| Water-retaining agent(WRA),also known as polymer water-absorbing agent or resin,refers to a new type of water-saving material with development prospect and application value in modern agricultural production.The central and western regions of Jilin province are the main production areas of spring corn(Zea mays L.),soybeans(Glycine max(L.)Merr)and other crops.However,the agricultural production there is limited by uneven water and heat resources,leaving large growth space for water use efficiency and agricultural output.On the basis of performance test of Hankewei WRA and the indoor water application test at the seedling stage,this study conducted field test researches in combination with the crop growth and the characteristics of different climate zones to provide scientific evidence for the development of drought-resistant water-saving agriculture and the practical application of WRA.The main results of this study are as follows:1.Agricultural WRA Hankewei possessed a good absorption rate and water absorption capacity,which could quickly absorb water to more than half of the maximum amount of absorption in a short period of time and retain the water for over 17 hours.The times of repetition of its water absorption might reach more than 20-50.With the increasing application of WRA,its water absorption rate in soil tended to increase and then decrease.2.Under semi-arid and semi-humid water conditions,the application of WRA to maize to some extent promoted the seedling emergence rate,seedling emergence date,seedling plant height,leaf age,leaf area,relative chlorophyll content,the dry matter accumulation of the whole plant while caused inhibitory effects on the above indexes under drought conditions.For soybeans,by applying WRA,the above indexes were only promoted under sub-humid conditions,while inhibited either in drought or semi-drought conditions.3.The application of WRA in the semi-wet zone increased the indexes like plant height,stem diameter,leaf area per plant,leaf area index,relative chlorophyll content,root number,dry weight of the overground,dry weight of root,dry weight of the whole plant,and yield composition of maize and soybean.The application of WRA resulted in an improved trend toward spike height,spike coefficient,stem thickness coefficient,and resistance of pest,disease and lodging of maize,as well as the emergence rate,partial productivity of nitrogen fertilizer and nitrogen harvest index of soybean.Compared to the control groups,the yields of maize and soybean were respectively increased by 2.64% and 18.6% under the application of WRA,and the economic efficiency of soybeans can be improved by 10%.4.The combination of WRA and drip irrigation most obviously affected the growth and yield of maize in semi-arid agricultural areas,performed by the significant differences in plant height,spike height,and the improvement of stem thickness,spike coefficient,and relative chlorophyll content.The application of WRA on the basis of shallow drip and sub-membrane drip irrigation significantly increased maize yields by 7.88% and 4.67%,respectively,compared to the control groups.What’s more,the economic benefits can also be raised by the combination of shallow drip irrigation and the application of WRA,externalized by 2.44% improvement of the production ratio.5.Through a comprehensive analysis of the crop growth,yield and economic efficiency,it is more suitable to use WRA in semi-humid rain-fed agricultural areas,which may promote the soybean growth,increase the yield and economic efficiency.The application of WRA has a positive effect on the growth and yield of maize.In semi-arid irrigated agricultural areas WRA is suitable for being used in combination with shallow drip irrigation,which may improve the maize production and economic efficiency. |
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