scholarly journals Eucalyptusand Water Use in South Africa

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Janine M. Albaugh ◽  
Peter J. Dye ◽  
John S. King
Keyword(s):  
South Africa ◽  
Water Use Efficiency ◽  
Water Use ◽  
Canopy Structure ◽  
Wood Products ◽  
Future Research ◽  
Physiological Processes ◽  
Wide Range ◽  
Use Efficiency ◽  
Use Studies

TheEucalyptusgenus yields high rates of productivity and can be grown across a wide range of site types and climates for products such as pulp, fuelwood, or construction lumber. In addition, many eucalypts have the ability to coppice, making this genus an ideal candidate for use as a biofuel feedstock. However, the water use ofEucalyptusis a controversial issue, and the impacts of these fast-growing trees on water resources are well documented. Regardless, the demand for wood products and water continues to rise, providing a challenge to increase the productivity of forest plantations within water constraints. This is of particular relevance for water-limited countries such as South Africa which relies on exotic plantations to meet its timber needs. Research results from water use studies in South Africa are well documented and legislation restrictions limit further afforestation. This paper outlines techniques used to quantify the water use of eucalypt plantations and provides recommendations on where to focus future research efforts. Greater insights into the water use efficiency of clonal material are needed, as certain eucalypt clones show fast growth and low water use. To better understand water use efficiency, estimates should be combined with monitoring of stand canopy structure and measurements of physiological processes.

scholarly journals Inoculant, nitrogen and phosphorus improves photosynthesis and water-use efficiency in soybean production

2021 ◽  
pp. 1-14
Author(s):  
C. E. N. Savala ◽  
A. N. Wiredu ◽  
J. O. Okoth ◽  
S. Kyei-Boahen
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Management Practices ◽  
Climatic Conditions ◽  
Growth Stages ◽  
Nitrogen And Phosphorus ◽  
Area Index ◽  
Physiological Processes ◽  
Wide Range ◽  
Use Efficiency

Abstract Soybean yield within the Southern Africa falls below its potential despite similar climatic conditions across some agroecologies, replicable agronomic management practices and introduced improved varieties. Understanding physiological processes and water-use efficiency (WUE) of soybean offer information on bridging this yield gap. A field study was conducted in 2017 and 2018 seasons in two agroecologies (Angonia and Ruace) in Mozambique to evaluate the effects of Bradyrhizobium diazoefficiens strain USDA110 formerly known as Bradyrhizobium japonicum inoculant, nitrogen and phosphorus on nodulation, physiology and yield of non-promiscuous (Safari) and promiscuous (TGx 1740-2F) soybean varieties. Data on transpiration, photosynthesis, leaf area index, radiation interception and WUE from the beginning of flowering to maturity were collected. Transpiration rate varied considerably with interaction between locations, growth stages, varieties and treatments. At podding, phosphorus-treated soybean at Angonia transpired less (6.3 mmol/m2/s) than check plants (6.6 mmol/m2/s). Photosynthesis rate and WUE were distinct with variety, growth stages and inputs within agroecologies. For instance, in Angonia 2018 season, phosphorus fertilized TGx 1740-2F photosynthesized more at flowering (25.3 μmol/m2/s) while the lowest was phosphorus-treated Safari at podding with 17.2 μmol/m2/s. At the same site in 2017, inoculated soybean photosynthesized more at 22.8 μmol/m2/s leading to better WUE of 3.6 that corresponded to 2894 kg/ha yield. Overall, soybean WUE was higher when inoculated than N-treated, while P application yielded better. Results from this study will complement breeders’ effort in developing phosphorus efficient varieties suited for a wide range of changing climatical conditions.

scholarly journals A preliminary investigation of the water use efficiency of sweet sorghum for biofuel in South Africa

Water SA ◽  
2016 ◽  
Vol 42 (1) ◽  
pp. 152 ◽  
Author(s):  
MG Mengistu ◽  
JM Steyn ◽  
RP Kunz ◽  
I Doidge ◽  
HB Hlophe ◽  
...  
Keyword(s):  
South Africa ◽  
Water Use Efficiency ◽  
Water Use ◽  
Sweet Sorghum ◽  
Preliminary Investigation ◽  
Use Efficiency

scholarly journals Effect of Ploughing Techniques on Water Use and Yield of Rice in Maugo Small-Holder Irrigation Scheme, Kenya

2021 ◽  
Vol 3 (1) ◽  
pp. 110-117
Author(s):  
Pius Kipchumba Cheboi ◽  
Shahida Anusha Siddiqui ◽  
Japheth Onyando ◽  
Clement Kiprotich Kiptum ◽  
Volker Heinz
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Future Research ◽  
Experimental Site ◽  
Irrigation Scheme ◽  
Shopping Centre ◽  
Tillage Practices ◽  
Rice Season ◽  
Use Efficiency ◽  
Small Holder

The objective of this study was to determine the effect of paddy rice ploughing techniques on water use and the yield of rice crop, as well as water use efficiency for rice growing in small-holder irrigation schemes. The study was conducted at a farmer’s field in Powo B sub-block of Maugo Irrigation Scheme. The period of study was from July 2019 to January 2020, which is the rice season. The experimental site was located in the vicinity of Olare Shopping Centre, Kamenya Sub-location, Kochia East Location, Kochia Ward, Rangwe Sub-County, Homa Bay County, Nyanza Region, Kenya in Maugo rice scheme in Kenya. In the study, four irrigation tillage practices were applied: ox-plough, conventional ox-plough, hand hoe and tractor ploughing. The results showed that conventional ox-ploughing consumed the highest amount of water at 1240 mm. The highest water use efficiency of 0.49 kg/m3 and highest yield of 5.7 tons/ha were observed for hand hoe ploughing. Use of the hand hoe ploughing technique increased yields by 20 percent, as compared to the conventional ox-ploughing. Therefore, the use of water for ploughing is not necessary in the study area. Future research will be needed to see how farmers are adopting the technology before scaling up to full mechanization, as partial mechanization was not profitable.

Water Use Efficiency as a Constraint and Target for Improving the Resilience and Productivity of C3and C4Crops

2019 ◽  
Vol 70 (1) ◽  
pp. 781-808 ◽  
Author(s):  
Andrew D.B. Leakey ◽  
John N. Ferguson ◽  
Charles P. Pignon ◽  
Alex Wu ◽  
Zhenong Jin ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Crop Production ◽  
Crop Improvement ◽  
Canopy Structure ◽  
Complex Trait ◽  
Carbon Gain ◽  
Crop Development ◽  
Component Traits ◽  
Use Efficiency

The ratio of plant carbon gain to water use, known as water use efficiency (WUE), has long been recognized as a key constraint on crop production and an important target for crop improvement. WUE is a physiologically and genetically complex trait that can be defined at a range of scales. Many component traits directly influence WUE, including photosynthesis, stomatal and mesophyll conductances, and canopy structure. Interactions of carbon and water relations with diverse aspects of the environment and crop development also modulate WUE. As a consequence, enhancing WUE by breeding or biotechnology has proven challenging but not impossible. This review aims to synthesize new knowledge of WUE arising from advances in phenotyping, modeling, physiology, genetics, and molecular biology in the context of classical theoretical principles. In addition, we discuss how rising atmospheric CO2concentration has created and will continue to create opportunities for enhancing WUE by modifying the trade-off between photosynthesis and transpiration.

Multidisciplinary teams to conduct integrated research on farming systems - a challenge

Soil Research ◽  
1995 ◽  
Vol 33 (4) ◽  
pp. 659 ◽  
Author(s):  
RJ French
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Systems Approach ◽  
Farming Systems ◽  
Future Research ◽  
Multidisciplinary Teams ◽  
Cooperative Effort ◽  
Soil Organic Nitrogen ◽  
Use Efficiency ◽  
Groups And Teams

This paper reviews changes in farming practices that helped farmers to reduce soil erosion, and increase water-use efficiency and yield on their specific soils and climate. The program initially involved working with Soil Conservation Boards and conducting research on farmers' properties and on research stations. This work then extended from evaluating single factor effects to assessing the combined factors limiting yield in specific crop and pasture rotations. Benchmarks were established for different soils and climates as guides for farmers to measure their success. These included yield and water use efficiency, adequate and lower limit levels of soil organic nitrogen, and the need to maintain a nutrient input-output balance to provide a sustainable agriculture. The paper highlights the need for future research to adopt an integrated systems approach to overcome the major limitations to growth. This will require a cooperative effort between farmer groups and teams of soil scientists and agronomists to conduct multifactor research in farmers' paddocks.

scholarly journals Analysis of virtual water flows associated with the trade of maize in the SADC region: importance of scale

2009 ◽  
Vol 13 (10) ◽  
pp. 1967-1977 ◽  
Author(s):  
J. M. Dabrowski ◽  
E. Masekoameng ◽  
P. J. Ashton
Keyword(s):  
South Africa ◽  
Water Use Efficiency ◽  
Water Content ◽  
Water Use ◽  
Water Scarcity ◽  
Virtual Water ◽  
Blue Water ◽  
Maize Production ◽  
Water Flows ◽  
Use Efficiency

Abstract. The concept of virtual water encourages a country to view agricultural crops in terms of the amount of water required to produce those crops, with a view to implementing trading policies that promote the saving of scarce water resources. Recently, increased attention has focussed on partitioning the virtual water content of crops into green and blue water (derived from rainfall and irrigation, respectively) as the latter has higher opportunity costs associated with its use and therefore impacts directly on scarcity. Maize is the most important crop traded within the SADC region. South Africa is the largest producer and exporter of maize, with the majority of its exports destined for other SADC countries. In comparison to other SADC countries, South Africa produces maize relatively efficiently, with a low virtual water content and a high green (868 m3 t−1) to blue (117 m3 t−1) water ratio. The blue water content is however higher than for maize produced in all other SADC countries, with the exception of Namibia (211 m3 t−1). Current trade patterns therefore result in a net expenditure of blue water (66×106 m3), almost all of which is exported by South Africa (65×106 m3). South Africa is one of the most water scarce countries in the region and analysis of virtual water flows indicates that current SADC maize trading patterns are influenced by national productivity as opposed to water scarcity. The virtual water content of maize was estimated for each of South Africa's nineteen Water Management Area's (WMA) and used as a proxy to represent water use efficiency for maize production. The virtual water content varied widely across all of the WMAs, ranging from 360 m3 t−1 in the Ustutu Mhlatuze to 1000 m3 t−1 in the Limpopo. A comparison of the virtual water content and production of maize (expressed as a percentage of the total national production) identified those WMAs where maize production is highly water inefficient (e.g. Lower Orange and Limpopo WMAs). Results suggest that, while a national estimate of the virtual water content of a crop may indicate a relatively efficient use of water, an analysis of the virtual water content at smaller scales can reveal inefficient use of water for the same crop. Therefore, analysis of the virtual water content of crops and trading of agricultural products at different spatial scales (i.e. regional, national and WMA) could be an important consideration within the context of water allocation, water use efficiency and alleviation of water scarcity.

scholarly journals Screening Wheat Genotypes for Drought Tolerance and Co-relation Study among Morpho-physiological Traits

2013 ◽  
Vol 14 ◽  
pp. 65-77
Author(s):  
Dipendra Pokhrel ◽  
Kiran Baral ◽  
Bishnu R Ojha ◽  
Surya K Ghimirey ◽  
Madhav P Pandey
Keyword(s):  
Water Use Efficiency ◽  
Plant Height ◽  
Water Use ◽  
Moisture Stress ◽  
Physiological Traits ◽  
Wheat Crop ◽  
Growth Stages ◽  
Wheat Genotypes ◽  
Wide Range ◽  
Use Efficiency

Wheat crop in developing world including Nepal is grown under rainfed condition and thus face moisture stress at one or more growth stages limiting grain yield. An experiment was conducted at Greenhouse to screen the 60 different genotypes of wheat including Nepalese landraces, commercial cultivars CIMMYT derived advanced lines, NWRP derived advanced lines, and three international drought tolerant check cultivars. The wheat genotypes were grown in pots (single plant) arranged in a replicated split plot design under two contrasting moisture regimes, optimum and moisture stressed. The genotypes were evaluated for water use, water use efficiency, plant height, number of tillers and biomass production. The analysis revealed significant variance between environments and among the wheat genotypes for most of these traits. A wide range of variability was observed for water use, water use efficiency, days to anthesis, plant height, number of tillers and biomass yield in both moisture stressed and non stressed environments. Gautam showed superiority than Bhrikuti and Vijaya among Nepalese cultivar for drought adaptive physiological traits. Landrace NPGR 7504 showed high level of water use efficiency and other positive traits for drought adaptation.

scholarly journals Implications of water policy reforms for virtual water trade between South Africa and its trade partners: economy-wide approach

Water Policy ◽  
2014 ◽  
Vol 17 (4) ◽  
pp. 649-663 ◽  
Author(s):  
Rashid Hassan ◽  
Djiby Racine Thiam
Keyword(s):  
South Africa ◽  
Water Use Efficiency ◽  
Water Use ◽  
Water Policy ◽  
Virtual Water ◽  
Policy Reforms ◽  
Virtual Water Trade ◽  
Agricultural Exports ◽  
Recent Trends ◽  
Use Efficiency

This paper employs an economy-wide framework to evaluate impacts of water and trade policy reforms in South Africa (SA) on virtual water flows. To pursue this analysis, the study derives net virtual water trade flows between SA and its partners to assess implications of recent trade agreements within the South African Development Community compared to economic cooperation with other major trading blocks (e.g. European Union, Asia, and Brazil, Russia, India and China (BRIC)). Recent trends in actual trade confirm model predictions that liberalization of water allocation would switch water from field crops to horticulture and promote growth in non-agricultural exports. The results suggest that it is necessary to introduce policies that enhance likely outcomes of liberalization promoting higher water use efficiency within irrigation agriculture such as increased adoption of more efficient irrigation methods (sprinkler, drip, etc.) as water becomes more expensive under wider open competition. Moreover, investment in higher water use efficiency and improved competitiveness of dryland agriculture therefore represent the sound economic options for strengthening the capacity to achieve food security objectives as the country strives to lower net water exports. Finally, careful coordination of trade and water policy reforms is another necessary challenge for SA's strive to manage a water stressed economy.

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