نتایج جستجو برای: irrigation timing

تعداد نتایج: 128491  

2016
Xuejun Dong Wenwei Xu Yongjiang Zhang Daniel I. Leskovar Peter Langridge

High air temperatures during the crop growing season can reduce harvestable yields in major agronomic crops worldwide. Repeated and prolonged high night air temperature stress may compromise plant growth and yield. Crop varieties with improved heat tolerance traits as well as crop management strategies at the farm scale are thus needed for climate change mitigation. Crop yield is especially sen...

2008
C. G. Abourached I. I. Bashour

This study investigated the interactive effects of different rates of deficit irrigation and timings of N application on wheat and barley yields since there was no report on this important subject. Field experiments in strip-plot designs using sprinkler line sources were conducted for two years at a semi-arid Mediterranean site. The experiments consisted of 4 and 7 irrigation levels with 3 and ...

2001
J.-E. BERGEZ

Irrigation scheduling is an important decision problem in agriculture. The purpose of the study presented in this paper is to compare dynamic programming (DP) and reinforcement learning (RL) methods for identifying optimal starting irrigation strategies, when a limited amount of water is available for irrigation. Both of the optimization methods use the MODERATO simulator, which includes a grow...

2003
Hovav Talpaz James W. Mjelde

Intraseasonal water allocation to a single crop has been studied extensively. Previous studies have emphasized the need to coordinate irrigation scheduling with several factors including economic and physical constraints, amount of soil moisture available at the time of irrigations, growth stage of the plant, interactive effects from previous and/or subsequent irrigation, and the effect, timing...

2002
Frank Casey Patrick Byrne Richard Weldon

This report investigates the costs and benefits associated with the conversion from semi-enclosed seep irrigation to either automated seep or automated sub-drip irrigation for potato production in Northeast Florida. These costs and benefits are estimated at the level of the individual grower and for the public at large. The analytical tools in the report include financial budgeting and regressi...

Journal: :Environmental science & technology 2011
Rebecca B Neumann Allison P St Vincent Linda C Roberts A Borhan M Badruzzaman M Ashraf Ali Charles F Harvey

Irrigation of rice fields in Bangladesh with arsenic-contaminated groundwater transfers tens of cubic kilometers of water and thousands of tons of arsenic from aquifers to rice fields each year. Here we combine observations of infiltration patterns with measurements of porewater chemical composition from our field site in Munshiganj Bangladesh to characterize the mobility of arsenic in soils be...

2005
C. P. Baillie S. R. Raine

Between 1995 and 2003 sugarcane farmers in Bundaberg had access to limited irrigation water. Over this time water allocations were effectively a quarter of the requirements for a fully irrigated crop. In response to this problem irrigation strategies were developed to assist farmers. Field investigations focused on the performance of water winch and furrow irrigation systems, which make up 91% ...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه فردوسی مشهد - دانشکده ادبیات و علوم انسانی دکتر علی شریعتی 1393

this study aimed at examining the effects of iranian efl learners’ anxiety, ambiguity tolerance, and gender on their preferences for corrective feedback (cf, henceforth). the effects were sought with regard to the necessity, frequency, and timing of cf, types of errors that need to be treated, types of cf, and choice of correctors. seventy-five iranian efl students, twenty-eight males and forty...

2017
Guoyong Leng Xuesong Zhang Maoyi Huang Qichun Yang Rashid Rafique Ghassem R. Asrar Ruby Leung

In this study, we applied version 4.5 of the Community Land Model (CLM) at a 0.1258 resolution to provide the first county-scale model validation for simulating crop yields over the Conterminous United States (CONUS). Large bias was found in simulating crop yields against U.S. Department of Agriculture (USDA) survey data, with county-level root-mean-square error (RMSE) of 42% and 38% for simula...

2004
F Olivier A Singels

Effective irrigation scheduling is a prerequisite to optimising the use of expensive irrigation water for sugarcane production in South Africa. Accurate irrigation scheduling is not widely practised in the sugar industry despite the many scheduling tools available to sugarcane growers. This leads to very low water use efficiencies (WUE) of approximately 50% of what could be achieved theoretical...

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