MSc

A field experiment was conducted at Vellanikkara, Thrissur, Kerala from May 2017 to February 2018 to assess the understorey productivity of four fodder grasses viz congosignal (Brachiaria ruziziensis), guinea (Panicum maximum) and two hybrid napier cultivars CO-3 and CO-5 when grown under mature coconut (Cocos nucifera L.) and rubber (Heavea barsiliensis Muell. Arg,) plantations, which are the two prominent land use systems in Kerala. The biophysical attributes influencing the productivity of these land use systems and the biochemical changes in the products of understorey crops were also studied. Growth parameters of understorey fodder crops varied remarkably among these land use systems. The fodder grasses grown in coconut plantations showed an increased plant height, leaf area index, leaf area ratio, and leaf weight ratio as compared with treeless open plot. However, the number of tillers per clump and number of leaves per clump showed a decreasing trend when grown as understorey crops in mature coconut and rubber plantations. Rubber grown fodder grasses expressed substantially poor performance both in growth and yield attributes. Regarding fodder production, open grown fodder grasses consistently showed maximum biomass dry weight throughout the harvests. On comparing with the open, the rubber plot showed a substantial reduction of 91.35% in the total biomass dry weight from all harvests whereas the reduction was only 39.02% under coconut plantations. Mean mid day (12–1p.m) understorey photosynthetic Photon Flux Density (PPFD) were 1342.5 moles μ m -2 sec -1 in rubber and 1575 μ molesm -2 sec -1 in coconut, with respective understorey PAR transmittance of 39.84 % and 56.08% of full sunlight. The understorey crops in coconut and rubber showed an increased chlorophyll-a, chlorophyll-b, and total chlorophyll content and leaf moisture content over treeless control. The maximum crude protein value was noticed in the rubber (11.97%) grown fodder grasses and was on par with open while 124 coconut (9.29 %) accounted the least crude protein content. The understorey crops showed a decreased crude fibre content as compared to open. The maximum leaf nitrogen content was observed in the rubber plot (1.92%) and this was followed by open plot (1.87%). The lowest nitrogen content was observed in the coconut plot (1.49%). No noticeable changes were observed in foliar phosphorus and potassium content across both land use systems. The soil analysis revealed that the organic carbon and available nitrogen content of the top soil were increased under both the tree based cropping systems as a result of understory intercropping. However, on comparing with the initial values of different soil properties studied, only modest changes were observed in the soil properties in general across both the land use systems and treeless open plot. It is concluded that the coconut based fodder production systems with these grasses are almost comparable, in terms of growth and yield, to the open areas and hence recommended for farmers adaption. This practice of integrating fodder grasses in coconut plantations gains immense importance in Kerala, where mature coconut plantations forms one of the extensive and prominent land management system. Thus, judicious use of the vast area of interspaces under these matures coconut plantations for fodder production is very ideal especially in the state of Kerala. The best proven combination of land use system and the fodder grass in a coconut based intercropping scenario was the cultivation of CO-3 fodder grass under matured coconut plantations. However, the rubber based fodder production system is not at all feasible and further conclusive studies may be done for affirming more reasons for such a substantial reduction of growth and yield in rubber based system.