等氮条件下双氰胺添加量对江西红壤芝麻产量和硝态氮的影响

Effects of Different Dicyandiamide Rates on Sesame Yield and Nitrate Nitrogen under the Equivalent Nitrogen Condition in Red Soil,Jiangxi Province

双氰胺与氮肥配施可以显著提高氮肥利用率,但是不同土壤上双氰胺的适宜施用量存在较大差异。为探讨旱作红壤适宜的双氰胺用量对芝麻的产量和土壤硝态氮含量变化影响,研究设置了等氮（90 kg N·hm-2）条件下7个双氰胺用量,即0%、3%、5%、7%、10%、15%和20%。试验结果表明：与不施双氰胺相比,双氰胺配施比例为5%的芝麻产量、收获指数和净利润分别增加了126%、29.0%、183%,而当双氰胺的添加量超过5%时,芝麻产量、收获指数和净利润呈现出随比例增加而逐渐降低的趋势。在阻控土壤硝化方面,芝麻成熟期各处理的土壤硝态氮含量表现出随双氰胺添加量的增加而逐渐降低的趋势。与对照相比,各处理的土壤硝态氮降低了11.6%~22.3%。因此,90 kg N·hm-2氮肥施用条件下,5%的双氰胺添加量是较适宜的用量,能够显著提高芝麻产量和经济效益,并可降低红壤旱地中土壤硝态氮累积。表3,图3,参20。

Dicyandiamide and nitrogen combination can improve nitrogen use efficiency,but the optimal rate of dicyandiamide varies in different soils. The objective of this study was to explore the effect of optimal rate of dicyandiamide on sesame yield and nitrate nitrogen under the equivalent nitrogen condition in red soil. Seven dicyandiamide rates were implemented with 0%,3%,5%,7%,10%,15% and 20% in field,respectively. The result showed that dicyandiamide with nitrogen fertilizer could improve sesame yield,harvest index and economic benefits. The 5% dicyandiamide rate treatment was the best in all treatments. Compared with control treatment,5% dicyandiamide rate increased sesame yield,harvest index and economic benefits by 126%,29. 0% and 183%,respectively; sesame yield,harvest index and economic benefits decreased with the increase in dicyandiamide rate. However,soil nitrate nitrogen content decreased with the increase in dicyandiamide rate,and the nitrate nitrogen content in all dicyandiamide application treatments decreased by 11. 6% ~ 22. 3% compared to control treatment. Therefore,5% dicyandiamide was the optimal rate for sesame under 90 kg N·hm- 2application,which not only significantly increased the sesame yield and economic benefits,but also decreased soil nitrate nitrogen accumulation in red soil.