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Conservation of water using mulches is a viable option under semiarid conditions for enhancing water use efficiency. Effect of mulches varies among years and with the amount and timing of mulching. Lucerne is a key crop for organic farming systems under semiarid conditions in Austria. Effect of mulching with lucerne has not been thoroughly investigated. Field experiments were conducted to assess the effect of lucerne utilization system (nonmulch versus mulch) on its shoot and root dry matter yield, biological nitrogen fixation and water use efficiency. Experiments were laid out in randomized complete block design with four replicates at the experimental farm of University of Natural Resources and Life Sciences, Vienna, Austria, during 2007–2008. Mulching was effective in lowering soil temperature by 1–6°C in the top 5 cm of soil. Utilization systems did not significantly affect the other studied parameters (P < 0.05). Lucerne shoot and root dry matter yield, biological nitrogen fixation, and water use efficiency were greater in 2008 than in 2007. Effect of lucerne utilization systems on soil properties needs to be investigated over long-term studies to verify results of this 2-year study. [ABSTRACT FROM AUTHOR]

This paper presents results on the spatial and temporal fluctuations of the groundwater table depth (GWTD) at Wonji-Shoa Sugar Estate (WSSE). Accordingly, spatial maps of GWTD were produced in a GIS (ArcView 3.3) environment from 35 groundwater monitoring piezometers. Results of the study revealed that WSSE, after nearly 60 years of irrigation, is experiencing a serious waterlogging problem. The groundwater (GW) depth is extremely shallow (<1 m below ground) in most of the piezometers throughout the entire season and showed great spatio-seasonal variability. The rate of annual increment of GW rise, coupled with seasonal fluctuation, has obvious repercussions and grave consequences for the sustainability of WSSE in particular and to the region in general. Unless the potential causes for the rise of GWTD are identified soon and feasible corrective measures for mitigating GW rise are introduced, severe crises in the region are inevitable. [ABSTRACT FROM AUTHOR]

Given the possibility of waterborne diseases caused by inappropriate rainwater harvesting systems, a survey was conducted in Uganda to assess existing knowledge of both physical and non-physical measures that safeguard harvested rainwater. Households who had received rainwater tanks were assessed on issues related to harvested rainwater quality. The study shows that 84% of respondents were aware of various sources of rainwater contamination, but only 5% were aware that they needed to adjust use of rainwater, depending on whether they cleaned the tank or not. Most of the respondents were not aware that gutter cleaning was necessary to improve water quality. Indeed, as the water from the collection surface is channelled through gutters, a number of measures need to be taken to control the entry of contaminations and subsequent growth of pathogens in the tank, e.g. first flush diverts, installation of filters, chemical use and mesh cleaning. The majority, however, did not take adequate care of the gutters and this impacts on health and social livelihood. Overall, the findings emphasize the need to provide more information to households when installing water harvesting tanks to ensure that the harvested rainwater is of high quality. [ABSTRACT FROM AUTHOR]

This study evaluates the cause of salinization in an irrigation scheme of 100 ha supplied from a reservoir. The scheme is located in Gumselasa catchment (28 km2), Tigray region, northern Ethiopia. The catchment is underlain by limestone–shale–marl intercalations with dolerite intrusion and some recent sediments. Water balance computation, hydrochemical analyses and irrigation water quality analyses methods were used in this investigation. Surface waters (river and reservoir) and groundwater samples were collected and analyzed. The water table in the irrigated land is ranging 0.2–2 m below the ground level. The majority of groundwater in the effective watershed area and the river and dam waters are fresh and alkaline whereas in the command area the groundwater is dominantly brackish and alkaline. The main hydrochemical facies in the groundwater in the effective watershed area are Ca-Na-SO4-HCO3, Ca-Na- HCO3-SO4, and Ca-Na-Mg-SO4-HCO3. The river and dam waters are Mg-Na-HCO3-SO4 and HCO3-SO4-Cl types, respectively. In the command area the main hydrochemical facies in the groundwater are Ca-Na-HCO3-SO4 and Ca-Na-Mg-SO4-HCO3. Irrigation water quality analyses revealed that salinity and toxicity hazards increase from the effective watershed to the irrigated land following the direction of the water flow. The results also showed that the analyzed waters for irrigation purpose had no sodicity hazard. The major composition controlling mechanisms in the groundwater chemistry was identified as the dissolution of carbonate minerals, silicate weathering, and cation exchange. One of the impacts of the construction of the dam in the hydrologic environment of the catchment is on its groundwater potential. The dam is indirectly recharging the aquifers and enhances the groundwater potential of the area. This increment of availability of groundwater enhanced dissolution of carbonate minerals (calcite, dolomite, and gypsum), silicate weathering and cation exchange processes, which are the main causes of salinity in the irrigated land. The rising of the brackish groundwater combined with insufficient leaching contributed to secondary salinization development in the irrigated land. Installation of surface and subsurface drainage systems and planting salt tolerant (salt loving) plants are recommended to minimize the risk of salinization and salt accumulation in the soils of the irrigated land. [ABSTRACT FROM AUTHOR]

Plant root systems are essential for sustainable agriculture, conveying resource-efficient genotypes and species with benefits to soil ecosystem functions. Targeted selection of species/genotypes depends on available root system information. Currently there is no standardized approach for comprehensive root system characterization, suggesting the need for data integration across methods and sources. Here, we combine field measured root descriptors from the classical Root Atlas series with traits from controlled-environment root imaging for 10 cover crop species to (i) detect descriptors scaling between distant experimental methods, (ii) provide traits for species classification, and (iii) discuss implications for cover crop ecosystem functions. Results revealed relation of single axes measures from root imaging (convex hull, primary-lateral length ratio) to Root Atlas field descriptors (depth, branching order). Using composite root variables (principal components) for branching, morphology, and assimilate investment traits, cover crops were classified into species with (i) topsoil-allocated large diameter rooting type, (ii) low-branched primary/shoot-born axes-dominated rooting type, and (iii) highly branched dense rooting type, with classification trait-dependent distinction according to depth distribution. Data integration facilitated identification of root classification variables to derive root-related cover crop distinction, indicating their agro-ecological functions. [ABSTRACT FROM AUTHOR]