MST-Department of Agricultural Resources Management (ARM)

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Browsing MST-Department of Agricultural Resources Management (ARM) by Subject "Fertilization"

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    Growth and Yield Responses of Beans, Cowpea and Bambara Nuts to Phosphorus Fertilization in Kakamega County, Kenya
    (Kenyatta University, 2022) Makari, Christabel M.; Joseph P. Onyango Gweyi; Sylvia Amondi Henga
    Western parts of Kenya are characterized by acid soils with phosphorus deficiency and aluminum toxicity. Reports indicate a declining trend in yields of legumes such as cowpeas and common beans. Though legumes can fix Nitrogen, starter phosphorus need to be supplied for better yields and more often plants develop adaptive strategies for better P acquisition, probably through increased Al tolerance by carboxylates exudation, improved nodulation for enhanced P uptake through better root development. Therefore this study was undertaken in Kakamega County to investigate the effect of low phosphorus rates on development and yields of legume crops. The experimental factors were six legumes: four improved common beans varieties, one cowpea variety, one Bambara nut variety and two phosphorus levels: 0 and 25 Kg/ha P2O5. The experiment was laid out in a Complete Randomized Block Design (RCBD), with three replicates. Data on soil pH plant growth (height, number of leaves and leaf length, growth rate, days to flowering and days to maturity), plant nodulation and yield parameters (number of pods, number of grains per pod, dry weight, and grain yield) were collected for two seasons (long rains- March to August 2019, and the short rains-September to November 2019). Data collected were subjected to a two way-ANOVA using R software version 3.6.0. Significant means were separated by Tukey’s HSD test. To check the relationships between measured growth and yield parameters, the Pearson's correlation was done. All the statistical analysis was done at 95% level of significance. Phosphorus fertilizer (25 Kg/ha P2O5) level did not have an influence on plant stand vigour during early development. There was significant difference in Leaf Area Index (LAI) in both the cowpeas and beans during early development, however, this was only consistent in the 10th week in common beans after germination. Phosphorus fertilizer applications enhanced nodulation in cowpeas and common beans but not in Bambara nuts. Moreover, in all the legumes, the controls corresponded to higher root to shoot ratios, probably a sign that P limited shoot growth. In terms of yields, P fertilizer significantly enhanced grain yields in the majority of common bean varieties, especially in KK13, KK16 and KK33, but there was no significant (p value > 0.05) differences in grain yields between different P rates for KK8, Cowpeas and Bambara nuts. In general, there were significant (p value ≤ 0.05) interactions between the legume crops and phosphorus fertilizer rates on growth and yields, particularly in common beans with exception of Cowpeas and Bambara nuts. Therefore, under limited P inputs, farmers in western Kenya may adopt Bambara nuts and some common bean varieties such as KK8 that have low P demand for better yields.