适当化肥配施有机肥减少稻田氮磷损失及提高产量

Formulated fertilization for reducing nitrogen and phosphorus losses from paddy fields and increasing rice yield

为了减少稻田氮磷损失量,并有效利用畜禽固废物,该研究在广东省东江上游典型农业集水区,开展田间不同施肥方式(不施肥、常规施肥、配方施肥1～3)氮磷损失监测及不施肥处理的室内土柱模拟试验。不施肥、常规施肥、配方施肥1～3的肥料施用量分别为:碳铵0、750.0、510.0、472.5、510.0kg/hm2;磷肥0、375.0、255.0、255.0、236.25kg/hm2;尿素0、225.0、172.5、156.0、172.5kg/hm2;有机肥:0、0、1162.5、1162.5、1162.5kg/hm2。通过室内土柱试验,获取不施肥小区氮磷地表径流及淋溶流失量,并结合不施肥小区的田间监测数据(土样、水样、植株样等),测算出水稻生长季固氮量为31.54kg/hm2。采用元素守恒的方法,综合考虑氮磷淋溶、流失、氨氮挥发、氮素干湿沉降以及水稻固氮等多方面的影响,构建稻田系统氮、磷损失模型,分别计算出5种不同施肥方式的氮磷损失量。研究表明,配方施肥1、2、3较常规施肥,氮、磷损失量减幅分别为7.7%～30.0%、61.2%～70.8%;氮、磷农学利用率增幅分别为24.6%～84.4%、12.8%～78.9%;实现节支增收分别为2716元/hm2、-2169元/hm2、-1646元/hm2。配方施肥方案可有效减少农田氮磷损失量,其中配方施肥1经济效益、环境效益俱佳,可作为常规施肥的替代方案。该研究综合考虑了整个稻田系统中氮、磷的输入与输出,定量评估不同施肥方式的氮磷损失量、农学利用率及其经济环境效益,可为稻田氮磷损失综合防控提供参考。

In order to reduce the losses of nitrogen and phosphorus from paddy fields and to effectively dispose livestock manure, laboratory and field experiments were conducted in the upper Dongjiang river basin, Guangdong Province, China. The field experiments involved five fertilization rations including no fertilizer, conventional urea fertilizer, and three recipe fertilizers. The fertilizers used in these experiments are Ammonium Bicarbonate, Phosphate fertilizer and Organic manure. In respect of Ammonium Bicarbonate, the application rates for these five treatments were 0, 750.0, 510.0, 472.5 and 510.0 kg/hm2; Phosphate fertilizer were 0, 375.0, 255.0, 255.0 and 236.25 kg/hm2; Urea were 0, 225.0, 172.5.0, 156.0 and 172.5 kg/hm2, and 0, 0, 1162.5, 1162.5 and1162.5 kg/hm2 of organic manure were applied for organic manure. Using simulated soil columns indoors, the losses of runoff, nitrogen and phosphorus were obtained for the paddy fields under the condition of no fertilizer. Combined with the laboratory experiment and investigated data from soil samples, water samples, plants, and fertilizer applications in the field, according to the element conservation theory, nitrogen and phosphorus loss models were constructed considering the eluviations, losses and volatilizations of nitrogen and phosphorus as well as their wet and dry sedimentations from the atmosphere. The nitrogen fixation amount in the paddy field was calculated as around 31.54 kg/hm2 during the growth period. The losses of nitrogen and phosphorus were estimated for each of the five treatments, and valuable results were obtained. Compared to the traditional fertilizer application, the three fertilizer rations can decreases in 7.7%-30.0%, 61.2%-70.8% for nitrogen and phosphorus losses, and increases in 24.6%-84.4%, 12.8%-78.9% for their utilization efficiencies. The three fertilizer applications can increase in around 2716 yuan/hm2, -2169 yuan/hm2, and -1646 yuan/hm2, respectively. Among the three fertilizer rations, the first ration one can achieve the high benefit both economically and environmentally, and thus can be considered as a substitute as the conventional urea fertilizer. The study analyzed the input and output of nitrogen, phosphorus in the rice paddy system. Considering the inputs and outputs of nitrogen and phosphorous in the paddy field system, different fertilization rations were evaluated and each fertilization ration were obtained in view of their agronomic efficiency and their ecological and environmental effects. This study would provide rational references using fertilizers in paddy field and control their nitrogen and phosphorus losses in South China.