Nutrient Uptake and Use Efficiency of Irrigated Rice in Response to Potassium Application

HU Hong; WANG Guang-Huo

摘要

Potassium is one of the most important nutrients for rice production in many areas of Asia, especially in southeast China where potassium deficiency in soil is a widespread problem. Field experiments were conducted for four consecutive years in Jinhua City, Zhejiang Province, to determine utilization of nutrients (N, P and K) by inbred and hybrid rice and rice grain yields as affected by application of potassium fertilizer under irrigated conditions. Grain yield and nutrient harvest index showed a significant response to the NPK treatment as compared to the NP treatment. This suggested that potassium improved transfer of nitrogen and phosphorus from stems and leaves to panicles in rice plants. N and P use efficiencies of rice were not strongly responsive to potassium, but K use efficiency decreased significantly despite the fact that the amount of total K uptake increased. A significant difference between varieties was also observed with respect to nutrient uptake and use efficiency. Hybrid rice exhibited physiological advantage in N and P uptake and use efficiency over inbred rice. Analysis of annual dynamic change of exchangeable K and non-exchangeable K in the test soil indicated that non-exchangeable K was an important K source for rice. Potassium application caused an annual decrease in the concentration of available K in the soil tested, whereas an increase was observed in non-exchangeable K. It could be concluded that K fertilizer application at the rate of 100 kg ha-1 per season was not high enough to match K output, and efficient K management for rice must be based on the K input/output balance.

机译：钾是亚洲许多地区，尤其是中国东南部的水稻生产中最重要的养分之一，在中国东南部，土壤钾缺乏是一个普遍的问题。在浙江省金华市进行了连续四年的田间试验，以确定自交和杂交水稻的养分利用率（N，P和K）以及灌溉条件下施用钾肥对水稻籽粒产量的影响。与NP处理相比，NPK处理对谷物的产量和养分收获指数显示出显着的响应。这表明钾改善了水稻植株茎叶中氮和磷向穗的转移。水稻对氮和磷的利用效率对钾的响应不是很强，但尽管钾的吸收总量增加，但钾的利用效率却显着下降。在养分吸收和利用效率方面，还发现品种之间存在显着差异。与自交稻相比，杂交稻在氮和磷的吸收和利用效率方面具有生理优势。分析土壤中可交换钾和不可交换钾的年动态变化表明，不可交换钾是水稻重要的钾源。钾肥的施用使被测土壤中有效钾的含量逐年减少，而不可交换的钾肥则有所增加。可以得出结论，每季施用100 kg ha-1钾肥的比例不高足以匹配钾肥的产量，必须根据钾肥的投入/产出平衡来有效管理水稻。

Nutrient Uptake and Use Efficiency of Irrigated Rice in Response to Potassium Application

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