Effect of introduction of Kazungula grass (Setaria sphacelate), spacing and nitrogen on the productivity of a natural grassland

An experiment was conducted during 1995 and 1996 under rainfed condition, to study the effect methods of introduction of Kazungula grass [Setaria sphacelata Schum (L.) Stapf & Hubbard ex Moss], spacing and N levels productivity of natural grasslands of Assam Agricultural University, Jorhat. Introduction of Setaria either by killing or without killing the existing vegetation at different spacings could not influence the production of herbage and crude protein during both the years. However, no killed plots produced higher dry matter and crude proteins than killed plots. Closer spacings of 30 cm x 30 cm and 40 cm x 40 cm recorded 5.18 and 4.79% higher green forage and 20.75 and 14.23% dry matter yield, respectively, over the wider spacing of 50 cm x 50 cm. On an average, increasing the N levels up to 120 kg/ha increased the green forage, dry-matter and crude protein yields as well as enriched the soil with organic carbon, available N, P and K. The optimum economic dose of N was 145.66 kg N/ha in respect of green forage production.