Maximizing precipitation utilization in dryland agriculture in South Africa — a review

Bennie, A. T.P.; Hensley, M.

doi:10.1016/s0022-1694(00)00377-2

Cited by 85 publications

(50 citation statements)

References 12 publications

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“…Furthermore, Verhulst et al (2011), comparing no-tillage and conventional tillage with and without residues in an experiment in Mexican highlands, confirmed that higher soil water content was generally found under residue covered treatments, particularly during dry periods. According to Bennie et al (2001), evaporation reduction by residues is effective during the first 10 days after surface wetting and requires a minimum of 80 % shading. The high effect during the energy limited first stage of evaporation decreases during the flux limited second stage and diffusion limited third stages of evaporation (Steiner 1994).…”

Section: Mulchingmentioning

confidence: 99%

Management of crop water under drought: a review

Bodner

Nakhforoosh

Kaul

2015

Agron. Sustain. Dev.

455

234

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Drought is a predominant cause of low yields worldwide. There is an urgent need for more water efficient cropping systems facing large water consumption of irrigated agriculture and high unproductive losses via runoff and evaporation. Identification of yield-limiting constraints in the plant-soil-atmosphere continuum are the key to improved management of plant water stress. Crop ecology provides a systematic approach for this purpose integrating soil hydrology and plant physiology into the context of crop production. We review main climate, soil and plant properties and processes that determine yield in different water-limited environments. From this analysis, management measures for cropping systems under specific drought conditions are derived. Major findings from literature analysis are as follows. (1) Unproductive water losses such as evaporation and runoff increase from continental in-season rainfall climates to storage-dependent winter rainfall climates. Highest losses occur under tropical residual moisture regimes with short intense rainy season. (2) Sites with a climatic dry season require adaptation via phenology and water saving to ensure stable yields. Intermittent droughts can be buffered via the root system, which is still largely underutilised for better stress resistance. (3) At short-term better management options such as mulching and date of seeding allow to adjust cropping systems to site constraints. Adapted cultivars can improve the synchronisation between crop water demand and soil supply. At long term, soil hydraulic and plant physiological constraints can be overcome by changing tillage systems and breeding new varieties with higher stress resistance. (4) Interactions between plant and soil, particularly in the rhizosphere, are a way towards better crop water supply. Targeted management of such plant-soil interactions is still at infancy.We conclude that understanding site-specific stress hydrology is imperative to select the most efficient measures to mitigate stress. Major progress in future can be expected from crop ecology focussing on the management of complex plant (root)-soil interactions.

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Section: Mulchingmentioning

confidence: 99%

Management of crop water under drought: a review

Bodner

Nakhforoosh

Kaul

2015

Agron. Sustain. Dev.

455

234

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“…However, it is not only about total water use per se, but about water use compared with water resources and competing demands of human being and agriculture. According to Bennie & Hensley (2001) agriculture consumes 74.5% of the rainfall in South Africa. From this, 60% is utilized by natural vegetation, 12% by dry land crop production and 2.5% by irrigation.…”

Section: Livestock Production Systems and Water Usagementioning

confidence: 99%

A South African perspective on livestock production in relation to greenhouse gases and water usage

et al. 2013

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The general perception that livestock is a major contributor to global warming resulted mainly from the FAO publication, Livestock's Long Shadow, in 2006, which indicated that livestock is responsible for 18% of the world's greenhouse gas (GHG) emissions. This figure has since been proved to be an overestimation, since it includes deforestation and other indirect contributions. The most recent figure is in the order of 5% -10%. Although only ruminants can convert the world's high-fibre vegetation into highquality protein sources for human consumption, ruminant production systems are targeted as they are perceived to produce large quantities of GHG. Livestock is also accused of using large quantities of water, an allegation that is based on questionable assumptions and the perception that all sources of food production require a similar and equal quantity and quality of water. In the case of ruminants, extensive systems are usually found to have a lower per-area carbon footprint than grain-fed systems, but a higher footprint if expressed in terms of kg product. Feedlots maximize efficiency of meat production, resulting in a lower carbon footprint, whereas organic production systems consume more energy and have a bigger carbon footprint than conventional production systems. Cows on pastures produce more methane than cows on high concentrate diets. In South Africa, as in most of the countries in the sub-tropics, livestock production is the only option on about 70% of the agricultural land, since the marginal soils and rainfall do not allow for crop production and the utilization of green water. An effective way to reduce the carbon and water footprint of livestock is to decrease livestock numbers and increase production per animal, thereby improving their efficiency.________________________________________________________________________________

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“…With aridity index (i.e., ratio between precipitation and potential evapotranspiration (ET0)) ≤ 0.65 (Wang et al, 2012), crop production in drylands is a continuous exercise to allocate the limited rainwater supply to meet the ET demand of growing crops. Therefore, increasing water use efficiency (WUE; crop yield per unit of available water) in dryland cropping systems is essential in order to maximize productivity (Bennie and Hensley, 2001;Lu et al, 2016a).…”

Section: Introductionmentioning

confidence: 99%