Plant Morphoecological Traits, Grass-Weed Interactions and Water Use Efficiencies of Grasses Used for Restoration of African Rangelands

Degradation characterized by depleted vegetation cover is a serious environmental problem in African rangelands. It poses a serious threat to millions of pastoralists and agropastoralists who depend on livestock as a source of livelihood. Consequently, there has been a growing global interest to consolidate efforts to restore degraded ecosystems. For example, the UN decade of Ecosystem Restoration initiative aims at uniting the world behind a common goal of preventing, halting and reversing the degradation of ecosystems. Grass reseeding using native perennial species has been identified as one of the practical ecological strategies for restoring degraded African rangelands, enhancing vegetation cover and forage production. Knowledge of the multifaceted performance of African rangeland grasses in terms of morphoecological traits, interaction with weeds and water use efficiencies is however largely limited and often elusive. Perennial grasses indigenous to African rangelands Cenchrus ciliaris L. (African foxtail grass), Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) and Eragrostis superba Peyr. (Maasai love grass), were established in an African semi-arid rangeland under natural conditions to fill this knowledge gap. Morphoecological plant traits: aboveground biomass (shoot, leaf and stem) production, plant densities, basal cover, tiller densities and plant height were measured 9 months after establishment. Interaction between the target grass species and weeds and water use efficiencies (WUE) were also determined. Enteropogon macrostachyus displayed significantly higher values for plant densities, tiller densities and basal cover, indices commonly used to estimate the potential of grasses for ecological restoration. Eragrostis superba produced the highest shoot biomass and water use efficiencies. This is attributed to its higher leafy biomass fraction. Higher aboveground biomass production of E. superba demonstrate its suitability for enhancing rangeland productivity. Cenchrus ciliaris suppressed the weeds. This is linked to its aggressive and allelopathic nature. In conclusion, the three perennial grasses displayed distinct morphoecological traits. In order to achieve successful seed-based restoration of degraded African rangelands using native perennial grasses, careful selection species to maximize on their unique traits is recommended. Ultimately, this selection process should match the desired restoration outcomes and subsequent use of the rangeland.Peer reviewe

Dry matter yields and hydrological properties of three perennial grasses of a semi-arid environment in east Africa

Enteropogon macrostachyus (Bush rye), Cenchrus ciliaris L. (African foxtail grass) and Eragrostis superba Peyr (Maasai love grass) are important perennial rangeland grasses in Kenya. They provide an important source of forage for domestic livestock and wild ungulates. These grasses have been used extensively to rehabilitate denuded patches in semi-arid environment of Kenya. This study investigated the dry matter yields and hydrological properties of the three grasses under simulated rainfall at three phenological stages; early growth, elongation and reproduction. Laboratory seed viability tests were also done. Hydrological properties of the three grasses were estimated using a Kamphorst rainfall simulator. Results showed that there was a significant difference (p > 0.05) in dry matter yields and soil hydrological properties at the different grass phenological stages. Generally, all the three grasses improved the soil hydrological properties with an increase in grass stubble height. C. ciliaris gave the best soil hydrological properties followed by E. macrostachyus and E. superba, respectively. E. macrostachyus recorded the highest seed viability percentage. C. ciliaris and E. superba were ranked second and third, respectively. C. ciliaris yielded the highest biomass production at the reproductive stage followed by E. superba and E. macrostachyus, respectively. (Résumé d'auteur

Combining Rainwater Harvesting and Grass Reseeding to Revegetate Denuded African Semi-arid Landscapes

In African drylands, perennial grasses preferred by grazing livestock are disappearing at an alarming rate. This has led to recurrent livestock feed shortages threatening pastoralist’s livelihoods. Combining native grass reseeding and rainwater harvesting offers a viable and innovative solution to reverse this trend. However, studies to determine how biomass yields are affected by soil moisture availability attributed to in situ rainwater harvesting in African drylands are limited. We investigated how biomass yields of three grasses native to Africa, i.e., Enteropogon macrostachyus (Bush rye grass), Cenchrus ciliaris (African foxtail grass), and Eragrostis superba (Maasai love grass), are affected by soil moisture content in a typical semi-arid landscape. Rainwater harvesting structures included trenches, micro-catchments and furrows. Additionally, rain runoff was diverted from an adjacent road used as a catchment area. Soil moisture was measured between November 2018 and August 2019 using PlantCare Mini-Logger sensors installed at 40 and 50 cm depths and 0, 1, 5 and 15 m away from the trench. Quadrat method was used to determine biomass yields in August 2019. Peaks in soil moisture were observed after rainfall events. Soil moisture content gradually decreased after the rainy season, but was higher closer to the trench. This is attributed to the prolonged rainwater retention in the trenches. Biomass yields were in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. Biomass production was higher near the trenches for all the studied species. Sensitivity to soil moisture demonstrated by the magnitude to yield reduction during the growing season was in the order Eragrostis superba > Cenchrus ciliaris > Enteropogon macrostachyus. These results suggest that Eragrostis superba is more sensitive to drought stress than Enteropogon macrostachyus that is adapted to a wide range of soil moisture conditions. We demonstrated that in situ rainwater harvesting structures enhanced soil moisture availability and displayed great potential for revegetating denuded natural rangelands in semi-arid African landscapes. Thus, combining rainwater harvesting and reseeding techniques can produce measurable improvements in pastoral livelihoods and should be incorporated in dryland development policies in the region. Ultimately, incorporating such innovative strategies can strengthen the effectiveness of ecological restoration in African drylands to meet the objectives of the UN Decade on Ecosystem Restoration and achieving the UN Sustainable Development Goals.Peer reviewe

Multi‐stakeholder participation for successful implementation of applied research projects in Africa

Rainwater harvesting from Roads For Indigenous Pasture production and improved rural livelihoods in Kitui, Kenya (ROFIP) is an applied research project. It assessed the potential of combining multiple sustainable land management practices, for example native grass reseeding, rainwater harvesting from roads and in situ microcatchments to enhance vegetation cover in a semi-arid dryland in Kenya. Rural earth roads were used as a catchment. Runoff generated from rainfall events was diverted into reseeded pastures with trenches established at intervals, across a slope. The ROFIP project also integrated microcatchments created using ox-driven ploughs, a traditional practice for seedbed preparation and harnessing in situ rainwater harvesting in African drylands. Combining the diversion of runoff from roads and harvesting rainwater in situ improves and prolongs soil moisture availability in reseeded pastures. Consequently, this translated to higher biomass yields (i.e. forage for livestock) and vegetation cover (land degradation mitigation and enhanced soil health). This project clearly showed that combining rainwater harvesting and native pasture reseeding improves water retention and soil health, thus improving sustainable pasture production. However, for this to be achieved, it is prudent to involve practitioners to co-design practical solutions that are socially, economically and environmentally sustainable. Multi-stakeholder engagement, effective knowledge sharing, and community involvement can be major enablers in the pursuit of environmental and socioeconomic relevant benefits in applied research projects in Africa. This approach enhances a sense of shared purpose among practitioners and empowers them to become points of reference to their peers

Development of and Policy on the Range and Pastoral Industry with Special Reference to Kenya

Rangeland” or simply “range” is, by definition, “inferior” land by reason of physical and socio-economic limitations such as low rainfall, high temperatures, poor soils, and long distances from market outlets and supply centres. It has been variously defined by others (cf. Stoddart and Smith, 1955; Pratt and Gwynne, 1977); but, in general, it is land that carries natural vegetation that provides forage for both domestic and wild herbivores. It may also be a source of other products, including water, minerals, and services such as recreation. The rangelands of Kenya, for example, receive less than 750 mm of rain per year and have average temperatures that occasionally rise to 40°C. These are extensive lands covering about 85% of the total land area of 583,000km2. This expansive area is home to 25% of the total human population, estimated at 29 million (GOK, 1999). The density is as low as two persons per km2 in the very arid part

Climate variability, land use and livelihoods in the Rangelands

This book explores the interrelationships between climate variability, land-use and livelihoods in the rangelands, taking Makueni and Kajiado Counties of southern Kenya as a case. Makueni County is predominantly inhabited by an agropastoral community while Kajiado County is mainly occupied by a pastoral community. Available statistics suggest that Makueni County was more food secure with a vulnerability to food insecurity (VFI) of 0.27 compared to Kajiado County whose VFI was 0.59. Estimation through Two-Stage and Generalised Least Squares regression models showed that rainfall, land holdings, herd sizes, livestock offtake, agroforestry, household sizes, beef prices and stocking rates influence VFI in Makueni while access to climate information, temperature, herd size, livestock offtake, agroforestry, maize price, female household headship and off-farm opportunities influenced VFI in Kajiado. Therefore, improved livestock breeds, access to climate information, micro-industries, women organisations, access to land, better beef prices, correct stocking rates and agroforestry are critical in improving land-use systems and livelihoods in the rangelands

The performance of Husani dairy goats under water restriction in the arid western lowlands, Eritrea

Eighteen adult Husani female goats of approximately equal age and body weight, and in their late pregnancy were purchased from Eritrean western lowlands. They were randomly assigned to three watering regimes (treatments): once in 24 h (T1), once in 48 h (T2) and once in 72 h (T3). The goats were browsed together in the same ecological area to ensure access to a similar diet. They also received the same husbandry and veterinary car

Range Use and Trophic Interactions by Agropastoral Herds in Southeastern Kenya

Habitat utilization patterns and feeding interaction of free ranging agropastoral herds were investigated in two cycles of four consecutive grazing periods, in a semiarid environment, southeastern Kenya. The bites count and herd locations per area methods were used. During the dry season, areas of concentrated drainage; river valleys, bottomlands and ephemeral drainage ways absorbed a greater feeding load, taking 57.1 to 60% of the grazing time by the animals. In contrast, areas of limited moisture concentration, the open sandy/clay plains, were mainly exploited in the wet season and accounted for 52.6 to 55.6% of the grazing time. The trophic interaction patterns indicated that goats and cattle had a seasonal mean diet overlap index of less than 0.5 for all forage classes. Sheep and cattle, and sheep and goats had a seasonal mean diet overlap index of greater than 0.5 on grass and forbs, and browse and forbs, respectively. This indicated that during periods of resource scarcity, sheep and cattle or sheep and goats could become competitive feeders for same feed resources. Grazing management strategies aimed at even distribution of grazing pressure and enhancing complementary trophic interactions could be central to sustainable livestock production in such environment

Seasonal energy extraction patterns by agropastoral herds in semiarid south-eastern Kenya

Primary energy extraction patterns by livestock under agropastoralism and ranching were investigated by the bite count method in semiarid south-eastern Kenya. Sward biomass for optimal energy intake by cattle was derived using intake-digestibility constraint curves and realised livestock productivity from the systems compared. Cattle and sheep, and goats primarily consumed herbaceous and woody plants, respectively. Enteropogon macrostachyus and Panicum maximum, E. macrostachyus and Blepharis integrifolia, and Combretum exalatum and Duosperma kilimandscharica accounted for 33.5% and 9.9%, 16.6% and 10.3%, and 11.7% and 10.7% of cattle, sheep and goats' total energy intake, respectively. Cattle optimised energy intake at 370-610gm−2 of sward biomass and 55.5-64.3% organic matter digestibility. Panicum maximum yielded the highest optimal sward biomass. The energy expenditure of the animals was generally lower under agropastoralism across seasons. During the dry season, more animals (33-50%) lost weight under ranching. Agropastoralism was an efficient system as animals were moved across quality grazing microenvironments that minimised feeding costs and enhanced energy intake. Therefore, mobile grazing strategies, plant diversity and complementary trophic interactions stabilise energy extraction patterns and enhance livestock productivity under agropastoralism. However, human activities that affect plant diversity and mobility will undermine sustainable livestock production in such environments