Productivity of Perennial Grasses under \u3cem\u3eMachillus bombicinii\u3c/em\u3e Tree in Assam

Homestead agroforestry system is the most common production system in Assam. It varies with the agroclimatic zones and economic condition of the farmers. In lower Brahmaputra valley zone, generation of employment under such system varies from 16.5 to 19.1% whereas in upper Brahmaputra valley zone, it ranges from 30.6 to 64.1%. For increasing forage productivity homestead garden can play a major role in augmenting fodder production for year round supply of green forage through non competitive land use system. There is scope for growing suitable perennial grasses like Guinea, setaria and Congo-signal for increasing fodder production. However research information on the performance of setaria and Guinea grasses are not available in Assam under tree shade. Through the performance of Guinea grass under tree shade has already been tested and found to be feasible for growing. On the other hand in Assam there are many plantation areas where Machilus bombicina King (Family Lauraceae) locally known as “Som” tree is grown. This is a very common tree for Munga silk worm rearing (Dutta, 1985) which is middle to big tree with spreading crown. Wood is hard and used as ordinary timber. It is a good fire wood and suitable for making charcoal. The present study was proposed to study the productivity and quality of two perennial grasses viz. Setaria and Congo-signal at varying levels of nitrogen under tree shade of Machilus bombicia

Effect of Irrigation Regimes and Applied Nitrogen Levels on Growth and Physiological Responses of Ryegrass

A field experiment was conducted at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat. The experiment was laid out in split-plot design with three replications. The treatments consisted of five levels of irrigation in main plot viz., I0:Rainfed, I1: Irrigation at critical growth stages, I2: Irrigation at IW:CPE ratio of 1.0, I3: Irrigation at IW:CPE ratio of 1.2 and I4: Irrigation at IW:CPE ratio of 1.4 along with four levels of N- N0: 0 kg N/ha, N1: 30 kg N/ha, N2: 60 kg N/ha and N3: 90 kg N/ha in sub- plots. The soil of the experimental site was sandy loam in texture, medium in organic carbon, available N and available P2O5, acidic in reaction and low in available K2O. The result revealed that the highest leaf area index (LAI) recorded in irrigation at IW:CPE ratio of 1.4 at all the three cuts respectively during both the years. The crop growth rate (CGR), relative growth rate (RGR) and net assimilation rate (NAR) of ryegrass as influenced by different irrigation regimes were found to be non-significant at 30 DAS while at later growth stages i.e. 45 DAS, 60 DAS, 90 DAS and 120 DAS were significantly influenced during both the years. The application of irrigation at IW:CPE of 1.4 produced higher value of CGR, RGR but the highest NAR was recorded in rainfed treatment. The data on LAI as influenced by different N levels was found to be significant in all three cuts. Application of 90 kg N/ha recorded the highest LAI. The CGR, RGR and NAR as influenced by different N levels were found to non significant at 30 DAS but significantly influenced at later growth stage i.e. 45 DAS, 60 DAS, 90 DAS and 120 DAS during both the years. The highest data on CGR and RGR were recorded in 90 kg N/ha but the highest NAR was found in 0 kg N/ha