Mohanty Sangita, Patra Ashok K, Chhonkar Pramod K
Division of Soil Science and Agricultural Chemistry, Indian Agricultural Research Institute, New Delhi 110 012, India.
Bioresour Technol. 2008 Mar;99(4):894-9. doi: 10.1016/j.biortech.2007.01.006. Epub 2007 Mar 13.
A laboratory experiment was conducted to examine the potentiality of a natural resource neem (Azadirachta indica) seed kernel powder (NSKP) to reduce the urease and nitrification activities in different soils (viz., normal, acid, and sodic) at contrasting moisture (1:1 soil to water and field capacity) and temperature regimes (10 degrees C and 37 degrees C). Results have revealed that application of NSKP with urea did not exhibit any urease inhibitory property in normal and sodic soils, but in acid soil it had maintained higher concentration of urea than the urea alone treated samples for two weeks after application. At 37 degrees C and under field capacity moisture level, urea hydrolysis was more rapid than at 10 degrees C and under waterlogged (1:1) conditions. The NSKP has showed variable effects (4-28%) to inhibit nitrification during 7-21 days after application, depending upon the soil types, temperature and moisture regimes. The nitrification activity was significantly low in acid soil followed by normal and sodic soils. The present study suggests that NSKP has the potential to retard the urease activity in acid soil, and nitrification in all the soils, and thus it may be used along with urea for the better use of applied -N.
进行了一项实验室实验，以研究天然资源印楝（Azadirachta indica）种仁粉（NSKP）在不同土壤（即正常土壤、酸性土壤和盐碱土壤）中，在不同水分（土壤与水比例为1:1和田间持水量）和温度条件（10摄氏度和37摄氏度）下降低脲酶和硝化作用活性的潜力。结果表明，在正常土壤和盐碱土壤中，NSKP与尿素一起施用未表现出任何脲酶抑制特性，但在酸性土壤中，施用后两周内，其尿素浓度一直高于单独施用尿素的样品。在37摄氏度和田间持水量水分水平下，尿素水解比在10摄氏度和渍水（1:1）条件下更快。施用后7至21天，NSKP对硝化作用的抑制效果因土壤类型、温度和水分条件而异（4%-28%）。酸性土壤中的硝化作用活性显著低于正常土壤和盐碱土壤。本研究表明，NSKP有潜力抑制酸性土壤中的脲酶活性以及所有土壤中的硝化作用，因此它可与尿素一起使用，以更好地利用施用的氮。
