不同施氮量对蓖麻产量和生物及营养性状的影响

为确定绿洲灌溉区蓖麻栽培的最佳施氮量，采用田间试验方法，对不同施氮量下蓖麻产量和生物、营养性状的变化规律进行了研究。结果表明：(1) 通过数据拟合得出：蓖麻种植的最佳施氮量为195 kg·hm^-2，预计最高产量为8×10³ kg·hm^-2；(2) 蓖麻株高、茎粗和穗数等生物性状总体上随施氮量提高逐渐增大，而主穗长、主穗种仁数、百粒重及产量均随施氮量增加呈现出抛物线变化趋势，其中产量峰值出现在施氮量200 kg·hm^-2时，其余指标均在施氮量150 kg·hm^-2时达到最高值；(3) 在花果期，增加氮肥施用量能够促进蓖麻对氮素和钾素的积累，磷素积累量随施氮量增加呈抛物线上升的趋势，峰值出现在施氮量150 kg·hm^-2时；(4) 施氮量与叶片氮素、磷素含量表现出明显的相关性。蓖麻在灌浆期对钾素的需求很高，叶片钾素大量转移到穗部。

Effects of nitrogen levels on yield and biological and nutritional characters of castor

A field experiment was conducted to investigate the effects of nitrogen(N) application on yield, biological and nutritional properties of castor in irrigated oasis area, with six N levels, including 0 kg·hm^-2 (N0), 50 kg·hm^-2 (N50), 100 kg·hm^-2 (N100), 150 kg·hm^-2 (N150), 200 kg·hm^-2 (N200) and 250 kg·hm^-2 (N250). The results showed that, (1) the best N application was 195 kg·hm^-2, and it could produce the highest castor yield (8×10³ kg·hm^-2). (2) N application could promote biologi cal character of castor e.g. plant height, stem diameter, number of ears. Main ear length, number of seeds, hundred-grain weight and yield of castor showed increase under appropriate N application (150 kg·hm^-2 or 200 kg·hm^-2). (3) At flowering stage, the accumulation of N and potassium(K) of castor plant increased with N application, with the rate of 150 kg·hm^-2 having the largest effect on phosphorus(P). (4) There existed a positive relation between the rate of N application and the contents of leaf N and P. In addition, at filling stage, K in leaf was transferred to panicle, it suggested castor need abundant K at this stage.