introduction: use of unbalanced chemical fertilizers especially p, having low absorption efficiency and low solubility compounds with soil components, has resulted in the production and use of bio-fertilizers (17, 23 and 29). bio-fertilizer is a preservative material consisting of one or several specific beneficial micro-organisms or their metabolic products used to supply plant nutrients and d...

abstract soil drying and rewetting (drw) cycles are considered as environmental stress that would affect the physical, chemical and biological properties of soil and nutrient cycles. the study of soil drying and rewetting effects on plant nutrition and soil fertility is very important and crucial specially their environmental effects. in this study, the effects of 1, 2, 3, 4 and 5 drying and re...

Phosphorus (P) deficiency is a major constraint to crop production on highly weathered, lowactivity clay soils in the humid zone of West Africa. Past research suggested a linear relationship between grain yield and P uptake over a range of fertilizer P applied to upland rice cultivars. However, there is lack of information on how these relationships are affected by the long-term fertilizer ...

Several methods have been proposed for recommendation of phosphorus fertilizers. Each of them only examines the concentration of phosphorus in the soil or plant, while none of them investigates the correlation between phosphorus concentrations in the soil and plant. In this study, a method called "integrated plant and soil system" (IPSS) is proposed to describe phosphorus fertilizer. In this sy...

ruminal bacteria and protozoa provide excellent organic phosphorus (p) sources for the host animal. this experiment was conducted to compare the bioavailability of bacterial and protozoal p in comparison with that of dicalcium phosphate (dcp) as a reference phosphorus source. bacteria and protozoa were isolated from the rumen contents of dairy cows and the chick-model was used to determine the ...

in order to study of the effect of seed inoculation with pgpr on nitrogen and phosphorus use efficiency of spring wheat in different levels of nitrogen and phosphorus fertilizers, an experimental was conducted at the research farm of mohageh ardabili university, ardabil, iran during 2012 year. the combination of nitrogen fertilizer in three levels (0, 40 and 80 kg n/ha as urea) and phosphorus f...

the parameters used to determine the trophic state of a water body are: total phosphorus (tp),transparency (secchi disk depth) and chlorophyll a. however, these parameters show strong seasonalfluctuations which may hinder the estimation of trophic state. some authors have proposed that sediments be used as an additional tool to evaluate the trophic state of a water body. the aim of this study w...