Irrigation act as important role in main challenges which are caused by food insecurity and other uncertain conditions. Accordingly, world have problem to face drought shock due to increase in population pressure. Under these conditions the appropriate way to balance the agricultural productivity is through irrigation.
By Muhammad Saqlain1 Dr. Safura Bibi2
But under ever increased population density in some arid areas and catastrophe caused by drought, irrigation boosting is not easy.
Pakistan have some huge project like Jalal pur irrigation project (JIP), Chashma Right Bank irrigation project etc. Many of other schemes are either fully or partially desolated due to lack of suitable management.
There will be a big competition in future, is to increase food productivity with less water availability. Particularly Sindh and Baluchistan, where drought condition is rapidly increasing and there is a great loss in food productivity.
Some strategies are required to balance the food and agricultural productivity, which is done by promoting existing irrigation schemes or by increasing areas which are under irrigation. However there are many chances to enhance the production of developed system.
Types of Irrigation
There are many methods of irrigation for supplying water to plants. The main object is to apply the water to plant consistently as possible. By applying these methods we can increase agricultural productivity with less water consumption.
The oldest form of irrigation and also called as gravity irrigation. In this system water moves onto the surface of agricultural lands. The main order of surface irrigation is to wet the soil and infiltrate to the soil. In this system field must be leveled. It’s a common method of irrigation to improve the agricultural productivity and mainly used in part of the world.
It is a Most Efficient process to supply water to the plant uniformly as possible. In which water supplied to plants drop by drop at position of the roots. Water dropped at or near the root zone and it decreases the evaporation rate if managed accurately. Accordingly, we also deliver fertilizer to the plant through trickling in this process.
Deep percolation, occurred when the infiltrated water exceeds the storage capacity of soil and it is done by the operating for too long or when the water delivery rate is too high. This method can be used for consistency throughout a field or for accurate water delivery to individual plant in a farmland or different species. In this system field does not have to be leveled. Ayub Agricultural Institute Faisalabad has longest drip irrigation system.
This system is permanently fitted in the field at different location. Water provided to the plant using sprinklers, sprays or guns which are mounted overhead like a nozzle on pipe. Some sprinkler can rotate in full or partial circle to supply the water. Water pressure is under controlled in this device.
The Deficit Water Irrigation
The deficit irrigation management is different from old methods of irrigation. In the deficit irrigation management we need to know the Water Use Efficiency of plants WUE. In this way we can reduce the decrease in yield due to water deficiency. We can provide water according to the Water Use Efficiency of the plants and can provide enough water to the plants that will not cause decrease in yield or will minimize the yield loss. The conserved water can be provided to the other plants which need more water to maintain their yield. In this way we can reduce the yield loss which was not possible from the traditional methods But before using the method of Water deficit irrigation management we should also be aware of the crop yield .response to the Crop to the water stress. The successful use of the Water Deficit irrigation management also depends on the water holding capacity of the soil or ability of water retention of the soil.
All type of soils has different water holding capacity. The soil with larger sand particles has low water holding capacity and soil with fine texture of its particles have high water holding capacity. Therefore the sandy soils lose more water and water deficit management can be used properly in the sandy soils. The plants in such soil remain less affected by the amount of underground water.
Agronomic practices may vary according to the situation. These techniques may involve the less use of fertilizers and low plant populations etc. Deficit irrigation can lead to profit in the areas where the irrigation much costly and water is low Therefore in these areas where water supply is limited the deficit irrigation can be a better choice to reduce expenses. There are many crops which were successful using deficit irrigation. Example of such crops is Cotton, sugarcane and potato. Such plants can be cultivated under deficit irrigation as they are resistant to water stress or they develop deep roots to manage the water stress.
These allow soil moisture deep in the soil layers. The efficient ways of deficit irrigation are Drip irrigation and sprinkler irrigation and furrow irrigation. The maximum quality and quantity of potato have been achieved by using these techniques of deficit irrigation. Deficit irrigation is useful also in the areas where there is low labor available low energy and water. Therefore the deficit irrigation management lowers the expenses of labor, energy and water. Water use efficiency is increases by providing low irrigation water or by decreasing the number of irrigations. It also decreases the yield loss due to water runoff and over irrigation etc.