نتایج جستجو برای: 20 cm in soil layer in totally
تعداد نتایج: 17154190 فیلتر نتایج به سال:
with the increasing population and the need for more food, as well as with the development of science and technology, human approach to unnatural and often chemical inputs to increase agricultural production has been a great expansion and problems such as increased cancers, chronic diseases has created environmental pollution. implementation of organic organic is a solution to these problems . ...
The experiment of artificial afforestation combining with soil amendment was carried out to investigate the effects of soil amendment on antimony (Sb) chemical forms, and its bioavailability in Chinese antimony mining. This research provides the technical basis for ecological remediation of Sb contaminated soils. The results showed that the soil pH values increased with the increasing of discha...
development of industry in sistan and baluchestan (sb) province in iran, has increased the amount of cadmium (cd) in industrial wastewater, which is used as a secondary water supply in this area. the present study aimed to investigate the variation of cd concentration in soil column and cultivated cucumber plant in greenhouse under short-term simulated industrial wastewater irrigation. to simul...
introduction: nitrogen (n) is one of the most important growth-limiting nutrients for dryland wheat. mineral nitrogen or ammonium (nh4+) and nitrate (no3−) are two common forms of inorganic nitrogen that can serve as limiting factors for plant growth. nitrogen fertilization in dryland area can increase the use of soil moisture, and improve wheat yields to some extent. many researchers have been...
The study was aimed to examine total concentrations and pools of Hg in surface layers of soils in the Karkonosze Mountains, dependent on soil properties and site locality. Soil samples were collected from a litter layer and the layers 0-10 cm and 10-20 cm, at 68 sites belonging to the net of a monitoring system, in two separate areas, and in three altitudinal zones: below 900 m, 900-1100 m, and...
Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive ...
Rice is an essential crop in Iran that is grown mostly in areas where depth to groundwater is low. Root growth and water uptake of rice under shallow groundwater has not been thoroughly studied. This experiment was conducted to determine the lowland rice (cv. Ghasrodashti) root distribution above shallow groundwater in relation to deficit irrigation and groundwater depth in cylindrical gre...
37 PBDE congeners were analyzed at six different depths in two soil cores taken from a typical electronic waste polluted area in South China. The PBDEs were congregated in the surface layer (0-5 cm) of soil cores and were 29 times in MK and 18 times in NW higher than the second lower layers (5-10 cm). As a whole, the concentrations of PBDEs were decreased with the soil depth increased in two co...
Crust restoration is increasingly being done but we lack quantitative information on soil improvements. The study aimed to elucidate the dynamics involving soil microbial biomass carbon and soil dissolved organic carbon in the re-vegetation chronosequences of a hillslope land with purple soil in Hengyang, Hunan Province. The soil can cause serious disasters with both soil erosion and seasonal d...
a semi-empirical mathematical model for predicting physical part of ignition delay period in the combustion of direct - injection diesel engines with swirl is developed . this model based on a single droplet evaporation model . the governing equations , namely , equations of droplet motion , heat and mass transfer were solved simultaneously using a rung-kutta step by step unmerical method . the...
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