Effects of tillage method and fertilizer type on the yield of Sudan grass (Sorghum bicolor L.)

The Sudan grass plant (Sorghum bicolor (L.) Moench subsp. drummondii) density and yield were determined in this 2-year research with different tillage systems and fertilization at 3 locations. After harvesting the main crops, 3 tillage treatments were applied: conventional (CT) mouldboard ploughing (25-30 cm deep), followed by disk harrowing and sowing: reduced tillage 1 (HDH) with 2 passes by a disk harrow (15-20 cm deep), followed by seedbed preparation, and reduced tillage 2 (LDH) with a single pass by a disk harrow. Soil penetration resistance was measured at each tillage treatment. A total of 5 side dressing fertilizer treatments were applied: the control (NO), calcium ammonium nitrate (CAN) 100 kg ha-1 in granular form, 60 kg ha?1 urea applied as foliar fertilizer (UF), 8 L ha-1 of foliar fertilizer Profert Mara (0.9 kg N, 0.22 kg P, 0.38 kg K, 0.24 kg Ca, 0.01 kg S, and 0.03 kg Mg) (PM1), and double rate PM1 (PM2). Significant differences (P ≥ 0.05) among the tillage treatments were present (19.023, 18.934, and 17.489 t ha-1 of dry matter for CT, HDH, and LDH, respectively). The tillage treatments resulted in significant differences (P ≥ 0.05) in the average plant density in both experimental years, with the greatest plant number with HDH (104.11 m2) and highest soil penetration resistance value with CT (more than 2.00 MPa). All of the fertilizer treatments resulted in a higher yield than the control (14,698 kg ha-1). CAN, UF, and PM1 were not different among themselves, whereas PM2 resulted in significantly higher dry matter yield. The results suggested better effects of foliar than granular fertilizers for postharvest-sown Sudan grass in the drought of 2009 or the over-wet conditions of 2010.