Fodder Production of Multipurpose Trees in a Maize Farming System of Subhumid Southern Africa

Ways to integrate fodder production into maize production systems under Southern Africa’s subhumid conditions have been studied. One way involves the planting of tree and grass fodder hedges along soil conservation contour-bunds in maize fields. Management factors that influence the productivity of maize and fodder components in the system are fodder spp., side-pruning and deferment of wet season cutting. The other option involves interplanting tree fodders with maize through the use of a coppicing tree such as Acacia angustissima. Practical applications of these methods in mixed crop-livestock production systems are discussed

Differences in Chemical Composition Among Provenances of Browse Species in a Subhumid Environment: Relation to use as Supplements

Studies were initiated in a subhumid Southern African environment to assess the chemical composition and nutritive value of Acacia angustissima (Mill.) Kuntze, Calliandra calothyrsus Meiss. and Leucaena species. The objective was to determine variability in crude protein (CP) concentration, acid detergent fibre (ADF), neutral detergent fibre (NDF), and soluble and insoluble proanthocyanidins from fodder samples of species, subspecies and provenances. A wide range was found in these parameters. The implications of these chemical composition factors, especially proanthocyanidins, on the use of these browse fodders in livestock feeding systems are discussed

Differences in Chemical Composition Among Provenances of Tree Fodder Species in a Subhumid Environment: Relation to use as Supplements

Studies were initiated in a subhumid Southern African environment to assess the chemical composition and nutritive value of Acacia angustissima (Mill.) Kuntze, Calliandra calothyrsus Meiss. and Leucaena species. The objective was to determine variability in crude protein (CP) concentration, acid detergent fibre (ADF), neutral detergent fibre (NDF), and soluble and insoluble proanthocyanidins from fodder samples of species, subspecies and provenances. A wide range was found in these parameters. The implications of these chemical composition factors, especially proanthocyanidins, on the use of these browse fodders in livestock feeding systems are discussed

Chemical composition, phenolic content and in vitro gas production contants of forage of psyllid-resistant Leucaena species grown in Zimbabwe

Leaves from Leucaena species L. esculenta, L. diversifolia, L. pallida, L. pulverulenta, L. salvadorensis, L. shannonii, L. trichodes and the interspecific hybrid L. Leucocephala x L. diversifolia that are resistant to the psyllid Heteropsylla cubana were harvested at the end of the rainy season (April) and the dry season (November) from two sites. The leaves were either sun or oven ( 50ºC) dried and subsequently analysed for concentrations of dry matter (DM), organic matter (OM), crude protein (CP), neutral and acid detergent fibres (NDF and ADF), lignin, extractable proanthocyanidins (PAs), soluble phenolics (SPs) and protein precipitating potential (PPP). In vitro gas production was measured over 72 hours. Season of harvest and method of drying had no significant (P>0.05) effect on the variables measured. Species significantly affected concentrations of CP, lignin, PAs, SPs and PPP. Cluster analysis based on content of fibre or content of polyphenolics or total gas produced identified L. shannonii, L. salvadorensis, L. esculenta and the intraspecific hybrid L. leucocephala x L. diversifolia as potentially good quality forages. Key Words: Gas production, Heteropsylla cubana, leucaena, nutritive value, phenolic, tannin (African Crop Science Journal: 2000 8(1): 63-76

Relação entre qualidade e liberação de N por plantas do semiárido usadas como adubo verde Relationship between biomass quality and N mineralization in plant species used as green manure in semi-arid Brazil

O uso de plantas como adubo verde pode ser uma alternativa para melhorar a fertilidade do solo porém a liberação de nutrientes desses adubos para o solo irá depender dos teores de lignina, polifenóis (PP) e N no material vegetal utilizado. Tais teores foram determinados em 24 espécies vegetais encontradas em propriedades rurais do semiárido e relacionados com a mineralização de N, quando incorporados ao solo. Os materiais apresentaram grande variação nos teores os quais, por sua vez, sinalizaram baixa correlação com as proporções do N mineralizado depois da incorporação. Utilizando os teores e suas relações, realizou-se análise de componentes principais agrupando os materiais de acordo com suas similaridades, visando verificar a existência de relações entre a formação dos grupos referidos e o N mineralizado após incubação dos materiais orgânicos. Quatro grupos foram formados; no entanto, pouca informação útil foi gerada no sentido de tentar predizer a mineralização de N com base na qualidade dos materiais testados. O comportamento da lignina não foi bem definido na formação dos grupos e não apresentou relação clara com a mineralização do N devido, talvez, ao curto prazo de avaliação da metodologia adotada (28 dias). Todos os materiais que apresentaram relação PP/N menor que 0,5, mineralizaram N enquanto que os apresentaram a mesma relação acima de 5, imobilizaram N.<br>The use of plants as green manure may be an alternative to improve soil fertility in the region, but the release of nutrients to the soil will depend on the concentrations of lignin, polyphenols (PP), and nitrogen of the green manures used. These variables were analyzed for 24 plant species commonly found in farms of the semi-arid region of NE Brazil, and the relationship between plant biomass quality and N release after incorporation into the soil was evaluated. There was a large variation in the concentration of lignin, PP and N of the green manures tested but these variables presented a low correlation with N mineralization after incorporation to the soil. In order to try to identify patterns among the different manures regarding quality and N release, these were grouped using Principal Component Analysis techniques, but very little meaningful patterns were observed to help predict N release based on the quality of the materials. The lignin content of the materials played an important role to form different groups, but may be the short time of the incubations (28 days) did not allow for the development of the correlation between lignin content and N release. In general, it was observed that all materials that presented a PP/N ratio lower than 0.5 mineralized N, while those that presented values of this ratio above 5 caused N immobilization