Effects of green manures on growth, yield and quality of green okra (Abelmoschus esculentus L.) Har Lium Cultivar.

This green manure experiment with the use of okra crop as indicator plant was carried out at Mahasarakham University Experimental Farm, Mahasarakham province, Northeast Thailand during May to September 2005 to investigate four types of green manure legume crops on growth, yield and quality of edible fresh pods of okra crop when grown on Roi-Et soil series (Oxic Paleustults). The four types of green manure plants include Jack bean, Cowpea, Green gram, and Giant sensitive plant. The experiment consisted of five treatments, i.e., T1 (Control), T2 (Jack bean), T3 (Cowpea), T4 (Green gram) and T5 (Giant sensitive plant). The experiment was laid in a Completely Randomized Design (CRD) with four replications. The results showed that Roi-Et soil series (Oxic Paleustults) contained some considerable mean values of organic matter (1.64-1.66%) but soil available phosphorus and exchangeable potassium were relatively low, particularly potassium. Green manures of the four legume plants slightly improved soil property of the Roi-Et soil series (tested at the end of the experimental period). The most effective green manure on stem diameter, bushy diameter, leaf numbers plant(-1) and leaf area of the fifth leaf of the okra plants, in most cases, was found with Jack bean and Cowpea ranked the second. However, in most cases, Cowpea gave a similar effect as that of Green gram and Giant sensitive plant. Pod length and weight pod(-1), pod diameter and edible fresh pod yields (5941.86 kg ha(-1)) were highest with Jack bean green manure treatment (T2), whilst the rest, in most cases, were similar. Green manure treatments gave highly significant effect on total soluble solids of pods over the control treatment, whilst total acidity, fibre and pectin contents were unaffected by green manure treatments. Green manure of Jack bean was the best legume crop for green manure to be used in improving soil fertility, particularly for Roi-Et soil series (Oxic Paleustults).