Seasonal effects of Rhus lancea and Celtis africana on intake preference and physiological responses in South African indigenous goats

This study investigated the seasonal effects of Rhus lancea and Celtis africana leaves on preference, intake, weight, and serum metabolites in South African indigenous, mature, male goats. Twelve mature, male goats weighing 34 ± 5.9 kg (mean ± SD) were randomly allocated to two groups of six and kept in metabolic crates for periods of 21 days in October 2015 and March, May, and August of 2016. A browser diet of R. lancea and C. africana and a control diet (lucerne and concentrates) were randomly allocated to each group. Measurements taken included nutritional composition of browse per season, and browse preference, intake, weight changes, and serum metabolites in the goats. The acid detergent fibre (24–36%) and neutral detergent fibre (26.9–70.4 %) in R. lancea over the months were greater than in C. africana (50.3–53.2% and 49.4–55.4%, respectively). In the preference study, the goats preferred C. africana more in October (51.2 vs 48.8%), March (51.4 vs 48.6%), and May (54.3 vs 45.7%). Goats on the browser diet lost weight in March, May, and in August whereas those on the control diet gained weight. The serum urea concentration of goats consuming browser diets in May and August (1.8–3.3 mmol/l) was lower than the normal range, consistent with animals failing to derive their protein requirements from the diet. Goats prefer to browse C. africana more than R. lancea. The study also indicated the need for supplementation to meet maintenance requirements in animals fed R. lancea and C. africana.College of Agriculture and Environmental Science

Effects of soil amendments on bacterial wilt incidences and potato tuber yield across different environments in Malawi

This study investigated the effects of soil amendment on potato yield and incidences of bacterial wilt caused by Ralstonia solanacearum that can cause up to 80% yield loss in potato. The research was conducted at four research stations in Malawi during the 2020/21 and 2021/22 growing seasons, using a randomized complete block design (RCBD) with six treatments: lime, four Calciprill rates (CALC25%, CALC50%, CALC100%, and CALC150%), and NPK fertilizer (control). Data on soil properties, bacterial wilt incidence, and potato tuber yield were collected and analyzed using R programming. Soil fertility was found to be low, with a pH range of 4.4–6.05. Control resulted to significantly higher incidences of bacterial wilt at Kandiyani during 2020/21 (63.6%) and 2021/22 (34.6%) and at Lunyangwa during 2021/22 (20.4%) while lime and all levels of Calciprill led to relative incidence reduction (4%–89%) across sites and season, except CALC25% at Bembeke. Marketable yield showed interaction between amendments and season at Bvumbwe (p = 0.04), highest being 10.02 tha−1 in CALC150% during 2020/21 while non-marketable yield showed interaction at Lunyangwa (p = 0.02) highest being 3.9 tha−1 recorded in CALC150% during 2021/22. A significant negative correlation between bacterial wilt incidences and yield at all sites except Bembeke highlighted the importance of controlling bacterial wilt for yield improvement. The findings suggest that soil amendment through liming is an effective and sustainable approach for managing bacterial wilt and increasing potato yields. Further research on-farm conditions required to ensure the applicability of the findings for different sites