30-11-2012, 12:35 PM
SIGNIFICANCE OF MICRO IRRIGATION IN CROP PRODUCTION
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ABSTRACT
Combating persistent rural hunger and poverty in a world of increasing water scarcity requires new approaches for the agricultural and economical development. To meet the food grain requirement for ever increasing population of the India, there is a need to use all agricultural inputs particularly the water efficiently. Optimization of water use in agricultural activities is necessary to achieve the desired production level. Despite a remarkable gain, the conventional irrigation technologies have failed to meet the widespread need of inexpensive, divisible irrigation systems, suitable for poor and marginal farmers. An entirely new approach is needed to develop such irrigation systems which must be affordable, responsive, divisible and expandable. Micro irrigation techniques have provided an alternative to the farming community because of its water-saving and yield increasing potential which raises the prospect of increasing the crop productivity. The micro-irrigation techniques such as drip irrigation, micro-sprinkler, micro-jet system etc, is a technology that offer unique, agronomic, water conservation and economic advantage that address the challenges for irrigated agriculture in future.
Soltanpour et al. (1999) reported that the traditional methods of irrigations have very low application efficiency (20 to 50 per cent) while micro irrigations can achieve it to the tune of 85 to 95 per cent. Micro-irrigation cover large numbers of irrigation practices and are applicable on relatively small cross sections of supply and distribution lines, the low water emission rates per distributary as well as localized delivery of water to limited area. It was estimated that the widespread use of affordable micro irrigation technique has the potential to boost annual net income among the rural poor. Adoption of micro-irrigation systems found to be effective in increasing water use efficiency which described below in brief.
Microirrigation method
LEPA irrigation
Howell et al. (1995) recorded significantly higher grain yield and dry biomass yields, crop WUE and harvest index of corn under LEPA irrigation either at 100 or 80% replenishment of water in 1.5.m depth soil profile than other treatments. Similar results were also observed by Yazar et al. (2002) in cotton. Williams et al. (1996) reported superiority of LEPA method over other methods with respect to field WUE in sorghum and corn crops.
Drip irrigation
Sagarka et al. (2002) reported higher seed cotton yield under drip irrigation at 0.8 CPE than lower CPE ratios, surface and alternate furrow irrigation but WUE was maximum under alternate furrow followed by drip irrigation at 0.6 CPE. Cetin et al. (2002) reported that higher cotton yield was obtained under drip irrigation as compared to other methods of irrigation. Drip irrigation was found superior over micro-sprinkler and surface methods of irrigation in summer groundnut at Junagadh (Anon., 2003). Similar results were also reported by Pawar et al. (2002) in potato. Sharanappa et al. (2001) obtained significantly higher yield of cabbage and WUE with drip irrigation given daily than other treatments. Chauhan (1998) observed significantly higher values of yield and yield attributes of chilli and WUE with drip irrigation given at 80% CPE than other treatments. Shinde et al. (1998) reported the highest B:C ratio with canewall drip tape system, while maximum net income was under stationary micro-sprinkler irrigation system. On the contrary to this, drip irrigation in rustica tobacco was found detrimental for yield due to continuous wetting promoted orobanche infestation (Anon. 1994). Sharmasarkar et al. (2001) reported that the Sugar beet yields and sugar contents under drip irrigation were higher (3±28%) than those with flood irrigation. It was observed that 100% irrigation requirement through drip irrigation along with black plastic mulch gave higher okra yield and BCR as compared to furrow irrigation (Tiwari et al., 1998). A study indicated that drip irrigation increased yields as well as CBR in arecanut and banana as compared to surface irrigation (Shashidhara et al. 2006). Raina et al. (1998) reported the highest pea yield and WUE under plastic mulch with drip irrigation treatment.
Micro-sprinkler
Pawar et al. (2003) indicated that head yield of cabbage was increased under micro-sprinkler system as compared to other methods of irrigation. Nikam et al. (2002) observed maximum yields of groundnut dry pod, kernel, haulm and oil under broad bed furrow (BBF) with micro-sprinkler followed by BBF with micro-jet. It was also observed that micro-sprinkler irrigation system was found superior over other treatments in respect of groundnut dry pod, net return, water saving and WUE (Firake et al., 2000). Pawar et al. (1998) reported that minimum micro-sprinkler spacing (1.75 x 1.75 m) recorded the highest garlic yield. Krishnamurthy et al. (2003) reported that micro-sprinkler at 80% pan evaporation in groundnut recorded the highest pod yield and WUE besides 10-12% water saving.
Micro-jet irrigation
Shirgure et al. (2001) observed maximum plant height, stock girth and canopy volume in acid lime with micro-jet irrigation system. Shinde et al. (2002) reported that micro-jet with 50% irrigation water and mulch recorded significantly higher yield of green chillies, net returns, CBR and WUE as compared to other treatments
Sub-surface irrigation
Sub-surface drip irrigation was found superior in recording the highest lint cotton yield and WUE over LEPA and sprinkler irrigation (Bordovsky, 2001) and drip spaced at 40 cm registered higher dry matter yield of alfalfa than 60 cm spaced (Alam et al., 2002). Gupta (2000) observed higher plant height, root length, collar diameter, fresh and dry weight of ber plant under ‘Jaltripti, an indigenous subsurface micro-irrigation system than conventional pit planting.
Conclusion
Microirrigation techniques provide an array of technologies such as drip irrigation, micro-sprinkler, micro-jet system etc. which have not only helped in conservation of water but also ensured its timely supply and efficient use. Different microirrigation methods like LEPA, drip irrigation, microjet sprinkler, subsurface along with mulch and proper crop geometry increases the water use efficiency and yields of crops by many folds.
Microirrigation techniques have materialized the concept of ‘more crop per drop, by insuring the availability of adequate quantity and quality of water especially in dryland agriculture where water is the most limiting factor in crop production.