نتایج جستجو برای: current soil p test methods such olsen

تعداد نتایج: 5069783  

Journal: :Journal of environmental quality 2001
D T Westermann D L Bjorneberg J K Aase C W Robbins

Phosphorus (P) often limits the eutrophication of streams, rivers, and lakes receiving surface runoff. We evaluated the relationships among selected soil P availability indices and runoff P fractions where manure, whey, or commercial fertilizer applications had previously established a range of soil P availabilities on a Portneuf silt loam (coarse-silty, mixed, superactive, mesic Durinodic Xeri...

Journal: :Journal of environmental quality 2004
Benjamin L Turner Mary A Kay Dale T Westermann

Management strategies that minimize P transfer from agricultural land to water bodies are based on relationships between P concentrations in soil and runoff. This study evaluated such relationships for surface runoff generated by simulated sprinkler irrigation onto calcareous arable soils of the semiarid western United States. Irrigation was applied at 70 mm h(-1) to plots on four soils contain...

پایان نامه :0 1374

the rationale behind the present study is that particular learning strategies produce more effective results when applied together. the present study tried to investigate the efficiency of the semantic-context strategy alone with a technique called, keyword method. to clarify the point, the current study seeked to find answer to the following question: are the keyword and semantic-context metho...

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: :تحقیقات آب و خاک ایران 0
علیرضا حسین پور محمدحسن صالحی

such ion-sink methods as feo coated strips, (pi), can adsorb and collect p from soil solution. ion sink methods function similar to plant-root surface, adsorbing available p ions from the p pool in the soil. the objective of this study was to compare pi test with olsen, ab-dtpa, bray 2 and mehlich 2 methods to estimate the availability of soil p in alfalfa (medicago sativa). available p was det...

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 ...

2014
Yan Deng Keru Chen Wan Teng Ai Zhan Yiping Tong Gu Feng Zhenling Cui Fusuo Zhang Xinping Chen

Sustainable agriculture requires improved phosphorus (P) management to reduce the overreliance on P fertilization. Despite intensive research of root adaptive mechanisms for improving P acquisition, the inherent potential of roots for efficient P acquisition remains unfulfilled, especially in intensive agriculture, while current P management generally focuses on agronomic and environmental conc...

ژورنال: علوم آب و خاک 2004
امیرحسین قانعی, , علیرضا حسین‌پور, ,

Iron oxide-coated strips (Pi) can serve as a sink to continuously remove P from solution. In this way, probably, P extraction is analogous to P absorption by plant root. The objective of this study was to evaluate the iron oxide-coated paper strips to estimate the availability of soil P of corn (Zea mays) grown under greenhouse conditions in some soils of Hamadan Province. Sixteen soil samples ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده منابع طبیعی و علوم دریایی 1388

this research was conducted in two protect and destroy region in the middle zagros, in illam province. in order to identification of ecological species group and evaluate density of regeneration, effect of many factors such as protection, vegetation, physiographic factors, physical and chemical properties of soil in study locations were studied. to achieve these purpose number of 54 plots using...

D. Bao D. Guo Sh. Huang Sh. Zhang Y. Ma,

Repeated application of manures to agricultural soils could cause the accumulation of phosphorus (P) in soils. However, it is unclear if manure P can behave similar to P in soluble fertilizers in accumulation Olsen-P (0.5 mol L-1 NaHCO3 at pH 8.5) in soils. A long-term wheat-maize rotation experiment was conducted to investigate the effects of repeated application of manures on P accumulation i...

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