Phosphorus (P) is one of the most important minerals required for plant growth occupying a strong position among soil macro nutrients. Soil P deficiency is often fulfilled by phosphate fertilizers....

Phosphorus and phosphate solubilizing bacteria: Keys for sustainable agriculture

Identification of Growth Limiting Nutrient(s) in Alfisols: Soil Physico-chemical Properties, Nutrient Concentrations and Biomass Yield of Maize

https://research.bangor.ac.uk/portal/files/20422067/2018_Quantifying_the_contribution_of_riparian_soils.pdf

Quantifying the contribution of riparian soils to the provision of ecosystem services

Soil organic matter (SOM) content is a key indicator of riparian soil functioning and in the provision of ecosystem services such as water retention, flood alleviation, pollutant attenuation and carbon (C) sequestration for climate change mitigation. Here, we studied the importance of microbial biomass and nutrient availability in regulating SOM turnover rates. C stabilisation in soil is expected to vary both vertically, down the soil profile and laterally across the riparian zone. In this study, we evaluated the influence of five factors on C mineralisation (Cmin): (i) substrate quantity, (ii) substrate quality, (iii) nutrient (C, N and P) stoichiometry, (iv) soil microbial activity with proximity to the river (2 to 75 m) and (v) as a function of soil depth (0–3 m). Substrate quality, quantity and nutrient stoichiometry were evaluated using high and low molecular weight 14C-labelled dissolved organic (DOC) along with different nutrient additions. Differences in soil microbial activity with proximity to the river and soil depth were assessed by comparing initial (immediate) Cmin rates and cumulative C mineralised at the end of the incubation period. Overall, microbial biomass C (MBC), organic matter (OM) and soil moisture content (MC) proved to be the major factors controlling rates of Cmin at depth. Differences in the immediate and medium-term response (42 days) of Cmin suggested that microbial growth increased and carbon use efficiency (CUE) decreased down the soil profile. Inorganic N and/or P availability had little or no effect on Cmin suggesting that microbial community growth and activity is predominantly C limited. Similarly, proximity to the watercourse also had relatively little effect on Cmin. This work challenges current theories suggesting that areas adjacent to watercourse process C differently from upslope areas. In contrast, our results suggest that substrate quality and microbial biomass are more important in regulating C processing rates rather than proximity to a river.

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Stoichiometric constraints on the microbial processing of carbon with soil depth along a riparian hillslope

Adsorption and desorption of nitrogen (N), phosphorus (P), and potassium (K) soils are controlled by pH, pH buffering capacity, organic matter, and cation exchange capacity (CEC). These factors optimized to improve timely availability of N, P, and K crop use using organic amendments such as chicken litter biochar (CLB). The objective of this study was to determine the effects of CLB on N, P, K sorption and pH buffering capacity of an acid soil. Different rates of CLB were mixed with an acid soil for N, P, and K sorption and pH buffering capacity determination. The CLB increased soil pH and pH buffering capacity, but unlike P and K adsorption, the different rates of CLB significantly increased N adsorption, suggesting that this soil amendment has high affinity for N than P and K. Also, because CLB reduced N, P, and K desorption, it suggests that N in particular will be slowly released with time. The reduced N desorption but higher N adsorption further indicates that N can be temporary fixed by CLB. This work has revealed CLB is more effective controlling soil N availability for timely crop use to avoid losses.

Adsorption and Desorption of Nitrogen, Phosphorus, Potassium, and Soil Buffering Capacity Following Application of Chicken Litter Biochar to an Acid Soil

2 Abstract: The present study was conducted to measure the phosphorus (P) adsorption capacities in a typic Camborthid (Bhalike series) soil of rice tract of Punjab, Pakistan to compute P fertilizer quantities for field application, internal and external P requirements of the wheat, sorghum fodder and rice, Phosphorus Fertility Build-up Factor (PFBF) and level of phosphorus build-up. The soil selection was based on clay percentage, calcium carbonate content. The data showed that soil was free from salinity and sodicity, deficient in organic matter and adequate in available potassium. Sorption isotherm was constructed in the laboratory by equilibrating and shaking 2.5 g soil with 25 ml of 10 m M CaCl containing 0, 5, 10, 15, 20, 40, 60 and 80 g P mL 2 1 as KH PO for 24 h. Sorption data was fitted into linear form of Langmuir and modified Freundlich models and 24 P adsorption capacity was determined from the equations. Theoretical doses were computed from modified Freundlich model for field application. The studies were conducted in permanent layout according to Randomized Complete Block Design (RCBD) with three replications. Different theoretical P doses were applied in the field to develop soil solution P level of 0.01, 0.02, 0.03, 0.04, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.40 and 0.50 mg L alongwith a control of native P soil solution. An overall check (NK = 0 with native P) was also kept. 1

/pdf/adsorption-capacities-and-availability-of-phosphorus-in-soil-2kzbraqhh2.pdf

Muhammad Sarfraz

Papers

Adsorption Capacities and Availability of Phosphorus in Soil Solution for Rice Wheat Cropping System

Wheat Response to Applied Phosphorus in Light Textured Soil