Effect of deficit irrigation and mulching on consumptive use and yield of potato in gypsiferous soil under drip irrigation.

Abstract

In order to determine the effect of the lack of irrigation and mulch in water consumption use and yield of potatoes under gypsiferous soil conditions in spring season in 2013 at experimental station of soil and water resources department, college of Agriculture, Tikrit university. The experimental design was split plot in three replicates. The main plots were irrigation treatment (I), and sub plots were no mulch (C1) and mulch with wheat straw (C2). The treatments were as follows: for no mulch full irrigation (control), C1I1, the deficit irrigation treatment included omitting two irrigations at vegetative growth C1I2, tuber initiation C1I3 and tuber bulking and maturation C1I4. For the mulch, The treatments were (C2I1, C2I2, C2I3 and C2I4) for four treatments, respectively. The mulch was spread on the soil surface of 12 ton ha-1. Potato tubers, Rudolph variety were planted on 3-2-2013 for spring season and harvested on 20-6-2013. Reached values ​​ ETa for potato was (345 and 338 mm/season) for full irrigation with the no mulch and the mulch, respectively. Whears the values of ETa for deficit irrigations were reduced to (419-428 mm/season) for the no mulch, and (326-330 mm/season) for the mulch conditions. The value of the Reference ET0 estimated using the equation Penman- Monteith adjusted higher than the rate of ETa values ​​in the cases of no mulch and mulch (688, 426 and 330 mm/season) respectively. Mulch treatment caused higher water saving as compared with no mulch conditions. The amounts reached (22.3, 22.9, 22.3 and 22.1%) for full irrigation, and deficit irrigation in vegetative growth, tuber initiation and tuber bulking and maturation, respectively. Maximum value of KC was 1.1 in full and deficit irrigation treatments under no mulch compared with 0.84 for full irrigation under mulch conditions. significant decrease in tuber yield was found in deficit irrigation vegetative growth and tuber initiation stage with mulch. The yield was (12.6 and 12.3 ton ha-1) respectively compared with (14.0 ton ha-1) for full irrigation. On the other hand, deficit irrigation showed no effect on yield in tuber bulking stage. The non mulch treatment showed the same behavior, No significant differences in yield was found for no mulch (13.2 ton ha-1) and mulch (14.5 ton ha-1).