The Effect of Shade and NPK Fertilization on Growth and Yield of Asystasia gangetica as a Forage
Asystasia gangetica is a weed usually found in oil palm plantations, which is used as a source of forage and cultivated at a known effective shade level and optimal fertilizer dosage. Therefore, this study was carried out at a place without shade (NS) and 75% of shading net (S) at the Experimental Field of the Faculty of Agriculture, Universitas Mulawarman, Samarinda, Indonesia. The seedlings used were planted and fertilized with NPK at doses of 0 g, 1.6 g, and 3.2 g per polybag. The results showed that the level of shade affected plant height, several branches, yield of dry matter shoot, the content of chlorophyll a, b, and a/b content, CP, CF, EE, NFE, and ash, but not on chlorophyll a+b. The dosage of NPK fertilizer affected plant height, the number of branches, yield of dry matter, chlorophyll a, b, and a+b content, CP, CF, EE, NFE, and ash content, while chlorophyll a/b ratio was not influenced. The interaction between shade level and NPK fertilizer dose only occurred in the number of branches, chlorophyll a, b, and b+c content, CP, CF, EE, and ash content, but not on chlorophyll a/b ratio and NFE content. The flowering rate was faster in NS plants, where those with NPK fertilizer dose of 0.32 g/polybag gave the highest yield, except for CP and ash content which had the highest yields on S plants with 0.32 g NPK/polybag.