氮素基、蘖肥用量对水稻氮素吸收与利用的影响

Effects of the Amount of Basic and Tillering Nitrogen Applied on Absorption and Utilization of Nitrogen in Rice

以粳稻品种武香粳 9号和籼稻品种H97 32 2为材料 ,在基础地力和穗肥施氮相同的条件下 ,研究了氮素基、蘖肥不同施用水平对水稻氮素吸收利用的影响。结果表明 :(1)各处理水稻相对吸氮速率随生育进程而降低 ,其降低速度随氮素基、蘖肥占总施氮量比重增大而加快。增施氮素基、蘖肥 ,增加了拔节前吸氮量 ,但抑制了拔节后吸氮 ,尤其是显著增加了有效分蘖临界叶龄期至拔节期阶段吸氮量 ,显著降低了抽穗期至成熟期阶段吸氮量 ;增施氮素基、蘖肥 ,虽然有利于拔节前氮素基、蘖肥利用率的提高 ,但不利于整个生育期的氮素基、蘖肥利用率和总氮肥利用率的提高。 (2 )氮素基、蘖肥用量适宜 ,相对吸氮速率平稳减小 ,各生育阶段吸氮比例协调 ,氮素利用率和产谷效率协同提高是高产的重要条件。研究还表明目前一般的氮素基、蘖肥用量存在偏高现象。

Two cultivars of Wuxiangjing 9 ( japonica ) and H97-322 ( indica ) were used to study the effects of different level of nitrogen applied as basic and tillering dressing (BT) on the absorption and utilization of nitrogen in rice in the condition of same soil fertility and same nitrogen application at panicle initiation stage. The relative rates of absorbing nitrogen (RRA) in all treatments decreased with the development of rice during the whole lifetime,the greater the ratio of BT to total nitrogen applied,the faster their declining speed became. When the amount of BT was improved,the more nitrogen was absorbed before elongation,and the absorbing nitrogen was inhibited after shooting,especially the uptake of nitrogen was increased from the critical stage of productive tillering to the elongation stage and decreased from the heading stage to the mature stage both significantly. With the increase of BT,BT use efficiency before shooting period was improved,but BT use efficiency and nitrogen use efficiency in the whole growing period of rice were not. It was important for high yield that the amount of BT was at an optimal level,RRA decreased stably and reasonably,the uptake of nitrogen in each development stage met the requirement of population growth and development,nitrogen use efficiency and productivity of grains were coordinative improved. According to the results,the amount of BT applied in the rice production currently was more than necessary.