几种氮素诊断仪在棉花上的比较研究

Comparative Research on Nitrogen Diagnosis of Cotton Leaves by Several Nitrogen Diagnosis Meter

选择3组不同叶色的棉叶为研究对象,以叶绿素仪、植物氮平衡指数测量仪、植物氮测量仪为工具,将3种仪器测量的各项指标与使用微量凯氏定氮法测定的棉叶氮含量进行回归分析。结果表明,使用叶绿素仪进行氮素诊断时在棉叶叶色正常条件下的可靠性要高于衰老叶。氮平衡指数仪所测定的叶绿素含量值比叶绿素仪测定的SPAD值低,2组测量值之间线性回归达到极显著水平(P<0.001),二者具有同样的测量效果,在棉花盛花期的临界值分别为39.8、29.7。氮平衡指数与实测氮含量之间线性回归也达到极显著水平(P<0.001),指数值越小,表示叶片衰老程度越高,在棉花盛花期的临界值为23.9。使用植物氮测量仪进行棉叶氮含量估测时,可以优先选择小麦参比程序,在棉花盛花期的临界值为3.3。低于以上临界值时可考虑追施氮肥。

In this paper,three nitrogen diagnosis meters,including SPAD-502 chlorophyll meter,nitrogen balance index measuring device and nitrogen content measuring device,were used to measure 3 groups of cotton leaves with different colors,and their different measuring results by 3 measuring devices and the nitrogen contents by the trace Kiadhal method were studied with regression analysis method,respectively.The result showed that when performing nitrogen diagnosis by SPAD-502 chlorophyll meter,the reliability of the test results on the leaves with normal color were better than that with aging leaves.Chlorophyll content values by nitrogen balance index measuring device were less than SPAD values by SPAD-502 chlorophyll meter,and there were significant linear regression between 2 groups of measuring values（P ＜0.001）,therefore,the measuring effects of 2 measuring devices were the same,and the critical values at full-bloom stage of cotton were 39.8and 29.7,respectively.When performing nitrogen diagnosis by nitrogen balance index measuring device,there was significant linear regression between nitrogen balance index and the nitrogen contents by the trace Kiadhal method（P ＜ 0.001）,less nitrogen balance index values indicated that the degree of leaves senescence was more serious,and the critical value at full-bloom stage of cotton was 23.9.When performing nitrogen diagnosis by nitrogen content measuring device,wheat reference program could be first selected,and its critical value at fullbloom stage of cotton was 3.3.When the actual measured values were less than the critical values above-mentioned,nitrogen fertilizer application could be taken into account.