紫外分光光度法在杂交棉氮素营养诊断中的应用研究

Application of UV-Spectrophotometry in the Nutrition Diagnosis of Nitrogen in Hybrid Cotton

在滴灌条件下,应用紫外分光光度法测定了杂交棉不同生育期叶柄硝酸盐含量,对杂交棉氮素营养诊断及氮肥推荐进行了田间试验。结果表明:杂交棉在现蕾期、初花期、盛铃期和铃期的倒4叶叶柄硝酸盐含量与施氮量之间呈极显著线性相关,各生育期叶柄硝酸盐含量与产量之间也具有极显著相关性,由此确定了杂交棉现蕾期、初花期、盛铃期和铃期的硝酸盐临界值,分别为18596.3、2625.7、3431.3和2462.8 mg L-1;用一元二次模型模拟氮肥与产量之间的关系,得到在滴灌条件下,最佳产量为6413.7 kg hm-2,对应的最佳施氮量为348.1 kg hm-2;根据杂交棉各生育期叶柄硝酸盐浓度与施氮量和产量之间的关系,建立了各生育期氮肥推荐模型。

Under drip irrigation,field experiments were conducted to test the nitrogen diagnosis of hybrid cotton and nitrogen fertilizer recommendation.UV-Spectrophotometry was applied to measure NO3-concentration of the fourth expanding petiole at different growth stages of hybrid cotton.The results showed that there were distinctly significant linear correlation between the nitrate concentrations in the fourth expanding petiole of hybrid cotton and the application amounts of N fertilizer at the budding stage,early blooming stage,peak bolling stage and bolling stage.Also,distinctly significant correlation between the nitrate concentrations and the cotton yield was observed.The critical values of nitrate concentrations were respectively 18596.3,2625.7,3431.3 and 2462.8 mg L-1 at the budding stage,early blooming stage,peak bolling stage and bolling stage of hybrid cotton.Under the drip irrigation,the optimal yield was 6413.7 kg hm^-2,and the corresponding optimal rate of N fertilizer was 348.1 kg hm^-2.According to the relationship between the nitrate concentrations in the leaf petiole at different stages and the application rates of N fertilizer and cotton yield,the N recommending models at different growth stages were developed.