Understanding the mechanisms by which plants cope with environmental stresses is critical for gaining an understanding of the likely effects of global climate change on species and communities. In Afro-temperate grasslands of southern Africa, increasing abundance of evergreen C3 grasses may displace C4 grasses and impact fire regimes. Using a pot experiment in a greenhouse, we evaluated the effect of the addition of limestone ammonium nitrate (LAN) fertiliser on the performance of a C3 grass, Festuca costata, when subjected to defoliation treatments (i.e. no defoliation, defoliation of F. costata, defoliation of a neighbouring plant and defoliation of both F. costata and a neighbouring plant). The F. costata plants were grown in different neighbourhood types, i.e. F. costata?growing alone, growing with Themeda triandra,?or with Aristida junciformis. At six-week intervals over a five-month period, we counted the number of tillers on F. costata and concurrently measured above-ground biomass production by clipping the target plants at 50 mm aboveground, tuft circumference, and specific leaf area (SLA).?The effect of the treatments on these dependent variables was compared using generalised linear models. Nutrient addition showed a significant negative effect on the number of tillers of F. costata and tuft size but showed no significant effects on above-ground biomass production and SLA. Defoliation significantly reduced above-ground biomass production, number of tillers and tuft circumference while SLA increased. Plant neighbourhood types showed significant negative influences on tuft circumference. The interactions between defoliation of the focal plant and F. costata growing with A. junciformis were significant. Defoliation accounted for the most variations in reduced tuft size, above-ground biomass and number of tillers, however, it resulted in increased SLA. Consequently, a management strategy using selective herbivory may alter the relative dominance on common C3 species in the high altitude range of the Drakensberg grasslands.

Bush encroachment/thickening by Senegalia mellifera (black thorn) has long been considered as an environmental and economic problem in the rangelands of Namibia and other southern African countries. Recently, harvesting bush thickets (encroacher bushes) and manufacturing various products from these woody plants has gained popularity. Among various products, bush-based feed production has gained special interest from farmers, as it has the potential to enhance livestock feed availability. The objective of this study was to determine the dry matter intake (DMI), apparent digestibility and nitrogen retention of Boer goats fed with S. mellifera bush-based feeds treated with tannin deactivating methods. Eight female Boer goats, with an average initial body mass of 31.5 ± 2.5 kg were randomly assigned to a total mixed meal ration made of 40% of browse plant (S. mellifera), 25% crushed yellow maize, 25% marula cake press and 10% minerals and vitamins. The four treatments; wood ash (WA), polyethylene glycol (PEG) and biochar (BIO) were evaluated against the control (CNT) diet as tannin deactivation treatment methods and were added in a powder form at a level of 5 g per day during feeding time. Goats were penned individually in metabolic cages where total faecal and urine outputs were determined. Goats were fed in a 4 × 4 cross over Latin Square Design with two goats assigned per diet during the four experimental feeding periods. Each period lasted for 17 days (10 days of adaptation and 7 days of data collection). Goats were fed the meal diets twice daily at 09:00 h and 16:00 h. All diets had a protein content of 14% and neutral detergent fibre of 41%. The level of dry matter (DM) of feed offered was 4% of body weight. The study showed that the apparent digestibility coefficient of DM, organic matter and neutral detergent fibre were not significantly different (p  > 0.05) among treatments and the control diet. Goats fed BIO treated diet had the highest (p < 0.05) nitrogen intake of 13.7 g/d, faecal nitrogen of 8.43 g/d and nitrogen retention of 5.11 g/d, while goats fed the control diet, PEG and WA were similar (p > 0.05). All treatments resulted in positive nitrogen retention (p > 0.05) with mean values ranging from 3.79 to 5.11 g/d. There were a lower DMI and nitrogen balance (p  < 0.05) in Boer goats fed with S. mellifera feeds treated with WA, PEG, and BIO compared with the control diet. The study concluded that the high protein content (14%) of the S. mellifera bush based feeds, if treated with WA, PEG or BIO and mixed with various agricultural by-products such as marula oil cake press can be considered as a suitable supplement for poor quality (low nitrogen content) natural pastures and crop residues such as grass hay, straw and stover. The study, therefore, recommends that each detannification method should be tested at different rates of inclusion in S. mellifera bush-based feed resources.

The causes of woody plant encroachment are many, and the encroachment effects on ecosystem processes and functioning have been limited in extent and confined largely to pastoral land uses or particular geographic regions. Consequently, hindering the trade-offs that need to be considered when controlling or managing encroaching woody species. The aim of this study was to investigate the interaction effect of fire, soil depth, and Seriphium plumosum canopy cover in the semi-arid grassland on components of soil fertility; potassium (K), phosphorous (P), magnesium (Mg), total nitrogen (TN), sodium (Na), calcium (Ca), soil organic carbon (SOC), and pH. Data were analysed as a complete randomised design with 3 × 1 factorial analysis of variance using GLM procedure. There was a significant interaction effect of fire x soil depth on K, P, Mg, TN, Ca, SOC, and pH (p < 0.05). Potassium content was the same as the subsurface soil after (79 ± 5.22 mg/kg) and before (74 ± 3.01 mg/kg) fire and significantly lower than at the surface soil before fire (115.04 ± 4.98 mg/kg), which was also significantly lower than at the surface soil after fire (152.83 ± 8.98 mg/kg). Phosphorus content was the same as the subsurface soil after (2.36 ± 0.20 mg/kg) and before fire (2.27 ± 0.16 mg/kg), but significantly lower than at the surface soil before fire (4.22 ± 0.18 mg/kg), which was also lower than after fire (6.50 ± 0.29 mg/kg). Magnesium content at the subsurface soils before (39.53 ± 2.19 mg/kg) and after (40.10 ± 3.09 mg/kg) fire were similar and significantly lower than at the surface soil before burning (53.44 ± 3.52 mg/kg), which was significantly lower than after burning (75.23 ± 5.28 mg/kg). Calcium content at subsurface soils before (97.43 ± 5.27 mg/kg) and after (94.29 ± 7.37 mg/kg) fire were similar and significantly lower than at the surface soil before fire (136.97 ± 8.16 mg/kg), which was also significantly lower than after fire (189.72 ± 11.31 mg/kg). Soil organic carbon (SOC) content at subsurface soils before (1.30 ± 0.03 mg/kg) and after (1.25 ± 0.02 mg/kg) fire were similar and significantly lower than at the surface soil before (1.50 ± 0.03 mg/kg) and after (1.61 ± 0.04 mg/kg) fire, which were similar. Soil pH level at subsurface soils before (4.70 ± 0.02 mg/kg) and after (4.74 ± 0.02 mg/kg) fire was similar and significantly lower than similar surface soil before (4.87 ± 0.03 mg/kg) and after burning (5.02 ± 0.03 mg/kg). The result suggests that S. plumosum encroachment has no effect on soil fertility, while fire may contribute to improving soil fertility, especially on the soil surface, thus improving conditions for S. plumosum seed germination and recruitment. 

Brachiaria grass is one of the most important tropical forages native to Africa. It is adapted to drought and low fertility soils, and known for palatability and high-quality biomass production, and thus improves livestock productivity. Due to these desirable attributes, Brachiaria grass has become increasingly popular among livestock farmers in Africa. However, the susceptibility of Brachiaria grass to diseases has been observed as an emerging challenge to the sustainable production of the grass in Africa, and current knowledge on the diseases affecting Brachiaria grass in Africa is inadequate. Therefore, this study was carried out to assess incidence, severity, and distribution of Brachiaria grass diseases in Bugesera, Huye, Nyagatare, Nyamagabe and Rwamagana districts representing five agro-ecological zones of Rwanda during the dry (July–August 2018) and wet (November 2018–January 2019) seasons. A total of 25 and 75 Brachiaria fields were surveyed in the dry and wet seasons, respectively. Disease incidence and severity were assessed on 20 stools per field from four different quadrats following established procedures. Leaf blight, rust, and leaf spot were the major Brachiaria diseases in Rwanda. The surveyed districts significantly (p < 0.001) differed in the incidence and severity of all the three diseases in both seasons. Leaf blight incidence ranged from 26% to 72% in the dry season and 24.7% to 64% in the wet season. Rust incidence ranged from 20% to 47% in the dry season and 11.3% to 47.7% in the wet season. Leaf spot incidence ranged from none to 56% in the dry season and 3.7% to 66% in the wet season. Similarly, leaf blight severity ratings ranged from 0.62 to 1.92 in the dry season and 0.37 to 1.14 in the wet season. Rust severity ratings ranged from 0.68 to 1.55 in the dry season and 0.24 to 0.86 in the wet season. Leaf spot severity ratings ranged from none to 1.85 in the dry season and 0.14 to 0.99 in the wet season. Huye, Nyamagabe and Bugesera districts had the highest incidence and severity of leaf blight, rust, and leaf spots diseases, respectively in both seasons. This study showed leaf blight, rust and leaf spots as emerging disease challenges for sustainable production of Brachiaria grass in Rwanda. This warrants immediate attention towards the development of effective management methods that are affordable to smallholder farmers in Rwanda. 

The interaction between arbuscular mycorrhizal fungi (AMF) and Rhizobium bacteria is known to enhance N fixation and nutrient uptake on the plant host. Soil microorganisms commonly known as biofertilisers can be used to decrease input of fertilisers, pesticides and other chemicals in agriculture. By doing so, they increase soil fertility, elevate soil pH, and nutrient availability in the soil profile. To support this view, the current experiment was conducted to study the influence of AMF and Rhizobium inoculation on soil physiochemical properties in field grown forages legumes in Alice, South Africa. Three forage legumes were sown in the field trial, being cowpea, lablab, and mucuna. This was laid out in a complete randomised block design with four replicates per treatment. There were twelve treatment factors as follows (cowpea control; cowpea+AMF; cowpea+R; cowpea+AMF+R; lablab control; lablab+AMF; lablab+R; lablab+AMF+R; mucuna control; mucuna+AMF; mucuna+R; mucuna+AMF+R). Soil analyses were done prior to planting, during the early stage, and after harvesting the forage legumes. The soil chemical properties were determined using standard procedures. It was observed that the addition of dual inoculation over time greatly improved soil physiochemical properties compared to the control, which resulted in improved soil condition. This was advocated by a significant (p < 0.05) increase in soil pH, SOC, SOM, and concentration of macronutrients (total N, P, Ca, K, Mg, Na, S, and Fe) on soil varying from mucuna and cowpea legumes. On the other hand, the concentration of CEC was significantly (p < 0.05) higher on cowpea treated with Rhizobium compared to other treatment combinations. The control treatment of mucuna forage greatly improved (p < 0.05) the concentration of micro minerals (Mn, B, Cu, Mo, and Zn) over other treatment combinations only before the flowering stage. However, after harvesting the concentration of micro minerals were significantly higher on the treatment combination of lablab and single inoculation of AMF. Thus, it can be concluded that interactive effect of AMF and Rhizobium inoculation has the potential to increase some soil properties including soil pH, SOC, SOM and concentration of macro nutrients (total N, P, Ca, K, Mg, Na, S, and Fe). However, it did not significantly affect the concentration of some micro minerals and the concentration of micro minerals efficiency was differentiated by control treatments.

The main aim of the study was to determine different inclusion levels of Opuntia–Moringa (OPM) silage to Cenchrus ciliaris (blue buffalo grass) on growth performance and carcass characteristics of mutton merino wethers. The chopped Opuntia cladodes and ground Moringa leaf meal was mixed at a ratio of 60 Opuntia cladodes: 40 Moringa and prior to ensiling, microbial inoculants and molasses were added and ensiled for 42 days. The composition of the diet was chemically analysed and the experimental diets were 0 (OM0), 50 (OM50), 100 (OM100), 150 (OM150), and 200 (OM200) g/kg DM, producing five dietary treatments. The experimental design was a completely randomised design. Thirty (30) mutton merino wethers were treated for internal parasites and vaccinated for heart water and pulpy kidney one week before the trial commenced. Growth performance was measured for a period of 30 days and carcass characteristics were measured upon slaughter at the end of the feeding period. The effect of the experimental diets on the final body weight showed that there was a significant differences (p < 0.05) among the dietary treatments. The higher final body weight observed in the diet containing 20% silage could be ascribed to better protein quality and mineral contents of the silage. This is because Moringa has been reported to have a very good amino acids profile and is also rich in mineral content. It could also be due to higher feed intake and a better feed conversion ratio. The higher weight gains in the diet containing 15% and 20% silage may be due to a better protein quality, likely arising from higher methionine supply as well as lysine. Methionine and lysine are normally required for optimum growth in animals. The best feed conversion ratio was obtained in the diet containing 15% and 20% silage. The poorer feed conversion ratio in control, 5% and 10% could be due to lower feed intake and weight gain. The significant higher feed intake obtained in the diet containing 15% and 20% silage may be due to its higher protein quality, greater palatability and higher protein content of the diet. This is in line with the statement that diets high in protein content increase intake. Intake, body weight, weight gain and carcass weight showed improvement when the blue buffalo grass was supplemented with the OPM silage diet. The wether fed diet containing 15% and 20% had higher slaughtering weight, hot carcass weight and cold carcass weight. This was due to higher deposition of muscle and fat in the carcasses, however, the fat amount in the carcasses remained optimal because the animals were slaughtered at the same age and with very close weights. The diet containing 15% and 20% silage inclusion had the best performance.