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.

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.

The effect of elemental sulfur on some chemical soil properties and wheat grown was studied by two performing experiments, under high terrace soils of northern region of the Sudan. First experiment (incubation experiment) was executed to quantify the rates and application time of elemental sulfur to be applied in the field experiment. It consisted of five rates of elemental sulfur (0, 165, 330, 495 and 660 kg sulfur feddan-1) and five application times (2, 4, 6, 8 and 10 weeks). In the second experiment (field experiment), two wheat varieties (Wadi Elneel and Debeira), three sulfur rates (0 kg S feddan-1, 495 kg S feddan-1 and 660 kg S feddan-1) and three application times (0, 5 and 7 weeks) were arranged in split plot design with four replications. Wheat varieties were assigned to the main plots and the combination of the rates and time application to the sub plots. Results obtained from the incubation experiment indicated differences in soil pH among treatments. Application of elemental sulfur decreased soil pH in each of the two experiments. The effect of elemental sulfur on wheat grain yield and the other studied yield components was not limited the plant height and the 1000 seeds weight. The nitrogen content of the plant tissue was affected by the applied elemental sulfur. Application of 495 kg sulfur feddan-1, 6 weeks before sowing gave the lowest soil pH (7.8) and the least available phosphorus compared to other treatments.