Daniel Brain Akakpo

Mixed crop-livestock (MCL) farming is common in West Africa: it is practised by about two-thirds of the farmers and produces about 70% of the food. In MCL systems, livestock support crop production through the supply of manure and draught power, whereas crops supply crop residues as a major feed for livestock. In West Africa, feed scarcity is a major challenge for livestock production, especially during the dry season when grass quality and quantity on grazing lands are inadequate. In northern Ghana, as in other West African countries, population pressure is affecting the development of farming systems. The pressure on land calls for the intensification of farming systems as a way of enhancing productivity. Grain legume crops are often introduced into the farming system as a route to intensification. Grain legumes are important crops in the MCL systems because they provide food and cash for humans, fodder for animals and improve soil fertility through biological nitrogen fixation. The residues of grain legumes, also known as grain legume fodders (GLFs), have better nutritional quality than cereal residues, such as maize and rice straw. Besides their function as livestock feed, GLFs supply fuel, construction material and mulch for soil improvement. However, knowledge about factors that drive the diversity of use of GLFs in different farming systems in West Africa is lacking. Also, the grain and fodder yields of grain legumes remain low across West Africa due to poor soil fertility and inadequate input use. The main objective of this PhD thesis was to understand the roles of grain legume fodders in mixed crop livestock systems and identify options to improve their quality and utilisation by smallholders in northern Ghana. To address this objective of the study, we adopted a multi-disciplinary research process to study four sub-objectives. These sub-objectives were addressed in Chapters 2, 3, 4 and 5.

In Chapter 2, we aimed to assess the variation in the use of GLFs and to identify potential drivers for their use in MCL systems in northern Ghana. The variation between MCL systems was studied by comparing three regions with different population pressure and agro-ecological conditions, and consequently, different farming systems. Through focus group discussions and household interviews, we studied the use of GLFs in MCL systems in the Northern region (NR), the Upper East region (UER), and the Upper West region (UWR) of northern Ghana. In UER, most of the GLFs (87%) was brought home and stall-fed, whereas in UWR GLFs were for a considerable extent (61%), left on the field and used for mulching. In NR, both stall-feeding and grazing of GLFs was important. Compared to UWR and NR, UER had a high population density, low potential for crop production and low level of mechanisation of crop production, which all are explanations for the relatively high importance of livestock in the farming systems. We conclude that with increasing importance of livestock in intensified systems, GLFs become more important and more valuable for feeding, especially in the dry season. The consequence of increased use of GLFs in intensifying MCL systems is that GLFs turn from being a communal resource that can be freely grazed during the dry season into a private resource with restrictions on use.

Chapter 3 evaluated the effects of rhizobium inoculation and phosphorus (P) fertilization on grain and fodder yield and fodder quality of the major grain legumes (cowpea, soybean and groundnut) in two agro-ecological zones of northern Ghana. This was done through field agronomic and laboratory studies. The findings of Chapter 3 indicate the possibility of improving both grain and fodder yields of grain legumes simultaneously through the application of P and rhizobium inoculants. In this chapter, in cowpea, for example, application of inoculation alone increased grain yield by 44%, P-fertilizer alone increased grain yield by 102% while the combination of P and inoculation increased grain yield by 123% compared to the control treatment where no input was applied. The positive correlation between grain yield and fodder yield in the current study implies that agronomic interventions may contribute to increasing availability of fodder for livestock feeding without a reduction in grain yield. Also the nutritive quality of GLFs was not affected by these interventions.

Chapter 4 evaluated the effects of storage conditions on dry matter recovery and the nutritional quality of GLFs during storage. In this chapter we also tracked the development of aflatoxins in groundnut fodder during storage. GLFs of cowpea, groundnut and soybean were stored separately in three locations (rooftop, room and tree-fork) and with two packaging types (polythene sacks or tied with ropes) for 120 days. Stored GLFs were evaluated for loss in dry matter and nutritional quality at day 0, 30, 60, 90, and 120. We found that dry matter loss during storage for 120 days was on average 24% across all storage conditions, 35% for the worst condition (tied in bundles and stored on roofs or tree-forks) and 14% for the best condition (sacks and in rooms). During storage, the CP content and OMD decreased, and the content of cell wall components increased. The reduction of nutritional quality was lowest when GLFs were stored in sacks. Storage in sacks and to a lesser extent, storage in rooms (indoor) may reduce the loss of DM and nutritive quality during storage compared to tying in bundles with rope and outdoor storage. The absence of aflatoxin in the groundnut fodder samples indicated that there is a minimal risk of aflatoxin development when stored under dry conditions as in our study.

In Chapter 5, we further assessed the nutritional quality of stored GLFs from Chapter 4 using four different methods: farmers’ perception, sheep preference, leaf-to-stem ratio, and laboratory analysis of organic matter digestibility, crude protein content, neutral detergent fibre and acid detergent fibre. We also determined correlations among these variables. Selected farmers scored the perceived quality of GLFs on a scale of 1 to 10 (1 = bad and 10 = good) based on physical characteristics. Sheep preference was assessed by a cafeteria feeding trial based on the rate of dry matter intake of GLFs by a flock of 12 sheep during a 14 hr period. leaf-stem ratio was determined based on the mass of the botanical fractions, i.e. leaf (leaf blade only) and stem (stem and petioles) samples separated carefully by the hand. Laboratory analysis was done by near infra-red spectroscopy (NIRS). Results showed that all quality assessment methods successfully discriminated GLF quality between crops. Only farmers and sheep could distinguish quality differences among storage conditions, whereas laboratory assessment methods could not. We reasoned that these findings could be due to that fact that farmers use sensory criteria (leafiness, colour (vision), smell, texture) to evaluate feed quality and that laboratory assessment methods do not assess these directly. These findings show that farmers are knowledgeable in predicting what their sheep prefer to consume and how to evaluate the quality of GLFs through storage.

Finally in Chapter 6, I integrated and reflected on implications of the findings of the previous chapters for sustainable intensification, policy and future research. Major uses of GLFs are ruminant feed (stall feeding and grazing) and mulch. Minor uses of GLFs were for fuel, compost and for sale to generate income. The overarching driver for the different uses of GLFs was the importance of livestock in the farming system. In the future, the importance of livestock will increase in the farming systems because of the increasing demand for animal-source food leading to increase in number of livestock and a higher livestock productivity. In Ghana for example, the government of Ghana recently launched the “Rearing for Food and Jobs” (RFJ) programme to increase livestock production for food security while creating jobs for the citizens. As a result, the livestock production systems in Ghana will need to intensify in a sustainable way to which conserving feed for stall-feeding may contribute. The smallholders currently depend heavily on crop residues, especially GLFs, which are generally low-quality feedstuffs. To increase yield and quality of GLFs to provide enough good quality fodder, research programmes should target breeding and selection for fodder quantity and quality in existing grain legume varieties and new breeding lines. In such work the fodder nutritional quality traits should be considered by plant breeders as a criterion for developing new varieties. In addition, there should be further research work done on the storage of GLFs to maintain their quantity and nutritional quality for a longer time.