Browsing by Author "Gitari, Harun"

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    Exogenous Melatonin Application Improves Shade Tolerance and Growth Performance of Soybean Under Maize–Soybean Intercropping Systems
    (MDPI, 2025-08-01) Jia, Dan; Meng, Ziqing; Hu, Shiqiang; Nasar, Jamal; Shao, Zeqiang; Zhang, Xiuzhi; Amin, Bakht; Arif, Muhammad; Gitari, Harun
    Maize–soybean intercropping is widely practised to improve land use efficiency, but shading from maize often limits soybean growth and productivity. Melatonin, a plant signaling molecule with antioxidant and growth-regulating properties, has shown potential in mitigating various abiotic stresses, including low light. This study investigated the efficacy of applying foliar melatonin (MT) to enhance shade tolerance and yield performance of soybean under intercropping. Four melatonin concentrations (0, 50, 100, and 150 µM) were applied to soybean grown under mono- and intercropping systems. The results showed that intercropping significantly reduced growth, photosynthetic activity, and yield-related traits. However, the MT application, particularly at 100 µM (MT100), effectively mitigated these declines. MT100 improved plant height (by up to 32%), leaf area (8%), internode length(upto41%),grainyield(32%),andbiomassdrymatter(30%)comparedtountreated intercropped plants. It also enhanced SPAD chlorophyll values, photosynthetic rate, stomatal conductance, chlorophyll fluorescence parameters such as Photosystem II efficiency (ϕPSII), maximum PSII quantum yield (Fv/Fm), photochemical quenching (qp), electron transport rate (ETR), Rubisco activity, and soluble protein content. These findings suggest that foliar application of melatonin, especially at 100 µM, can improve shade resilience in soybean by enhancing physiological and biochemical performance, offering a practical strategy for optimizing productivity in intercropping systems.
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    Investigating the effect of seaweed extract and humic acid on the quantitative and qualitative performance of sugar beet under water stress
    (Islamic Azad University, 2025-01-16) Ajirlu, Tawakkel Fekri1; Farzaneh, Salim; Tobe, Ahmed; Sharifi, Rauf Seyed; Nouri, Mohsen; Gitari, Harun; Heydarzadeh, Saeid
    Water stress is one of the major limitations in crop production and performance stability. This study aimed to investigate the effect of biological stimulants on the quantitative and qualitative performance of sugar beet under drought stress. A field experiment was conducted to evaluate the effect of irrigation regimes (irrigation after 80, 160, 240, and 320 mm of water evaporation from the class A pan) and the application of biological stimulants at 5 levels (control, seaweed extract at 3 and 6 kg ha⁻¹, humic acid at 3 and 6 kg ha⁻¹). The results showed that the highest gross sugar (15.99%), extraction coefficient (77.31%), and pure sugar (12.37%) were obtained under irrigation conditions after 240 mm of water evaporation, while the highest levels of sodium (16.4%) and nitrogen (3%) were ob tained under irrigation conditions after 320 mm of water evaporation. The use of biological stimulants caused a significant increase in gross sugar and pure sugar and a reduction in sodium and nitrogen compared with the control treatment. The maximum root yield (74.06 t ha⁻¹) and pure sugar yield (8.42 t ha⁻¹) were obtained in the foliar application of 6 kg ha⁻¹ of humic acid under irrigation conditions after 80 mm of water evaporation. In general, 6 kg ha⁻¹ of seaweed extract and 3 kg ha⁻¹ of humic acid under moisture stress conditions reduced sugar beet root impurities such as sodium and harmful nitrogen. As a result, the efficiency of root sugar extraction was significantly improved, and the sugar percentage of molasses was reduced
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    Review of Scientific Advances and Importance of Biochar for Agricultural and Industrial Uses
    (International Journal of Bioresource Science, 2024-12-07) Mwadalu, Riziki; Ndufa, James; Maitra, Sagar; Gweyi-Onyango, Joseph; Gitari, Harun
    Biochar has been known as an effective soil amendment with capabilities of boosting soil moisture storage, increasing soil fertility, and enhancing crop productivity. Biochar also has the potential for industrial use for wastewater treatment, water purification, steel making, building insulation, and air pollution control. The current metadata analysis evaluated the importance of biochar for agricultural and industrial uses and its relevance for use in Kenya. A total of 120 reference materials comprising journal papers, conference proceedings, and book chapters were used. Numerous studies conducted across the globe have documented the positive effects of biochar in increasing available soil nutrients (increased by 28.6% and phosphorus by 2 folds), lowering bulk density by 3-31%, enhancing soil moisture storage by 18-108%, and boosting microbial activities in the soil thus enhancing nutrient cycling. The metadata analysis also showed that biochar can reduce CO2 emissions by up to 33% thereby mitigating climate change. Biochar equally increased maize yield by 32-135% and rice yield by 8.5-10.7%. The review also showed that biochar can play a crucial role in different industrial uses such as wastewater treatment, steel making, and water purification. Some of the main impediments to the adoption of biochar were; the lack of a regulatory framework to govern the sector and the lack of a decision support system for use by end users.
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    Spatial Distribution of Soil Organic Carbon Stocks, and Soil Total Nitrogen in Central Equatorial State, South Sudan
    (International Journal of Bioresource Science, 2024-12-06) Malo, Meshack Oguna; Ladu, John Leju Celestino; Mukeka, Joseph; Maitra, Sagar; Gitari, Harun; Onyango, Joseph Gweyi
    The composition of soil organic carbon (SOC) and soil organic nitrogen (SON) is imperative to soil health in different agroecological zones globally. The proliferation of anthropogenic activities triggers the nitrogen and carbon stocks in soils. This study presents the spatial distribution of SOC and SON in six counties in Central Equatoria State, South Sudan counties. This study sought to determine the effect of pastoral activities on SOC and SON. We collected the soil samples within a 12-14 km radius from specific areas including congregation, grazing, degraded, water points, and agricultural land. The soil was collected at depths of 0–10 cm, 10–20 cm, and 20–30 cm respectively. The results indicate that land use activities had varied impacts on SOC and SON at different depths. The results showed that the interactive effects of the three sites and land uses differed in soil organic carbon (SOC) under different soil depths, which varied from 0.3 to 5.3%. The grazing area also recorded a higher SOC than the other land use types under 0-10 cm soil depth. The means showed that the SOC in the deep soils (20-30 cm) was lower than the surface soils in all the areas and land uses. The interactive effects of the districts and land uses differed in soil organic carbon (SOC) under different soil depths, which varied from 0.3 to 5.3%. The highest mean SOC of 5.73% was recorded in 0-10 depth in Kajokeji in the grazing area. The grazing area also recorded a higher SOC than the other land use types under 0-10 cm soil depth. The means showed that the SOC in the deep soils 20-30 cm was lower than the surface soils in all the areas and land uses. The results thus underscore that study areas and land use activity could impact the SOC and SON directly or indirectly.
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    Sustainable fodder production in South Asia through silvopastoral systems
    (Current Science, 2024-05-25) Sow, Sumit; Ranjan,Shivani; Kumar, Navnit; Nilanjaya; Gitari, Harun; Daya, Parmeswar; Kumar, Sanjay
    Silvopasture is a farming practice involving the integration of tree and livestock grazing operations on the same land. Intensive management of these systems enables them to generate short and long-term economic returns from forest products and forage. Silvopastoral systems have been considered to increase efficiency while reducing the environmental burden and extreme ranching/animal husbandry systems. Over the past few years, there has been a rapid accumulation of scientific evidence supporting the role of silvopasture in meeting the fundamental needs of not only humans but also the animal population in the era of climate change. In South Asian countries like India, the silvopastoral system can be a viable option to provide balanced food as well as shelter for the livestock. This review aims to provide a critical and systematic evaluation of the scientific literature about the effect of different silvopasture systems on the fodder production, environment and performance of livestock, especially in the context of South Asia. We conducted a search using PubMed, Scopus, Science Direct, Web of Science and Google Scholar to identify the key literature on the theme. A total of 98 manuscripts underwent a four-step PRISMA appraisal process, resulting in the final selection. This process resulted in a final sample of 56 articles, which were used to explore the potential for long-term improvement in fodder quality through expanding the silvopastoral system. One of the key conclusions is that by improving the social acceptability of these silvopastoral systems and also addressing the challenges, their economic and environmental sustainability can be further enhanced.
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    Synergetic Effect of Potassium, Biochar and Cattle Manure on the Growth and Yield of Maize, and Soil Physio-Chemical Characteristics
    (MDPI, 2024-11-24) Shao, Zeqiang; Zhang, Xiuzhi; Nasar, Jamal; Gitari, Harun
    Biochar (BC) and cattle manure (CM) are carbon-nutrient-rich organic substances and have long been used to improve crop yield and soil fertility. Nevertheless, their combined effect with potassium (K) fertilizer remains unknown. Against the previous context, a 2-year (2021–2022) field experiment was conducted to assess the effect of K fertilization coupled with BC and CM on the growth and yield of maize and soil physio-chemical characteristics. The K application combined with BC and CM increased (p ≤ 0.05) the majority of the growth indices of maize crop compared with CK. Compared with CK, the combined application of K (60 kg K ha−1) with BC and CM resulted in an increased number of seeds cob−1 by up to 451 and 465, and up to 383 and 396, the 1000-seed weight up to 22 and 23 g, and up to 27 and 34 g, and the grain yield up to 1979 and 2900 and up to 3240 and 3341 kg ha−1, respectively, in 2021 and 2022. The integrated application of these inputs increased the chlorophyll of maize crops by 29 and 36% and by 30 and 44%, respectively, in 2021 and 2022. Such application also increased the photosynthetic activities of maize such as transpiration rate (Tr), stomatal conductance (Gs), and photosynthetic rate (Pn) by 21 and 23%, 143 and 110%, and by 64 and 66% in 2021 and by 19 and 30%, 163 and 118%, and by 63 and 72% in 2022. Similarly, the combined application of K, BC, and CM increased the K uptake of maize due to an increase in the soil extractable K. Equally, soil total N and organic matter improved under the combined application of K, BC, and CM. However, it did not affect the soil extractable P in 2021 but increased it in 2022. Conversely, these applications reduced (p < 0.05) the soil electrical conductivity, sodium adsorption ratio, and bulk density. This suggests that K fertilization combined with BC and CM enhances the growth and yield of maize by improving the soil nutrients availability, increasing soil organic matter, and enhancing soil structure and moisture retention.