Study of Green Manure (Tithonia diversifola and Chromolaena odorata) and NPK Fertilizer Combination on Soil Chemical Properties and Yield of Pakcoy (Brassica rapa) in Ultisols

Abstract

The Problem with ultisols are it lack nutrients such as nitrogen, phosphorus, and potassium. Ultisols potentially developed into cropland by addressing the existing constraints. This research was conducted to study the effect of the combination of NPK fertilizer with green manure on various soil chemical properties and the yield of pakcoy on ultisols Jatinangor. A Randomized Complete Block design (RCBD) was utilized in this investigation, with eight treatments and four replications, which consist of SO (soil only), SN (NPK 300 kg ha-1), T1 (NPK 300 kg ha-1 + 10 t ha-1 Tithonia diversifolia), T2 (NPK 225 kg ha-1 + 15 t ha-1 T. diversifolia); T3 (NPK 150 kg ha-1 + 20 t ha-1 T. diversifolia), C1 (NPK 300 kg ha-1 + 10 t ha-1 Chromolaena odorata), C2 (NPK 225 kg ha-1 and 15 t ha-1 C. odorata), C3 (NPK 150 kg ha-1 + 20 t ha-1 C. odorata). The results showed that combining NPK with green manure significantly affects soil chemical properties of pH, organic-C, total N, available P, uptake of P, and uptake of N in ultisols. It did not significantly affect exchangeable K and cation exchange capacity (CEC). The best and effective average yield of pakcoy was found in C2 treatment with a yield of 63.75 g.