磷钾调控对冷浸田水稻产量和养分吸收的影响

【目的】冷浸田是典型低产稻田，其施肥结构和模式与普通稻田应存在差异。本研究拟在普通稻田施肥结构的基础上，通过调整肥料结构，探索冷浸田最佳施肥模式，为提高冷浸田水稻产量提供数据支撑和理论依据。【方法】通过连续3年的定位试验，以水稻产量为目标，通过测定产量构成因素、水稻养分吸收和土壤养分变化，分析冷浸田施肥模式，提出冷浸田最佳施肥用量。【结果】土壤速效磷含量介于2.7~7.3 mg/kg之间，速效钾含量介于20~80 mg/kg，明显低于普通稻田（平均速效磷11.5 mg/kg，平均速效钾95.8 mg/kg），是冷浸田主要养分障碍因子；施肥可以极大提高水稻产量，其中NPK、NP2K、NPK1、NPK+Zn和NPK2处理的产量比不施肥（CK）或习惯（FP）高20%~30%左右。在氮磷钾基础上增施锌肥、硅肥和钾肥增产达到显著水平，降低磷肥和钾肥用量则有降低产量的趋势。连续三年种植水稻土壤碱解氮、速效钾呈现平稳，速效磷有增加趋势。施肥处理水稻籽粒和茎部钾含量明显高于CK，籽粒氮累积量显著高于CK和习惯施肥处理。相对于NPK、CK、FP处理，增施磷、钾肥，添加微肥可显著提高籽粒氮、磷、钾累积量。【结论】鄂东南低丘区冷浸田速效磷、速效钾含量低，是主要营养限制因子，需要长期加大磷、钾肥施用量；该地区冷浸田适宜施肥量为N 180、P2O5 90~108、K2O 120~144 kg/hm2，同时配施锌肥和硅肥，连年施用可保证冷浸田水稻的稳步增产。

Effects of regulating phosphorus and potassium supply on rice yield and nutrient absorption

【Objectives】Cold waterlogged paddy field is typical low-production soil, fertilization pattern should be different from general paddy field. A suitable fertilization pattern in the cold waterlogged paddy was studied through adjusting the fertilization pattern on the basis of general paddy field. 【Methods】 A three-years field experiment was conducted in cold waterlogged field in the southeastern Hubei Province. According to the rice yield, yield components and the change of soil nutrients, different fertilization patterns were assessed and the optimum rates of fertilization were proposed.【Results】 The soil available phosphorus contents in the tested paddy fields ranged from 2.7 to 7.3 mg/kg, quickly available potassium from 20 to 80 mg/kg, both were obviously lower than those of the general paddy fields (the average available phosphorus and potassium were 11.5 and 95.8 mg/kg, respectively), and were major nutrient limiting factors in rice production. Fertilization can increase the rice yield obviously, the grain yields of NPK, NP2K, NPK1, NPK+Zn and NPK2 treatments are about 20%-30% higher than those of the CK and farmars' practice treatment (FP). On the basis of NPK, adding silicon, zinc and potassium dosages could increase the grain yield significantly (P0.05), reducing phosphorus and potassium rates has little impact on the yield. The soil available nitrogen and available potassium contents are stable after planting rice for three years, the soil available phosphorus is increased. The contents of potassium in grains and straws in all of fertilization treatments are significantly higher than that of CK, and nitrogen accumulation in grains of all fertilization treatments in significantly higher than that in CK and FP treatments.【Conclusions】 Phosphorus and potassium are the major nutrient limiting factors in rice production in the southeastern Hubei Province, so the phophorus and potassium application rates should be increased. The suitable fertilizer rate in the southeast of Hubei province is N 180,P2O5 90-108,K2O 120 kg/ha. Zinc and silicon fertilizer should be considered at the same time.