IRRIGATION SCHEDULING AND TECHNIQUES IN POTATO NextEnd

IMPORTANCE  Water is the key input in crop production and plants take nutrients from the soil in the medium through water.  It also helps maintaining the plant temperature and enables the plants to face the varied climatic conditions smoothly.  The irrigation schedule should be such that neither plant faces any excessive water stress nor there is excess water causing leaching of nutrients. PreviousNextEnd

EFFICIENT IRRIGATION MANAGEMENT PreviousNextEnd Time of application Methods of application Depth of water per irrigation

. PreviousNextEnd  Management of soil moisture is essential for optimum yield under assured irrigation.  Water from snow melt, rivers and natural springs are used for irrigation by gravitational system.  High wind velocity and low atmospheric humidity lead to more evapo- transpiration which increases the water requirement of potato crop in the region.  Mulching with 200 micron thick black polythene sheet saved about 30% water to the crop. Sandy soils required comparatively 20-30% higher number of irrigations  Pre-planting irrigation is beneficial for uniform emergence and also increase the duration of first irrigation after planting.

 Normally, first light irrigation is given days after planting and subsequent irrigations at days interval depending upon the type of soil and weather conditions prevailing in the area.  During the irrigation, water should not be reach more than 2/3 height of the ridges.  Potato is relatively sensitive to soil water deficits. To optimize yields the total available soil water should not be depleted by more than 30 to 50 percent  Depletion of the total available soil water during the growing period of more than 50 percent results in lower yields. PreviousNextEnd

PreviousNextEnd  Water deficit during the period of stolonization and tuber initiation and yield formation have the greatest adverse effect on yield, whereas ripening and the early vegetative periods are less sensitive.  In general, water deficits in the middle to late part of the growing period thus tend to reduce yield more than in the early part.  However, varieties vary in their sensitivity to water deficit. Some varieties respond better to irrigation in the earlier part of the yield formation period while others show a better response in the latter part of that period.  Yields of varieties with few tubers may be somewhat less sensitive to water deficit than those with many tubers.

 To maximize yield, the soil should be maintained at relatively high moisture content.  This, however, can have an adverse effect when frequent irrigation with relatively cold water may decrease the soil temperature below the optimum value of 15 to 18°C for tuber formation.  Also, soil aeration problems can sometimes occur in wet, heavy soils. PreviousNextEnd

 Since the potato is a relatively sensitive crop in terms of both yield and quality, under conditions of limited water supply the available supply should preferably be directed towards maximizing yield per hectare rather than spreading the limited water over a larger area.  Savings in water can be made mainly through improved timing and depth of irrigation application PreviousNextEnd

IRRIGATION SCHEDULING  Water management practices vary from region to region.  Water requirement of Potato ranges from mm depending upon the length of growing season. i. e. whether it is a short duration early season crop of days (as is commonly raised in Punjab) or it is a long season crop of long duration variety like Kufri Sindhuri which extends over days, from September to March.  Normally, the early season crop grown in Punjab has it growth Cycle of days, coinciding much its latter growth (tuber development) with falling temperature regime of low evaporability and its seasonal water needs are moderate PreviousNextEnd

High yield realization of Potato, apply irrigation immediately after planting which leads to proper germination of the crop in general.  The Potato crop in Punjab should be irrigated at 7-10 days interval  The last irrigation should be with held days before harvest to allow the tubers to harden their skin before harvesting/digging of potato. PreviousNextEnd

Light and frequent irrigation is applied as and when needed in Sikkim. Potato should be irrigated mainly during 3 stages: PreviousNextEnd Irrigated at three stages Stolon formation stages (20 – 25 DAP) Stolon development and tuber formation stage (45-50 DAP) Tuber development stage (65 DAP) DAP- Days After Planting

METHOD OF IRRIGATION Most common irrigation methods for potato are furrow and sprinkler.  Yield response to frequent irrigation is considerable because the crop has a shallow root system and requires low soil water depletion.  For example, very high yields are obtained with the mechanized sprinkler systems where evapo- transpiration losses are replenished each or every two days.  The crop is generally grown under assured irrigation. Surface (furrow) irrigation systems is widely adopted and irrigation scheduling is based on the time interval approach. PreviousNextEnd

 A fixed depth of water (about mm) is applied at each irrigation.  Sprinkler and drip irrigation systems have been evaluated and compared with the standard furrow irrigation in Indian plains.  The drip system was most economical followed by sprinkler system.  For the hills, several methods of water harvesting have been developed.  These are used to conserve snow melt water and runoff water during rainy seasons to meet the water requirements during dry period. PreviousNextEnd

ASSESMENT 1.Excess water causing leaching of (Nutrients) 2.Water requirement of Potato ranges from depending upon the length of growing season. a) mm b) mm c) mm 3. In potato, to maximize yield, the soil should be maintained at relatively_________. a). Low moisture content b). High moisture content 4.Most common irrigation methods for potato are __________ and _________. (Furrow and Sprinkler). 5. The ________ was most economical followed by sprinkler system. a). Drip system b). Furrow system c). Ring basin method PreviousEnd Next

References: Previous  Smith, Potatoes; Production, storing, processing - The Avi publishing company. INC  Narendra singh & Zakwan Ahmed,2010 – Potato production, storage & marketing.  