Manure is a substantial source of ammonia volatilization into the atmosphere before and after soil application. The purpose of the study was to investigate the effects of temperature and alkalization treatments on the release of ammonia and ammonia recovery (AR) from cow manure and to characterize the chemical properties of the resultant effluents. In a closed glass reactor, 100 g of fresh cow manure was mixed with 100 mL of deionized water and the mixture was treated with various volume of KOH to increase the manure pH to 7, 9, and 12. Ammonia was distilled from the mixture at temperatures of 75, 85, 95, and 100 °C for a maximum of 5 h. Ammonia was received as diluted boric and sulfuric acids. Results indicated that the highest ammonia recovery was 86.3% and 90.2%, which were achieved at a pH of 12 and temperatures of 100 and 95 °C, respectively. The recovered ammonia in boric acid was higher than in sulfuric acid, except at a pH of 12 and temperatures of 95 and 100 °C. The effluents, after ammonia was removed, showed that the variation in pH ranged between 6.30 and 9.38. The electrical conductivity ranged between 4.5 and 9. (dS m−1) and total potassium ranged between 9.4 and 57.2 mg kg−1.

No abstract

In Saudi Arabia, more than 335,000 tons of cow manure is produced every year from dairy farming. However, the produced cow manure is usually added to the agricultural soils as raw or composted manure; significant nitrogen losses occur during the storage, handling, and application of the raw manure. The recovery of ammonia from cow manure through thermochemical treatments is a promising technique to obtain concentrated nitrogen fertilizer and reducing nitrogen losses from raw manure. However, the byproduct effluents from the recovery process are characterized by different chemical properties from the original raw manure; thus, its impact as soil amendments on the soil carbon and nitrogen dynamics is unknown. Therefore, a 90-day incubation experiment was conducted to study the impact of these effluents on CO2 efflux, organic C, microbial biomass C, available NH4+, and NO3− when added to agricultural soil. In addition to the two types of effluents (produced at pH 9 and pH 12), raw cow manure (CM), composted cow manure (CMC), cow manure biochar (CMB), and control were used for comparison. The application of CM resulted in a considerable increase in soil available nitrogen and CO2 efflux, compared to other treatments. Cow manure biochar showed the lowest CO2 efflux. Cumulative CO2 effluxes of cow manure effluents were lower than CM; this is possibly due to the relatively high C:N ratio of manure effluent. The content of P, Fe, Cu, Zn, and Mn decreased as incubation time increased. Soil microbial biomass C for soil treated with cow manure effluents (pH 12 and 7) was significantly higher than the rest of the soil amendments and control.

To cite this paper: Al-Farhud, A., M. Al-Sewailem and A.R.A. Usman, 2017. Status of selenium and trace elements in some arid soils cultivated with forage plants: A case study from Saudi Arabia. , respectively. Meanwhile, in soil samples collected from corn farms, available Fe, Mn, Zn, Cu, and Mo ranged from 1. 70-8.35, 0.74-10.5, 0.82-3.12, 0.32-3.91, undetectable-0.04 mg kg -1 , respectively. The shoot contents of Se, Mo, Zn and Cu were low and deficient in alfalfa and corn plants. However, it was observed that the shoot contents of Fe and Mn were sufficient. Based on correlation coefficients and multivariate analyses including principal component (PCA) and cluster analyses (CA), soil properties of clay content, CEC and OM altered trace elements availability and consequently can modify the response of forage plant in study area.

Although carbon (C) efflux from soils treated with organic wastes was widely covered in temperate and cold regions, still such data is not sufficient from arid and semi-arid regions. Saudi Arabia produces more than 335,000 tons/year of cow manure (CM), this CM either left as raw manure or being composted. The application of high C/N amendments is expected to increase soil organic carbon and reduce CO2 fluxes. A 90-day incubation experiment was conducted to study CO2 efflux, organic C microbial biomass C, available NH4+and NO3-when added to agricultural soil. Six manure types were added: cow manure, cow manure compost, cow manure biochar, cow manure stripped ammonia at pH 12 with a temperature of 95oC, cow manure stripped ammonia at pH 9 with a temperature of 95oC and control. The application of CM resulted in a considerable increase in soil available nitrogen, CO2 efflux compared to other treatments. Cow manure biochar showed the lowest CO2 efflux. Cumulative CO2 effluxes of cow manure effluents were lower than CM this possibly due to the relatively high C:N ratio of manure effluent. The content of, P, Fe, Cu, Zn and Mn were decreased as incubation time increased. microbial biomass C of cow manure stripped ammonia at pH 12 with a temperature of 95oC were increased at 7 and 60 days illustrating to temperature effect on the decomposing of manure materials.