| In order to improve the regulation and utilization of rainwater in rice fields and reduce the loss of rainwater and nutrients such as nitrogen and phosphorus,this paper uses Ningjing 7 widely cultivated in Jiangsu Province as the tested variety,based on the previous pot experiment simulation,in the rice tillering stage.In the jointing stage and milking stage,the flood tolerance test of rice in different flooding depths was carried out to study the growth traits and yield formation of rice under flooding conditions,and the flooding depth and flooding duration of rice were put forward,and the rainwater regulation of field engineering was analyzed.The control effect of storage and nitrogen and phosphorus loss from rice field runoff is of great significance for rice water saving and emission reduction.The main results are as follows:(1)Influenced by flooding,the differences in plant height,tiller number and SPAD value between rice tillering stage and jointing stage were more obvious,especially in the case of ineffective tillering increased by more than 7%,the number of green leaves decreased,and the plant height increased compared with the control group.Flooding 3d increased by up to 8.8%.Compared with shallow storage,rice has higher tiller number,plant height and SPAD value.The effect of rice milk maturity on plant height and tiller number was small,and the deep storage was more affected than the shallow storage,and there were obvious differences in the number of green leaves.(2)Flooding in the tillering and jointing stages of rice has a great influence on the formation of yield.Compared with the control group,the empty shell rate is increased by more than 70%,the thousand-grain weight is reduced by 5%to 7%,the total number of grains is increased,and the yield per mu is reduced.1%.The effect of flooding on the maturity of rice was reduced by thousand-grain weight,and the yield per mu was slightly decreased,which had little effect on the ear and ear weight of rice.Deep storage treatment has a greater impact on rice yield than shallow storage.The tillering stage and jointing stage are the main vegetative growth stages of rice.It is sensitive to the morphological characteristics and yield of rice flooding.The milk ripening stage is the stage of nutrient proliferation,so it has little effect on morphological characteristics and slightly decreases in yield.Within 20%.(3)The content of N and P in the water layer of rice in the tillering,jointing and milking stages also showed different trends.In the tillering stage and the jointing stage,the overall flooding depth of the 3d flooding period is consistent with the change of N and P elements in the paddy field,but compared with the shallow storage treatment,the deep storage treatment TP emission is reduced by 17.6%or more,and the TN emission is reduced.Reduced by 16.8%or more.This is mainly due to the deep treatment of deep water layer,which has a strong inhibitory effect on rain splashing,which can reduce the nutrient elements in the soil to enter the field water layer,thereby reducing the entry of nutrient elements into surface runoff and reducing the pressure of non-point source pollution in farmland.It can also achieve the effect of rainwater utilization to reduce irrigation water and achieve the practical effect of water saving and emission reduction.(4)When the height of ridge is increased to 150mm,200mm,250mm,300mm,350mm,shallow wet irrigation is compared with traditional irrigation when it is once in ten years,once in fifteen years,and once in a single day.The mode rainwater utilization rate is increased by 10.98%?31.14%,which not only saves irrigation water resources,but also reduces the discharge of farmland runoff.The interception effect of nutrients such as nitrogen and phosphorus is also significant. |
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