Effect of Watering Frequency and Harvesting Date on Fodder Yield and Nutritive Value of Selected Herbaceous Legumes under Hydroponic Systems at Wollega University, Western Ethiopia

Abstract

Three experiments were carried out to evaluate the effect of frequency of watering, harvesting dates and species difference on fodder yields and nutritional values of three selected herbaceous legumes under hydroponic systems in Wollega University. In all the three experiments, completely randomized design (CRD) with three replications was used to manage the experiments and the general linear model procedure of Statistical Analysis System (SAS) was used analyze the data and Tukey HSD was used to separate means. The legumes (Lupinus albus, Vigna unguiculata and Lablab purpureus) were grown hydroponically at 2hrs, 3hrs and 4hrs watering intervals and for 13th, 15th, 17th and 19th, harvesting dates in lath house. All the fodder yield and yield related components of the legumes species were affected (p= 0.0001) by watering frequencies. The dry matter yield (DMY) (t/ha) for all the three legumes at one production cycle was highest at 2 hours interval of watering followed by 3 hours while the least was 4 hours of watering. The fodder yield and related components for L.albus and V.unguiculata consistently decreased with increasing watering intervals from 2 hours to 4 hours except for herbage to root ratio while that of L. purpureus did not revealed like others growth pattern. The fodder yield and yield related components of the legumes were all affected (p= 0.0001) by harvesting dates except the stem weight (p>005) of V.unguiculata. The dry matter yield (DMY) (t/ha) for L. albus and L. purpureus was significantly (p= 0.0001) affected by harvesting dates and showed consistently decreasing trend with increasing dates of harvesting. The DMY of V.unguiculata was not affected (p>0.05) by differences in harvesting dates. The components such as leaves weight (t/ha), roots weight (t/ha), stem weight (t/ha), plant height (cm), canopy circumference (cm) and herbage to root ratio for L. albus and L. purpureus followed similar trend of their DMY while most of the studied parameters of V.unguiculata did not show clear trend. The nutrient composition and in vitro DM digestibility of all the three legume species were significantly (p=0.0001) affected by variation in harvesting date. The ash, NDF, ADF and ADL content of the sprouted legumes was higher (P=0.0001) than that of their grain counterparts. The DM and CP composition, and in vitro DM digestibility was higher (P=0.0001) for the grain than the sprouted fodders across all the three legumes. The sprouted legumes, the DM composition of the V.unguiculata was increased with increased date of harvesting whereas that of L.albus and L. purpureus did not vary (P>0.05). The Ash, NDF, ADF and ADL contents of the sprouted fodder was significantly increased with delayed date of harvesting while the in vitro DM digestibility was in reverse trend. The study revealed that watering frequency of 2 hours interval at one production cycle had resulted in optimum hydroponic fodder yield and yield related components. Delayed date of harvesting had resulted in decreased fodder yield of all the three species of legumes. In addition all the legume species had attained different optimum harvesting dates for fodder yield and related parameters. Accordingly, L. purpureus had its maximum DM yield at 17th day of harvesting; V. unguiculata at 19th day but L.albus had a linear growth potential even at 27th day of harvesting. Delayed date of harvesting resulted in reduced CP composition, reduced in vitro DM digestibility and increased fiber contents. Thus the L. purpureus had best hydroponic characteristics while L.albus had highest fodder nutritive values.