American Journal of Agricultural Research

  • Evaluation of Compost Integrated with Chemical Fertilizer for better production of Maize in Shashemene District of West Arsi Zone, Oromia

    The effect of integrated use of compost and urea on yield of and yield component was assessed in a field experiment in Shashemene district during 2016-2018. In this experiment, compost was replaced UREA at different rate depending on its quality. Compost quality was analyzed mainly for Total nitrogen to compute its equivalency with UREA. Accordingly, It was identified that average total nitrogen in compost was 1%.Therefore, 100kg UREA (46kg N) is equivalent to 4600kg compost (4.6ton). The treatments were control (100kg DAP+100kg UREA), 100%compost (4.6ton) +100kg DAP, 75% compost (3.45ton)+25%UREA+ 100kg DAP, 50% compost (2.3ton) +50%UREA+100kg DAP, 25%compost (1.15ton) +75%UREA +100kg DAP. Maize (variety: Shano)) was planted in rows. Data on grain yield and yield components were analyzed. Soil samples were also collected to evaluate the residual effect of compost on soil properties. The results indicated that maximum grain yield (93kunt ha-1) of maize was obtained in treatment (2) that received sole compost plus 100kg DAP ha-1. The next higher yield was obtained in treatment 3 and 4 that received both compost and UREA with the ratio of 75:25 and 50:50 respectively. Comparing with sole chemical fertilizer treatment, the crop yield was significantly higher and different (p≤0.05) in all treatments. The residual soil fertility after maize harvest was proportional to the level of compost used. Except for total nitrogen, available potassium and phosphorous in sole chemical fertilizer application is smaller and highly significantly different (p≤0.05) from the rest of the treatments indicating that all total nitrogen in compost is available for crop in the first year of application while potassium and phosphorous availability for the crop is partially delayed. Based on the result, it was economically and environmentally recommended to use ISFM for sustainable maize production in the area.

  • Use of natural products for weed management in high-value crops: An Overview

    Over the last five decades, weed management systems have relied primarily on synthetic herbicides. Due to the concerns over the potential impact of chemicals on human health and the environment, efforts are being made to reduce the heavy reliance on synthetic herbicides. To reduce synthetic herbicides, use of natural products such as essential oils, plant extracts, allelochemicals, agricultural by-products, and some microbes are gaining attention because they are safe due to their short environmental half-life and low toxicity. These natural product bioherbicides are a good alternative to synthetic herbicides especially in organic agriculture since they focus on environmental protection, practical viability, compatibility for integrated programs, and ecological stability. Most of the commercially available natural herbicides are non-selective and require careful application in order to preserve the crop of interest. Although many studies in this direction have been undertaken, the use of these natural products is still not common because of the difficulties in their synthesis due to their complex structure, cost effectiveness, poor results in field trials, and rapid degradation. No single above mentioned natural product has the potential to comprehensively replace chemical weed management; however, an integrated approach may provide better results. Thus, the role of bioherbicides in modern weed management is complementary rather than exclusive.

  • Contribution of Cover Crops and Reduced Tillage Systems for Weed Management in Organic Vegetable Production

    In recent years, organic vegetable production systems have become an increasingly important segment of agriculture; and weed control is a principal concern for organic vegetable growers. In the absence of herbicides, tillage and cultivation are the most commonly used tools by vegetable growers for managing weeds in organic systems; however, intensive tillage may have adverse effects on soil and environmental health. In recent times, to reduce intensive soil tillage and achieve successful weed management, integration of cover crops with conservation tillage (reduced or no-tillage) is emerging as an innovative alternative production practice in organic farming. Research over the globe has shown that cover crops can be used to control weeds in vegetable fields, and also play an important role in improving productivity of subsequent crops by improving soil physical, chemical, and biological properties. In agronomic crops, the benefits of cover crops in conjugation with reduced tillage on weed management are well documented but, such information is scarcely available for vegetables grown in organic production systems. This review focuses on different types of cover crop species and conservation tillage systems for weed management in organic vegetable production.

  • Field performance of Solid Manures and their Slurries on Growth, Yield and Quality of Potato in Old Brahmaputra Floodplain Soils

    Continuous use of chemical fertilizers declines crop yield and deteriorates soil fertility. For sustenance of crop productivity and soil fertility integration of chemical fertilizers with manures is a timely approach. An experiment was, therefore, conducted to evaluate the field performances of different types of manure including cowdung (CD), cowdung slurry (CD slurry), trichocompost (TC), vermicompost (VC), poultry manure (PM) and poultry manure slurry (PM slurry) with integrated use of chemical fertilizers during 2011-12 and 2012-13 at Bangladesh Agricultural University farm. The field trials comprised eight treatments which included T1: Control (no manure or fertilizer), T2: High yield goal (HYG) based 100% chemical fertilizers (CF), T3: CD + CF (IPNS basis), T4: CD slurry + CF (IPNS basis), T5: PM + CF (IPNS basis), T6: PM slurry + CF (IPNS basis), T7: TC + CF (IPNS basis) and T8: VC + CF (IPNS basis). Cowdung, CD slurry, TC and VC were added to soil at 5 t ha-1 while PM and PM slurry were applied at 3 t ha-1. The results revealed that TC and VC containing treatments produced higher crop yield and next to them PM slurry and CD slurry performed better in respect of potato yield. Integrated use of manure and fertilizers gave on an average 6.7-33.7% yield increase in potato over sole chemical fertilizers treatment. The lowest yield was observed in control. These results show that Trichocompost and vermicompost in combination with chemical fertilizers are suitable for quality potato production.

  • Response of Growth and Yield of Potato to Neb-26 as a Source of Nitrogen

    This Urea is a vital source of nitrogen (N) to be supplied for plants but most of it is lost through processes including volatilization, denitrification, leaching and run-off. So, it is timely to find out an alternative source of nitrogen fertilizer. A field experiment was, therefore, carried out at Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during 2016-2017 with a view to investigating the effectiveness of NEB-26 (a liquid N fertilizer introduced by Advanced Chemical Industries (ACI) Limited) in combination with urea on the growth and yield of potato. The soil was silt loam in texture having a pH 6.4, organic matter 1.55%, total N 0.091%, available P 3.30 mg kg-1, available K 0.08 me 100-1 g soil, available S 6.46 mg kg-1 and available Zn 0.86 mg kg-1. The experiment consisted of five treatments laid out in a Randomized Complete Block Design with four replications. The treatments were T1: Control (no N fertilizer), T2: 100% N from urea, T3: 50% N from urea, T4: 50% N from urea + 500 ml ha-1 NEB-26 and T5: 50% N from urea + 750 ml ha-1 NEB-26. The potato variety used in the experiment was ‘Diamant’. The recommended doses of N (140 kg ha-1), P (25 kg ha-1), K (135 kg ha-1) and S (15 kg ha-1) were supplied from urea, TSP, MoP and gypsum, respectively. All the fertilizers except urea were applied as basal dose. Urea was applied in three installments and the NEB-26 was applied as per treatment at the time of second installment of urea application. The crop was harvested at maturity and the yield components and yields were recorded. The results indicate that the yield attributes, tuber yield and haulm yield of potato were significantly influenced by N supplied from urea and NEB-26. The tuber yield…

  • Efficacy of Deep Placement of Nitrogen Fertilizers on N Use Efficiency and Yield of Boro Rice (cv. BRRI Dhan29)

    The efficiency of nitrogen (N) fertilizers in rice culture is low due to their losses in different ways. An experiment was, therefore, conducted at the Soil Science Field Laboratory of Bangladesh Agricultural University, Mymensingh during boro season of 2016 to evaluate the effect of deep placement of N fertilizers on N use efficiency and yield of BRRI dhan29 under alternate wetting and drying (AWD) condition. The soil was silt loam in texture having pH 6.07, organic matter content 1.10%, total N 0.055%, available P 3.6 ppm, exchangeable K 0.22 me% and available S 11.76 ppm. The experiment was laid out in a randomized complete block design with three replications. There were eight treatment combinations including T1 (Control), T2 (PU, 130 kg N/ha), T3 (USG, 130 kg N/ha), T4 (USG, 104 kg N/ha), T5 (USG, 78 kg N/ha), T6 (NPK briquette, 129 kg N/ha) and T7 (NPK briquette, 102 kg/ha) and T8 (NPK briquette, 78 kg N/ha). All the treatments except T6, T7 and T8 received 25 kg P and 64 kg K /ha as TSP and MoP, respectively. Treatments T6, T7, T8 received NPK briquette fertilizer. Prilled urea (PU) was applied in three equal splits. Urea super granule (USG) and NPK briquettes were applied at 10 day after transplanting (DAT) and the briquettes were placed at 8-10 cm depth in the centre of four hills in alternate rows. The results demonstrate that all the yield components except 1000-grain weight responded significantly to the deep placement of N fertilizers in the form of USG and NPK briquette. The grain and straw yields of BRRI dhan29 were also influenced significantly due to deep placement of N fertilizers under AWD condition. The highest grain yield (6163 kg/ha) was recorded for T3 [USG, 130 kg N/ha) which was statistically similar with T4 (USG, 104…

  • Impact of application of rock phosphate (RP) inoculated with phosphate solubilizing fungi (PSF) as a fertilizer on total nitrogen (TN), total organic carbon (TOC) and microbial count (MC) in clay soil

    In this study the effect of four treatments of phosphate fertilizers (NS, RP, SP & RP inoculated with PSF (A. niger & A. fumigatus) using three doses (RD, 1/2 RD&2RD) on TN, OC and MC of Nile delta clay soil and its impact on some growth parameters of phasoleous vulgaris was monitored. The Results indicated that OC content of clay soil was positively affected by the amendment of soil with inoculated RP. Inoculation of RP with A.niger culture increased the OC content of the soil by 4.91%, 18.28%, 14.38% and 19.61% comparing to A.fumigatus, NS, RP and SP respectively. the highest soil organic carbon content obtained when soil was amended with inoculated RP in 1/2RD it increased by 1.02% and 7.232% comparing to the amendment of with RD and 2RD. RP inoculated with A.niger culture clay soil showed the highest TN content when amended with 2RD the presence of phasloeus vulgaris plant it was 19.19%. Different phosphate treatments affected MC in clay soil to reach the highest count when inoculated rock phosphate with the RD as a fertilizer it increased by5.66% & 20.75% case of A.fumigatus & A.niger respectively comparing to NS. The lowest count obtained when SP was used as a fertilizer, it decreased by 26.4% comparing to NS.

  • Assessing Vegetable Growth and Yield Response to Graywater Irrigation

    The impacts of graywater irrigation on soil properties and vegetable yields were assessed through a three-year field experiment for Bell Pepper, Chile, and Tomato in El Paso, Texas in the United States. Two irrigation treatments including freshwater (well water and sand filter effluent) and graywater (laundry water) with three replications were utilized in the study. Duncan’s multiple range test at the significance level of 0.05 was used to test changes in soil properties including soil pH, salinity, and sodicity, and mean differences in vegetable growth and yields in terms of fruit height, fruit count, weight, and fruit sizes under freshwater and graywater irrigation treatments. The statistical analysis suggests that no evident salt accumulations or changes in salinity and sodicity were observed at the soil surface in the depth of 0-15cm, while soil pH is increased significantly with graywater irrigation. The growth and yield of Bell pepper and Chile under graywater irrigation tend to increase as compared to freshwater irrigation although the results for the third year were not significant. No yield decreases regarding fruit weight, fruit counts and fruit sizes were observed for all vegetables. It can be concluded from the experimental research that the graywater has shown promising potential as an alternative water supply for vegetable production in the El Paso region, Texas.

  • The Effect of N,N-Diethyl-3-methylbenzamide (DEET) on the Germination of Raphanus sativus (Radish Plants)

    DEET is one of the major chemical constituents of bug repellant with an estimated global use of 7 million liters in 2016. While there has been research concerning the health safety of bug repellent, research concerning its environmental impact is very limited. This study was designed to determine the impact bug repellent on the germination of plant seeds. The build-up of bug repellent found in water and soil was simulated by exposing radish seeds to various concentrations of repellent during the germination process. This two-phased experimental set up demonstrated a significant correlation between higher bug repellent concentrations and lower germination rates. Even in the group containing 0.01% concentration of repellent, only 60% of seeds germinated comparing to 93.3% in the control group on day 10. The differences in germination rates was found to be statistically significant (P=0.0025). The experimental groups with repellents also delayed the process of germination.

  • Natural resource modelling: accounting for gillnet size selectivity in dynamic deterrence model

    This paper applied the two times dynamic deterrence model (DDM) and relax the assumption of perfect size selectivity in gillnet in order to specify factors that determine violation rate. The method of comparative statics is employed to derive analytical results on the sensitivity of optimal violation to a number of key factors of high relevance to compliance with regulation designed to protect against over fishing. Analytical results obtained with this extended DDM confirm findings of earlier empirical studies. The study concludes that in developing country artisanal fisheries where probability of detection, enforcement and levels of fine are typically low, and poverty levels deriving high impatience about the future (discount rate) violation rates are bound to be high. The relative magnitude of the effects of each of these factors on compliance with regulation however, remains an important empirical question that requires further investigation for prioritization of policy actions.