Minor Irrigation --- Drip Irrigation Part 1 --- www.nabard.org

Minor Irrigation

Drip Irrigation: Part 1

1.0 Introduction Drip irrigation, also known as "trickle" irrigation, is one of the methods of water management. Under this system, water is carried to the plant under low pressure, through small diameter plastic pipes and delivered at the root zone, drop by drop through drippers. Drip irrigation is widely practised and established method of irrigation in developed countries and is slowly gaining popularity in India. It is most suited for horticulture crops, vegetables etc. and finds applicability in hard rock areas where groundwater is scarce and helps in optimisation of the limited water resources. The system has its advantages and limitations. Its advantages are in terms of savings of water (50-60%) of that required for flow irrigation, effective use of fertilizers, less labour and energy cost. The limitation for adopting of this method is its high initial cost which is beyond the purchasing capacity of small and marginal farmers and thus mainly adopted by large farmers. As a policy to encourage use of such systems, the Govt. of India announced the Centrally sponsored Micro Irrigation Scheme during 2005-06. The total cost of the scheme is being shared between Central Government, the State Government and the beneficiary either through his/her own resources or soft loan from financial institutions in the ratio of 40%, 10% and 50% respectively. Bankable schemes have to be formulated for availing bank loans. This model gives broad guidelines for scheme formulation by banks for financing drip irrigation systems. 2.0 SCHEME REQUIREMENTS Scheme formulation for installation of drip irrigation systems against bank loan requires both technical and financial details. This should briefly give the command area, type of plant/tree, required spacing between plants, land scope etc. and general topographic features. The important items that should be included in a scheme for drip irrigation system are given bellow : 2.1 Soil The general nature of the soil and its characteristics should be indicated. Soils have a bearing on the water requirements of crops and setting up the irrigation schedule. A drip system is not suitable for clayey or gravely soils as would be seen from table 4. Best results with this system are obtained with medium textured soils. 2.2 Climate and Rainfall The climatic condition and rainfall of the area governs the irrigation requirements of the crops. The evapo - transpiration data is also important. The normal monthly evaporation data as per Indian Meteorological Department (IMD) should necessarily be given which would greatly help in determining the daily water requirements and irrigation needs in different seasons. 2.3 Groundwater quality Groundwater quality in the scheme area should be given. Its suitability for irrigation may be indicated in sodium absorption ratio, total dissolved solids etc. 2.4 Designs of Drip System The designs of the drip system especially the layout, size and length of mains, sub-mains, laterals etc. based on land slope and field plot layout should be given in the scheme. Emitter selection, number of emitters to the plant, water discharge through the emitter and total pumping schedule should be indicated. 2.5 Well Capacity The source of water should be indicated. If the source of water is a groundwater structure, the diameter, depth and well yield together with HP of the pump set already installed may be given. This is necessary to decide the discharge available from the well and its optimum utilisation. 2.6 Economics  The economics of investment should be given in detail to justify the loan. The scheme should also give details about repayment period, rate of interest, subsidy available etc. 2.7 Basic Data Information A drip irrigation system requires certain basic data information to plan its layout and ensure trouble free operation. A format for the required information is given in the Annexure I which necessarily should be provided in the scheme.

Continue....................Click Here