Dry matter yield and quality of forages derived from three grass species with and without legumes using organic production methods

Abstract

This study was the second year of an experiment which was carried out to investigate the use of forage grass species with and without legumes using organic production methods to produce forages for optimal dry matter yield and quality in Korat soil series (Oxic Paleustults). A field investigation was conducted from April 2007 to April 2008 at Khon Kaen University Experimental Farm, Northeastern Thailand. The experiment was a 3 x 4 factorial arranged in a randomized complete block design (RCBD) with 4 replications. The 12 treatment combinations consisted of 3 species of grass (G), viz., (1) Ruzi grass (Brachiaria ruziziensis), (2) purple Guinea grass (Panicum maximum cv. TD 58), and (3) Napier grass (Pennisetum purpureum cv. Taiwan); and 4 organic production methods (PMs), viz., (1) control (no fertilizer application, no legume mixture), (2) cattle manure (CM) at the rate of 25 tons/ ha, and broadcast seeds of (3) Verano stylo (Stylosanthes hamata cv. Verano) and (4) Wynn cassia (Chamaecrista rotundifolia cv. Wynn) for grass-legume mixtures. The results showed that G and PMs produced significantly different (p<0.01) dry matter yields of grass alone (g). Purple Guinea tended to produce higher g than Ruzi. PM with CM application produced significantly higher dry matter yield of g (11,112 kg/ha) than other PMs. Dry matter yield of Ruzi + dry matter yield of legumes (l) and purple Guinea+l were not significantly different (p>0.05), but both produced significantly higher g+l than Napier+l. G-Verano stylo and G-Wynn cassia mixtures produced no significant difference in g+l. Interactions (p<0.01) between G and PM were found in g, g+l and dry matter yield of weed. Purple Guinea with CM produced the highest g (15,591 kg/ha) of purple Guinea alone. Napier with Verano stylo mixture tended to produce higher g+l than Ruzi and purple Guinea with Verano stylo or with Wynn cassia mixture. Napier with CM produced the highest dry matter yield of weed while the lowest was with Ruzi-Wynn cassia mixture. There were significant effects (P<0.01) of G on CP, NDF, ADF, ash and DMD; and on ADL (P<0.05) of grass plus legumes where Napier gave the highest CP, ADL and ash contents. On the other hand, Napier plus legumes gave the lowest NDF and ADF contents. Ruzi plus legumes gave the highest DMD. There were significant effects (P<0.01) of PMs on CP, NDF, ADF, ADL, ash and DMD of grass plus legumes. G-Verano stylo mixture gave the highest value of CP (12.09%), the lowest NDF and ADF contents, and the highest DMD value (78.75%) of grass plus Verano