کد مقاله کد نشریه سال انتشار مقاله انگلیسی ترجمه فارسی نسخه تمام متن
8893955 1629390 2018 9 صفحه PDF سفارش دهید دانلود رایگان
عنوان انگلیسی مقاله ISI
Divergent composition and turnover of soil organic nitrogen along a climate gradient in arid and semiarid grasslands
ترجمه فارسی عنوان
ترکیب متقابل و گردش نیتروژن آبی خاک در امتداد گرادیان آب و هوایی در مراتع خشک و نیمه
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
سفارش ترجمه تخصصی
با تضمین قیمت و کیفیت
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فرآیندهای سطح زمین
چکیده انگلیسی
Greater aridity predicted with climate change in drylands worldwide will affect soil nitrogen (N) cycling and the associated ecosystem functions. Despite >90% of soil N occurring in organic forms, the pathways of soil organic N (SON) turnover remain largely unknown in drylands, where biological activity is typically limited by water availability. Here we examined patterns of SON fractions and soil N-hydrolyzing enzyme activities across a 3700 km aridity gradient in arid and semiarid grasslands of northern China. We found that both the concentrations of all SON fractions and the proportion of more stable SON increased with increasing aridity index (AI, defined as mean annual precipitation/potential evapotranspiration). The largest SON fraction was hydrolysable NH4+ in arid sites, but amino acid-N in semiarid sites. The activities of enzymes that hydrolyze relatively stable SON polymers (protease, peptidase, and N-acetyl-β-glucosaminidase) were negligible in arid sites (AI < 0.2), but increased significantly as AI increased in semiarid sites (AI > 0.2). Structural equation modeling indicated that the direct effect of microbial biomass on soil amidase was insignificant in arid sites, indicating that microbial SON turnover via enzymes is relatively weak. In semiarid sites, however, microbial biomass exerted significant direct positive effects on all soil N-hydrolyzing enzymes, suggesting strong microbial regulation of SON turnover via enzymatic mineralization. Altogether, our findings provide empirical evidence for divergent patterns of storage and turnover of SON between arid and semiarid grasslands.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geoderma - Volume 327, 1 October 2018, Pages 36-44
نویسندگان
, , , , , , , ,
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
سفارش ترجمه تخصصی
با تضمین قیمت و کیفیت