Suchergebnisse

Irrigation remains a critical input into farming and, therefore, it remains a proxy for food security and poverty alleviation in developing countries. Despite their role in economic growth and the received investment, irrigation schemes are still underperforming. Among many irrigation schemes, transferring more management responsibilities to farmers proved to be a viable path toward improving performance. However, the large diversity of implementation strategies makes evaluation difficult, while its well-demonstrated benefits have paramount importance to convince reluctant smallholders to take additional roles. In order to address this gap, we analyze the effects of participation on farming outcomes (yield, revenue, net profit) by estimating the treatment effect. We present the case study of a Mubuku small-scale irrigation scheme, Uganda. We provide a framework to construct the Farmers Participation Index while distinguishing farmers into participating and not participating groups. The effects of participation are investigated through econometric methods including nonparametric and semiparametric estimation methods such as a difference in means, a regression adjustment, propensity score matching, and entropy balancing. The analysis reveals a positive and significant treatment effect of participation on farming outcomes. The obtained results endorse the efforts of governmental programs to foster responsibility transfer and the farmers&rsquo ; role in irrigation management. A strong causal relationship between management and profitability provides incentives for farmers to engage in participation.

River floodplains sustain irrigated agriculture worldwide. Despite generalised groundwater level falls, limited hard data are available to apportion groundwater sources in many irrigated regions. In this paper, we propose a workflow based on: hydrochemical analysis, water stable isotopes, radiocarbon contents and multivariate statistical analysis to facilitate the quantification of groundwater source attribution at regional scales. Irrigation water supply wells and groundwater monitoring wells sampled in the alluvial aquifer of the Condamine River (Queensland, Australia) are used to test this approach that can easily be implemented in catchments worldwide. The methodology identified four groundwater sources: 1) river/flood water; 2) modified river/flood water; 3) groundwater recharged through regional volcanic materials and 4) groundwater recharged predominantly through sands and/or sandstone materials. The first two sources are characterised by fresh water, dominant sodium bicarbonate chemistry, short residence time and depleted water stable isotope signatures. Groundwater sources 3 and 4 are characterised by saline groundwater, sodium chloride chemistries, enriched water stable isotopes and very low radiocarbon contents, inferred to correspond to long residence times. The majority of wells assessed are dominated by flood water recharge, linked to decadal >300 mm rainfall events and associated flooding in the region. The approach presented here provides a groundwater source fingerprint, reinforcing the importance of floodwater recharge in the regional water budgets. This apportioning of groundwater sources will allow irrigators, modelers and managers to assess the long-term sustainability of groundwater use in alluvial catchments. ; This research was funded by the Cotton Research and Development Corporation, Australia, Grant Number UNSW1401. The authors would like to thank Lucienne Martel for her assistance with sample collection. We would also like to thank all cotton growers who provided access to their irrigation water supply wells and the staff at the Queensland Department of Natural Resources and Mines (Toowoomba, Office) who facilitated at short notice access to the government groundwater monitoring wells. Dr. Matthias Raiber (CSIRO) is also acknowledged for conversations and assistance in the field during sampling. Chris Dimovski, Barbora Gallagher, Robert Chisari, Henri Wong, Brett Rowling and Vlad Levchenko from ANSTO are also acknowledged for their constant logistic and analytical support. Laura Scheiber and Enric Vázquez-Suñé would like to thanks Spanish Ministry of Science and Innovation (Project CEX2018-000794-S). The authors also thank Lisa Williams for editing and proofreading the manuscript. ; Peer reviewed

AbstractThis paper summarizes the present position of agricultural spray irrigation in England and Wales, providing (a) national statistics and regional information, (b) the reasons why farmers irrigate, (c) the place of agriculture in the economy, and (d) the value of irrigation. A review of the Ministry of Agriculture, Fisheries and Food irrigation surveys highlights the important crops in terms of area and volume of water used, sources of water and storage, and application methods. The predictions for the future, including the effects of climate change are reviewed with examples of how farmers, the EA, and the agricultural industry, are helping to overcome problems.

20 Pags.- 2 Tabls.- 8 Figs. The definitive version is available at: http://ascelibrary.org/journal/jidedh ; This work presents and applies a new methodology to find the optimal topography of a surface irrigation field, achieving a theoretically uniform surface irrigation. For any variant on surface irrigation (basin, border or furrow, with open or blocked end), the method's result is a particular curved topographical shape of a field. This shape distributes water evenly over the field so that distribution uniformity is theoretically 100% and deep percolation disappears. The methodology was applied to two theoretical cases: (1) a one-dimensional blocked-end field, and (2) a two-dimensional square field with corner inflow. For each case, the methodology reached a particular topography in which distribution uniformity was near 100%. To put this methodology into practice, the optimized topography (which has a curved shape) can be fitted with two or more different slopes. An example is shown in which a real field was laser-levelled with two consecutive slopes to fit the optimized topography; it previously was calculated with the methodology presented in this paper. The irrigation was evaluated before and after the optimization. The results indicated an increase of distribution uniformity from 82 to 96%. The topographic optimization methodology offers new information about topography influence on irrigation performance indicators. The main practical conclusion is that this method can be useful to determine the best slope, set of slopes or curved shape when levelling any field for surface irrigation. ; This work was supported by the Government of Arag ´on (Spain) and the European Social Fund (European Union). ; Peer reviewed

Numerous field studies related to irrigation management have been conducted in Nepal since the last national seminar on irrigation issues in 1983. The relationship between organizational structure and resource mobilization was the topic of several. Another examined changes in organization and resource mobilization as property relationships and water rights changed when systems expanded and allowed new members. Concern for improving intervention strategies to existing farmer-managed irrigation systems has stimulated work on finding methods for quickly collecting data for identification and assessment of systems where substantial gains can be made by giving assistance. Numerous case studies have expanded the information available on management of operation and maintenance in both farmer- and agency-managed systems. These seminar papers report the findings of eleven of the studies.

Argues that single irrigation systems managed by autonomous system-specific organizations accountable to their customers, perform better and are more sustainable than those managed by agencies dependent on the government, or by agencies responsible for multiple systems. Selected cases are reviewed and the plausibility of this hypothesis established. General recommendations are made for policy makers designing irrigation reform programs.

For many decades, Uzbekistan has been one of the largest cotton producers in the world.
The irrigation water needed for these high production levels has been delivered by the massive
diversion of the Amu Darya and Syr Darya rivers, which naturally flowed into the Aral Sea. This
diversion for agriculture was the main cause of the rapid decline of the Aral Sea, which is at only 10% of its original size today. The traditional method of irrigation, which relies on simple open canal systems, is highly inefficient for managing the region's critical and limited water resource. It has been qualitatively estimated, for example, that irrigation water lost to evaporation and system inefficiencies is quite large. With the future availability of water at risk for agriculture in Central Asia, primarily due to the loss of glacial volume from global warming, along with declines in seasonal snowpack, it is clear that new approaches to water management are needed. Any serious efforts to restore the Aral Sea and its ecological services would also reduce supplies of irrigation water for Uzbekistan. While regional conflict over water is unlikely, it must be considered since Uzbekistan is a downstream country among several that rely on the Amu Darya and Syr Darya rivers for most of their water supplies. To insure against these risks to cotton poduction and the underlying economy, better irrigation technologies are needed across Uzbekistan. However, these technologies can be quite expensive, especially given that water is still nearly free. In this case study we explore the use of real options nalysis (ROA) to look for optimal investment strategies in efficient irrigation technologies in light of variable climate and policy uncertainties.

O feijão é uma das principais culturas na dieta humana brasileira, apresentando baixa produtividade nacional, o que pode ser explicado pela ocorrência de períodos de deficiência hídrica para a cultura. Desta maneira, objetivou-se avaliar os componentes de rendimento da cultura, a produtividade de grãos e a eficiência do uso da água, em diferentes manejos da lâmina de irrigação e validar a planilha Lâmina para recomendação de irrigação da cultura. O delineamento experimental foi de blocos casualizados com quatro repetições. Os tratamentos foram: não utilização da irrigação; manutenção da umidade do solo na capacidade real de água no solo em 45% da capacidade total de água do solo; manutenção da umidade do solo equivalente em 100% da umidade da capacidade de campo; e ajuste da lâmina de irrigação utilizando a planilha "Lâmina". Determinou-se a quantidade total de água recebida pela cultura, a produtividade de grãos, a relação litros por quilograma de grãos, o ciclo e os componentes do rendimento. O tratamento Lâmina apresentou os melhores resultados para a produtividade, e maior eficiência no uso da água, no entanto não se obteve diferenças significativas para as componentes do rendimento exceto para a componente espessura das vagens. Assim, a planilha Lâmina apresentou grande potencial, tendo alta produtividade e colaborando para a racionalização do uso de água na cultura do feijão.

Palavras-chave: Phaeseolus vulgaris L. Déficit de Água. Precipitação.

Abstract
Dry beans are one of the most important crops for Brazilians people diet, features a low national yield, which can be explained by the occurrence of water deficit events. Thus, this study aimed to evaluate the yield components, the grain yield and the water use efficiency of dry beans submitted to different ways to adjust the irrigation depth, and validate the Lâmina spreadsheet to recommend irrigation to the culture crop. The experimental design was a randomized block with four replications. Four treatments: non-use of irrigation; soil moisture equivalent to actual capacity of water in the soil at 45% of the total capacity of the ground water; soil moisture equivalent to 100% of the field capacity; and irrigation depth adjustment provided by Lâmina spreadsheet. The Lâmina treatment showed the best results for grain yield and water use efficiency, however the yield components were not significant, except for pods thickness. Thus, the Lâmina spreadsheet showed great potential, with high yield and contributing to the rational water use in dry beans crop.

Keywords: Phaeseolus vulgaris L. Water Deficit. Rainfall.

Abstract:Elinor Ostrom was a leader in using multiple methods to perform institutional analysis. In this paper, we discuss how a multi-method approach she pioneered may be used to study the robustness of social–ecological systems. We synthesize lessons learned from a series of studies on small-scale irrigation systems in which we use case-study analysis, experimental methods in laboratory and field settings, and mathematical models. The accumulated insights show the importance of creating institutional arrangements that fit the human ecology within the biophysical constraints of the system. The examples of work based on multiple methods approaches presented here highlight several lessons. For example, experimental work helps us better understand the details of how the ability to maintain trust relationships, low levels of inequality, and low transaction costs of coordination are critical for success. Likewise, the integration of case-study analysis and modeling helps us better understand how systems that can leverage biophysical characteristics to help address challenges of monitoring, sanctioning, and coordination may be able to increase their chances of success.

Flood irrigation on western rangelands is important for diverse social and ecological reasons, providing forage for many agricultural operations and maintaining many critical wetlands across the region. However, recent debate over the efficiency of flood irrigation and resulting transition to other "more efficient" types of irrigation has put many of the working wet meadows sustained by flood irrigation at risk. As the sustainability of these landscapes is primarily dependent on ranchers' management decisions, we sought to gain a deeper understanding of factors influencing ranchers who flood irrigate and how these factors interrelate. We applied the Community Capitals Framework to explore what considerations act as enablers and constraints to maintaining flood irrigation and to evaluate the role of each type of capital in enabling and constraining the coproduction of working wet meadows for ranchers and the environment. Our qualitative analysis of facilitated workshop transcripts and observation notes from two study areas within the Intermountain West showed that ranchers perceived constraining and enabling factors of flood irrigation related to all seven types of community capitals: natural, financial, built, cultural, human, social, and political. The irrigation methods used by ranchers were heavily influenced by environmental components of the landscape rather than reflecting a choice among alternative methods. Other prominent enablers included a commitment toward maintaining the natural history of the landscape and the ranching lifestyle. Primary constraints included the impact of public misperception and the ability to pass their operation on to the next generation. Ranchers weighed multiple considerations simultaneously in a holistic, community-scale approach to management decisions and described how diverse enablers and constraints interacted to determine the viability of flood irrigation and ranching. These results indicate rancher decisions are driven by complex social-ecological considerations and demonstrate the importance of each capital type to rangeland conservation. (C) 2019 The Author(s). Published by Elsevier Inc. on behalf of The Society for Range Management. ; US Dept of Agriculture (USDA) Natural Resource Conservation Service (Oregon State Office); US Fish and Wildlife Service (Mountain-Prairie Region) through the US Geological Survey Cooperative Research Unit [RWO 174]; USDA Farm Service Agency ; This work was funded by the US Dept of Agriculture (USDA) Natural Resource Conservation Service (Oregon State Office) and the US Fish and Wildlife Service (Mountain-Prairie Region) through the US Geological Survey Cooperative Research Unit RWO 174 to Virginia Tech with a subcontract to University of Montana. In addition, the PI of the project and second author (Dr. Ashley Dayer) has another research project studying agricultural producers outside of the study area funded by the USDA Farm Service Agency.