Author: J. DoorenbosPublisher:
ISBN:
Category : Crops
Languages : en
Pages : 202
Book Description
Calculation of crop evapotranspiration; Selection of crop coeficient; Calculation of field irrigation requirements.
Guidelines for Predicting Crop Water Requirements
Author: J. DoorenbosPublisher:
ISBN:
Category : Crops
Languages : en
Pages : 202
Book Description
Calculation of crop evapotranspiration; Selection of crop coeficient; Calculation of field irrigation requirements.
Guidelines for Predicting Crop Water Requirements
Author: J. DoorenbosPublisher:
ISBN: 9789251002797
Category : Crops
Languages : en
Pages : 144
Book Description
This publication is intended to provide guidance in determining crop water requirements and their application in planning, design and operation of irrigation projects; Part I.1 presents suggested methods to derive crop water requirements. The use of four well-known methods for determining such requirements is defined to obtain reference crop evapotranspiration (ETo), which denotes the level of evapotranspiration for different set of climatic data. To derive the evapotranspiration for a specific crop, relationships between crop evapotranspiration (ETcrop) and reference crop evapotranspiration (ETo) are given in Part I.2 for different crops, stages of growth, length of growing season and prevailing climatic conditions. The effect of local conditions on crop water requirements is given in Part I.3; this includes local variation in climate, advection, soil water availability and agronomic and irrigation methods and practices. Calculation procedures are presented together with examples. A detailed discussion on selection and calibration of the presented methodologies together with the data sources is given in Appendix II. A computer programme on applying the different methods is given in Appendix III. Part II discusses the application of crop water requirements data in irrigation project planning, design and operation. Part II. 1 deals with deriving the field water balance, which in turn forms the basis for predicting seasonal and peak irrigation supplies for general planning purposes. Attention is given to irrigation efficiency and water requirements for cultural practices and leaching of salts. In Part II. 2 methods are presented to arrived at field and scheme supply schedules with emphasis towards the field water balance and field irrigation management. Criteria are given for operating the canal system using different methods of water delivery, and for subsequent design parameters of the system. Suggestions are made in Part II. 3 on refinement of field and project supply schedules once the project is in operation. The presented guidelines are based on measured data and experience obtained covering a wide range of conditions. Local practical, technical, social and economic considerations will, however, affect the planning criteria selected. Therefore caution and a critical attitude should still be taken when applying the presented methodology.
Guidelines for Predicting Crop Water Requirement
Author: FAO.Crop Water Requirements
Author: J. DoorenbosCrop Water Requirements
Author: J. DoorenbosPublisher:
ISBN: 9789251002797
Category : Crops
Languages : en
Pages : 144
Book Description
This publication is intended to provide guidance in determining crop water requirements and their application in planning, design and operation of irrigation projects; Part I.1 presents suggested methods to derive crop water requirements. The use of four well-known methods for determining such requirements is defined to obtain reference crop evapotranspiration (ETo), which denotes the level of evapotranspiration for different set of climatic data. To derive the evapotranspiration for a specific crop, relationships between crop evapotranspiration (ETcrop) and reference crop evapotranspiration (ETo) are given in Part I.2 for different crops, stages of growth, length of growing season and prevailing climatic conditions. The effect of local conditions on crop water requirements is given in Part I.3; this includes local variation in climate, advection, soil water availability and agronomic and irrigation methods and practices. Calculation procedures are presented together with examples. A detailed discussion on selection and calibration of the presented methodologies together with the data sources is given in Appendix II. A computer programme on applying the different methods is given in Appendix III. Part II discusses the application of crop water requirements data in irrigation project planning, design and operation. Part II. 1 deals with deriving the field water balance, which in turn forms the basis for predicting seasonal and peak irrigation supplies for general planning purposes. Attention is given to irrigation efficiency and water requirements for cultural practices and leaching of salts. In Part II. 2 methods are presented to arrived at field and scheme supply schedules with emphasis towards the field water balance and field irrigation management. Criteria are given for operating the canal system using different methods of water delivery, and for subsequent design parameters of the system. Suggestions are made in Part II. 3 on refinement of field and project supply schedules once the project is in operation. The presented guidelines are based on measured data and experience obtained covering a wide range of conditions. Local practical, technical, social and economic considerations will, however, affect the planning criteria selected. Therefore caution and a critical attitude should still be taken when applying the presented methodology.
Deficit Irrigation Practices
Author: Food and Agriculture Organization of the United NationsPublisher: Food & Agriculture Org.
ISBN: 9789251047682
Category : Technology & Engineering
Languages : en
Pages : 116
Book Description
In the context of improving water productivity, there is a growing interest in deficit irrigation, an irrigation practice whereby water supply is reduced below maximum levels and mild stress is allowed with minimal effects on yield. Under conditions of scarce water supply and drought, deficit irrigation can lead to greater economic gains than maximizing yields per unit of water for a given crop; farmers are more inclined to use water more efficiently, and more water-efficient cash crop selection helps optimize returns. However, this approach requires precise knowledge of crop response to water as drought tolerance varies considerably by species, cultivar and stage of growth. The studies present the latest research concepts and involve various practices for deficit irrigation. Both annual and perennial crops were exposed to different levels of water stress, either during a particular growth phase, throughout the whole growing season or in a combination of growth stages. The overall finding, based on the synthesis of the different contributions, is that deficit or regulated-deficit irrigation can be beneficial where appropriately applied. Substantial savings of water can be achieved with little impact on the quality and quantity of the harvested yield. However, to be successful, an intimate knowledge of crop behavior is required, as crop response to water stress varies considerably.
Crop Evapotranspiration
Author: Richard G. AllenWater Quality for Agriculture
Author: R. S. AyersPublisher:
ISBN:
Category : Technology & Engineering
Languages : en
Pages : 196
Book Description
Richtlijnen voor de werker in het veld om problemen te ondervangen ten aanzien van de waterkwaliteit voor irrigatie-doeleinden. Tenslotte worden praktijkervaringen uit diverse gebieden vermeld
Guidance on realizing real water savings with crop water productivity interventions
Author: Van Opstal, J., Droogers, P., Kaune, A., Steduto, P., Perry, C.Publisher: Food & Agriculture Org.
ISBN: 9251341362
Category : Technology & Engineering
Languages : en
Pages : 63
Book Description
This technical document contains clear and practical guidelines on how to implement real water savings in agriculture through interventions for enhancing crop water productivity. A distinction is made between real water savings and “apparent” water savings. Apparent water savings record reductions in water withdrawals but do not account for changes in water consumption. Real water savings record reductions in water consumption and non-recoverable return flows (runoff or percolation). This guidance document emphasizes the paradox of water savings at field and basin scales, which usually do not translate into increased water availability for other users, as is commonly believed.
Handbook of Irrigation Hydrology and Management
Author: Saeid EslamianPublisher: CRC Press
ISBN: 1000865231
Category : Science
Languages : en
Pages : 536
Book Description
Ever-increasing population growth has caused a proportional increased demand for water, and existing water sources are depleting day by day. Moreover, with the impact of climate change, the rates of rainfall in many regions have experienced a higher degree of variability. In many cities, government utilities have been struggling to maintain sufficient water for the residents and other users. The Handbook of Irrigation Hydrology and Management examines and analyzes irrigated ecosystems in which water storage, applications, or drainage volumes are artificially controlled in the landscape and the spatial domain of processes varies from micrometers to tens of kilometers, while the temporal domain spans from seconds to centuries. The continuum science of irrigation hydrology includes the surface, subsurface (unsaturated and groundwater systems), atmospheric, and plant subsystems. Further, the book includes coverage of environmental and economic impacts, water quality issues, water harvesting, satellite measurements for irrigation, and more. Features: Offers water-saving strategies to increase the judicious use of scarce water resources Presents strategies to maximize agricultural yield per unit of water used for different regions Compares irrigation methods to offset changing weather patterns and impacts of climate change