Biomass production and feed quality of three summer fodder species planted under two nitrogen levels

Three fodder species namely millets, sorghum and sudan grass were grown at Agronomy Research Farm of NWFP Agricultural University, Peshawar during summer 2002. Objective of this study was to compare growth, biomass production and chemical composition of the fodder species under low (90 kg per ha) and high (135 kg per ha) nitrogen (N) supplies for inter and intra species comparison. Field was prepared with normal cultural practices and planting was done in rows 30 cm apart in a randomized complete block design (RCBD). Each treatment was replicated four times with maximum 8 rows per experimental unit. Each experimental unit was of 5.0 m length and 2.4 m width. Fertilizer was uniformly broadcasted amounting 90 (N), 60 (P) and 40 (K) kg per ha at the time of seedbed preparation. High N treatment was subsequently applied as 45 kg N per ha, 25 days after sowing. Planting was done on July 11, 2004. Periodic growth was additionally observed from germination to 50% flowering for about 65 day duration. Fresh matter (FM) dry matter (DM) relative water content (RWC), plant height (PH), leaf number per plant (LN), leaf to stem ratio (LSR) and crop growth (CGR) were recorded. Samples were analyzed for ash content, crude protein (CP), in vitro dry matter digestibility (IVDMD). Metabolized energy (ME) was estimated from the IVDMD results. N levels significantly affected (P less than 0.05) FM and DM of millet but did not influence yield of sorghum and sudan grass. Millet was highest (P less than 0.05) in production than any other species. However, sorghum and sudan grass did not differ from each other. RWC of all the three species did not show any statistical difference. PH of millet was maximum (P less than 0.05) than sorghum and sudan grass. LN mimicked sequence already explained for PH. LSR decreased for millet with increasing N supply. CGR during the linear growth phase decreased significantly for millets under low N. Among the fodder quality parameters, all observation found non-significant for the species irrespective of the N levels. However, millets showed higher (P less than 0.05) ash content, CP, IVDMD and ME to sorghum and sudan grass. The study suggests that among the fodder species, millet yielded greater biomass in an area where the natural precipitation is enough to meet the crop water demand. Additionally high N application improved both forage quantity and quality.