نتایج جستجو برای: top soil
تعداد نتایج: 304166 فیلتر نتایج به سال:
We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the ...
Abstract: A greenhouse study was conducted to assess growth and elemental uptake by canola (Brassica napus) on acidic soils amended with four chemically different unweathered fly ashes. The ashes were incorporated into the top 10 cm of 1 m long intact soil cores at the rates of 0, 12, 36 and 108 Mg ha. The objective of this study was to characterise growth responses and distribution of B, Mo an...
saving in irrigation water is important in the early season of sugar beet. the effect of early season deficit irrigation on the sugar beet growth indexes was investigated in kabotarabad agricultural research station (esfahan) in 1998. the soil texture was silty clay and the experiment design was randomized complete block with 4 relications. six irrigation regimes were applied after. 1) 100 mm (...
Publication 1. A. Manceau et al, “Quantitative Zn speciation in smelter-contaminated soils by EXAFS spectroscopy,” Am. J. Sci. (in press, 2000). Figure 3 (top) Soil samples were taken at several depths from a contaminated site. (bottom) Model compounds derived from polarized-EXAFS data at the ESRF and μ-EXAFS data at the ALS provide a good fit with powder-EXAFS spectra from a soil sample, there...
درک الگوی توزیع مکانی ماکروفون خاک بدلیل اثرات آن روی فرآیندهای اکوسیستم بسیار مهم است. لیکن اطلاعات کمی در این خصوص وجود دارد. درمورد تنوع زیستی ارگانیسم ها وجانداران خاکزی که ازاجزای مهم وکلیدی درهرسیستم اکولوژیکی هستند و در بهبود حاصلخیزی خاک و تولیدات زمین وپایداری اکوسیستم ها(ازطریق فرآیندهای بیولوژیک)نقش عمده دارند تحقیقات کمی انجام شده است. این تحقیق جهت بررسی الگوی مکانی پارامترهای تنوع...
soil salinity is one of the problems threatening agricultural lands. parts of this phenomenon are related to geologic formations and saltpans, while some major factors are resulted from irrelevant agricultural activities, issue of irrigation, and improper cultivation systems which lead to increase in soil salinity. to avoid such consequences that would end up with ecosystem degradation, suitabl...
Estimation of carbon contents and stocks are important for carbon sequestration, greenhouse gas emissions and national carbon balance inventories. For Denmark, we modeled the vertical distribution of soil organic carbon (SOC) and bulk density, and mapped its spatial distribution at five standard soil depth intervals (0-5, 5-15, 15-30, 30-60 and 60-100 cm) using 18 environmental variables as pre...
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