Effect of sowing date and nitrogen fertilizer on sorghum (Sorghum bicolor L. var. Speed feed) forage production in a summer intercropping system

Abstract

To evaluate the interaction effects of planting date and different levels of nitrogen fertilizer on sorghum (Sorghum bicolor var. Speed feed) forage production, an experiment was conducted in split plots based on a complete randomized block design in Agricultural Research Station of Khorramabad, Lorestan province, Iran. The experimental treatments comprised of three nitrogen fertilizer levels of control (N0), 100 (N1), and 150 kg per hectare (N2), assigned to main plots and three sowing dates of T1 (June, 10th), T2 (June 26th) and T3 (July 11th) assigned to subplots. Results showed that in sum of two harvests, the yield of hay, forage, leaf and shoot hay weigh in second planting date and N2 and N3 level of fertility was higher than all treatments. In the case of quality treatments the percent of crude protein in first harvest had the most amounts in first and second planting date and N1, N2 and N3 fertility levels. Crude fiber percentage in first harvest of second planting date was highest in N1, N2 and N3 levels of fertility. Treatment interactions had not any significant effect for crude fiber. The most ash percent was observed in first harvest and N1, N2 and N3 fertility level. In second harvest time N2 and N3 fertility levels were superior to the rest. Also, fat percentage in first and second planting date and N1, N2 and N3 increased than the control fertility treatment.