Effect of Different Irrigation and Planting Methods on Water Productivity and Health of Commercial Varieties of Potato

Water crisis as a main factor of agronomy limitation exists in all over the arid and semiarid regions such as Isfahan, province which is located in the central part of the Zayandehrud River Basin (ZRB). Due to the increase in the cultivated area of potato in Fareidan Region located in the west of Isfahan province, it will be necessary to use pressurized irrigation systems to achieve the highest irrigation application efficiency and water productivity.
The ZRB (41,500 km2) is a closed basin with no outlet to the sea. The research was conducted in the Fareidan region of Isfahan, which is located in the west part of the ZRB. The Rozveh Agricultural Research Station (32°, 58' N, 50°, 25' E) is located at the altitude of 2390 m above the sea level. This study was conducted as a randomized complete blocks design as a split strip plot layout with three replications and during two years (2007-2008). Three irrigation systems (Drip tape, Sprinkler and furrow) were considered as main plots, two planting methods (one - row planting and two-row planting) as split subplots and two potato cultivars (Marfuna and Agria) as split-split subplots. Production (Tuber-yield), the consumption water and cultivars reactions to common diseases were evaluated in different treatments. The soil of the experimental area, according to USDA Soil Taxonomy 1994 is of silty loamy. At the soil depth of 1m, soil salinity (1.1-2.0 dS m-1), water salinity (1.24 dS m-1), soil moisture at field capacity (23 Vol. %), and bulk density (BD = 1.44 g/cm3) at the field site were measured or experimentally obtained in the Isfahan Soil and Water Laboratory. The results were subjected to an ANOVA to analyze the effects of the treatments and their interactions. The data obtained were analyzed using the compound variance analysis and the averages of different treatments were separated using the Duncan multiple range test using the statistical software (SAS Institute, Inc., Cary, NC). The probability level of 0.05 (Duncan's test) also was selected.
An analysis of variance (ANOVA) was conducted on the irrigation systems and planting methods using PROC GLM (SAS 9.1, SAS institute Ltd., USA). Duncan’s multiple range tests at 0.05 probability level was used for paired mean comparison. The Results provided in two years show that the effect of irrigation systems × year (P≤0.05) and cultivars × year (P≤0.01) on (Tuber-yield), the consumption water and cultivars reactions to common diseases were found to be significant. There is no interaction between irrigation and planting methods, Variety × planting methods, Variety × irrigation, irrigation × Variety × planting methods and irrigation × Variety × planting methods × Year for (Tuber-yield), the consumption water and cultivate reactions to common diseases. On the contrary, the effects of the irrigation system treatments on the Tuber-yield and water productivity were significant (p≤0.05). The effects of variety on Tuber-yield and water productivity were not significantly (P≥0.05) detected.
Sprinkler irrigation method with 26152 kg ha-1 of production mean was preferred significantly to tape irrigation method with 23974 kg/ha of production mean. Tape irrigation leaded to the highest mean of WP equal to 4.69 kg m-3. Two years comparison of yield mean showed no significant difference between Agria and Marfuna potato cultivars. The two year comparison results of yield means using different planting methods indicated that one row planting method (24839 kg ha-1) was preferred significantly comparing to two row planting methods (22927 kg ha-1). Evaluation of tuber infection by ordinary scab and rhizoctonia showed that the highest mean of infection way observed in furrow method and the lowest one was observed in tape method of irrigation. Scab infection in furrow irrigation was 47% higher than sprinkler irrigation and 78% higher than tape irrigation.
During the three (2) years of the experiments with the three (3) irrigation treatments imposed on the potato crop, it was found that the drip type irrigation system, despite its lower yield than sprinkler irrigation, increased water productivity. A lowest pollution tuber to scab infection and rhizoctonia was determined by Drip type method. Thus, using this method, particularly in water restrictions on potato planting is required. The highest tuber yield was obtained in sprinkler irrigation, as well as from the point of view of the intensity and the infection rate of diseases on the tuber to Scab and rhizoctonia there was significant advantage compared to furrow irrigation. Therefore, in the lack of water restriction and the high speed wind can be used. The results showed that the one row planting method for all treatments is desirable therefore highly recommended for agricultural potato production.