Effect of differential irrigation regimes on potato (Solanum tuberosum) yield and post-harvest attributes

Abstract

Potato (Solanurn tuberosurn L.) is a temperate crop that grows and yields well in cool and humid climate or seasons yet it is grown in climatic region from the tropics to subpolar and comprises a major food crop in many countries (Shalhevet el al. 1983). In India its area has increased from 0.6 million ha in 1980 to 1.3 million ha in 2000 and production has increased faom 11.88 to 26.0 million tomes (Kashyap and Panda 2002). The yield in our country is, however, below than average worldproduction. Hence water application is critical to make the most efficient use of drip irrigation system for irrigation water management. The yield, quality and disease resistance is greatly influenced by timing and frequency of irrigation applied (Can: 1989, Murtani and Guz 1989). The farmers on the other hand apply water to the crop without regard to whether the plant actually needs water at that stage. The reasons behind improper use of irrigation is that sufficient information is not available on the scheduling of irrigation in general and using drip irrigation in particular in relation to higher yield with better produce quality. Thus there is a great need of an appropriate irrigation scheduling to get higher production with better post-harvest characteristic. Hence a comprehensive field investigation was undertaken to study the effects of various irrigation regime on the growth, crop yield and post-harvest attributes of potato tuber This study was conducted during the winter seasons of 2002-2003 and 2003-2004 (October-January) at research farm of the Institute, Abohar, Punjab. The soil moisture content at field capacity (- 113 Mpa) and wilting point (-1 5 Mpa) was 11.49 and 3.94% on dry weight basis (wiw) respectively. The plant available water was 117 dm. The depth of water at the time of irrigation was equal, ie the readily available water (RAW). The experiment was laid out in a randomized block esign with 4 replications. Farnlyard manure @ 50 tonnesiha was applied prior to field preparation. Water soluble fertilizers @ 187 kg Nlha, 63 kg P,O,/ha and 125 kg K,O/ha (recommended dose) were applied through fertigation which started two weeks after planting. 'Kufri Chandramukhi' potato crop was planted at 60 cm x 10 cm in plots measuring 6 cm x 6 m. Immediately after planting, irrigation was given through furrow. Four irrigation regimes (0.60,0.80 1.00 and P .20 fraction of open pan evaporation ) were taken for drip irrigation treatment. The depth of water in each irrigation was 10.50 m approximately (equal to RAW). Irrigation for 0.60,0.80 1.00 and 1.20 of Ep was applied when cumulative pan evaporation (CPE) reached to 17.50, 13.10, 10.50 and 8.75 mm respectively after accounting the effective rainfall. Plant height was measured at the tallest point of the shoot. Before vine kill, each vine was taken to determine total above ground biomass. However many of the vines had already senesced. Tubers were classified as A (> 45 mm), B(28-45 m) and C (< 28 m) grade. Specific gravity was determined as ratio of weight of potatoes in air and water. Starch in tuber was estimated using the procedure given in AOAC (2000)