African Journal of Range and Forage Science

Two reviews of GrassPro Southern Africa (online app)

Robyn Nicolay — 2025-02-13

No abstract

Book Review. Contested Karoo: Interdisciplinary perspectives on change and continuity in South Africa’s drylands

Suzanne J Milton — 2025-02-13

No abstract

Book Review. Caring for Natural Rangelands (improved 2nd edition)

Gustav le Roux — 2025-02-13

No abstract

Ensiling as a technique for preservation of the nutritional quality of Vachellia nilotica

Fortune L Manganyi — 2025-02-13

Fodder tree species are considered to have high nutritional value and have always played a significant role in feeding livestock during the dry seasons. The study was conducted to explore the possibility of preserving chopped Vachellia nilotica shoots as silage. Edible plant material of V. nilotica were harvested, chopped and ensiled in 1.5 L anaerobic glass jars under laboratory conditions with four treatment applications: control, shoots + seedpods, shoots + molasses, and shoots + molasses + seedpods. Three jars per treatment were opened at Days 3, 7, 21 and 60 to determine fermentation characteristics, and subjected to a five-day aerobic stability test at Day 60. Thereafter samples were analysed for chemical composition, mineral nutrients, fermentation characteristics and aerobic stability. Dry matter content of V. nilotica differed (p < 0.05) at ensiling with an average of 433 g kg⁻¹ DM, CP (70–81 g kg⁻¹ DM), ADF (360–426 g kg⁻¹ DM), aNDF (468–524 g kg⁻¹ DM) and pH (4.3–5.0) at Day 60. Butyric acid was < 0.1 g kg⁻¹ DM, acetic acid (4–6 g kg⁻¹ DM) and propionic acid was not detected. These findings demonstrated that V. nilotica edible parts can be effectively preserved as legume silage to bridge the dry season gap.

Calibration and evaluation of a CROPGRO Perennial Forage Model for Brachiaria humidicola yield simulation under future climate in subhumid environments of Ethiopia

Fantahun Dereje — 2025-02-13

Crop simulation models can be employed to assess the impacts of climate change and aid in strategic planning and decision making regarding forage strategies. This study focused on calibrating and assessing the performance of the CROPGRO Perennial Forage Model in simulating Brachiaria humidicola yield under projected future climates for high and moderate representative concentration pathway (RCP) scenarios in the central and western subhumid regions of Ethiopia. The model was calibrated to accurately represent rainfed growth and biomass yield, using field data from the Debre Zeit and Bako Agricultural Research Centers. Climatic data, including rainfall, temperature and solar radiation, were sourced from weather stations, whereas future climate scenarios for the near future, mid-century and end-of-century periods were derived from the CORDEX Africa outputs under RCP 4.5 and RCP 8.5. The calibration process refined species parameters related to vegetative partitioning, and enhanced the d-statistic and reduced the root mean square error (RMSE) for herbage, leaf, stem and total biomass accumulation. Despite projected decreases in leaf biomass, stem biomass is projected to increase. In addition, there are projected increases in herbage and total biomass accumulation under elevated greenhouse gas concentrations and warmer temperatures. Ultimately, the projected climate under both RCPs had no significant effect on Brachiaria humidicola grass production in Ethiopia.

Estimation of standing crop biomass in rangelands of the Middle Atlas mountains using remote sensing data

S. Boukrouh — 2025-02-13

In the Middle Atlas rangelands, traditional methods for estimating standing crop biomass are labour-intensive and impractical. Remote sensing offers an initiative for standing crop biomass large-scale monitoring. The aim of this study was to estimate standing crop biomass, comprising annual and perennial forbs, grasses and perennial shrubs, using remote sensing data. The vegetation indices (NDVI, DVI, RVI, MSAVI and OSAVI) were derived from medium-resolution Landsat 8 and MODIS imagery. Sixty sampling sites were used for the biomass data collection. These sites were located across three grazing areas and data were collected in May and June 2016. Regression models were established between biomass field data and the five indices. Correlation analysis indicated that among the five vegetation indices, only DVI had the lowest value (r = 0.60). Linear models developed between the biomass field data and vegetation indices showed that NDVI, OSAVI and RVI explained a reasonable percentage of the variance in biomass. Values for R² were 0.74, 0.77 and 0.71, respectively. Among these indices, the OSAVI performed better, with a high R² and low error (MAPE = 11.03%). The established models represent a key tool for long- term monitoring of these rangelands.

Seasonal dynamics of forage nutrition in smallholder goat production systems in Malawi

Andrew S Cooke — 2025-02-13

Forage and browse are a valuable natural resource in Malawi that can be used to support livestock production which, in turn, can contribute towards delivering income and nutrition to households and communities. However, the quality and quantity of forages can be poor, especially during the dry season. The objective of this study was to assess the nutritional composition of naturally available forages across smallholder livestock systems in Malawi, with particular focus on seasonal differences in quality and quantity. Samples of herbaceous forages and browse were collected over 17 months, across four sites (30 farms/smallholders) in central Malawi. Forages underwent nutritional analysis for crude protein, fibre and ash/organic matter. NDVI obtained from satellite imagery was used as a proxy for forage availability. Forage nutrition and availability were most adequate in the wet season, with higher concentrations of crude protein and a greater availability of herbaceous plants. There were significant differences in low-digestibility fibre fractions between locations, likely due to local factors such as soil and hydrology. The fall in crude protein concentrations from the wet season to the dry season along with a reduction in forage biomass represents a seasonal nutritional feed gap that may impact productivity within livestock systems.

Grazing effects on forage quality parameters of three rangeland species in arid regions of Semnan, Iran

Milad Kamiziani — 2025-02-13

Forage quality determines livestock production and overgrazing results in significant changes in forage quality of rangeland species. This study aimed to compare the effects of overgrazing on forage quality of Artemisia sieberi, Zygophyllum eurypterum and Stipa barbata as dominant species producing more than 90% of livestock feed in arid rangelands of Semnan, Iran. The study area was classified into non-grazed and overgrazed sites based on the estimated carrying capacity. Data collection was conducted at the end of the grazing season. The collected forage samples were analysed for crude protein (CP), potassium (K), phosphorus (P), acid detergent fibre (ADF), digestibility, percentage of dry matter digestibility (DMD) and metabolic energy (ME). Results from the t-test indicated that overgrazing led to significant (p < 0.05) reduction in CP, K, P, DMD and ME and a significant (p < 0.05) increase in ADF in A. sieberi and Z. eurypterum, in comparison to plants from non-grazed areas, with CP being the most sensitive qualitative parameter to overgrazing in the two species. Shrubs including A. sieberi and Z. eurypterum showed more susceptibility to overgrazing while the grass species S. barbata proved to be less affected. A rational grazing system is required where A. sieberi and Z. eurypterum are present.

Threshold changes in the production potential of bush clumps along piosphere gradients in arid thicket mosaics

Anton Schmidt — 2025-02-13

Various studies have noted threshold changes in vegetation composition and structure and soil physical and chemical properties in the Albany Thicket biome of South Africa. The aim of this study is to assess if these changes to the environment have transformed the ecosystem’s forage production potential. To estimate forage production potential we compare three models that make use of the mean and variance of the Normalized Difference Vegetation Index (NDVI) obtained from two WorldView-2 satellite images. For the models, NDVI values were sampled along four independent piosphere gradients that vary in their intensity of use and rest from herbivory. Our results indicate that the model that makes use of NDVI variance after a good rainfall year is able to discern changes in the forage production potential that corroborate threshold changes in the vegetation and soil environment. Our results support the growing body of evidence that increases in the variance of ecosystem processes and services are important indicators of impending
threshold changes in social-ecological systems.