基于DNDC模型与二分法的滨海盐渍土水稻最佳施氮量研究

Optimizing N-Fertilizer Inputs for Rice Production in Coastal Saline Based on a Biogeochemical Model and Dichotomy

[目的]探讨滨海盐渍土水稻田的最佳施氮量,为研究区科学施氮提供一定决策依据。[方法]基于DNDC模型与数学二分法,模拟水稻在加施10%,20%,30%和减施10%,20%,30%等6种施氮条件下产量变化特征,划定最佳施氮量所在区间,并对最佳施肥量下的环境效益进行评价。[结果](1)在减施10%,20%,30%和增施10%,20%,30%氮肥时,水稻产量依次为6 431.67,5 939.22,5 439.66kg/hm2和7 686.51,7 739.94,7 739.94kg/hm2;(2)最佳施氮区间在增施10%~20%,即施氮区间为519.0~566.18kg/hm2。经二分法测算,该地最佳施氮量为528.214kg/hm2;(3)采用该最佳施氮量时,水稻种植期间总氮氧化合物排放量为9.24kg/hm2,具有良好环境效益。[结论]水稻全生长期内施用528.214kg/hm2的氮肥,滨海盐渍土水稻田产量达到最大值,兼具良好环境效益。

[Objective]Determing the optimal amount of N-fertilizer inputs for rice production is significant to improve the agricultural management in the coastal saline reclamation area,Eastern China.[Methods]Combining denitrification decomposition model（DNDC）and dichotomy method,this study simulated rice yield dynamics during the whole life cycle under six fertilization situations（10%,20%,30%,-10%,-20% and-30% of additional N-fertilizer inputs）.And the optimal interval of N-fertilizer inputs and corresponding ecological impacts were explored.[Results]（1） The rice yield in the study area was 6 431.67,5 939.22,5 439.66,7 686.51,7 739.94 and 7 739.94 kg/hm^2 10%,20%,30%,-10%,-20% and-30% N-fertilizer inputs,respectively.（2） The optimal interval of fertilization was from 10% to 20% of additional fertilizer inputs,namely,519.0~566.18 kg/hm^2 of N-fertilizer inputs.And the optimal N-fertilizer inputs was 528.214 kg/hm^2,according to dichotomy analysis.（3） Based on the optimal amount of N-fertilizer inputs,the nitrogen oxide emission was 9.24 kg/hm^2 during full rice growth period,which showed a good environmental benefit.[Conclusion]The optimal amount of N-fertilizer inputs during rice production in thestudy area is 528.214 kg/hm^2.This optimal N-fertilizer inputs,can improve the rice yields of saline soil to the top level and produce a better environmental benefit.