Effect of nitrification inhibitor DMPP on nitrogen leaching, nitrifying organisms, and enzyme activities in a rice-oilseed rape cropping system.
DMPP (3,4-dimethylpyrazole phosphate) has been used to reduce nitrogen (N) loss from leaching or denitrification and to improve N supply in agricultural land. However, its impact on soil nitrifying organisms and enzyme activities involved in N cycling is largely unknown. Therefore, an on-farm experiment, for two years, has been conducted, to elucidate the effects of DMPP on mineral N (NH4(+)-N and NO3(-)-N) leaching, nitrifying organisms, and denitrifying enzymes in a rice-oilseed rape cropping system. Three treatments including urea alone (UA), urea + 1% DMPP (DP), and no fertilizer (CK), have been carried out. The results showed that DP enhanced the mean NH4(+)-N concentrations by 19.1%--24.3%, but reduced the mean NO3(-)-N concentrations by 44.9%--56.6% in the leachate, under a two-year rice-rape rotation, compared to the UA treatment. The population of ammonia oxidizing bacteria, the activity of nitrate reductase, and nitrite reductase in the DP treatment decreased about 24.5%--30.9%, 14.9%--43.5%, and 14.7%--31.6%, respectively, as compared to the UA treatment. However, nitrite oxidizing bacteria and hydroxylamine reductase remained almost unaffected by DMPP. It is proposed that DMPP has the potential to either reduce NO3(-)-N leaching by inhibiting ammonia oxidization or N losses from denitrification, which is in favor of the N conversations in the rice-oilseed rape cropping system.
College of Environmental and Resource, Zhejiang University, Hangzhou 310029, China.
Hua
H
Li
Xinqiang
X
Liang
Yingxu
Y
Chen
Yanfeng
Y
Lian
Guangming
G
Tian
Wuzhong
W
Ni
D001419:Bacteria / Q000302:isolation & purification / Q000378:metabolism; D001937:Brassica; D015169:Colony Count, Microbial; D018556:Crops, Agricultural; D005308:Fertilizers; D050901:Nitrate Reductase / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism; D009572:Nitrite Reductases / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism*; D012275:Oryza; D011720:Pyrazoles / Q000494:pharmacology*; D000644:Quaternary Ammonium Compounds / Q000378:metabolism; D012988:Soil Microbiology; D014508:Urea / Q000494:pharmacology; D014876:Water Pollution / Q000517:prevention & control*
C433304:3,4-dimethylpyrazole phosphate; D005308:Fertilizers; D009566:Nitrates; D011720:Pyrazoles; D000644:Quaternary Ammonium Compounds; D014508:Urea; D009572:Nitrite Reductases; D050901:Nitrate Reductase; D009584:Nitrogen