Experimental Study On Efficient Utilization System Of Water And Fertilizer Integration Of Rice In South China

At present,the integrated technology of water and fertilizer is mainly applied to cash crops in China,but the integrated technology of water and fertilizer is seldom applied in rice planting areas in the south.In recent years,with the development of high-efficiency water-saving irrigation technology,pipeline irrigation technology has been widely applied in rice planting areas,which provides basic conditions for the application of rice water and fertilizer integration technology The lack of integrated technology of rice water and fertilizer becomes an urgent problem to be solved.Pot experiments were conducted to study the efFects of Different Topdressing periods,types of nitrogen fertilizers,amount of nitrogen fertilizers,times of Topdressing and amount of straw returning on rice morphological index,physiological characteristics and yield.The integrated system of rice water and fertilizer was put forward.The results are as follows(1)The effects of Different Topdressing stages and times of Topdressing on morphological and physiological indexes of rice were studied.The results showed that topdressing at tillering stage and heading stage was suitable for two times of topdressing.Topdressing at tillering stage was beneficial to improving the external morphology of nee plants,and topdressing at heading stage could promote dry matter accumulation,thus obtaining higher yield.The water production efficiency of two topdressing treatments was 19.0%and 26.5%higher than that of three topdressing treatments ana four topdressing treatments,respectively.Nitrogen uptake efficiency of two topdressing treatments was the highest(45.63%).Nitrogen uptake efficiency of four topdressing treatments was increased by 4.4%(2)The physiological indices and yield of rice under different kinds of nitrogen fertilizer were compared.The results showed that ammonium sulfate could be used as a nitrogen fertilizer variety for integrated selection of water and fertilizer in rice.Ammonium sulfate treatment can significantly promote rice tillering,obtain higher plant height and leaf area,and improve the external morphology of rice.When anunonium sulfate was used,rice yield and water production efficiency increased by 7%and 4.5%respectively compared with conventional treatment Anunoiium sulfate treatment had the highest agronomic utilization rate of nitrogen fertilizer,reaching 18.79 kg/kg.Nitrogen absorption and utilization rate was 9.9%higher than that of conventional treatment,and partial productivity of nitrogen fertilizer was 20.9%and 15.l%higher than that of ammonium chloride and conventional treatment,respectively.(3)The effects of different amount of straw returning were compared,and the results showed that half amount of straw returning was the best.Half straw returning could promote rice tillering,increase leaf area index and photosynthesis at heading and filling stage,and promote dry matter accumulation.The yield of rice was the highest when half straw was returned to the field,which was 6.2%higher than that without straw,and the nitrogen absorption and utilization efficiency was 10.5%higher than that without straw.The water production efficiency of half straw returned to the field was 2.88 kg/m3,4.0%higher than that without straw returned to the field,and 28%higher than that of the whole straw returned to the field.(4)The amount of nitrogen fertilizer under straw returning and no straw returning was studied.The results showed that it was more suitable to convert the amount of nitrogen fertilizer into 15 kg/mu of pure nitrogen without straw returning.When straw returning was carried out,the amount of nitrogen fertilizer could be increased to 18 kg/mu of pure nitrogen.When the amount of nitrogen fertilizer was 18 kg/mu,the yield was the highest,21.4%,7%and 50%higher than that of 12 kg/mu,15 kg/mu and blank treatment respectively,andthe water production efficiency was 18.5%,6.5%and 24.3%higher than that of 12 kg/mu,15 kg/mu and blank treatment respectively.