Zhang Manyun, Wang Weijin, Wang Jun, Teng Ying, Xu Zhihong
Environmental Futures Research Institute, School of Natural Sciences, Griffith University, Brisbane, QLD, 4111, Australia.
Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
Environ Sci Pollut Res Int. 2017 Apr;24(12):11340-11348. doi: 10.1007/s11356-017-8762-6. Epub 2017 Mar 17.
Agrochemical applications may have side effects on soil biochemical properties related to soil nitrogen (N) mineralization and thus affect N cycling. The present study aimed to evaluate the effects of nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) and fungicide iprodione on soil neutral protease (NPR), alkaline protease (APR), chitinase (CHI), and their functional genes (nprA, aprA, and chiA) related to soil N mineralization. The following four treatments were included: blank control (CK), single DMPP application (DAA), weekly iprodione applications (IPR), and the combined applications of DMPP and iprodione (DI). Compared with the CK treatment, DMPP application significantly inhibited the CHI activity in the first 14 days of incubation, and iprodione applications, particularly when applied alone, decreased the NPR, APR, and CHI activities. Relative to the IPR treatment, extra DMPP application had the potential to alleviate the inhibitory effects of iprodione on the activities of these enzymes. DMPP application significantly increased aprA gene abundances after 14 days of incubation. However, repeated iprodione applications, alone or with the DMPP, decreased nprA and chiA gene abundances. Relative to the CK treatment, DMPP application generated negligible effects on the positive/negative correlations between soil enzyme activities and the corresponding functional gene abundances. However, the positive correlation between the CHI activity and chiA gene abundance was changed to negative correlation by repeated iprodione applications, alone or together with the DMPP. Our results demonstrated that agrochemical applications, particularly repeated fungicide applications, can have inadvertent effects on enzyme activities and functional gene abundances associated with soil N mineralization.
农用化学品的施用可能会对与土壤氮（N）矿化相关的土壤生化特性产生副作用，从而影响氮循环。本研究旨在评估硝化抑制剂3,4-二甲基吡唑磷酸盐（DMPP）和杀菌剂异菌脲对土壤中性蛋白酶（NPR）、碱性蛋白酶（APR）、几丁质酶（CHI）及其与土壤氮矿化相关的功能基因（nprA、aprA和chiA）的影响。试验设置了以下四个处理：空白对照（CK）、单施DMPP（DAA）、每周施用异菌脲（IPR）以及DMPP与异菌脲混合施用（DI）。与CK处理相比，施用DMPP在培养的前14天显著抑制了CHI活性，而异菌脲的施用，尤其是单独施用时，降低了NPR、APR和CHI的活性。相对于IPR处理，额外施用DMPP有可能减轻异菌脲对这些酶活性的抑制作用。培养14天后，施用DMPP显著增加了aprA基因丰度。然而，重复施用异菌脲，无论单独施用还是与DMPP混合施用，都会降低nprA和chiA基因丰度。相对于CK处理，施用DMPP对土壤酶活性与相应功能基因丰度之间的正/负相关性影响可忽略不计。然而，重复施用异菌脲，无论单独施用还是与DMPP一起施用，都会使CHI活性与chiA基因丰度之间的正相关变为负相关。我们的结果表明，农用化学品的施用，尤其是重复施用杀菌剂，可能会对与土壤氮矿化相关的酶活性和功能基因丰度产生意外影响。
