施氮方式对木薯养分利用和土壤有效养分变化的影响

Effects of Nitrogen Application Methods on Cassava Nutrient Utilization and Soil Available Nutrient Content Change

为提高施肥效率,在田间条件下,以不施氮肥为对照,研究氮(纯N)量130 kg/hm2全部基施(T1)、50%基施+50%苗期追施(T2)及25%基施+50%苗期追施+25%块根膨大期追施(T3)3种方式对木薯品种新选056干物质积累、养分利用及土壤有效养分含量的影响。结果表明:施氮显著提高木薯块根、茎及叶的干物质积累量,且均以T3处理最高,其次是T2处理;施氮可以提高木薯块根、茎及叶的氮、磷、钾含量及其积累量,其中以T3处理的氮、磷、钾积累总量最高,其次是T2处理;木薯收获时,T3处理的氮肥农学利用率、氮肥生理利用率及氮肥吸收利用率显著大于T1、T2处理;木薯收获后,种植地各土层碱解氮、有效磷及速效钾含量变化因施氮方式而异,其中T3处理各有效养分含量变化均小于T1、T2处理。可见,本研究条件下氮肥25%基施+50%苗期追施+25%块根膨大期追施是木薯生产较理想的施用方式。

In order to improve fertilizing efficiency,a field experiment of nitrogen fertilizer was conducted by using cassava variety Xinxuan 056 as tested material. The 130 kg/ha nitrogen fertilizer （ NF） was designed as three treatments,including 100% for basal fertilizer（T1） ,50% for basal fertilizer and 50% for topdressing at seedling stage （T2） ,and 25% for basal fertilizer ,50% for topdressing at seedling stage and 25% for topdressing at root-tube expanding stage（T3 ） ,and no nitrogen fertilizer as the control（ CK） . The dry matter accumulation, nutrient utilization and soil available nutrient contents were measured for different treatments in leaf, stem and root-tube of cassava. The results showed that the application of nitrogen significantly increased the dry matter accumulation in root-tube, stem and leaf of cassava, and T3 treatments presented the highest value, followed by T2 treatment. The application of nitrogen also increased the contents and accumulations of N , P and K in root-tube, stem and leaf of cassava, and T3 treatment presented the highest value,followed by T2 treatment. At harvesting stage, the agronomic use efficiency, physiological use efficiency, and absorption and utilization efficiency of nitrogen fertilizer of T 3 treatment was significantly higher than that of T 1 and T2 treatments. After harvest of cassava, the contents change of alkali-hydrolyzed nitrogen, available phosphor and available potassium contents in soil layer were differed among nitrogen application method. Of which,the available nutrient contents variation of T 3 treatment were less than that of T1 and T2 treatments. Therefore, the optimum application method of nitrogen fertilizer for cassava was 25% for basal fertilizer ,50% for topdressing at seedling stage and 25% topdressing at root expanding stage.