Enteropogon Macrostachyus Research Articles

In-vitro digestibility and methane gas emission of indigenous and introduced grasses in the rangeland ecosystems of south eastern Kenya

Various grass species with high biomass yield and low moisture demand have been introduced in the rangelands of Kenya to realize increased ruminant productivity that could not be achieved with the low quality of the indigenous grasses. However, this intervention ignores the different methane emission of the indigenous and introduced grasses, a necessary consideration for realizing increased productivity while minimizing greenhouse gas emissions. This study determined in-vitro digestibility and methane emission of three indigenous grasses: Eragrostis superba (E. superba), Cenchrus ciliaris (C. ciliaris), Enteropogon macrostachyus (E. macrostachyus) and two introduced grasses (two varieties of Chloris gayana; Boma rhodes and Extozi rhodes. Samples of these five grasses (whole plant above ground) were collected from established pasture plots in South Eastern rangelands of Kenya. The grass samples were collected at bloom stage using one-meter square quadrats for proximate analysis and determination of neutral detergent fiber (NDF), acid detergent lignin (ADL) and acid detergent fiber (ADF) using AOAC (1990) methods. On average, relative to the indigenous grasses, the introduced grasses were higher in crude protein (74.05 g Kg-1 dry matter (DM) vs. 52.11 g Kg-1 DM), organic matter digestibility 62.7% vs 53.6%) and in NDF (712.7 g Kg-1 DM vs. 708.0 g Kg-1 DM), metabolizable energy (16.35 vs 12.90 MJ/kg DM), methane emission (25.61 ml vs 15.93 ml) but with lower in-vitro-dry matter digestibility 54.24% vs 58.12%. Methane production positively correlated with crude protein, NDF, metabolizable energy, ADF and in-vitro organic matter digestibility. Hence, utilizing the introduced grasses to boost cattle production would achieve increased productivity but a point of concern are the higher methane emissions, not to mention the ecosystem change caused by the introduction of new species, which should affect the sustainability of the rangeland ecosystem.

Leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of two C4 African grasses under simulated drought

AbstractBackgroundFew studies have evaluated the effect of drought on the morpho‐physiological characteristics of African C4 grasses. We investigated how drought affects leaf gas exchange characteristics, biomass partitioning, and water use efficiencies of Enteropogon macrostachyus and Cenchrus ciliaris.MethodsThe grasses were grown in a controlled environment under optimum conditions, that is, 70% of the maximum water‐holding capacity (WHC) for the first 40 days. Thereafter, half of the columns were maintained under optimum or drought conditions (30% of maximum WHC) for another 20 days.ResultsUnder optimum conditions, C. ciliaris showed a significantly higher photosynthetic rate, stomatal conductance, and transpiration rate than E. macrostachyus. Drought decreased the photosynthetic rate, stomatal conductance and transpiration rate only in C. ciliaris. The net photosynthetic rate, stomatal conductance, and leaf transpiration of E. macrostachyus did not differ significantly under optimum and drought conditions. E. macrostachyus showed an increase in its water use efficiencies under drought to a greater extent than C. ciliaris.ConclusionsOur results demonstrate that C. ciliaris is more sensitive to drought than E. macrostachyus. The decrease in the intercellular CO2 concentration and the increase in stomatal limitation with drought in C. ciliaris and E. macrostachyus suggest that stomatal limitation plays the dominant role in photosynthesis of the studied African C4 grasses.

EFFECTS OF WEED CONTROL METHODS ON WEEDS AND PRODUCTIVITY OF RANGE GRASSES IN SEMI-ARID KENYA

<p><strong>Background:</strong> Weeds are a common occurrence and challenge in different crops eventually influencing crop development and yields. Weed control and management are key in enhancing the productivity of cultivated pastures. In semi-arid Kenyan drylands, the main methods employed for weed management are manual cultural practices and recently, the application of commercial herbicides. <strong>Objective:</strong> To evaluate the effects of two weed control methods on weed characteristics and productivity of four rangeland grasses commonly used in reseeding and pasture improvement in a semi-arid environment. <strong>Methodology:</strong> In a randomized complete block design in a field experiment, we determined the effects of two weed control methods (manual and herbicide use) in four rangeland cultivated grasses. These are Buffel grass (<em>Cenchrus ciliaris</em>), Horsetail grass (<em>Chloris roxburghiana</em>), Masaai love grass (<em>Eragrostis superba</em>) and Bush rye (<em>Enteropogon macrostachyus</em>). Weed characteristics (species, density, diversity and weed biomass,) were evaluated, as well as the effectiveness of the weed control methods in the grasses. <strong>Results:</strong> Broad-leaved weeds and annual grasses were prevalent in the established grasses. Generally, higher grass dry matter yields were obtained in <em>Cenchrus ciliaris</em> grasses (2.05 t h<sup>-1</sup>) while lowest yields were in <em>Chloris roxburghiana</em> (1.2 ton ha<sup>-1</sup>). Weed management interventions increased biomass production in the grasses by a mean of 19% in general. The mean yield increase varied with species and weed control method ranging from 8-39%. Weed control methods significantly reduced weed density, diversity and eventually weed biomass within the grass species. The efficacy of manual weed control and chemical application was in the range of 27-74%. <strong>Implications: </strong>Weed control is, therefore, necessary if one is to realize higher productivity and returns in cultivated pasture and fodder systems in semi-arid environments. <strong>Conclusion:</strong> Both chemical and manual control methods of weed control are important and effective approaches to manage weeds in pasture systems in semi-arid environments.<strong> </strong></p>

Vegetation Composition, Forage Biomass and Soil Seed Bank of a Continuously Grazed Rangeland Site in Tropical Sub-Humid Environment, Tanzania

Most rangelands along the agro-pastoral villages of Tanzania are yearlong grazed and at various states of degradation. These rangelands contribute to over 60% of the meat and milk production in the country. An inventory was conducted to assess the status of grazing resources in a typical agro-pastoral village of Tanzania having communal rangelands. Systematic random sampling techniques were employed whereby line transects and quadrat frame were used following standard procedures to collect samples and undertake field measurements for both vegetation and soil parameters. The vegetation cover for desirable pasture species, undesirable pasture species and litter were 67.7%, 10.5% and 9.4%, respectively. The soil bare patches covered 12.3 % of the surveyed rangeland site. The most dominant grass species were Enteropogon macrostachyus, Bothriochloa insculpta and Heteropogon contortus. Forage dry matter (DM) yield was 806.8 kg DM/ha. Tree density was 1500 trees/ha and the total canopy cover was 63.49%. Combretum collinum was the most dominant tree species. Soil bulk density, pH, organic carbon, nitrogen, phosphorus and potassium were 1.4 g/cm3, 6.3%, 1.14%, 0.09%, 0.89 mg/kg and 0.33 g/kg, respectively. A total of 11 dicotyledonous species mainly forbs and 9 monocotyledonous species including two perennial grasses were revealed from the incubated soil samples. The findings of this study demonstrate that the communal grazing areas have low pasture productivity, poor soil seed-bank and high cover of woody plants mainly bushes. In order, to improve forage biomass at the study site and elsewhere with similar environments selective bush clearing and re-seeding should be considered.

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.Graphical abstract

Morphoecological characteristics of grasses used to restore degraded semi‐arid African rangelands

AbstractProgressive loss of productivity and plant diversity is a concern in global rangelands. In African rangelands, this process is partly attributed to heavy and uncontrolled grazing by livestock and wildlife, leading to land degradation. Therefore, restoring such degraded rangelands is critical for enhancing ecosystem health and securing the livelihoods of millions of people.Active restoration strategies, for example, reseeding using indigenous perennial grasses, have been identified as a viable ecological solution for restoring degraded African rangelands. Grass species indigenous to African rangelandsCenchrus ciliarisL. (African foxtail grass),Eragrostis superbaPeyr. (Maasai love grass),Enteropogon macrostachyus(Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass),Chloris roxburghianaSchult. (Horsetail grass) andChloris gayanaKunth. cv Boma (Rhodes grass) were established in a semi‐arid rangeland in Africa under natural conditions to compare their morphoecological characteristics and suitability for use in ecological restoration. Biomass dry matter yields, plant densities, basal cover, seed production, tiller densities and plant height were measured.Chloris gayanacv Boma andE. superbaproduced significantly higher dry matter biomass yields and attained higher seed production than other species. High biomass and seed production indicate their suitability to support livestock production and replenish depleted soil seed banks, respectively.Enteropogon macrostachyusandC. ciliarisdisplayed significantly higher values for components of establishment and ecological restoration success, that is, plant densities, tiller densities and basal cover. Overall,C. roxburghianaranked lowest in the measured morphoecological characteristics.Successful restoration of degraded African semi‐arid rangelands using indigenous grass reseeding can best be achieved through careful selection of grasses to take advantage of their specific morphoecological characteristics. This selection should primarily be informed by the intended use of the rangeland and the specific challenges of restoring each site.

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.

Forage value of vegetative leaf and stem biomass fractions of selected grasses indigenous to African rangelands

Context Rangeland grasses native to Africa constitute the main diet for free-ranging livestock and wild herbivores. Leaf:stem ratio is a key characteristic used for assessing quality of forages. However, studies to determine the allocation of biomass to leaves and stems as well as chemical components and nutritive value, especially of grasses in African rangelands, are rare. Aim This study was conducted to establish biomass allocation and chemical and mineral components in leaf and stem fractions of three grasses, Eragrostis superba, Enteropogon macrostachyus and Cenchrus ciliaris, all indigenous to African rangelands. Methods Plant height, plant densities, plant tiller densities and biomass yields were estimated at the elongation stage, before inflorescence. Chemical and mineral components were determined from biomass harvested at the vegetative phase for all three grass species. Dry matter, ash content, organic matter, crude protein, neutral detergent fibre, acid detergent fibre, acid detergent lignin, and calcium, phosphorus and potassium contents were determined. Key results Enteropogon macrostachyus displayed significantly greater plant and tiller densities and plant height than the other two species. Leaf and stem biomass fractions varied significantly (P < 0.05) among grasses. Leaf:stem ratio of E. superba was double that of E. macrostachyus and C. ciliaris. Crude protein and organic matter yields and net energy for lactation were highest (P < 0.05) in E. superba leaf biomass, as was Ca content. Conclusions Eragrostis superba demonstrated greater potential as a forage species for ruminant animal production than E. macrostachyus and C. ciliaris. Implications Eragrostis superba is a key forage species that warrants promotion in pasture establishment programs in its native environments.

Impact of Removal of Copper Leaf (<i>Acalypha fruticosa</i> Forssk.) on Plant Species Diversity and Abundance at Chemeron, Baringo County, Kenya

Invasive plant species may significantly alter plant species community composition and structure thereby negatively impacting on ecosystem services. Their impacts on plant communities may be both direct and indirect. The direct effects may include a reduction in the abundance and diversity of palatable plant species that constitute important forage for livestock, wildlife, and medicines for the local communities. Declines in ecosystem resilience are of the notable indirect effects of invasive species. The aim of this study was to assess the impacts of a plant species, copper leaf (Acalypha fruticosa) on floral diversity and abundance at Chemeron, Baringo County in Kenya. The study was guided by three questions: What is the plant composition in terms of grasses, herbs, shrubs, and trees in the study area? Are there any variations in plant abundance between the two sites (sites with and without Acalypha fruticosa)? Are there variations in plant species diversity between the two study sites? Two sites (one with A. fruticosa and another two without this invasive species) were selected within the Chemeron Research Centre. Two belt transects measuring 100 m × 20 m on each site were laid parallel to each other. Plant samples were collected from five 1 m × 1 m quadrats that were laid at intervals of 20 m. The plant species or specimens were identified to the species level using available taxonomic keys. Various indices including Shannon-Wiener (H’), Evenness Index, Richness Index and Simpson’s Index of Diversity Index (SDI) were calculated. All the diversity, richness and evenness indices were considerably higher in the site without A. fruticosa compared to that where this invasive species was present. Higher H’ (3.14 to 3.21) and SDI (0.93 to 0.94) values were noted in sites without the invasive species compared to H’ (2.11 to 2.20) and SDI (0.77 to 0.85) in sites with A. fruticosa present. Out of the 47 plant species identified, 39 and 20 of them occurred in the site without and with A. fruticosa, respectively. Further, there were more grasses (Aristida keniensis, Cynodon dactylon, Brachiaria lucrantha, Eragrostis racemosa, and Enteropogon macrostachyus) in the site without A. fruticosa compared to that with the invasive plant. The plants were also more evenly distributed in the site without A. fruticosa compared to that where the invasive plant was present. We conclude that A. fruticosa has a significant effect on plant species abundance and diversity as well as distribution. Its removal created a favourable environment for the growth of a variety of grasses. We therefore recommend to the agro-pastoralists and rangeland managers that A. fruticosa be mechanically removed by uprooting from grazing lands so as to increase forage availability and quality in the rangelands of South-Baringo.

Phenological Stage, Plant Biomass, and Drought Stress Affect Microbial Biomass and Enzyme Activities in the Rhizosphere of Enteropogon macrostachyus

Indigenous grasses have been effectively used to rehabilitate degraded African drylands. Despite their success, studies examining their effects on soil bioindicators such as microbial biomass carbon (C) and enzyme activities are scarce. This study elucidates the effects of drought stress and phenological stages of a typical indigenous African grass, Enteropogon macrostachyus, on microbial biomass and enzyme activities (β-glucosidase, cellobiohydrolase, and chitinase) in the rhizosphere soil. Enteropogon macrostachyus was grown under controlled conditions. Drought stress (partial watering) was simulated during the last 10 d of plant growth, and data were compared with those from optimum moisture conditions. The rhizosphere soil was sampled after 40 d (seedling stage), 70 d (elongation stage), and 80 d (simulated drought stress). A high root:shoot ratio at seedling stage compared with elongation and reproduction stages demonstrated that E. macrostachyus invested more on root biomass in early development, to maximise the uptake of nutrients and water. Microbial biomass and enzyme activities increased with root biomass during plant growth. Ten-day drought at reproduction stage increased the microbial biomass and enzyme activities, accompanying a decrease in binding affinity and catalytic efficiency. In conclusion, drought stress controls soil organic matter decomposition and nutrient mobilization, as well as the competition between plant and microorganisms for nutrient uptake.

Irrigation levels affects biomass yields and morphometric characteristics of range grasses in arid rangelands of Kenya.

Background Production of range grasses under irrigation has been widely adopted in the arid environments of Kenya as a strategy for seasonal forage supply gap. However, their productivity has only been done under conventional methods without an evaluation of their performance at varied soil moisture conditions. This information is needed for making sustainable management of irrigation water and also increased pasture productivity at the current intensification of the production systems.MethodsAboveground biomass of six rangeland grasses (Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense) in pure and mixed stands at 80, 50 and 30 % soil moisture field capacity (FC), and control under rainfed as main plots. The main plots were divided into 30 subplots and randomly allocated ten grass species in three replicates. The moisture content was monitored by gypsum blocks which aided in irrigation times and levels. Seeds were sown by broadcast method in tractor ploughed and harrowed to fine tilt land. Biomass and growth morphometric characteristics were measured at phenological growth stages of 10, 12 and 14 weeks, representing vegetative stage, flowering and seed setting and mature with ripened seed stages for the studied range grasses.ResultsAll the irrigated treatment yielded significantly (p ≤ 0.05) higher above ground dry matter than the rainfed. S. sudanense had the highest yields at 80 % FC (13.7 t ha−1), though not significantly different from the 50 and 30 % FC (11.6 and 7.7 t ha−1), respectively. C. gayana and C. roxbhurghiana yields were not significantly affected by changes in soil moisture content with yields ranging between 10.1 and 10.8 t ha−1. C. ciliaris performed better at 50 % FC (9.1 t ha−1). Differences in tiller numbers across the watering treatments and grass species were not significant, but very low under rainfed conditions. The tiller heights in all the species were lower under rainfed than irrigated treatments. S. sudanense had the highest tiller height and biomass followed by C. gayana and E. Macrostachyus, respectively.ConclusionHere we demonstrate that the production of range pastures under irrigation in the arid environments should consider individual species’ responses to different soil moisture content for better yields and water conservation. The results show the species of importance for consideration under irrigation systems are S. sudanense and C. gayana.

Field curing methods and storage duration affect the quality of hay from six rangeland grass species in Kenya

Rangelands are important source of pasture for livestock in Kenya since time immemorial to pastoral households. However, seasonality on forage availability has been a big challenge in meeting animals’ feed requirements. This demands harvest and storage of pastures for use during dry seasons. Hay making has been done to bridge this forage deficit periods. However, hay quality in the rangelands is affected by curing methods, phonological stage at harvest, and the storage duration. We therefore evaluated the effect of field curing and storage duration on the quality (Crude Protein (CP)) of hay from six rangeland grasses in Kenya. The grasses evaluated are Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense. These grasses are the common species in the rangelands of Kenya and have been promoted in the past for hay making and reseeding interventions. The grasses were harvested at the mature flowering stage (12 weeks phenological stage), which is a period that provides high biomass without much effect on quality as practiced in the study area. The grasses were then cured in the field for 1, 2, and 3 days before baling and stored indoors for 12, 24, and 36 weeks. Samples were taken for CP content determination at the three periods following Macro-Kjeldahl Method. There was significant decline (p ≤ 0.05) in crude protein content in all the grass species with storage periods. Curing period did not affect the CP content for all the species at a given storage period; however, 3 days curing changed the hay color from green to brownish which reduces palatability and consequently reduced feed intake. Storage period of over 12 weeks adversely lowered CP to less than 6 % for all the species which is the required minimum level for animal under production and maintenance. S. Sudanense had significantly higher decline in CP after 24 weeks storage compared to the other species. Therefore, hay from the six grass species harvested at mature flowering stage (12-week phonological stage) and stored longer than 12 weeks supplies the animals with low CP. Also, to maintain palatability, 1–2 days curing is recommended for the six grass species.

English

This study evaluated water use efficiency (WUE) of six range grasses, namely; Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense grown at 80, 50, 30% field capacity (FC) soil moisture contents and rainfed treatment which represented water deficit conditions. The changes in soil moisture content were measured by Gypsum Block which aided in determining the irrigation schedules. The grasses demonstrated varied levels of WUE which was evaluated by amount of biomass productivity in relation to evapotranspired water during the growing period. The three soil moisture content treatments had higher water use efficiency than rainfed conditions. There was a declining trend in WUE with grass species maturity where S. sudanense had higher WUE at 8, 10 and 12th weeks (> 15 kg DM ha-1 mm-) in all the treatments followed by C. gayana and E. macrostachyus and were significantly (p<0.05) different from E. superba, C. ciliaris and C. roxburghiana which had WUE less than 10 among the six grass species. The 30% FC soil moisture content had higher WUE at all the phenological stages for S. sudanense, C. gayana and E. macrostachyus compared to 80, 50% FC and rainfed with all having WUE greater than 20 kg DM ha-1 mm-1. These three species are recommended for irrigated pasture establishment in semi-arid lands where water supply uncertainties exist, owing to their high water use efficiency under lower soil moisture levels. Key words: Water use efficiency (WUE), water stress tolerance, range grasses, pasture irrigation, water deficit, Kenya.

Water Stress Tolerance of Six Rangeland Grasses in the Kenyan Semi-arid Rangelands

This study evaluated six grass species in terms of water stress responses by visual quality and living ground cover attributes and the recovery responses post water stress grown at 80, 50, 30% field capacity soil moisture contents. The grass species evaluated were Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana, and Sorghum sudanense. The grasses demonstrated varied levels of water stress tolerance as evaluated by quality ratings based on colour (greenness) and uniformity of colour, leaf firing, living matter and wilting signs. All species declined in visual quality rating with prolonged water stress treatment with exception of Sorghum sudanense and Cenchrus ciliaris that had better quality ratings of six after 42 days water stress period. Sorghum sudanense, Chloris gayana and Cenchrus ciliaris had accelerated recovery in quality, attaining a visual rating of eight at 21 days of water stress period. The three soil moisture content treatments had higher quality ratings than rainfed conditions which represented water deficit. Sorghum sudanense and Chloris gayana had higher quality ratings and water use efficiency under rainfed compared to the other species. All the grasses showed higher living ground cover greater than 40% at recovery period of 28 days, when irrigation was resumed at the prescribed level, and attained living cover of over 60% by day 42. Sorghum sudanense, Chloris gayana and Cenchrus ciliaris were able to withstand water stress longer and had also a quick recovery among the six grasses. These three species are recommended for pasture establishment in semi-arid lands where water supply uncertainties exist, owing to their high tolerance to water stress.

Competition indices of three perennial grasses used to rehabilitate degraded semi-arid rangelands in Kenya

Rangeland degradation is one of the most serious environmental challenges in arid and semi-arid environments in Africa. Grass reseeding technology, using indigenous perennial grass species has a great potential for restoring ecosystem functionality in these degraded lands. This study was aimed at investigating how the establishment of indigenous grasses used to rehabilitate degraded semi-arid rangelands in Kenya as monocultures or binary mixtures affect dry matter biomass yields and plant competition indices at different phenological stages of development: seedling, elongation and reproduction. Using plant competition indices, we demonstrated which among these grass species showed a complementary vis-à-vis competitive interaction in binary mixtures across their phenological stages. Monocultures and binary mixtures of three perennial grass species: Cenchrus ciliaris L. (Buffel grass), Enteropogon macrostachyus Munro ex Benth. (Bush ryegrass) and Eragrostis superba Peyr. (Wilman lovegrass) native to these semi-arid rangelands were established in a field experiment. Pure stands of E. macrostachyus yielded higher biomass than C. ciliaris and E. superba only at the seedling and elongation phases but not the reproduction phase, where the yields were lowest among pure stands. Negative plant interactions in binary mixtures were observed at seedling and reproduction stages, compared with positive interactions observed at the elongation phase. Binary grass mixtures had a significant advantage for exploiting available environmental resources only at the elongation phase but not at the seedling and reproduction phases. Based on the estimated competition indices, E. superba best complements C. ciliaris across the phenological stages. We therefore conclude that this binary mixture is the one most likely to ensure successful rehabilitation of degraded semi-arid rangelands in this region.

Effect of Different Soil Water Content and Seed Storage on Quality of Six Range Grasses in the Semi-Arid Ecosystems of Kenya

Seed quality and effects of storage on viability of six range grass species grown at 80, 50 and 30% Field capacity soil water content and rain fed were evaluated. Freshly harvested seeds at week 2 from date of harvest (DOH) had the lowest percent germination. Enteropogon macrostachyus showed low GP ( 50%) after storage period of 2 weeks from DOH and GP>75% from the three soil water content after storage period of 36 weeks. The results also showed after storage periods of 12 weeks, all the grass species start to germination after day 3 of incubation, unlike in the freshly harvested -2 weeks storage period where germination starts after 7 days of incubation except for Sorghum sudanense. Germination index (GI) increased with storage periods for all the grass species with Sorghum sudanense having the highest GI of over 20 after 12 weeks of storage. Storage period of 12 weeks increases seed viability of the six grasses and Sorghum sudanense has higher seed viability even when freshly harvested compared to the other species.

Effect of Varied Soil Moisture Content on Seed Yield of Six Range Grasses in the Rangelands of Kenya

Seed yields of six range grass species grown at 80, 50 and 30% field capacity (FC) soil moisture content and rain fed condition were evaluated. The grasses included Chloris roxburghiana, Eragrostis superba, Enteropogon macrostachyus, Cenchrus ciliaris, Chloris gayana and Sorghum sudanense (Sudan grass). Watered treatments had higher seed yields compared to rain fed for all the grasses. Chloris roxburghiana had higher seed yields at 50 and 30 % FC (516.1 and 633.4 kg ha -1 , respectively), and lower yields at 80% FC and rain fed treatment (103 and 54.3 kg ha -1 , respectively). Eragrostis superba and Enteropogon macrostachyus showed no difference in seed yields across watered. Cenchrus ciliaris had no significant difference among watered and rain fed. Chloris gayana produced higher seed yields at 30% FC (1066.8 kg ha -1 ) while 80 and 50% FC and rain fed having 766.9, 866.8 and 123.7 kg ha -1 , respectively. The highest yield was observed in Sorghum sudanense at 80% FC and was different (p≤0.05) from the others (1250 kg ha -1 ), with 50, 30% FC and rain fed having 700.5, 533.9 and 150.7 kg ha -1 , respectively. Sorghum sudanense was highest yielder under rain fed (150.7 kg ha -1 ) with least being Cenchrus ciliaris (21.8 kg ha -1 ). Chloris

The choice of grass species to combat desertification in semi‐arid Kenyan rangelands is greatly influenced by their forage value for livestock

AbstractLivestock production is the main source of livelihood in the arid and semi‐arid lands in Africa. However, desertification characterized by vegetation degradation and soil erosion is a major threat to the sustainability of land‐based production systems. Native rangeland forage species Cenchrus ciliaris L. (Buffel grass/African foxtail grass), Eragrostis superba Peyr. (Maasai love grass) and Enteropogon macrostachyus (Hochst. Ex A. Rich.) Monro ex Benth. (Bush rye grass) have been used to combat desertification. The objectives of the study were to identify the best‐suited native grass species to combat desertification in a semi‐arid environment in Kenya and to identify the preferred grass species among the agropastoralists in the area. Percentage basal cover, plant densities and frequencies of the three grasses in pure stands and mixtures were estimated. Grass species preferences were through household survey and focus group discussion. Results showed a significant difference (P &lt; 0·05) in plant densities and cover estimates: E. macrostachyus was ranked first; C. ciliaris and E. superba were ranked second and third respectively. The agropastoral farmers, however, preferred E. superba followed by C. ciliaris and E. macrostachyus, a reverse trend. These results suggest that the choice of grass species to combat desertification is influenced more by its contribution as a source of forage for livestock than its contribution for rehabilitation purposes.

Seedbed preparation influence on morphometric characteristics of perennial grasses of a semi-arid rangeland in Kenya

Semi-arid rangelands in Kenya are an important source of forage for both domestic and wild animals. However, indigenous perennial grasses notably Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye grass) are disappearing at an alarming rate. Efforts to re-introduce them through restoration programs have often yielded little success. This can partly be attributed to failure of topsoil to capture and store scarce water to meet germination and plant growth requirements. A study was undertaken in the semi-arid environment of eastern Kenya to determine the effects of land treatment on morphometric characteristics of E. superba, C. ciliaris and E. macrostachyus. Seed viability of the grasses was estimated by germination tests. Land treatments involved soil ripping using a tractor and hand-clearing. Thirty-five plants were randomly selected per sub-plot and tagged for sampling. Morphometric characteristics of the grass species were measured weekly. Aboveground biomass was estimated by harvesting standing biomass three months after establishment. Seed viability tests showed significant differences (p<0.05) among the three grass species. This was attributed to intrinsic properties of the grass seeds such as dormancy and tegumental hardness. Seedling survival, foliage cover, plant height, leaf and tiller numbers, and aboveground biomass were significantly higher in ripped plots than hand-cleared plots. It was concluded that soil disturbance influences plant morphometric characteristics and plays an important role in the success rate of restoration attempts in semi-arid rangelands.

The Role of Moisture in the Successful Rehabilitation of Denuded Patches of a Semi-Arid Environment in Kenya

This study investigated the role of moisture in the successful rehabilitation of denuded patches in semi-arid lands of Kenya and the primary productivity of three perennial rangelands grasses namely Cenchrus ciliaris (African foxtail), Enteropogon macrostachyus (Bush rye) and Eragrostis superba (Maasai love grass) at three phenological stages (early growth, elongation and reproduction) as pure stands and two-grass mixtures. The grasses were sown on either rainfed (Sites 1 and 2) or simulated rainfall conditions (site 3). Site preparation in all the 3 sites involved mechanical bush clearing, use of fire and creation of micro-catchments using an ox-drawn plough. Soils in site 3 were sandy clay loams and those in sites 1 and 2 were sandy clays. There was total failure in establishment sites 1 and 2 under natural rainfall. Site 3 had good germination and subsequent establishment. These results were attributed to the moisture conditions in the three sites. There was a significant difference (p