Soil moisture-holding capacity data are required in modelling agrohydrological functions of dry subhumid environments for sustainable crop yields. However, they are hardly sufficient and costly to measure. Mathematical models called pedotransfer functions (PTFs) that use soil physicochemical properties as inputs to estimate soil moisture-holding capacity are an attractive alternative but limited by specificity to pedoenvironments and regression methods. This study explored the support vector machines method in the development of PTFs (SVR-PTFs) for dry subhumid tropics. Comparison with the multiple linear regression method (MLR-PTFs) was done using a soil dataset containing 296 samples of measured moisture content and soil physicochemical properties. Developed SVR-PTFs have a tendency to underestimate moisture content with the root-mean-square error between 0.037 and 0.042 cm³·cm⁻³ and coefficients of determination (R²) between 56.2% and 67.9%. The SVR-PTFs were marginally better than MLR-PTFs and had better accuracy than published SVR-PTFs. It is held that the adoption of the linear kernel in the calibration process of SVR-PTFs influenced their performance.

Improvements in the crop productivity, soil health, and sustainable intensification should be premised on the better understanding of interactions between the cropping systems and soil microbial diversity. In this study, we assessed variations in the microbial communities across the traditional banana-based cropping systems of contrasting monocrop vigor (vigorous or V vs. non-vigorous or NV) and the cropping system (monocrop or MC vs. intercropped or IC) using 16S rDNA (V3–V4) and ITS2 amplicon deep sequencing via Illumina platform. Sequencing results of the bacterial and fungal communities showed high variability among MC and V cropping systems. The abundances of Proteobacteria, Firmicutes, and Actinobacteria were significantly higher in NV (non-vigorous) and V (vigorous) cropping systems; and the abundances of Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes in the MC (monocropping) than IC (intercropping). There were high relative abundances of Pseudomonas (6.1–37.43%), Bacillus (4.5–20.4%), Rhizobium (1.4–6.5%), and Devosia (1.5–6.7%) in the cropping systems. The dominant family of fungal class Incertae_sedis was Mortierellales, which accounted for 8.79–41.12% of total taxa. This result indicated that the cropping systems are vital for supporting the dynamic microbial diversity specifically beneficial for bacterial communities that helps in promoting synergistic plant-soil interactions and total productivity under resource poor conditions of smallholder farmers in sub-Saharan Africa (SSA).

Background: Fermentation is defined as a biochemical process that produces energy using microorganisms from various raw material substrates. It is an ancient form of bio-preservation of food and improvement of its nutrient content. In addition to enriching the nutritional components of plant materials and preserving food, fermentation promotes the growth of beneficial microbes that play a role in human and animal health, especially in the digestive tract, commonly known as probiotics. Objectives: The current study investigated the fermentation of ripe banana, jackfruit seeds and sweet potato tubers to produce Bacillus subtilis and also examined the effect of fermentation on the biochemical properties of the plant materials used in the current study. The mentioned plant materials are the most cultivated crops in many parts of Uganda and generate a lot of food waste. Methods: The study was carried out at the soil laboratory of Mountains of the Moon University in Fort Portal tourism western Uganda. The solid fermentation of ripe bananas, jackfruit seeds and sweet potato tubers in this study was a natural process hence no inoculation of microbes onto the sample was done. Solid fermentation involved the putting the solid substrates into fermentation vessel with limited moisture. In every 3 days, temperatures, relative humidity and pH were monitored in the fermentation vessels to establish the conditions in which microbes are growing. Gram staining was done on the sub cultured microbial colonies to view the shapes of the cells and endospore structures of the Bacillus species. There were 2 biochemical tests performed on sub cultured colonies i.e. catalase test and starch hydrolysis to confirm the presence of the presence of Bacillus in the fermented samples of ripe banana, jack fruit seeds and sweet potato tubers. For catalase tests: the microbial colonies from nutrient agar on petri-dishes of ripe banana, jackfruit seeds and sweet potato tubers cultures were transferred and smeared on microscope slides. For starch hydrolysis tests, the sub cultured microbial colonies from ripe banana, jackfruit seeds, sweet potato and mix petri-dish were transferred to starch agar. Results: There was decrease in carbon-nitrogen ratio due to fermentation effect except the ripe banana which experienced an increase in carbon content from 2.44 carbon: 2.8 nitrogen to 3:12 carbon: 1.7 nitrogen. In additional to that, ripe banana produced high population of microbes with colony forming units of 1.6 · 104 on day 3.4 · 104 on day 6, 1.05 · 105 and 1.08 · 105 on day 12. Conclusion: All the fermented samples ripe banana, jackfruit seeds, sweet potato tubers and mixed samples contained Bacillus since their microbial colonies displayed rod shaped cells and gram positive and they tested catalase. Fermentation improves the biochemical properties of ripe bananas as evidenced by increase of crude proteins and fats and carbon. For samples jackfruit seeds, fermentation negatively affect the biochemical properties since they lost carbon, crude proteins and fat.