Nitrogen (N) and phosphorus (P) nutrient enrichment is important for grasslands. This study aimed to determine how soils enriched with N and P influenced soil concentration correlations and affected the growth kinetics, mineral nutrition, and nitrogen-use efficiencies of Vachellia sieberiana grown in a greenhouse experiment. The soils used as the growth substrate were analysed and showed extreme acidity (low soil pH, 3.9). Nitrogen-enriched soils were more acidic than P-enriched soils. Exchangeable acidity was strongly negatively correlated with an increase in soil pH, with soil pH between 3.9 and 4.1 units showing the strongest decline. Plant saplings showed increased root biomass, shoot biomass, total biomass, and plant N and P concentrations when grown in soils with high soil P concentrations. Extreme soil acidification in N-enriched soil was one of the main factors causing P unavailability, decreasing sapling growth. Extreme soil acidification increased concentrations of toxic heavy metals, such as Al which may be alleviated by adding lime to the extremely acidic soils. Research implications suggest that soil pH is an important chemical property of the soil and plays a significant role in legume plant growth. Legume species that are unable to tolerate acidic soils may acquire different strategies for growth and functioning.

The agricultural sector receives substantial support from livestock, which greatly contributes to the well-being of rural communities. Livestock offers animal-derived products, such as meat and milk, which serve as abundant protein sources for human consumption. While the majority of South Africa’s agricultural land is suitable for livestock farming within the smallholder sector, these farmers often face a variety of challenges. Among these challenges, there is insufficient access to superior forage resources, resulting in the limited availability of high-quality feed. Traditional nutrient sources for ruminants, such as soybean meal, grain, sunflower meal, and fish meal, are employed as supplementary feeds to provide exceptional nutrition and improve animal performance. Nonetheless, they present logistical, economic, and environmental challenges. To circumvent these challenges, smallholder producers have turned to leguminous trees, including Vachellia species and other locally available feed resources. They are utilized as feasible and cost-effective alternatives to supplement livestock, especially during periods of extended drought. However, these locally available feed resources exhibit inherent limitations, including thorn presence, high fiber content, low digestibility, and the presence of anti-nutritional and toxic factors. Cool season forage crops such as fodder radish present promising alternatives as autumn and winter forages for these farmers. Despite being widely used globally as a supplement for livestock during winter, fodder radish remains relatively underutilized, particularly among smallholder farmers. There is a scarcity of comprehensive information regarding its chemical composition, nutrient utilization, and remarkable potential to revolutionize livestock production, especially within the smallholder sector. Most of the available literature demonstrates the positive effects of fodder radish on soil structure, soil carbon and nitrogen levels, weed suppression, and other benefits. This paper systematically reviews the current state of knowledge on the nutritive value, opportunities, and challenges associated with the utilization of this crop in the cooler eastern regions.

Although condensed tannins (CTs) are known to reduce forage intake by mammalian herbivores in controlled experiments, few studies have tested these effects in the field. Thus the role of CTs on foraging ecology of free-ranging herbivores is inadequately understood. To investigate the effects of CTs under natural savanna conditions, we pre-dosed groups of goats with polyethylene glycol (PEG, a CT-neutralising chemical), CT powder or water before observing their foraging behaviour. While accounting for the effects of season and time of the day, we tested the hypothesis that herbivores forage in ways that reduce the intake rate (g DM per minute) of CTs. We expected pre-dosing goats with CTs to reduce CT intake rates by (1) consuming diets low in CTs, (2) reducing bite rates, (3) increasing the number of foraging bouts, or (4) reducing the length of foraging bouts. Lastly, (5) expected CT to have no influence the number of dietary forage species. In both wet and dry seasons, pre-dosing goats with CTs resulted in lower CT consumption rates compared to PEG goats which seemed relieved from the stress associated with CT consumption. During dry season, the number of dietary forage species was similar across treatments, although goats that were dosed with PEG significantly increased this number in the wet season. Dosing goats with PEG increased the number and length of browsing bouts compared to goats from the other treatments. Pre-loading goats with PEG also tended to increase bite rates on browse forages, which contributed to increased consumption rates of CTs. Based on the behavioural adjustments made by goats in this study and within the constraints imposed by chemical complexity in savanna systems, we concluded that herbivores under natural conditions foraged in ways that minimised CTs consumption. More research should further elucidate the mechanism through which CTs regulated feeding behaviour.

Feed scarcity is a major challenge facing free-range beef farming in semi-arid areas. Specifically, low quality and quantity of forage in rangelands and higher feeding costs are the main constraint...