No description available.

Improved N management is required to enhance crop productivity, while reducing concomitant losses. Research was conducted for 4-y studying winter cover crops. Three legume species grown alone or with either cereal rye (Secale cereale) or ‘Tillage Radish®’ (Raphanus sativus L.) were used to quantify cover crop biomass and N content plus their effects on corn grain yield and N recovery. The effects of these cropping systems on selected soil health indicators was also determined. Rye bicultures enhanced biomass production, but antagonistically affected corn performance. Radish inclusion resulted in equal or greater cover crop N than rye. In year 3, the addition of radish across legume species increased corn N content (10.6 kg ha-1) and grain yield (1050 kg ha-1). Although cover crops did not affect soil bulk density, both bicultures increased soil C/N. The legume-radish association offers a novel practice towards improving crop performance and soil quality.

Iron deficiency chlorosis (IDC) is a frequent problem in soybean [Glycine max (L.) Merr.] production on calcareous soils. Greenhouse and soil incubation experiments were established to evaluate pyritic lignite efficacy to supply Fe as compared to Fe-EDDHA and Fe-EDTA sources across contrasting IDC tolerance varieties grown on a slightly acid and a calcareous soil. Soybean IDC incidence was influenced by the soil properties and variety tolerance. All iron sources increased plant dry matter accumulation on the Leeper soil, whereas on the Marietta soil only lignite at 0.672 kg ha-1 produced an increase. Lignite at 0.336 kg ha-1 successfully improved Fe availability to the plant as reflected by an increase in Fe content. Furthermore, no differences were found between the low rate of lignite and the commercial fertilizers on any of the evaluated parameters. Results from this study indicate that pyritic lignite may serve as an acceptable source of Fe on problem soils to prevent IDC.

No description available.

Drought, salinity, and low soil fertility have negative impacts on agricultural productivity, resulting in food scarcity and nutritional insecurity, particularly in Sub-Saharan Africa. Mungbean [Vigna radiata (L.) R. Wilczek] has seen increased interest as a short-duration and drought tolerant legume crop, capable of atmospheric N₂ fixation. Mungbean is a protein and iron-rich legume and can be used as vegetable or grain for human consumption or multipurpose crop. At present, few studies have simultaneously explored the best agronomic practices for mungbean cultivation and evaluated its potential for increasing crop yields via intercropping systems and improving soil fertility through biological N₂ fixation. To understand the agronomic practices and soil physical properties limiting mungbean production, the impacts of two mungbean cultivars (Berken and OK2000) with and without inoculation with Bradyrhizobium spp. grown in loamy sand and silt loam soils on mungbean growth and yield were investigated under glasshouse conditions. Promising results from this study led to the introduction of mungbean into pearl millet systems in Senegal and evaluation of the effects of intercropping on growth, yields, land equivalent ratio (LER), canopy cover estimates, and normalized difference vegetation index (NDVI). Finally, we evaluated plant growth and N₂ fixation of five mungbean genotypes grown in two soil textures using the ¹⁵N natural abundance technique leading to recommendations for those with the greatest overall benefit to the cropping system. The literature review shows mungbean often proposed as a strategic crop for increasing legume diversification within current cropping systems and providing increased food security as well as market diversification and economic sustainability. The greenhouse study revealed that OK2000 cultivar produced significantly higher yield when inoculated and planted on a silt loam soil than other treatments, indicating the importance of inoculation and soil texture in mungbean establishment. Intercropping mungbean and millet significantly (p≤ 0.05) increased combined yields (35% to 100% increase) and LER compared to sole millet cropping systems. Canopy cover estimates and NDVI values significantly increased up to 60% and 30%, respectively, in millet-mungbean intercropping over millet alone. The N2 fixation study showed that %Ndfa of mungbean was higher when grown in the loamy sand soil (27% increase). However, soil N uptake (235 mg plant⁻¹) and amount of N fixed (67 mg plant⁻¹) were greater in the silt loam soil. Among genotypes, IC 8972-1 significantly (p≤ 0.05) derived less N from the atmosphere (23%) but took more soil N (155 mg plant⁻¹) which yielded significantly greater dry biomass (7.85 g plant⁻¹) and shoot N content (200 mg plant⁻¹). The results from the N₂ fixation study indicated that choice of mungbean genotype can contribute to reducing N needs of agricultural systems. Overall, this research project demonstrated that mungbean has the potential for diversifying smallholder agriculture and adding biologically fixed N into soils, in line with transformative adaptation strategies being promoted for sustainable agriculture. Further research and development programs on good cultural practices, adaptation to cropping systems, and nutritional benefits for human consumption can promote mungbean cultivation in SSA. / Doctor of Philosophy / Global population growth is expected to reach 9.8 billion in 2050 while climate change is predicted to reduce food production. Sustainable solutions are needed for increasing food availability and satisfying nutritional needs under changing climatic conditions. Mungbean is a viable option because it is a legume crop capable of restoring soil fertility and has low water requirements. Mungbean also contains high levels of protein and iron and can, therefore, provide a nutritious and healthy food. Although the agronomic benefits of mungbean have been studied, best cultural practices and its impact on farming systems and soil fertility are scattered. The objectives of this research were to identify the best agronomic practices for mungbean production, assess its effects when grown together with millet, and measure its nitrogen contribution to the soil. The results showed that selecting the best genotypes to be grown in a particular soil texture can significantly increase mungbean growth and yield. In addition, incorporation of mungbean into cereal-based farming systems demonstrated its capacity for improving agricultural production in a low-input environment. Assessment of nitrogen fixation by mungbean showed that it can naturally add nitrogen into the soils, the most limiting plant nutrient, reducing nitrogen application needs. Thus, the ability of mungbean to diversify farming systems, improve soil fertility, and deliver nutritious food will provide agronomic, environmental, and economic benefits to farmers, especially in food-insecure households. However, exploitation of the full potential of mungbean won't be achieved without understanding the major factors influencing mungbean cultivation and production.

In general, the yields of alfalfa were increased by varying amounts of various fertility elements on the Norfolk sandy loam soil type at Williamsburg, Virginia. The yields of corn grown on the Hagerstown silt loam soil type at Blacksburg, Virginia, correspond closely to the fertilizer treatments and their availability. The milligrams of phosphorus absorbed by rye seedlings show no relation to the amounts of phosphorus added to the soil in fertilizers. In fact, in most trials the amount absorbed from treated plats was less than the amount produced from sand checks. It seems that all the phosphorus obtained came from the seed and not from the soil. From the studies reported herein, therefore, it must be concluded that the Neubauer seedling method is not applicable for determining the phosphorus requirements of the soil types used in this investigation. / M.S.

MSCAGR (Soil Sciece) / Department of Soil Science / In most parts of Limpopo Province of South Africa, crop yields are low and continue to decrease due to decline in soil fertility, which has been identified as a major constraint to crop production. Therefore, there is a pressing need for soil amendments such as the application of biochar, which has the potential to improve soil fertility due to its physical and chemical properties. Biochar is the product of incomplete combustion of biomass in the absence of oxygen. The overall objective of the study was to determine the effects of biochar and NPK fertilizer on maize performance and selected soil nutrient levels. A 3x2 factorial experiment was conducted at the School of Agriculture Experimental Farm for two consecutive seasons (2015/16 and 2016/17 seasons). Treatments consisted of biochar applied at three levels, viz. 0, 10 and 20 t/ha and NPK inorganic fertilizer applied at two rates viz. NPK0 (zero NPK fertilizer) and NPK1 {N (150 kg/ha) P (50 kg/ha) K (20 kg/ha)}. The treatments were laid out in a randomized complete block design (RCBD) and replicated three times. Maize cultivar (DKC 2147) was used as the test crop. Maize growth and yield measurements assessed included: plant height (cm), stem diameter (cm), number of leaves, leaf area, dry biomass (kg/ha), nutrient uptake, cob yield, grain yield and harvest index. Soil samples were collected from 0-10 cm and 10-20 cm soil depths at the end of each season to determine total N, P, K nutrient levels in the soil. Data collected was subjected to two-way analysis of variance using the general linear model (GLM) procedure of Genstat software version 17. Comparison of means was done using the Standard Error of Deviation (SED) method at 5% level of significance (p<0.05). Biochar and NPK fertilizer had no effect on total N and exchangeable K at all soil depths in 2015/16 and 2016/17 seasons. Biochar had no effect on phosphorus at all soil depths in 2015/16 and at 0-10 cm soil depth in 2016/17 season. The effect of biochar and NPK fertilizer was highly significant (p<0,001) on available P at 10-20 cm soil depth in 2016/17 season. Significant interactive effect of biochar and NPK fertilizer on soil total N at 10-20 cm (in 2015/16 season), available P and exchangeable K at 10-20 cm soil depth in 2016/17 season was also observed. Plant growth parameters increased with biochar addition at 20 t/ha and NPK1 (150 kg N/ha, 50 kg P/ha, 20 kg K/ha) fertilizer. The results of this study showed that biochar application at the rate of 10 and 20 t/ha has the potential to influence selected soil nutrient levels, maize growth, yield and yield components with and without NPK fertilizer application. Since this study was conducted over two seasons and biochar properties changes over a long-term period, more research is needed to evaluate the effect of biochar on soil nutrient levels and maize growth, nutrient uptake and yield over a long period of time. / NRF

Thesis (M.Sc. Agriculture. (Soil Science)) -- University of Limpopo, 2022 / The constant growth experienced by the coffee industry has led to the high-volume production of coffee waste worldwide. One of the main coffee wastes is spent coffee ground (SCG), a residue obtained after the ground coffee beans are treated under pressure. The present study was aimed to investigate the utilization of SCG to amend soil physicochemical properties. This study was conducted at Greenhouse Biotechnologies Research Centre of Excellence, University of Limpopo, South Africa, where the effect of various rates of SCG concentration in volume percentage (vol%) was tested for a period of nine months. The spent coffee ground residue was collected from four restaurants at Haenertsburg, and the application rates were 0, 5, 10, 20, 30, 50 vol%. To evaluate the change in soil physicochemical properties overtime, the incubation period was divided into four test periods namely T1 was after a month, T3 after 3 months, T6 after 6 months, and T9 after 9 months. Physicochemical properties including nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), total organic carbon (TOC), cadmium (Cd), copper (Cu), nickel (Ni), zinc (Zn), and lead (Pb), pH, electrical conductivity (EC), C:N ratio, large macroaggregates (LM), small macroaggregates (sM), microaggregates (m), unaggregated silt and clay (s+c), mean weight diameter (MWD) and soil moisture content (SMC) were quantified at the end of each test period. Results revealed that the interaction between incubation periods and various SCG application rates significantly (p<0.05) increased pHw, EC, MWD, LM, base cations and significantly decreased TOC, heavy metals, SMC, m, and sM. Spent coffee ground increased pHw and EC of the soil at all application rates and reached a maximum of 7.8 units at T6 in treatment SCG-5 and 202.30 S/cm at T9 in treatment SCG-50 above the control respectively. Total organic carbon increased by 548% above control in the highest treatment (SCG-50) at T1, but, however, started declining from T3 in all treatments across the incubation period. SCG’s highest application rates (SCG-20 to SCG-50) reduced the soil Cd toxicity (threshold of >2 mg/kg), but however, also reduced the availability of micronutrients (Cu and Zn) during the incubation period. At T9, Mg, Ca, K, and P increased from mean values of 55.9 to 77.9, 40.9 to 62.2, 77.4 to 112, and 22.0 to 30.0 mg/Kg above control in treatments with high application rates. LM increased whilst sM, and m decreased across the incubation period in all treatments. MWD increased by 46% at T1 and reached its maximum of 56% at T6 in treatment SCG-50 above control. Additionally, there was a positive relationship between LM and MWD. Soil moisture content however increased to 60.26% at T1 in treatment SCG-50 and decreased from T3 across the incubation period. Spent coffee ground has the potential to be used as a liming material, a chelating agent, and for water management in semi-arid areas. It retains and cycles nutrients and improves soil structure through aggregation. However, research should be done in field conditions to access the effectiveness of this residue. / NRF

No description available.

Thesis (MTech (Agriculture))--Cape Peninsula University of Technology, 2015. / A study was carried out at Bien Donné Experimental Farm, near Paarl in the Western Cape Region (South Africa), to evaluate the performance of solid winery waste compost (WWC) and inorganic fertilizer (N:P:K, 2:3:4 (30) - 5g Zn%) on growth and yield of cabbage (Brassica oleracea var. capitata L.) and Swiss chard (Beta vulgaris subsp. cycla). The experimental plot was fertilized as per treatment with WWC (100% and 400% equivalent recommended fertilizer application using N as reference mineral) and inorganic fertilizer. The experimental design was set up in a Randomized Complete Block Design (RCBD) with 4 treatments (control- without compost and inorganic fertilizers, inorganic fertilizer-2:3:4 (30) - 5g Zn% and LAN (28), WWC application at different application rates were (3485g/plot) (100%) and (13939g/plot) (400%)) replicated four times. Soil analysis showed that the experimental plot is dominated by sandy soil structure. Results of mineral analysis after application of treatments showed a significant (p>0.05) drop in soil pH over time in the untreated control and application of 400% WWC significantly (p<0.05) raised soil pH compared with the control. The application of mineral fertilizer showed significant (p<0.05) increase in soil P compared with the other treatments. However, WWC picked up significant (p<0.05) speed above inorganic fertilizer, thus making P available to the soil than NPK mineral fertilizer. A significant (p<0.05) drop in soil K content by 21% over time on amended soil with inorganic fertilizer treatment was observed. However, the application of WWC at 300 and 400% significantly (p<0.05) raised the soil K by 54.93 and 73.06% respectively. There were no significant differences in soil Ca over time, but high soil Ca concentrations from WWC (100%) were recorded compared to inorganic treatment that showed the lowest soil Ca concentration. There was a slight drop in soil Na over time in control and soil amended with inorganic fertilizer. The effects of the treatment on Mg values were not so prominent, suggesting that concentrations of nutrients are less essential characteristics of the soil or small portion of nutrients were readily available on the soil.