Estimating and tracing actual crop water demands during the growing season are necessarily essential as it can be the basic and useful information for achievement of irrigation water management and reservoir operation...
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The study aims to assess the effect of small scale irrigation adoption to farmers in Nasho sector, Kirehe District in Rwanda. The average yield was 12,309.73 Kg/2.62 ha or 4698.73 Kg/ha for adopters with the mean diff...
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The study aims to assess the effect of small scale irrigation adoption to farmers in Nasho sector, Kirehe District in Rwanda. The average yield was 12,309.73 Kg/2.62 ha or 4698.73 Kg/ha for adopters with the mean difference between adopters and non adopters ranged from 2819.63 Kg to 4766.59 Kg per unit area of production. For food security status, the average mean quantity of maize consumed at home level was 615.54 Kg with the mean difference ranged from 377.29 Kg to 474.68 Kg. For market participation, the average treatment effect of the treated (ATT) of quantity of maize sold was 11,694.24 Kg while the mean difference ranged from 7165.98 Kg to 9015.60 Kg. The Average Treatment Effect of the Treated market price was 213 Frws/Kg while the mean difference ranged from 44.51 Frws/Kg to 48.3053 Frws/Kg. The Average Treatment Effect of the Treated of farmer’s revenues for the users was 938,772 Frws/ha, however, the mean difference between adopters and non adopters ranged from 1,732,942 Frws to 2,007,039 Frws. The Average Treatment Effect of the Treated of farmer’s net farm income was 1,066,393 Frws while mean difference between users and non users ranged from 803,967 Frws to 854,141 Frws. For profitability analysis, the cost benefit ratio (CBR) was taken into account. The total benefit per unit area was 2,434,509 Frws and total average mean cost of 1,382,313 Frws and CBR = 1.761 > 1. The findings of this study will help the policy makers for deeper sector planning and also, it will facilitate other stakeholders to invest in irrigation technology to improve the livelihoods of Rwandan farmers and other surroundings.
The soil water retention curve (SWRC) is the basic information for analyzing hydrologic processes in the vadose zone. In practice, however, it is very costly and time-consuming to develop this function experimentally....
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ISBN:
(纸本)9781617388354
The soil water retention curve (SWRC) is the basic information for analyzing hydrologic processes in the vadose zone. In practice, however, it is very costly and time-consuming to develop this function experimentally. Empirical models have been developed to describe the SWRC. Applications of the fractal theory have provided a useful tool to fill the gap between the use of empirical models and physical interpretation of their parameters. Especially a more generalized model for the SWRC has been developed based on the pore-solid fractal (PSF) distribution. The PSF model covers several existing models as its special cases and theoretically provides a direct way to estimate the SWRC fractal dimension from particle size distributions (PSD). The field study was conducted in the 2.16×105 ha Jiefangzha irrigation Scheme (JFIS) of the Hetao irrigation District (HTID) of Inner Mongolia, China. Across the JFIS, 110 undisturbed soil samples were randomly collected. The first objective of this study was to evaluate the SWRC estimation with the PSF distribution using the 110 PSD data sets collected from the HITD. The second objective was to establish a relationship between the fractal dimension and soil texture, saturated soil water content (θ s), residual water content(θ r) and Van Genuchten model parameters (α and n) .Linear regressions of the predicted and measured SWRC showed good agreement. The results indicated that the fine-textured soils had higher values for PSF, while the coarse-textured soils had smaller values. This will provide a reliable method to determine soil properties and parameters of SWRC at regional scale in Hetao irrigation District, which are very important for understanding the regional water and salt transport as well as for developing water management scenarios.
A linear programming (LP) based optimization model and a simulation model are developed and applied in a typical diversion type irrigation system for land and water allocation during the dry season. Optimum cropping p...
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A linear programming (LP) based optimization model and a simulation model are developed and applied in a typical diversion type irrigation system for land and water allocation during the dry season. Optimum cropping patterns for different management strategies are obtained by the LP model for different irrigation efficiencies and water availability scenarios. The simulation model yields the risk-related irrigation system performance measures (i.e. reliability, resiliency and vulnerability) for the management policies defined by the optimization model. The alternative strategies are evaluated in terms of all performance criteria (i.e. net economic benefit, equity and reliability) simultaneously through a trade-off analysis using a multi-criteria decision making method (compromise programming). For the case study of the Kankai irrigation system in Nepal, with equal preference to the objectives, a management strategy with equal share of water among the project subareas appears to be the most satisfactory alternative under water shortage conditions. The existing water allocation policy is not economically efficient. Deficit irrigation in Early paddy appears attractive under favorable hydrologic scenario, particularly if accompanied by measures to improve existing irrigation system efficiency.
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