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

Abstract

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.

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

“…This is because higher density of plant stems increase the hydraulic roughness for surface flow. Our results differ from those of Koech et al (2016), who observed highest plant densities and cover in C. ciliaris compared to E. superba and E. macrostachyus, respectively. These differences can be linked to the inherent site specific edaphic (soil type, vertisol) and climatic (arid climate, annual rainfall range 220-500 mm) factors.…”

“…(Mnene et al, 2005), Chloris gayana Knuth., Sorghum sudanense (P.) Stapf. (Koech et al, 2016), Panicum maximum Jacq. (Ludwig et al, 2008) and Panicum coloratum L. (Macandza et al, 2004).…”

“…Active restoration methods such as prescribed burns, bush clearing and reseeding are key in addressing the problem of rangeland degradation in Africa. Reseeding using desirable indigenous forage species is an innovative intervention to restore denuded rangelands (Mnene et al, 2005;Kinyua et al, 2010;Mganga et al, 2015b;Koech et al, 2016) and increase the resilience of pastoral communities.…”

Yield and Irrigation Water Productivity of Three Varieties of Buffel Grass (Cenchrus ciliaris L.) in the Southern Coastal Plains of Yemen

“…There were significant differences observed in the number of tillers per plant among buffel grass varieties (P = 0.036). These results are in agreement with Koech et al (2016). Gayandah variety produced the highest forage fresh yield (404.9 kg/ha) in the year 2013, while the lowest forage fresh yield (57.5 kg/ha) was produced by the Local variety of buffel grass in the year 2012 (Table 4).…”

Grass species for range rehabilitation: Perceptions of a pastoral community in Narok North sub-county, Kenya

“…C. gayana preference for rangeland rehabilitation was attributed to its high biomass and palatability to all livestock in the study area. Koech et al (2016) found that the species produces high biomass even under limited water conditions. P. clandestinum was preferred by the community for its growth form and its ability to spread and cover the land.…”