نتایج جستجو برای: the available soil p olsen

تعداد نتایج: 16296744  

2017
Paul J A Withers Robin A Hodgkinson Alison Rollett Chris Dyer Rachael Dils Adrian L Collins Paul E Bilsborrow Geoff Bailey Roger Sylvester-Bradley

Soil phosphorus (P) fertility arising from historic P inputs is a major driver of P mobilisation in agricultural runoff and increases the risk of aquatic eutrophication. To determine the environmental benefit of lowering soil P fertility, a meta-analysis of the relationship between soil test P (measured as Olsen-P) and P concentrations in agricultural drainflow and surface runoff in mostly UK s...

حسین‌پور, علیرضا , رئیسی, طاهره ,

The chemical conditions of the rhizosphere are known to considerably differ from those of the bulk soil, as a consequence of a range of processes that are induced either directly by the activity of plant roots or by the activity of rhizosphere microflora. Plant species have involved various adaptive strategies to acquire P from soil pools. Therefore, the objective of this research was to evalua...

2015
Xiaoying Zhan Li Zhang Baoku Zhou Ping Zhu Shuxiang Zhang Minggang Xu Wenju Liang

The Olsen phosphorus (P) concentration of a soil is a key index that can be used to evaluate the P supply capacity of the soil and to estimate the optimal P fertilization rate. A study of the relationship between the soil Olsen P concentration and the P balance (P input minus P output) and their variations among different fertilization patterns will help to provide useful information for proper...

Journal: :Journal of environmental quality 2001
R W McDowell A N Sharpley

Phosphorus application in excess of crop needs has increased the concentration of P in surface soil and runoff and led many states to develop P-based nutrient management strategies. However, insufficient data are available relating P in surface soil, surface runoff, and subsurface drainage to develop sound guidelines. Thus, we investigated P release from the surface (0-5 cm depth) of a Denbigh ...

Journal: :آب و خاک 0
میترا کریمی امیر کیاسر محمد معز اردلان مسعود کاووسی حسن شکری واحد

abstract the increasing of yield per unit area is usually achievable by improving the soil fertility level through using (chemical) fertilizers. the purpose of the present research was to evaluate the 6 extraction methods including olsen, morgan, ammonium bicarbonate-dtpa, colwel, bray and mehlich 3 in order to specify a suitable extractant(s) for estimating available phosphorus through using 2...

Journal: :تحقیقات آب و خاک ایران 0
حسن توفیقی دانشیار، دانشکدة مهندسی و فناوری کشاورزی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران مصطفی شیرمردی دانشجوی دکتری، دانشکدة مهندسی و فناوری کشاورزی، پردیس کشاورزی و منابع طبیعی، دانشگاه تهران

effects of calcium carbonate and ph on the kinetics of p fixation were studied on four non-calcareous soils treated with different levels of pure caco3, and also on six soils which were adjusted for ph within the range of 5 to 9. soils were also treated with k2hpo4 at the rate of 45 mg p/kg before they were incubated for a period of 100 days at 25○c. soil samples were taken at certain predeterm...

ژورنال: علوم آب و خاک 2007
امیر فتوت, , غلامحسین حق‌نیا, , اکرم حلاج‌نیا, , رضا خراسانی, ,

Study of phosphorus reactions over time and the role of organic matter in the calcareous soils are important for the development of P fertilizer and manure management practices. The objective of this study was to determine the effect of applied manure on P availability and its chemical forms in the soil, over time. Eight samples were collected from semi-arid calcareous soils of Mashhad plain. T...

امیر فتوت, , غلامحسین حق‌نیا, , اکرم حلاج‌نیا, , رضا خراسانی, ,

Study of phosphorus reactions over time and the role of organic matter in the calcareous soils are important for the development of P fertilizer and manure management practices. The objective of this study was to determine the effect of applied manure on P availability and its chemical forms in the soil, over time. Eight samples were collected from semi-arid calcareous soils of Mashhad plain. T...

Journal: :Journal of environmental quality 2007
Marcel van der Perk Philip N Owens Lynda K Deeks Barry G Rawlins Philip M Haygarth Keith J Beven

Many models of phosphorus (P) transfer at the catchment scale rely on input from generic databases including, amongst others, soil and land use maps. Spatially detailed geochemical data sets have the potential to improve the accuracy of the input parameters of catchment-scale nutrient transfer models. Furthermore, they enable the assessment of the utility of available, generic spatial data sets...

ژورنال: علوم آب و خاک 2010
عطاردی , بصیر , نادری خوراسگانی , مهدی ,

Sorghum (Sorghum bicolor L. Var. Speedfeed) is a major forage crop in Birjand Region, and phosphorus (P) plays an important role in its nutritional value. During a field campaign, eighty soil samples from the region were collected and analyzed. Among them, 24 samples varying in physico-chemical properties and available P were selected. Five extractants were used for measuring sorghum available ...

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