Nursery media effects on tamarindus indica seedling establishment
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Trees are an important component of farming systems and contribute to human needs both directly through tree products andindirectly through their influence in soil fertility. Efforts by small-scale farmers to increase trees of high value in their farms are hampered by poor quality of seedlings withlowsurvival and slow growth rate. One reason for poor seedling development is inappropriate chemical and physical properties of the growing media used. This studyattempted to find out the effect of these chemical and physical properties of the growing media used by farmers on the seedlings of Tamarindus indica (L.) and the appropriate levels for the species. Therefore, samples of the growing media usedin 6 on-farm tree nurseries in two agroecological zones in Mount Kenya region - main coffee and marginal coffee zones - were collected and tested in an on-station experiment at ICRAF headquarters, Nairobi, Kenya. The media were analyzed for chemical (nitrogen, phosphorus, calcium, magnesium) and physical (pH, total pore volume, aeration pore volume and water holding capacity) properties. The root diameter, seedling height and root and shoot dry weights of seedlings raised in the media were measured periodically. Data were analyzed for variance (ANOVA) using Genstat 4.1 release and treatments compared using Students-Newman-Keuls test.Aeration pore volume, total pore volume and wet bulk density were the physical properties that had greatest influence on seedling quality parameters especially during initial period of growth (up to 75 days). Chemical properties, on the other hand, affected seedling growth and quality parameters at later stages of growth. Important nutrients were observed to be nitrogen, organic carbon, magnesium and calcium. From the findings of this study, farmers can curtail nursery period of Tamarindus indica (L.) from 130 days to as little as 75 days.