反射仪-硝酸根试纸法现场速测蔬菜硝酸盐水平及其应用

通过结球甘蓝、白菜和黄瓜的田间试验,研究了用反射仪-硝酸根试纸法田间现场速测黄瓜、白菜和结球甘蓝叶柄汁液硝酸根含量与土壤硝酸根含量、施氮量、蔬菜食部硝酸盐含量和产量的关系。结果表明,结球甘蓝心叶外第3展开叶叶柄中段、白菜心叶外第2展开叶叶柄中段、黄瓜心叶下第3叶叶柄中段、叶柄汁液硝酸盐浓度与施氮量和产量都有极显著和显著相关性,灵敏地反映了蔬菜及其土壤的硝酸盐水平。用于3种蔬菜氮素营养诊断推荐追肥,氮肥用量比常规高产施氮量减少40.7%￣66.4%,从而最大限度地控制过量化肥对蔬菜和环境的污染。结球甘蓝播种后40d心叶外第1、2和3展开叶叶柄汁液硝酸盐浓度与土壤硝酸根含量极显著和显著线性相关。反射仪-硝酸根试纸法现场测定外叶叶柄汁液硝酸盐含量与按GB/T15401-94的方法实验室测定可食部分硝酸根含量极显著线性相关。反射仪-硝酸根试纸法快捷简便,是蔬菜氮素营养诊断和蔬菜硝酸盐含量监测的理想的现场速测技术。

Nitrate Test-strip-reflectometer for Rapid Testing Nitrate Level in Cucumber, Chinese Cabbage and Cabbage in Field Scene

The nitrate levels in cabbage, Chinese cabbage and cucumber were determined by nitrate test-strip-reflectometer in the field experiments with the nitrogen application rates, the relationships among the nitrate content in leaf handle juices of tested vegetable, and that in the soil, yield and nitrogen application rates were analyzed. The results showed that the nitrate content in the leaf handle middle sect of the third spread leaf of cabbage, the outer second spread leaf from center leaf of Chinese cabbage and the third leaf under center leaf of cucumber were significantly correlated to the yield and the applied N rate, and reflected delicately the nitrate level of the tested vegetables. When these results were used in the nitrogenous nutrition diagnostic and fertilizer recommendation for three vegetables, the applied N rate recommended were lower 40.7%~66.4% than conventional high-yield, and the nitrate content of vegetables and environment pollution from nitrogen fertilizers were controlled remarkably. The nitrate content in the leaf handle middle sect of first, second and third spread leaf outer center leaf of cabbage were significantly correlated to that in the soil. The nitrate content of Chinese cabbages in outer leaves juice determined by the nitrate test-strip-reflectometer in field scene and in edible part determined by colorimetric analysis in laboratory showed a significantly linear correlation. So the nitrate test-strip-reflectometer method could rapidly monitor the nitrate level of vegetables and soils in the field and market scene.