Effect of Dry Season Cutting Management on Subsequent Forage Yield and Quality of Ruzi (Brachiaria ruziziensis) and Dwarf Napier (Pennisetum purpureum L.) in Thailand

Abstract

               A field study was conducted under rainfed conditions during 2002 – 2003 to determine the effect of dry season cutting management on the yield and quality of ruzi (Brachiaria ruziziensis) and dwarf napier (Pennisetum purpureum) grass during the dry season and the following wet season. The pastures were cut 1, 3, 6 times during the dry season and 7 times during the following wet season at 5 and 20 cms above ground level. The study was sited on a reddish brown sandy clay loam soil at Suwanvajokkasikit Field Crop Research Station in the Pakchong district of northeast Thailand.

               During both dry and wet seasons, leaf production and total plant production of dwarf napier were noticeably higher than ruzi grass but similar in stem production. Lax cutting (20 cm) produced significantly higher yield than close cutting (5 cm) and cutting every 2 months (3 times) tended to give higher yields than cutting more and less frequently of dwarf napier grass but not of ruzi. However, in the following wet season the pastures cut only once during the dry season produced significantly higher yields of herbage than those defoliation more frequently, particularly in the case of dwarf napier.

                The protein percentage in dwarf napier and ruzi grass was not significantly different, although tended to be higher in dwarf napier particularly during the wet season and in the stem fraction. Protein yields, however, between the two grasses were highly significant with dwarf napier yield being much higher than ruzi, which was largely a reflection of the respective dry matter yields. Both pasture species showed higher protein yields under lax cutting than close cutting in both seasons.

                  Lax cutting also tended to produce higher neutral detergent fiber (NDF) and acid detergent fiber (ADF) content in the total herbage than close cutting and in both seasons. NDF and ADF concentration significantly increased with delayed time of cutting in the dry season.