Investigation of intercropping corn (zea mays L.) and potato (solanum tuberosum L.) on yield and yield component in Jiroft area

To determine the effect of intercropping of corn with potato on yield and land equivalent ratio (LER), two separate experiments were conducted in Shahid Moghabeli Agricultural Research Center of Jiroft and Kahnooj, Iran in 2010 and 2011. The first experiment was an early-planting in spring. The experimental treatments included corn single-cropping (T1), potato single-cropping (T2) and intercropping of corn with potato:corn planting rows ratio of 1:2 (T3), 2:2 (T4), 1:1 (T5), 2:1 (T6), 2:2 (T7, in which 100% plant density was used for corn and 100% was used for potato), 1:3 (T8), 3:1 (T9), 2:3 (T10), 3:2 (T11), 4:2 (T12), 2:4 (T13), 2:2 (T14 in which 100% plant density was used for corn and 50% was used for potato). In total, 14 treatments were studied on the basis of a randomized complete block design with three replications. The second experiment was similar to the first one except that corn was planted in summer and potato was planted in autumn. In the first experiment (spring planting), the highest corn yields (11.69 and 11.14 t/ha) were obtained with the treatments of T8 (1 row of potato and 3 rows of corn) and T3 (1 row of potato and 2 rows of corn), respectively which were higher than that with corn single-planting. The highest potato tuber yields (16.01 and 14.67 t/ha) were produced under the treatments of single-planting and T9 (3 rows of potato and 1 row of corn), respectively. The highest LER was obtained from the treatments T8, T11 and T3 (1.61, 1.43 and 1.42, respectively). However, according to the results of the second experiment (summer planting), the highest corn grain yield was obtained with the treatments of T13 and T8 with the amounts of 10.90 and 10.78 t/ha, respectively; and the highest potato yields were obtained from single-planting and treatment T9 with the amounts of 18.28 and 14.3 t/ha. Finally given the yields and LERs, intercropping of corn with potato in summer planting is not recommended in Jiroft in a economic sense, but in early spring planting, the intercropping of corn with potato with potato: corn planting rows ratios of 1:3, 3:2 and 1:2 is recommended.