Session 4. Microirrigation With Saline Water
Pear Response to Saline Water Application Under Subsurface Drip Irrigation
Gideon Oron, Yoel DeMalach, Leonid Gillerman, Itsik David
Brackish water can be used for irrigation of a broad variety of crops. However, under arid and semi-arid conditions associated with low annual precipitation and high solar radiation intensive evaporation from the soil surface takes place. Therefore salt could accumulate in the root zone if leaching is not maintained, resulting in poor yields.
To alleviate salt accumulation saline water could be applied using subsurface drip irrigation, thus driving the saline front to below the main root zone. This concept has been examinated in a mature pear orchard. Emitters were installed at 30 cm and 60 cm below the soil surface as well as at the surface as a control. The field results so far have confirmed the approach, and economically viable yields were obtained. Further experiments are proceeding with the aim of reducing the amount of water applied.
Keywords: Drip irrigation, Saline water, Subsurface systems, Fruit trees
Abstract taken from paper found on pages 97 to 103 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Facilitating Improved Irrigation and Salinity Management in an Ethnically Complex Population
B. A. Cumming, C. Erol and G. McFarlane
The Goulburn-Broken catchment of the Murray-Darling River Basin in South Eastern Australia is affected by the environmental threat of land degradation, mainly through rising groundwater and salinity. Some areas of the catchment have a high proportion of Non-English-Speaking-Background (NESB) landowners, notably in irrigated horticulture. Because NESB farmers were perceived to be slow to address the environmental threat, a pilot project was jointly developed by the Department of Agriculture and the local Ethnic Communities Council. The project uses a "Philosophy of Inclusion" to involve all communities in the project, and as many individuals as possible. The project is facilitating change by developing new "hardware" (structures, networks and groups) while making use of those that already exist. However the work concentrates on facilitating activity "software" (inclusive methodologies, group discussion, holistic farm planning, awareness raising, on-farm works and joint projects.) The result of the work is uptake of both micro irrigation and improved drainage management by the communities.
Keywords: empowerment, inclusion, partnership, ethnic, ownership, facilitation
Abstract taken from paper found on pages 104 to 109 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Salinity and Boron Distribution in MicroIrrigated Almonds: Soil and Plant Accumulations
R. B. Hutmacher, H. I. Nightingale, S. S. Vail, F. Dale, D. E. Rolston, D. W. Peters, P. H. Brown, T. Pflaum, A. D. Bravo, and J. W. Biggar
Almond (Prunus amygdalus, Ruby and Butte cv.) trees planted in 1980 were drip irrigated for a period of twelve years using single drip laterals for each row of trees, with six emitters per tree. The primary objectives were to identify almond growth and yield responses for a range of irrigation treatments and two water qualities, and identify resulting soil salinity profiles. Six irrigation treatments applied amounts ranging from severe deficit (50 percent of estimated crop evapotranspiration (ETc) to excess irrigation. The irrigation water source from 1980 through 1987 was moderately saline, with an electrical conductivity (EC) of 1.7 dS m-1 and boron averaging 0.08 mol L-1. From 1987 through 1991, the orchard was split into one section which continued to receive moderately-saline water and another section receiving low-salinity (0.4 dS m-1), low-boron water. The amount of salt and boron accumulating in the upper root zone, the lateral distribution of these constituents and the quantity of leaching were greatly affected by water application treatments. Long-term use of even moderately-saline irrigation water in the low rainfall environment (140 mm annually) of the western San Joaquin Valley resulted in significant salt and boron accumulations within the root zone of some treatments and some plant injury.
Keywords: Almonds, Deficit Irrigation, Salinity, Surface Drip, Boron, Microirrigation
Abstract taken from paper found on pages 110 to 115 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Automatic Microirrigation and Salt Injection System for Research and Commercial Applications
W. P. J. Wessels, W. H. Steyn, and J. H. Moolman
An automatic irrigation system for an experiment with high and low frequency irrigation (2mm and 25mm depletion of root zone soil water) with saline water is described. The system is controlled by a program running on a 386 personal computer with a 8087 mathematical coprocessor and 212 mb hard disc. Weather data, rainfall, and flow data are gathered automatically and used in a modified Penman-type formula to calculate evapotranspiration, and to update the root zone soil water balance every 15 and 60 minutes. Irrigations are scheduled and the irrigation system controlled according to the calculated and prescribed soil water depletions. The system also controls the conductivity of the irrigation water to 150 and 350 mS/m as needed by dosing with a strong solution of a 1:1 molar ratio mixture of NaCl and CaC12 in water. The dosing is controlled by feedback from conductivity sensors utilized by digital Proportional and Integral (PI) compensators for activating normally open solenoid dosing valves by pulse width modulation. This system uses only one dosing pump supplying the dosing solution through a pipe manifold and 4 solenoid valves to the 4 main irrigation pipes resulting in considerable cost savings compared to conventional systems using a dosing pump and controller for each irrigation pipe.
Keywords: Automated irrigation control, Automated dosing, High frequency irrigation
Abstract taken from paper found on pages 116 to 122 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Salinity Effects on Vitis Vinifera L. (cv. Colombar) Grapevine
J. H. Moolman, W. P. de Clercq, W. P. J. Wessels, A. Meiri H. M. duPlessis
A five year research project was started in 1991 on a 1.2 ha microsprinkler irrigated Vitis vinifera L. (cv. Colombar) vineyard with the aim to determine the effect of saline water on the performance of the vines. The experiment consists of six levels of irrigation water salinity ranging from 30 mS/m to 500 mS/m, replicated four times. A stock solution of a 1:1 molar mixture of NaC1 and CaC12 was used and inline salinity sensors and a computerized salt injection system ensured a constant level of salt concentration in the irrigation water throughout an irrigation event. Salinity had an insignificant effect on yield and shoot growth in the first year (1991/92). During the second and third years of salinity treatments, yield reductions at the ECi 350 and 500 mS/m levels were in excess of 50%. The decrease in shoot growth at similar levels of irrigation water salinity during the third year was 37% and 57%, respectively. The first results of the time integrated soil salinity and yield relationship suggest that the yield of grapevine is very sensitive to salinity. Any increase above 75 mS/m ECe had an adverse effect on yield and vine growth. However, in view of the small data base this result should be regarded as provisional.
Keywords: Salinity, Salt tolerance, Grapevine
Abstract taken from paper found on pages 123 to 128 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
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Use of Brackish Water for Sustained Crop Production
N. Hussain, G. D. Khan, S. M. Mehdi, G. Sarwar, M. S. Dogar and T. Hussain
Green house studies were carried out for two years to investigate scientific use of brackish water in such a manner that sustained yields are obtained without disturbing soil health seriously. Soil having no salinity/sodicity problem was packed in lysimeters and two crops of rice as well as wheat were grown applying a basal dose of N, P and K. Mode of irrigations were, canal, brackish water, mixed (1+1), alternate, cyclic (seasonal and yearly), and brackish water along with farm yard manure/gypsum/sulfuric acid/green manure/rice straw incorporated. Yield and yield components of crops were recorded at maturity and soil was analyzed at each harvest. It was observed that persistent sole use of brackish water reduced rice and wheat yields by 25 and 38%, respectively, and had an adverse effect on soil properties. Cyclic use of brackish and canal water, however, proved helpful for obtaining sustained yield without deteriorating the soil physical and chemical properties significantly. Seasonal cyclic use was better than yearly. Irrigation of brackish water with gypsum and sulfuric acid proved safe. Incorporation of rice straw and manure was also a successful strategy. Green manuring produced good results as well. Mixing of canal and brackish water proved superior to sole use of brackish water. It may, thus, be inferred that the aforementioned techniques can successfully be applied for using brackish water to obtain sustained crops without significant detrimental effect of soil health.
Keywords: Saline water, Conjunctive use, Sulfuric acid, Green manuring, Soil properties, Rice-Wheat rotation, sustained yields
Abstract taken from paper found on pages 129 to 134 in Proceedings of 5th International Microirrigation Congress, April 2-6, 1995, Orlando, Florida. American Society of Agricultural Engineers, 2950 Niles Road, St. Joseph, Michigan 49085-9659, USA. Phone: 616-429-0300 FAX: 616-429-3852 EMAIL: HQ@ASAE.ORG
