Plant spacing and nitrogen management effects on growth, forage yield and quality of Mott elephantgrass

Statistically similar plant height of Mott elephant grass was recorded under 45x45 cm, 60x60 cm, 75x75 cm and 90x90 cm spacing patterns in all the three cuttings against the minimum at 120x120 cm spacing pattern. Significantly the maximum number of tillers stool-1, stem diameter and total fresh and dry weight stool-1 was recorded at a spacing pattern of 120x120 cm against the minimum at 45x45 cm. The crop sown at a spacing pattern of 45x45 cm gave significantly the highest forage yield of 387.50 t ha-1 followed by 60x60 cm and 75x75 cm spacing pattern giving on an average 252.91 and 177.54 t ha-1 respectively. Total dry matter yield was the highest (67.96 t ha-1) at 45x45 cm spacing pattern against the minimum of 18.44 t ha-1 at a spacing pattern of 120x120 cm. LAI, NAR and CGR were significantly higher at 45x45 cm than all the rest of the spacing patterns and was followed by a spacing pattern of 60x60 and 75x75 cm. The ash content of the leav es was affected significantly by the different spacing treatments with significantly higher at 45x45 cm and 60x60 cm. Whereas, stem ash content at all spacing patterns was statistically similar. Fat, protein and NDF contents of both leaves and stem were significantly the highest at 45x45 cm and were followed by 60x60 cm against the minimum at 120x120 cm spacing pattern. Digestibility of both leaves and stem was the highest at a spacing pattern of 45x45 cm followed by 60x60 cm against the lowest at 120x120 cm spacing pattern. The mean plant height was significantly greater at a spacing pattern of 45x45 cm and minimum at 75x75 cm in both years. Among the nitrogen levels, application of N @ 300 kg ha-1 produced plants of a significantly greater height than rest of the treatments in both years. The different spacing patterns with nitrogen levels affected significantly the tillering potential, stem diameter, fresh and dry weight stool-1 in both years. The crop spaced at 75x75 cm p roduced significantly greater number of tillers, more stem diameter, higher fresh and dry weight stool-1 than rest of the two spacing patterns. Similarly application of N @ 300 kg ha-1 improved tillering potential, stem diameter, fresh and dry weight stool-1 to a significant level in both years. The crop planted in the pattern of 45x45 cm and fertilized @ 300 kg N ha-1 (S1N3) produced significantly the maximum forage yield of 509.8 t ha-1 in 1997 and 461.8 t ha-1 in 1998 against the minimum of 160.6 t ha-1 1997 and 100.6 t ha-1 in 1998. Both the spacing pattern and nitrogen levels affected the LAI, NAR and CGR significantly in both years. The crop spaced at 45x45 cm and fertilized a 300 kg N ha-1 (S1N3) gave significantly more LAI, NAR and CGR followed by the crop spaced at 45x45 cm and fertilized 400 kg N ha-1 (S1N4) against the minimum in S3N0 (the crop planted in the pattern of 75x75 cm with no nitrogen). The interactive effect of spacing pattern and nitrogen levels on as h content of stem and leaves was significant in 1998. Although the crop grown in the pattern of 45x45 cm and given nitrogen @ 300 kg ha-1 (S1N3) gave significantly the maximum ash content (15.68%) but was on a par with S2N3, S2N4 and S1N4. Similarly the maximum ash contents in stem (11.39%) was recorded for the crop planted in the spacing pattern of 45x45 cm and fertilized @ 300 kg ha-1 which was at par with S1N1, S1N2, S1N4, S2N1, S2N2 and S2N3. The interactive effects of spacing patterns and nitrogen levels on fat content of leaves and stem were significant in 1998. The crop grown in the pattern of 45x45 cm and fertilized a 300 kg N ha-1 produced significantly the maximum fat content in leaves (3.51%) and stem (0.82%). The different spacing patterns did not affect the protein contents in leaves and stem to a significant level in both years. However, protein contents were affected significantly by the various nitrogen levels. Significantly the maximum protein contents in lea v e and stem were recorded at 300 kg N ha-1 in both years. In 1997, both the spacing patterns and nitrogen levels affected the NDF of leaves and stem significantly. The crop spaced at 45x45 cm produced significantly higher NDF both in leaves and stern than that grown either at 60x60 cm or 75x75 cm. Similarly the crop fertilized @ 300 kg N ha-1 produced significantly the maximum NDF both in leaves and stem. The different spacing patterns and nitrogen levels had significant effect on ADF of leaves and stem in 1997, whereas the effect of spacing patterns on ADF of stem was non-significant. Significantly the maximum ADF in leaves and stem was recorded at 300-kg ha-1 in both years and was followed by 200 kg N ha-1. The interactive effects of spacing pattern and nitrogen levels on dry matter digestibility (DMD) in leaves were significant in 1997. The crop grown at a spacing pattern of 45x45 cm and fertilized @ 300 kg N ha-1 (S1N3) gave significantly the maximum digestibility of leav e s and stem and was at par with S1N4 in leaves and S1N2 and S1N4 in stem.