The response of Napier-CIone 13 (Pennisetum p u rp u reu m ) to three types of organic manure grown in a simulated sub-canopy environment

Abstract

The mechanisms which control the biomass yield and quality o f Napier-CIone 13 (Pennisetum purpureum) when grown near and under canopies were investigated in a simulated pot experiment. Napier-CIone 13 was established in galvanized containers (2 plants/ 0.28m2 container) filled with normal soil (150 kg), treated with poultry litter (PL), goat manure (GM) or spent tea leaves (STL), at the rate o f 50kg N/ha/cut. Each manure type i.e. PL, STL and GM was pre analyzed and applied at a rate o f 335.7g, 76.38g and 103.5g respectively per container to provide a rate o f 50kg N ha'1. Plants were grown either in full sunlight (FL), or two levels o f shading, namely, near the canopy with a reduction o f 40% full light (NC) and under the canopy with a reduction o f 90% full light (UC) imposed by shade cloth. Nine treatments were replicated 3 times, and arranged in a randomized complete block design. Plant height, stem diameter, leaf area and root biomass yield (g/plant) were highest 2) when grown NC as compared with plants grown in FL which increased the rate o f tillering and the number o f leaves. Deep shade UC caused significant decrease in all the above parameters. Poultry manure responded (P<0.05) positively in increasing above parameters over STL or GM. The increase in ion biomass yield (BMY) was affected (P<0.05) by the level o f shading with more than two fold increase in full sunlight as compared to the deepest shade level. The difference in BMY between FL and NC was around 25%). PL responded similarly in increasing BMY over STL or GM. Deep shade UC augmented shoot nitrogen (N) concentration (P<0.001) over NC or FL. Poultry manure had a significant (P<0.05) effect on shoot N concentration over STL or GM as well. The results o f the simulated shade conditions on the yield and nutritive value o f Clone 13 suggested that there would be an increase in N content but the biomass yield was marginal. Vice versa was observed under FL due to the dilution effect o f N as a result o f increasing biomass yield. Interaction o f shade and soil fertility especially by the application o f poultry manure near the canopy substantially enhanced the yield and quality o f Napier CIone 13. Therefore, it could be suggested that the grass yield and quality near the canopies could be easily boosted by adding organic manures.