GROWTH AND HERBAGE YIELD OF SEVEN FORAGE LEGUMES IN THE RAIN FOREST ZONE OF NIGERIA

Abstract

A field experiment was conducted for three months during the early growing season (April - July) of 2014 at the Teaching and Research farm of the Faculty of Agriculture, University of Benin, Benin City. The objective was to evaluate the performance of 7 herbaceous forage legumes in term of growth and herbage yield. The seven forage legumes (Centrosema pascourum, Lablab purpureus (ILR I4612), Lablab purpureus ((PI 1388013), Mucuna pruriens, Pueraria phaseoloides, Stylosanthes hamata and Vigna unguiculata, were fitted into a Randomized Complete Block Design (RCBD) as treatments and replicated three times. The variables measured at 4, 8 and 12 weeks after sowing (WAS) were soil cover score (SCS), leaf fresh weight (LFW), stem fresh weight (SFW) , leaves: stems ratio (L:S ratio) and fresh herbage yield (FHY) while HERBAGE re-growth (RG) was evaluated at 8 and 12 weeks after sowing. The data collected were subjected to Analysis of variance (ANOVA) and the means were separated with Least Significant difference (LSD) method. Results reveal that all legumes increased in growth at each interval of sampling. At 12 weeks after sowing, Mucuna pruriens recorded the significantly tallest re-growth of 42.7 cm following cutting at 8 weeks after sowing. This legume also furnished the significantly (P<0.01) heaviest fresh herbage yield of 7.6 t ha-1. However it produced the poorest leaves: stem ratio of 0.3 whereas Pueraria phaseoloides recorded the best leaves: stem ratio of 1.4. Generally, the best three legumes were Mucuna pruriens (7.5 t ha-1) > Lablab purpureus (ILRI 4612), (4.5 t ha-1) > Lablab purpureus ((PI 1388013) (3.0 t ha-1). The poorest legumes were Centrosema pascourum and Pueraria phaseoloides, which produced fresh herbage yield of 0.3 t ha-1and 0.5 t ha-1, respectively. No forage legume was affected by fungal disease although a mild defoliation by insect pest occurred. The good growth and herbage yield exhibited makes these legumes favourable materials for inclusion in the farming system of the rainforest zone of Nigeria.

CHAPTER ONE

INTRODUCTION

Forage legumes are important in agricultural intensification (Tarawali et al., 2001) because they provide herbage for livestock, grains for humans, green manure to the soil, nitrogen to both companion and subsequent crops through legume fallows. Increased usage of forage legumes in the tropics and sub-tropics is inevitable because of limited supply and high cost of in-organic nitrogen fertilizer including the serious protein deficiency problems among human and animal populations (Hoveland, 1986). Forage legumes which are synonymously referred to as cover crops are reputed to be the backbone of sustainable annual cropping systems (Sullivan, 2012). Their use is very relevant in the humid tropics where high rainfall rapidly depletes soil nutrients especially nitrogen. They also replenish soil-organic matter content while suppressing weeds. Forage legumes accumulated 144 kg ha-1 N, 18 kg ha-1 P and 140 kg ha-1 K after 4 months of re-growth (Muhr et al., 1999).

In an effort to incorporate forge legumes into the local cropping system of different regions, several screening trials were conducted. Examples are in semi-arid Zimbabwe (Jingura et al., 2001), in the moist savannah of Ghana (Barnes, 1996), in sub-humid Nigeria (Odunze et al., 2004), in highland Cameroun (Pamo and Mubeteneh, 1995), in moist savanna of Nigeria (Abayomi et al., 2001) and in sub-humid south-West Nigeria (Muhr et al., 1999).

Justification for the Study

Research is needed to ascertain which forage legumes are adapted to the humid rainforest region of Nigeria. Moreover, it is apparent that no comprehensive evaluation of forage legumes has been carried out in the humid rainforest of Nigeria. Furthermore, it was reported that the performance of forage legume in terms of herbage and crude protein yields is influenced by location (Muhr et al., 1999). The use of forage legumes in the humid rainforest of Nigeria will increase because commercial livestock production has increased in the region. There are now more non-trypanotolerant breeds of beef cattle such as white Fulani, Zebu (ILCA, 1990) and trypanotolerant breeds such as Muturu and Ndama cattle in the region. These animals require protein rich forage legume herbage to supplement their feeding.

Consequently, this research was carried out in the humid rainforest region of Edo State, Nigeria with a specific objective,

Objective of the Study

To evaluate the performance of seven herbaceous forage legumes in terms of growth and herbage yield