Asian Soil Research Journal

The experiment was conducted in the research farm at Bangladesh Agricultural University (BAU) to investigate the zinc biofortification ability of rice grain at different doses of zinc fertilization. In this experiment two rice varieties (BRRI dhan28 and Binadhan-16) and five doses (0, 1.5, 3.0, 4.5 and 6.0 kg ha^-1) of zinc fertilization were used following split-plot design with three replications. Except 1000-grain weight and plant height, all other plant characters viz., tillers hill^-1, panicle length and grains panicle^-1 were significantly influenced by zinc fertilization. The treatment receiving Zn at 4.5 kg ha-1 (Zn 4.5) produced the highest grain yield (7.70 t ha^-1) in BRRI dhan28 which was statistically similar with the yield obtained with Zn 3.0 treatments. The zinc control treatment (Zn 0) produced the lowest grain yield in both varieties. The concentrations of N, Zn and Fe were significantly and positively influenced by the Zn treatments. The crop varieties did not differ significantly in respect of N and Fe concentrations, but the grain Zn concentration was considerably higher in BINA dhan16 than in BRRI dhan28. The grain N content as well as grain protein content linearly increased with the rates of Zn application. Thus, application of Zn at the rate of 6.0 kg ha^-1 demonstrated the highest Zn fortification in both varieties but maximum zinc fortification was observed in Binadhan-16 (24.1 µg g-1) in rice grain which was 12.2% higher over control treatment.

Sesame is one of the most popular oil crops in the Western Tigray Ethiopia. Blended fertilizers containing N, P, S, Zn and B have been recommended to ameliorate site specific nutrient deficiencies in different districts of Tigray. Field experiment was conducted during rainfall season of 2018 and 2019 to study the effect of NPSZnB fertilizer on sesame (Sesamum indicum L.) in vertisols of Western Tigray at the Humera station, Banat and Kebabo Kafta Humera and Tsegede Wereda’s. The treatments consisted of six levels of NPSZnB 0, 50, 100, 150, 200 and 250 kg ha^-1 and one blanket recommendation NP was applied. Data were recorded on sesame yield and yield components. The results revealed that addition of graded rate of NPSZnB significantly increased yield and yield attributes over the control. Analysis of variances showed that grain yield, number of capsule per plant, number of seeds per capsule and number of branching per plant was significant differences at (P< 0.001). Grain yield increases from 421 kg ha^-1 to 630.1 kg ha^-1 as NPSZnB increases from 0 (control) to 150 kg ha^-1 and 421 kg ha^-1 to 626.2 kg ha^-1 as NP increases from 0 (control) to 41 N kg and 46 P₂0₅ kg ha^-1 respectively. But NPSZnB was not significant with blanket recommendation of NP (41 kg N and 46 kg P₂0₅ ha^-1), this indicates that either the blend or blanket NP can be used but not one to replace the other.

This study investigated the impacts of spent engine oil on the physicochemical properties of soil, soil's microbial population and growth of Capsicum annuum. It covered assessment of different levels of contamination (0, 20, 40, 60 and 80%) in soil; which represents the degree of oil spillage concentration on the growth performance of C. annuum investigated. Percentage germination, seedling height, number of leaves and number of branches decreased as the concentrations of the spent engine oil in soil samples increased and affected soil physicochemical properties. The screening experiment conducted showed that poultry manure improved the physicochemical properties of sandy loam soils contaminated engine oil. The effects of poultry manure as an organic amendment was assessed using pepper (C. annuum) as test crop. All amendment made significant increase in soil organic carbon and calcium content over the polluted soils. Soil acidity increased, soil exchangeable ions decreased. N, P and K were altered in the polluted soils as compared to the controls. There were increased bacterial counts (2.21 – 2.85) and a decrease in fungi population (0.48 - 0.59) in the spent engine oil-contaminated soils compared with the control. The oil reduced germination percentage, depressed growth, reduction in leaf number and plant height of the C. annuum. Therefore the spent engine oil clearly had detrimental effects on soil's physicochemical and biological properties. The oil contributed largely to the extreme acidic nature of the polluted soils. However, maximum increase in plant height, germination percentage, number of leaves and branches were recorded with amendment of the polluted soils with poultry manure. Results show the considerable potential of remediation protocols with poultry manure as a remediating agent for oil spill remediation in the soil samples.

Plants, unlike animals are naturally able to synthesize whatever compounds they need, require more than a dozen different elements [majorly Nitrogen, Phosphorus and Potassium (NPK)] as such. This study investigated the effect(s) of application of cow dung (CD) and NPK fertilizer on the early growth response of Irvingia gabonensis. Top soil samples of between 0 – 15 cm depth (control group I), top soil + NPK (Group II), top soil + cow dung (Group III) and top soil + NPK + cow dung (Group IV) were collected at varying combinations. The soils were then taken to the laboratory for physio-chemical analysis of key components [pH, N, P, K⁺, Ca²⁺, Mg²⁺, Na⁺, Org. C, sand, silt and clay]. Prior to and after actual experimentation, the N, P, K, Ca, Mg, Na, pH constituents of the cow dung were also analysed. For every two weeks (in twenty weeks duration) after application, plant heights, leaf area, number of leaf, stem girth were obtained and noted. By way of a sensitive weighing machine, 20 WAP destructive sampling was conducted to determine the weights of the shoot and root after oven-drying for three days in an oven sets at 75°C. In any case, these samples were then analysed for the nutrient content of the stem, root and leaf. Following data collection, comparisons of mean differences was performed using the Fishers protected least significant test and Duncan Multiple Range Test (DMRT) at 5% level of probability. Upon careful observation of result, study found that Irvingia gabonensis seedlings grown with cow-dung and NPK combination (Group IV) performed better in growth (height, diameter and leaf area) than seedlings grown in only top soil medium (TS) with single fertilizer use (Group II). However, NPK 3 CD 3, NPK 3 CD 2 and NPK 2 CD 3 best support the early growth phase of Irvingia gabonensis seedlings as compared to others. Study therefore showed Cow dung to contain substantial amount of essential elements that may be beneficial for the physio-chemical growth of Irvingia wombolu seedlings and combating reports of deforestations across the globe. It is recommended that for better results, cow-dung and NPK mixtures should be used than single use of the either treatments. Further studies aimed at corroborating this research are also recommended.

Field trials were conducted during 2017 and 2018 rainy season, to investigate the effect of nitrogen fertilizer rates and time of application on the growth and yield of cowpea. The treatment consisted of three levels of urea: 0, 40, 80 kg N ha^-1 and the times of fertilizer application: during planting of cowpea, 2 weeks after planting, 4 weeks after planting and 6 weeks after planting; which were factorially combined to form twelve treatments and laid in Randomized Complete Block Design (RCBD). The results showed that, Nitrogen fertilizer rates and time of application had a significant increased on all the growth and yield parameters of cowpea in both years of trials. Application of 80 kg N ha^-1 produced the highest number of cowpea leaves (134.45 and 139.23), number of branches (9.45 and 10.54), vine length (78.23cm and 80.12cm) and highest seed weight of 0.52 t ha^-1 in both 2017 and 2018 trials. However, the control plots produced plants with the highest number of root nodules (14.78 and 12.49) in both years of cropping. Also, application of nitrogen fertilizer at two weeks after planting of cowpea produced the highest growth and seed weight of 0.68 t ha^-1 in 2017 cropping; while in 2018 trial, application of nitrogen fertilizer at two weeks after cowpea planting produced seed yield of 0.69tha^-1 which is statistically similar with application of nitrogen fertilizer on the fourth week after planting which produced 0.55 t ha^-1 of cowpea seeds. The interaction between nitrogen fertilizer application rates and time of application did not showed any significant difference in cowpea yield and yield components in both years of cropping.