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通过3年(2011—2013年)的双季稻田间小区试验,探明了不同施磷量对双季稻产量、土壤磷素积累、磷素流失风险的影响,并确定了土壤收支平衡的施磷阈值。研究结果表明:连续3年不同施磷量处理水稻早、晚季产量为5474~5552 kg·hm~(-2)和7096~7521 kg·hm~(-2),过量施用磷肥对水稻产量无显著增产效果,反而有减产的风险。施用磷肥后,土壤Olsen-P含量显著提高。田面水TP平均浓度与土壤中Olsen-P呈显著正相关关系;施磷后田面水磷素动态能用指数模型(Y=C_0·e~(k/t),k>0)拟合,即随着磷肥施用量增加,田面水磷素流失风险增加。结合水稻产量效应、土壤磷素表观平衡和磷素环境风险,推荐研究区域早、晚稻施磷阈值分别为(48.53±7.07)kg P_2O_5·hm~(-2)和(56.87±7.90)kg P_2O_5·hm~(-2)。
Through three-year (2011-2013) double cropping rice plot experiment, the effects of different P application rates on the yield of double cropping rice, soil phosphorus accumulation and the risk of phosphorus loss were ascertained and the balance of soil budget was determined Phosphorus threshold. The results showed that the early and late season rice yield was 5474 ~ 5552 kg · hm -2 and 7096 ~ 7521 kg · hm -2, respectively, with different P application rates for three consecutive years. Significant increase in yield, but the risk of yield reduction. After applying phosphate fertilizer, the soil Olsen-P content increased significantly. The average concentration of TP in surface water was positively correlated with Olsen-P in the soil. The phosphorus content of surface water after phosphorus application could be fitted by exponential model (Y = C_0 · e ~ (k / t), k> 0) With the increase of phosphate application, the risk of phosphorus loss in field water increases. Combined with the yield effects of rice, the apparent balance of soil phosphorus and the risk of phosphorus environment, the thresholds of phosphorus application in the early and late rice were suggested as (48.53 ± 7.07) kg P 2 O 5 · hm -2 and (56.87 ± 7.90) kg P 2 O 5 respectively · Hm ~ (-2).