免耕条件下川香优9838氮磷钾吸收规律与氮肥合理施用研究

在四川稻-油轮作制的免耕条件下，川香优9838不同生育期吸收养分的总量差异较大。氮（N）在整个生育期以拔节期的吸收量为最高；其次是成熟期，第三是分蘖期；对磷的吸收从苗期至成熟期表现为小幅持续升高；对钾的吸收主要集中在拔节期到抽穗期，占了全生育期吸收量的73．4％。在土壤养分管理上，川香优9838的氮肥施用宜早，主要在拔节期前。如果水稻在抽穗后土壤供氮不足，应考虑追施粒肥以保证高产优质。磷肥宜作底肥施用。如遇保肥能力很差的沙质土壤或对磷固定能力很强的强酸性／强碱性的土壤，在磷肥施用上则需要分次施用，保证中后期的磷素供应。钾肥的施用应主要在前中期。如遇土壤质地较轻，也可在抽穗期补施少量K肥。免耕栽培川香优9838产量为11t／hm^2时的最适施氮量为165kg左右。

Study on absorption characteristics of nitrogen ,phosphorus and potassium by rice cultivar Chuanxiangyou 9838 and its proper N application rate

There were considerable differences in amounts of nutrient uptake by the rice cultivar Chuanxiangyou 9838 in different growing periods under no till rape-rice rotation in Sichuan. The rice cultivar absorbed the highest quantity of N in the elongation stage and followed by its maturity and tillering stages. Uptake of P kept a steady increase from seedling stage to its maturity,and the maximal uptake of K occurred during the elongation to earing stages. Based on the nutrient uptake characteristics of the rice cuhivar Chuanxiangyou 9838, good nutrient management practices were therefore developed. Application of N should be conducted in early stages and no latter than its elongation. If the soil N supplying ability was not adequate after elongation,an extra N application should be considered to guarantee high yield and quality of the rice. Basal application of P was considered as a proper practice. When the soil as too sandy with low nutrient holding capacity, or too acidic or alkaline with strong ability to fix up P and lose bicavailability,it was better to split P fertilizer to meet requirement at its later stages. K fertilizers could be applied in early to middle growing stages. If the soil was sandy, it should consider an extra K application after earing stage. It was found that the proper N application rate for the rice cultivar Chuanxiangyou 9838 under no till rape-rice rotation was about 165 kg/hm^2 N with a goal of 11 t of rice yield.