Asian Soil Research Journal

Lettuce is one of the most abundant leafy vegetables and is consumed in its raw form by humans, all over the world. This study is conducted in one of the fields in the district of Al-Garmah City, Iraq, to investigate the effects of several fertilizers (Animal, Chemical, and Compost fertilizer). The crop of lettuce harvested from Aug 2017 to Mar 2018, was used in this study. The experiment is carried out in two stages. The first stage includes the multiplication of the earthworm and the production of the worm (vermicompost). The second stage includes the cultivation of lettuce in three replicates with ten coefficients and additions of animal fertilizer, vermicompost and chemical fertilizer (N, P, and K). The results show that the highest productivity is shown in the lettuce plant in vermicompost second with level recommendation half of the fertilizing, and second-ranked vermicompost and chemical. Only the second level and the third place in the recommendation vermicompost 1/2 second with level waste sheep 1/2 second level. The result showed the percentages of the treatment (T5), (T8), (T3), (T9), (T7), (T2), (T1). It is concluded that the production of vermicomposts in a specialized farm which is environmentally-friendly and hygienic, results in more healthy crops for the consumer, which should be given into consideration. More research in this area is needed to fully understand the ecology of different earthworm species, their interactions and their potential roles in promoting the more sustainable farming system.

Phosphorus is one macronutrient that commonly gets fixed and accumulates into soils after it has been in use for long, thus becoming readily unavailable to plants in subsequent years. Such scenario is ontological in Mwea where rice farming is practiced, yet this element is one main critical nutrient that plants cannot do without for they need it for root initiation, root development, photosynthesis, grain- formation, grain-filling, as well as yielding. In that view therefore, an experiment was undertaken in Mwea irrigation scheme with the aim of investigating on the influence of phosphorus levels on yield components and grain yield of Nerica 4 and 11. The experiment was laid out in a Randomized Complete Block Design in split-plot arrangement replicated thrice. Two rice varieties (Nerica 4 and Nerica 11) formed main plots and phosphorus levels (0 kg P/ha, 25 kg P/ha, 50 kg P/ha and 75 kg P/ha) formed split plots. Data was collected on appropriate parameters between week 4 and 19 after sowing at intervals of three weeks. Results demonstrated that phosphorus levels significantly influenced the 1000-grain weight and number of panicles in the tested varieties. Additionally, Grain yield mean variation was observed, where highest grain yield of 0.988 tons per hectare was produced in Nerica 4 on 50 kg P/ha in season 2, while least grain yield of 0.831 tons per hectare was still produced in the same variety on control in season 1, thus 50 kg P/ha on Nerica 4 is recommended for rice farming in Mwea. The study would be used as a body of guidelines and information for judicial, responsible, and promotion of prescribed application of phosphates in Nerica rice farming at planting for realization of higher yields between the two Nerica varieties (Nerica 4 and 11) in Mwea and with like agro ecological areas.

Microbial biodegradation of engine oil contaminated soil in Calabar Metropolis was studied for a period of six (6) months (January to June, 2017). The soil samples collected were ice boxed and taken to the laboratory for microbial, total hydrocarbon, total organic carbon and other physico-chemical parameters analysis. A total of thirteen (13)  indigenous bacteria species were identified in the soil of the sites analyzed during the study, which includes; Staphylococcus spp., Pseudomonas aeruginosa, Bacillus spp., E. coli, Enterococcus feacalis, Shigella spp., Arthrobacter spp., Alcaligen spp., Acinobacter spp., Azotobacter spp., Aeromonas spp., Xanthomonas spp. and Clostridium spp. The most abundant bacteria in the contaminated site was Staphylococcus spp. (65%) while the least bacteria count in the contaminated site was Clostridium spp. (9%). Staphylococcus spp. was the most abundant indigenous bacterial species and also the most effective biodegradation bacteria. The identified indigenous bacteria utilized the hydrocarbons, multiplied rapidly and then degraded the total hydrocarbon and total organic carbon more in the contaminated site compared to the control site. Site one recorded the highest bacteria count (927) while the least bacteria counts were recorded in the control site (81). The bacteria species showed its degradation and bioremediation capabilities prompting the need for its use in cleaning crude oil contaminated sites, due to the fact that it is cheap and not environmentally harmful.

A pot experiment was conducted in clay soil collected from Agricultural Research Center farm, Giza governorate, Egypt. Wheat grains (Triticum aestivum L., Giza 168) were cultivated to study the effect of silicate and phosphate ions as well as their interactions on the growth and nutritional status of the growing plants, beside their availability in the studied soil. Silicon (Si) in the form of sodium meta-silicate penta-hydrate (Na₂SiO₃.5H₂O) was added at a rate of 0, 200, 300 and 400 mg Si kg^-1 soil, and phosphorus (P) in the form of calcium super phosphate was given at a rate of 0, 3.5, 7.0, 10.0 and 13.0 mg P kg^-1 soil to represent 0, 25, 50, 75 and 100% of the recommended rate of P fertilization by the Egyptian Ministry of Agriculture for wheat cultivation. Also, the experiment included combinations between all these concentrations of Si and P. Obtained results showed that Si and P availability increased in the studied soil with increasing either Si or P concentrations added. This means that P availability in soil as an essential element for plant growth can be improved by addition of Si. Also, Si increased in plant with increasing applied Si concentrations. Interaction between Si and P generally increased all parameters of plant growth; such responses were significant for fresh and dry weights of wheat plants at booting stage. It could be recommended that selecting good P fertilization design, including time and rate of addition, goes along with values of available Si in the soil.

A field experiment (randomized complete blocks with three replicates) was conducted during two successive summer seasons of 2016 and 2017 at Sahl El-Houssinia Agriculture Research Station in El-Shakia Governorate, Egypt. Its lies between 32˚00/00 to 32˚15/00/ N latitude and 30˚50 / 00// to 31˚15 00// E longitude. The combined effect of bio-fertilizers inoculated with Rhizobium radiobacter sp strain (salt tolerant PGPR); Bacillus megatherium (dissolving phosphate) and Bacillus circulans (enhancing potassium availability) and yeast strains (Saccharomyces cerevisiae) combined with different rates of N, P and K fertilizers (50, 75 and 100%) was evaluated on some soil properties, nutrient content in rice plants, and rice productivity in a reclaimed saline soil. From the crop field of the Agricultural Research Institute (ARC), Egypt, 101 grain kernels from rice (Oryza sativa) var. Sakha were selected.  

The results indicated that soil pH and EC were decreased in soil treated with bio-fertilizers combined with different rates of mineral fertilizers in comparison with soil treated with yeast and control. Available N, P, K, Fe, Mn and Zn in the soil increased with the use of bio-fertilizers. Application of mineral fertilizers (N, P and K) alone or combined with bio-fertilizers (bacteria and yeast) resulted in increased yield grains and straw of rice plant. Macro- and micronutrients concentrations and uptake in grain and straw of rice plants increased in soil treated with bacteria + 75% N+P+K fertilizers compared with other treatments.