本研究設(shè)計(jì)中N180D39組合產(chǎn)量最高，并具有較高的氮素農(nóng)學(xué)效率、氮素吸收率、氮素內(nèi)在養(yǎng)分效率等，因此是適宜當(dāng)?shù)氐氖┑亢鸵圃悦芏取５诤侠淼牡视昧肯率褂酶叩囊圃悦芏?大于39×104hole/hm2)是否能夠進(jìn)一步增加本研究區(qū)域的水稻產(chǎn)量還有待進(jìn)一步研究。

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Effects of nitrogen and density interactions on grain yield and nitrogen use efficiency of double-rice systems

XU Xin-peng1, ZHOU Wei1*, LIANG Guo-qing1, SUN Jing-wen1, WANG Xiu-bin1,HE Ping1, XU Fang-sen2, YU Xi-chu3

(1InstituteofAgriculturalResourcesandRegionalPlanning,ChineseAcademyofAgriculturalSciences,Beijing100081,China;2CollegeofResourcesandEnvironmentalSciences,HuazhongAgriculturalUniversity,Wuhan430070,China;3JiangxiInstituteofRedSoil,Jiangxi,Jinxian331717,China)

【Objectives】 Over-fertilization by farmers driven by desire for higher yields does not always contribute to increase yield, however, the over-fertilization causes fertilizer waste and negative effects on environment, meanwhile leads to low nutrient recovery efficiency and agronomic efficiency. In order to determine effects of nitrogen(N) application and transplanting density(D) on double-rice systems, a field experiment was conducted to study yield, yield components and nitrogen use efficiency of double-rice in Jiangxi province. 【Methods】 A split-plot experimental design was used with different nitrogen application amounts in the main plots and transplanting density in the sub-plots to study grain yield and N use efficiency under four N rates(N 0, 135, 180 and 225 kg/hm2, and express as N0, N135, N180 and N225) and four transplanting densities(21×104, 27×104, 33×104and 39×104hole/hm2, and express as D21, D27, D33 and D39) for double-rice systems, the grain yield and its components were measured, and N uptake, N use efficiency and N harvest index were analyzed at rice maturity. 【Results】 The results show that there are significant effects of the N levels and planting density on the rice yield separately. The high transplanting density contributes to increase effective panicle number per unit area, grain yield and total N uptake of shoot. The high N rate increases total N accumulation of rice, but decreases the N recovery efficiency, N partial factor productivity, N internal efficiency, N physiological efficiency and N harvest index. The agronomic efficiency of N is increased with increasing of N application rate at first and decreased after N application rate exceeding 180 kg/hm2. Compared to other treatments, there are the highest yields under the 180 kg/hm2and 39×104hole/hm2treatment combination, the yields are 9823.0 and 11354.7 kg/hm2for early and late rice, and the N recovery efficiencies are 42.4% and 47.5% for early rice and late rice, respectively. The grain yield is not increased when N application rate exceeding 180 kg/hm2, while the yield is increased with increasing transplanting density in our study. 【Conclusions】 The rational combination of nitrogen application and transplanting density can indeed significantly increase the effective panicle number per unit area and total N uptake of rice shoot, which further increases the rice yield and nitrogen use efficiency. The N180D39 treatment combination is recommended for double-rice systems in Jiangxi province.

rice; N fertilizer rate; planting density; grain yield; N use efficiency

2014-02-18 接受日期： 2014-07-16

現(xiàn)代農(nóng)業(yè)產(chǎn)業(yè)技術(shù)體系建設(shè)專(zhuān)項(xiàng)資金(CARS-01-31)； 農(nóng)業(yè)部公益性行業(yè)(農(nóng)業(yè))科研專(zhuān)項(xiàng)(201003016)； 國(guó)家重點(diǎn)基礎(chǔ)研究發(fā)展計(jì)劃(2013CB127405)資助。

徐新朋(1984—)， 男， 河北承德人， 博士研究生， 主要從事高效施肥方面的研究。 E-mail: xinpengxu@163.com * 通信作者 E-mail: wzhou@caas.ac.cn

S511.4+2.062

A

1008-505X(2015)03-0763-10