稻田淹涝退水对产量及氮磷泥沙排放特征的影响研究OA

[Objective]Flooding and drainage in paddy fields strongly influence rice growth,yield formation,and nutrient losses.However,their mechanistic effects on crop productivity and nutrient leaching remain poorly understood.This paper aims to elucidate these mechanisms.[Method]Experiments were conducted in pots.Sediment contents of 0 kg/m3(S0),0.10 kg/m3(S1)and 0.25 kg/m3(S2),inundation duration with continuous flooding of 3 days(F1)and 6 days(F2),and water recession for 3 days(D1)and 6 days(D2)were applied during the tasseling and yellow ripening stages of early-season rice and the tillering and jointing stages of mid-season rice.The control(CK)was conventional management used by local farmers.In total,there were 13 treatments.In each treatment,we measured changes in sediment content,total nitrogen(TN),ammonium nitrogen(NH4+-N),nitrate nitrogen(NO3--N)and total phosphorus(TP)concentrations in the effluents,as well as rice yield and yield components.[Result]①Flooding resulted in yield reductions ranging from 11.07%to 69.96%;on average,the F1D1 and F1D2 treatments showed the least yield loss for both early-and mid-season rice.②Sediment concentration decreased significantly over time during the drainage process and was reduced by more than 50%six days after the onset of drainage.③TN,NH4⁺-N,NO3--N and TP concentrations increased during both flooding and drainage processes,with early-season rice exhibiting the highest concentrations at the tasseling stage and mid-season rice at the tillering stage.④TN,NH4⁺-N and TP concentrations in the effluent were negatively correlated with early-season rice yield,while their correlations with mid-season rice yield were not statistically significant.[Conclusion]Flooding and drainage critically influence rice yield and nutrient losses in paddy fields.Our experiment showed that flooding for 3 days followed by a 3-6 day drainage minimized yield loss to 18.67%-50.33%for early-season rice and 32.38%-38.35%for mid-season rice,with TN and TP concentrations in the effluent remaining below 25.82 mg/L and 1.41 mg/L,respectively.These strategies can be used in irrigation and drainage system design.