How ecology-friendly irrigation can sustain the environment
Dr.Menachem Dinar

Effective, correct irrigation is generally linked with WUE (Water Use Efficiency).It entails optimal water management with the aim of boosting agricultural productivity and improving food quality. High economic return on a water unit is generally the main parameter for commercial evaluation.

The efficient use of water is the prime challenge in worldwide farming practices where problems of water shortages or collection and delivery of water are widespread.

It is an accepted fact that industry and sometimes, agricultural

practices, play a significant role in environmental pollution. The
resulting damage is evident in a wide range of locations and also in
the visible impact on a broad variety of processes (2,4,5).

A significantly detrimental effect of agricultural practices on the
environment can be attributed to the irrational application of
irrigation and inefficient use of fertilizers, pesticides or other
chemicals (3,2).

Agriculture is presently undergoing significant changes in innovative irrigation, fertilizer technology and agronomic expertise. These elements constitute a vital platform for agricultural success and for preventing ecological impairment.

The following review presents several processes and their link with Environmental Irrigation that balances environmental protection with improved agricultural production. The Environmental Irrigation platform is based on the uniform application to the active root system zone of precise amounts of water and fertilizers, combined with rational agricultural knowledge of the plant’s water needs.   1.Environmental Irrigation is directly linked with the reduction in pesticide application (2) The widespread use of chemicals for disease, pest and weed control is an inherent factor in agriculture. A major principle in reducing this overuse is limiting use without damaging crop quality or the farmer’s profits.   Leaf disease development and weed growth are promoted by free accumulation of water on the leaf surface, air humidity and soil moisture.   Reduction of leaf wetness by applying water under the foliage, and control of soil moisture to a limited area will suppress leaf disease and prevent weed infestation.   Drip irrigation governed by the right timing and required amounts around the plant will impede leaf diseases and weed growth. It will therefore minimize dependence on pesticides.   Drip irrigation teamed with the rational application of pesticides using monitoring and models for predicting disease development is a substantial factor in minimizing environmental damage.   2. Optimizing nutrigation and meeting environmental needs. The tendency to increase agricultural production and make it more efficient is directly associated with the widespread application of a variety of fertilizers. Many countries are sensitive both to the predictable damage resulting from overuse of fertilizers (2) and their accumulation in the soil and in groundwater. This applies equally to greenhouses and open field agriculture.   Furthermore, there are crops such as lettuce where due to public health concerns, nitrate levels in the leaves are restricted by food agencies.(7,8)This constraint applies to nearly all fertilizers but in particular to nitrogenous fertilizers. Various forms of nitrogen (nitrate, ammonia, urea and organic nitrogen)are easily leached, and could reach fresh water sources (4).   Here too, the prevention of environmental pollution requires integration of drip irrigation and agronomic expertise. Correct forecasting of nitrate requirements, accurate application of nitrogen in the irrigation system and its precise application around the root systems is essential to prevent the pollution caused by excess use of fertilizers in general, and nitrogen in particular (6). Monitoring water quantities and nitrogen levels at root level and under it, will enable control and balance of fertilizer and water dosage.   3.Inhibiting erosion, surface and underground run-off. Soil erosion and destruction of the natural environment are widespread phenomena resulting from precipitation and uncontrolled and high water application flow rate. This applies to all topography and soil types but is particularly relevant to acute slopes. Here, the most effective solution is low volume and low flow drip irrigation that can supply water to suit the soil’s penetration abilities, and prevent excessive run-off (2,4,5).   4.Saving water and preventing dissipation of water resources. Environmental Irrigation is also applicable in cases where there is improper use of surplus water for irrigation. Dripirrigation is extremely economical because it integrates low evaporation on the soil surface, delivery of exact quantities of water to the active root zone, and uniform water distribution. The high uniformity of water distribution achieved by drip irrigation can prevent water loss of up to 30-40 %compared with flood irrigation, and 10-20 %compared with overhead irrigation. The benefit of uniform water supply and consequently fertilizer supply, will definitely contribute to an increase in production and quality.   5.Cutting down on energy requirements. Irrigating with a heavy surplus of water entails excessive use of energy (for pumping and water transportation).Drip irrigation has low energy requirements compared with the majority of other irrigation methods. High energy requirements are directly associated with environmental pollution because of gaseous emissions into the atmosphere.   6.Rational use of waste/recycled water by surface and sub-surface (below surface drippers.)drip irrigation Another aspect of irrigation and environmental protection is evident in the rational use of low quality water –in particular brackish or recycled water (5). Certainly, a drip system that enables low-quality water to be used successfully for agriculture, eliminates the need for costly purification a process with high energy requirements. Drip irrigation also enables extensive use of waste and recycled water in compliance with local authority standards. Controlled distribution of wastewater prevents pollution of the soil and water sources. Its use has increased following development of a relatively new system of drip irrigation that is installed under the soil surface (subsurface drip irrigation).This agro -technical system could be an optimal solution particularly for wastewater. Already in wide and successful application, it utilizes wastewater for crops and allows municipalities to irrigate large landscape areas. The topic will undoubtedly assume major importance in the future with the increased awareness of environmental issues.   Conclusion: Environmental Irrigation integrates agricultural and ecological concerns at their most optimized levels. In today’s modern farming systems, growers can rely on advanced tools and know-how to optimize the application of water.The choice of an effective, correct irrigation system in tandem with agronomic expertise is a crucial component for achieving high yields and preventing environmental pollution.