Morphological and physiological responses of Calobota sericea plants subjected to water limitation and subsequent rewatering

Abstract

This is the final version of the article that is published ahead of the print and online issue Large arid and semiarid regions around the world are generally characterised by high variability and unpredictability in rainfall, as well as rainfall that is insufficient for arable crop production under rain fed conditions (Abu-Zanat et al. 2004; Belkheiri and Mulas 2013). Within these drylands, plants are often exposed to a variety of environmental stresses, with drought stress or water limitation commonly regarded as the most significant factors, leading to substantial reductions in agricultural productivity (Lambers et al. 2008;Walter et al. 2011). Because of these stresses, most of the available lands are marginal to crop lands and are used primarily as grazing lands for extensive livestock production. Such rangelands have limited options to sustainably increase agricultural productivity, especially where irrigation is not an option (Palmer and Ainslie 2006; Belkheiri and Mulas 2013;Jordaan et al. 2013). These limitations to improving agricultural productivity within these water-limited rangelands are expected to worsen under the predicted future climate change conditions (IPCC 2007;Meissner et al. 2013).Generally, for South Africa, it is predicted that the current unpredictability and variability in temporal and spatial rainfall distribution will likely increase in the future. This will result in additional increases in marginal agro-ecological conditions, with increases in the duration and intensity of episodic drought events, resulting in further limitations to agricultural productivity (Kruger and Shongwe 2004; Benhin 2008; DEA 2013;Meissner et al. 2013). Therefore, in order to meet the future increase in the demand for livestock products in South Africa, the productivity of these water-limited rangelands will have to be improved. One of the ways to improve rangeland production is through better rangeland management, which includes the implementation of improved fodder flow programs that can adequately address the current dry season feed shortages occurring due to the seasonal deterioration of the natural veld (Müller et al. 2019a).The current stock of commercial forage species suitable for these water-limited agro-ecological conditions in South Africa is limited (Dickenson et al. 2010;Truter et al. 2015).

A Phytogeographical Classification and Survey of the Indigenous Browse Flora of South Africa, Lesotho, and Eswatini

“…Nenzhelele et al [35] highlight the importance of shrubs to provide a fodder bank, especially during drought in the Succulent Karoo Biome. Calobota sericea, with a relatively high occurrence in this browse-chorion (Figure S2), was recently investigated for its responses to abiotic stresses on germination and its nutritional quality [36,37]. Similar to the ST Browse-chorion, not many key species are present as key species in other browse-choria.…”

“…including some valuable pasture species. Leguminosae, well known for its members being important pasture and browse plants, was the focus of numerous southern African studies [22,36,37,[39][40][41]. Furthermore, Ulian et al [42] recognised Leguminosae and Asteraceae as some of the richest families in terms of globally edible plant species used by humans, as well as members of Ficus, Diospyros, and Grewia as having high numbers of edible species.…”

Nitrogen fertilization increases the growth and nutritional quality of the forage legume, Calobota sericea – A preliminary investigation

“…The plant has been identified as a potential cut-and-carry forage resource for water-limited agro-ecological areas due to its current contribution to extensive livestock production systems within the rangelands of the Mediterranean-like region of South Africa [ 2 , 3 ]. To date, studies into its distribution [ 1 ], climatic and edaphic niche [ 3 ], drought tolerance [ 4 ], germination requirements [ [5] , [6] , [7] ] and nutritional quality [ 8 , 9 ] has been done to characterise the species for its agronomic and forage potential. From these, it has been proposed that this species could potentially be developed further for use as a supplementary feed during the dry season within water-limited Mediterranean type agro-ecological areas.…”