Zuhua YUAN, Shuhua GAO, Zhuoyi DING, Hui TONG, Jian YANG

1. Hunan Vegetable Research Institute, Changsha 410125, China;

2. Taojiang County Vegetable Office, Yiyang 413400, China

As a major rice producing field,the region surrounding Dongting Lake is also a dominant area producing autumn and winter vegetables[1]. Confronted by issues of rural to urban migration and rising cost of labors in rural areas[2-3],Hunan Institute of Vegetable Science conducted no-tillage cultivation of Flowering Chinese cabbages in paddy fields in Taojiang County, Yiyang City, together with Taojiang Vegetable Office in order to explore high use efficiency of winter fallow fields around Dongting Lake,develop characteristic vegetable industry, improve land utilization and increase farmers’ incomes in Hunan Province.

Materials and Methods

Test site

The test was carried out from August 2013 to February 2014 in Luo’s farmlands under household-responsibility system in Banjiazhou Village,Taohuajiang Town, Yiyang City, Hunan Province from August 2013 to February 2014. The soils contain organic matter of 37.3 g/kg,available nitrogen of 152 mg/kg, available P of 17.5 mg/kg,available K of 85.9 mg/kg,as well as trace elements,such as Cu,Fe,Zn,Mn,and B,with pH of 4.5-6.5.The soil fertility keeps higher and structure is well. The soils are river soils and preceding crop was rice.

Test methods

Wucaihuangtai No.3, bred by Hunan Xingshu Seed Industry Co.,Ltd.,was taken as test materials. Rice stubbles were left with a height of 25 cm, and three treatments were set on the same farmland,involving no-tillage cultivation, machine-based ploughing and transplanting, and manual ploughing and transplanting. Every treatment was repeated for three times and the area of test zone was 120 m2.The experiment was conducted as per random arrangement. Specifically,Flowering Chinese cabbage was sown on September 15 and seedlings were cultivated as per floating nursing method. The base fertilizers included Russian compound fertilizers applied at 375 kg/hm2(16-16-16),P fertilizersapplied at 750 kg/hm2(12%),ammonium bicarbonate at 750 kg/hm2.Subsequently, seedlings were irrigated with little water until surface soils were moist. After water drying, in the treatment as per no-tillage cultivation, the farmlands were not ploughed and ditches and compartments were made by people.In the treatment as per machine-based ploughing, farmlands ploughing, soil and compartment preparations, ditching and compartment were all carried out by machines.In the treatment as per manual ploughing and transplanting, all the works were finished by people. However, all compartments and ditches were made with length of 2 m. The seedlings were transplanted on October 12, with a density of 30cm×20cm,followed by irrigation.

Every row including 11 plants was taken as a unit, and a row was sampled every 4 rows, totaling 10 rows.Then, 110 plants were all signed to investigate the number of Flowering Chinese cabbage and the plants injured by cutworms. As for yield and output value, every compartment at 120 m2was taken as a unit to explore survival rate. The harvested Flowering Chinese cabbages were all weighed and the output value was computed as per the price on that very day. From November 1 to January 27, 2014, totaling 19 batches of Flowering Chinese cabbages were harvested. In terms of production cost, the cost of machinebased ploughing was 1 500 yuan/hm2,ditching was 900 yuan/hm2, manual ploughing and soil preparation reached 8 250 yuan/hm2. The operation work in early stage,such as fertilization and irrigation, was listed into other management cost.In later stage,harvesting and medicine application were not included into costs.The other cultivations were the same as local method.

Results and Analysis

The survival rate and insect-damage survey

As shown in Table 1,as the transplanting time increased, both of survival rate and the number of survival plant decreased in the treatment of notillage cultivation and the treatment of machine-based ploughing and transplanting.What’s more,no-tillage cultivation had higher effects on survival rate of Flowering Chinese cabbage.Subsequently,15 d after transplanting,the survival rates of plants in the treatment as per machine-based ploughing and transplanting and the treatment as per manual ploughing and transplanting, reached 95.5% and 94.6%, respectively, and the survival rate of the treatment as per no-tillage cultivation was only 86.4%. It is notable that the fields around Dongting Lake are still very hot and dry, and water is the major factor affecting survival rate of Flowering Chinese cabbage after transplanting. Ploughing actually improved water retention and supply of soils, enhancing survival rate of transplanting.

September and October are peak-stage of cutworm damaging Flowering Chinese cabbage. As shown in Table 1,15 d after transplanting, the numbers of injured plants in the three treatments’ areas reached 21,44 and 41,and the damaging rates were 19.1%, 40.0% and 37.3%, respectively. It is clear that the damage degree of Flowering Chinese cabbage in the treatment as per no-tillage cultivation was significantly lower compared with the rest treatments,indicating no-tillage cultivation considerably prevent Flowering Chinese cabbage from cutworm damages, because ploughing improves active environment of cutworms besides promoting water retention and supplying.

Table 1 Effects of no-tillage and ploughing on survival rate and insect damages onFlowering Chinese cabbage

Table 2 Comparisons of production costs of the three treatments Yuan/hm2

Production costs

It can be concluded form Table 2 that gross cost of ploughing cultivation kept higher compared with the treatment as per no-tillage cultivation, of which gross cost of manual ploughing and transplanting treatment was 1.9 times as high as the treatment as per machin-based ploughing and transplanting, and twice as high as the treatment as per no-tillage cultivation,due to remarkable growth of labor cost. Nevertheless, gross cost of the treatment as per machine-based ploughing and transplanting showed little differences with that of the treatment as per no-tillage cultivation,which was just 225 yuan/hm2higher,because although no-tillage cultivation omits the cost of ploughing and soil preparation, the cost of ditching is higher, and transplanting is both labor consuming, increasing transplanting cost. As a result, no-tillage cultivation performs so significantly compared with manual transplanting and ploughing in terms of production cost,instead of machine-based work.

Yield and output values

As shown in Table 3, ploughing increased yield of Flowering Chinese cabbages, the cultivation yield of the treatment as per no-tillage cultivation reduced by 10.3% and 11.9% compared with the treatments as per machine-based cultivation and manual cultivation. In general, the productionbenefits of the treatment as per notillage cultivation lower by 11.9%compared with machine-based cultivation and grew by 11.1% compared with manual cultivation.

Table 3 Comparisons of production benefits of the treatments

Conclusions and Discussions

The test results showed that notillage cultivation of Flowering Chinese cabbage well protected soil structure,reduced insect damages, lowered labor work, and resolved the issues of labor shortage. Compared with manual cultivation, no-tillage cultivation saved ploughing fees and significantly decreased production cost. On basis of test data, no-tillage cultivation of Flowering Chinese cabbage took advantages in production benefits,with production benefits as high as 30 550.5 yuan/hm2,and the production benefits lowered by 11.9% compared with machine-based cultivation and increased by 11.1% compared with manual ploughing and transplanting treatment. Therefore, it is of significance for developing characteristic vegetable industry and increasing land use rate by cultivation of Flowering Chinese cabbage with rational employment of rural labors, and use of abandoned farmlands in Hunan Province.

The test has demonstrated that the reduction of survival rate and delaying of high-yielding after transplanting are major problems should be well considered for no-tillage cultivation.Therefore, it requires further exploration on how to improve transplanting survival rate and accelerate seedling growth.

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