Effects of foliar fertilizer application rates on productivity of selected bean (phaseolus vulgaris l.) varieties

Abstract

Food security is a global problem despite the many efforts put to produce enough food to feed the ever rising global population. Common bean (Phaseolus vulgaris L) is an important crop for food security and provision of proteins for poor households in sub Saharan Africa. In arid and semi-arid lands, beans are very important for they play a major role in food security and nutrition. However, its production in ASALs is constrained by erratic rainfall, moisture deficit, low nutrients uptake, nutrients fixation, poor bean germination and crop establishment. The main objective of this study was to determine the effect of water on bean seed germination in a laboratory study and performace of the beans with foliar fertilizer application under green house and field conditions. In the laboratory study, nine bean varieties (Wairimu,Wairimu dwarf, Piriton, KAT B9, KAT X56, KATRAM, GLP 1004, KATB 1 and GLP 2) were left to absorb distilled water for 3, 6, 9, 12, 15,18, 21 and 24 hours arranged in a completely randomized design with three replications and allowed to germinate under aerobic conditions. This was followed by a green house pot experiment which examined the productivity of the nine bean varieties in a completely randomized design replicated three times. The four best performing varieties were tested under field conditions in a randomized complete block design with three replications. In the green house and field experiments, the effect of three concentrations (0, 2.5mls/L and 5mls/L) of foliar fertilizer on bean productivity was tested for each variety. Data was collected on the effect of water imbibition on germination at different times in the laboratory study while data collected in the green house and field study included above ground biomass, grain yield, harvest index, pod length, weight of empty pod, weight of grain per pod, number of pods, chlorophyll content, stem girth, leaf area index, weight of 100 seeds and correlation of yield components. All the data from the experiments were analysed using Analysis of variance (ANOVA). Results from the laboratory experiment showed that the bean varieties which absorbed maximum water amounts in the first 9-12 hours were the first to germinate. In the green house, above ground biomass and grain yield increased with increasing foliar fertilizer application. Overall, there was a significant (p<0.05) increase in biomass production in piriton above all other varieties. Wairimu produced significantly higher biomass compared to other varieties except Piriton. It was followed by KAT B9, KAT B1, Wairimu dwarf, GLP 2, GLP 1004, KATRAM, and KAT X56 in that order.Wairimu had the highest harvest index while KAT B9 produced the lowest harvest index. In the field experiment above ground and grain yield also increased with the increasing foliar fertilizer application. Overall, KAT B9 showed a significant (p<0.05) increase in biomass production followed by Wairimu dwarf, Wairimu and Piriton in that order.Wairimu produced significantly (p<0.05) higher grain yield compared to other varieties. It was followed by Wairimu dwarf, Piriton and KAT B9 in that order. Wairimu had the highest harvest index while KAT B9 produced the lowest harvest index. The study confirmed that under laboratory conditions imbibed seeds germinates earlier compared to unimbibed seeds while foliar fertilizer application significantly increases yields and yields components under green house and field conditions.The study recommends that beans which germinated early and performed well in the greenhouse be considered for areas which are humid whilst those that germinated early and perfomed well in the field can be used for production in the semi-arid areas.