With increasing municipal and industrial demands for water, its allocation for agriculture is decreasing steadily. The major agricultural use of water is for irrigation, which, thus, is affected by decreased supply. Therefore, innovations are needed to increase the efficiency of use of the water that is available. There are several possible approaches.

1. Irrigation technologies and

2. irrigation scheduling may be adapted for more-effective and rational uses of limited supplies of water.

3. Drip and sprinkler irrigation methods are preferable to less efficient traditional surface methods.

It is necessary to develop new irrigation scheduling approaches, not necessarily based on full crop water requirement, but ones designed to ensure the optimal use of allocated water. Deficit (or regulated deficit) irrigation is one way of maximizing water use efficiency (WUE) for higher yields per unit of irrigation water applied: the crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season. The proper application of deficit irrigation practices can generate significant savings in irrigation water allocation. Among field crops, groundnut, soybean, common bean and sugar cane show proportionately less yield reduction than the relative evapotranspiration deficit imposed at certain growth stages.

https://www.slideshare.net/bhupeshkatriya/drip-irrigation-27594932

In developing countries, the problems are different and main cause of irrigation water shortage is its over irrigation by big land lords and forceful people and authorities. Strict and justified supply of water should be maintained

@Mushtaq Ahmad Exactly you are right. It is a great deal to maintain water supply in crop field and I think it is very possible. Actually we need to raise awareness to avoid wastage of water by over irrigation in our farming society. Thank you for your valuable comment.

Prem baboo given a valuable information about your query on alternative irrigation system.

@Prem baboo, @Virendra Singh, Thank you so much for your valuable information.

Using the modified Penman-Montih method to calculate the Kc at different stages of growth (Especially in critical growth stages)

more effective way of deficit irrigation? which is more effective for profitable crop production?

Irrigation frequencies with level/dose of irrigation plus correct interactive crop, could be helpful to achieve profitable crop production.

I think, if we do expanse on drip or other type methods, then why not, if we have big automatic umbrellas in the field, umbrellas should be closed during high sunshine in dry area, because need of irrigation to crop is caused by loss of water through soil surface and plant parts. 3-4 hours stop the high radiant of sun, can help to reduce irrigation need. High temperature rich countries, where irrigation is very short even for drinking, they use water tanks to supply drinking water to homes, where water for cultivation of vegetables is very difficult , they should use this idea.

Some of the respondents have already expressed it. Combine drip irrigation and techniques to retain water in the soil to limit evaporation. 1% more Organic matter in the soil translates to 255,000 liters of water per ha (see NCRS studies). Also in arid countries (and of proper soil) a top hard pan will retin moisture for the plants.

@ S J Leghari , @ Herve Bonin , Thank you so much for your valuable comments.

In connection with deficit irrigation, three strategies, partial irrigation, deficit irrigation, and supplemental irrigation are in vogue. Partial irrigation involves giving less water than a crop actually requires for expressing full production potential. The idea is to extend water supplies and increase total crop production and profit. A major techniques is partial root-zone drying, which allows part of the root system being exposed to drying soil while the other part is irrigated normally. However, the wetted and dried sides of the root system are alternated with a frequency based on soil drying rate and crop water use.

In deficit irrigation (DI), the crop is exposed to a certain level of water stress either during a particular period or throughout the whole growing season. It is a sustainable water management strategy with the objective of maximizing water productivity and to stabilize yields rather than maximizing the yield per se. In deficit irrigation, application of water is restricted to drought-sensitive growth stages often by adopting micro-irrigation methods.

Supplemental irrigation (SI) is followed in typically rainfed areas. It is the practice of adding small amounts of water to predominantly rainfed crops in situations when rainfall fails to provide sufficient moisture for normal plant growth. The aim is to improve and stabilize yields. Water for supplemental irrigation is obtained from surface water sources, treated sewage water, and water-harvesting.

@C George Thomas, Thank you so much for your very potential answer

This interesting discussion and participants' contribution is appreciable.

@Nazir Hussain, Thank you for your interest and appreciable comment

well, drip fertigation (surface as well as subsurface) instead of surface flood method (check basin) shall be immensely useful in such cases of deficit irrigation.

Results of literature suggested that incorporating remote sensing-based vegetation indices, such as NDVI, used to derive Kcb for the FAO method provides an opportunity to improve irrigation scheduling by a better estimation of water use and a more appropriate timing of irrigations. More study has demonstrated also that drip irrigation could be applied to the wheat crop, usually cultivated in rotation with other crops, which may justify the drip irrigation system adoption by farmers but economic parameters are to be considered more closely.

@ Kulvir Singh , Thank you for your valuable comments.

@ Hawre Kiani, Thank you for your valuable suggestion.

Thank you for your valuable answer.

Supplemental irrigation (SI) or Deficit irrigation (DI) has been extensively investigated as a valuable and sustainable production strategy for a wide range of crops in dry regions. By limiting water applications to drought-sensitive growth stages, this practice aims to maximize water productivity and to stabilize - rather than maximize - yields. It involves the addition of limited amounts of irrigation water to essentially rainfed crops, in order to improve and stabilize yields during times when rainfall fails to provide sufficient moisture for normal plant growth. Unlike full irrigation, the timing and amount of SI cannot be determined in advance given the natural variability in season-to-season and within season rainfall levels.

Supplemental irrigation can play a key role in increasing water productivity, and in ensuring more sustainable use of groundwater. For maximum benefit, supplemental irrigation must be part of an integrated package that includes non-water inputs, improved crop management methods and other components. Optimal supplemental irrigation regimes would be based on sound water management policies, economic evaluations (e.g. crop : water price ratios) and timely application.

Deficit irrigation (DI) has been widely investigated as a valuable and sustainable production strategy in dry regions. By limiting water applications to drought-sensitive growth stages, this practice aims to maximize water productivity and to stabilize – rather than maximize – yields. Research results confirm that DI is successful in increasing water productivity for various crops without causing severe yield reductions. DI requires precise knowledge of crop response to drought stress.

More informations about DI are given in attached paper.

Thank you so much for your contribution.

Deficit irrigation is an optimisation strategy in which irrigation is applied during drought-sensitive growth stages of a crop. Outside these periods, irrigation is limited or even unnecessary if rainfall provides a minimum supply of water. Water restriction is limited to drought-tolerant stages, often the vegetative stages and the late ripening period . Deficit irrigation techniques are very interesting when it comes to an efficient allocation of scarce resources like water. These techniques are maximizing water productivity, generally with good or unchanged harvest quality

Technique of partial root zone drying irrigation system (PRD)

Thanks, it is important topic.