Investigating viability of premium influenced land agro-usage structure for increased phyto-diversity and production of African leafy vegetables

Decreasing land holdings among smallholder farmers in Vihiga and Jinja have resulted in intensive land utilization. This has in turn led to low soil fertility level which has resulted in decline in the abundance and distribution of phyto-diversity found on farms of smallholder farmers. The declining amount and distribution of phyto-diversity has negatively affected the nutrition and the economic well being of the smallholder farmers. Therefore, as land holdings and soil fertility continue to decrease, there needs to be some impetus in place that can retain phyto-diversity (indigenous and exotic diversity) in the intensively cultivated systems, hence the introduction of cropping bed, the Premium Influenced Land Agro-usage Structure as a novel land use practice in these sites. This study, therefore, endeavoured to investigate the viability of Premium Influenced Land Agro-usage practices in line with a premium implied cropping bed for increased African Leafy Vegetable production on smallholder farming systems in Vihiga and Jinja sites of Kenya and Uganda respectively. The specific objectives were: (1) To identify the status and value of land and phyto-diversity on smallholder cultivation system (2) To investigate and justify the performance of selected vegetable variants ‘penned’ into a Premium Influenced Land Agro-usage Structure introduction based on a Mineral Micro-nutrient (MiMi) content criterion. (3) To evaluate the benefits of a Premium Influenced Land Agro-usage Structure as a novel land use introduction. The smallholder farm was delineated on a three Residence Directional (RD) Phyto-diversity Dependence Patterns with respect to distance from the main household. These patterns were; the Near House (NH), Mid Farm (MF) and Far Farm (FF). An onion layer with Z topography layout (onion-Z layout) was adopted to represent these patterns. In each pattern, an inventory of phyto-diversity contained therein was tracked across on 76 selected households (38 in Vihiga and 38 in Jinja) using a pre-coded questionnaire on a farm format 1 and 2 basis. An approximate area occupied by crops was also collected. Further analysis included determination of the Economic Net Benefits on each RD Phyto-diversity Dependence Pattern. Vegetable leaf samples and their corresponding soil samples for both indigenous and exotic vegetable crops from Vihiga and Jinja were sampled. They were sun-dried, ground to a powder of 0.2mm sieve size, pelletized and ran in X-ray Fluorescent (XRF) spectrometer and multi-channel analyser. Further data analysis included a nutrametric grading of the vegetables. Raised bed cum Premium Influenced Land Agro-usage were constructed on 20 randomly selected smallholder farm (10 from Vihiga and 10 from Jinja). Premium branded vegetable crops (indigenous and exotic types) were grown on these beds. The following agronomic appeal attributes were monitored to determine the performance of the vegetable crops namely; yield, leaf density, leafiness, disease incidence and branching. The same procedure was done on the flat beds. Further analysis included the determination of the benefits of Premium Influenced Land Agro-usage Structure using the Net Present Value and the assessment of the Satisfaction Index of the bed to the farmers. In Vihiga and Jinja, RD Phyto-diversity Dependence Patterns Near House, Mid Farm and Far Farm were consistently similar for both farm format 1 and 2 scenarios. A T test analysis showed a high significant difference p≤0.001 in mean ENB between the Near House (Ksh 9,926.3) and Far Farm (Ksh 5,933.6) and Mid Farm (Ksh 8,860) and Far Farm (Ksh 5,933.6). Patterns at a closer proximity to the main household had a high total mean Economic Net Benefits compared to ones that were located further from the main household. Results showed that there were high significant differences (p≤0.001) in the MiMi densities between Indigenous Vegetables (IVs) and Exotic Vegetables (EVs) in the following minerals; K, Ca, Fe and Mn. High significant differences at (p≤0.001) in MiMi densities on selected vegetable crops were also noticeable between Jinja and Vihiga sites in the following minerals; K, Ca, Fe, Cu and Zn. Comparisons of MiMi on selected vegetable crops between long rains (LR) and short rains (SR) for both sites were significantly different at (p≤0.001) for the following mineral; K, Ca, Fe, and Zn. Further analysis showed a high correlation at (R=0.9969) in Mineral Micro-nutrient between vegetable samples and the corresponding soil samples. Amaranthus hybridus and Solanum nigrum from Vihiga and Jinja respectively were found to be nutraceutically superior to Cleome gynandra, Brassica acarinata, Daucas carota, Oleum cepa and Spinacia oleracia. Generally, Indigenous Vegetables had higher nutra-ceutical grade rankings compared to Exotic Vegetables. In both Vihiga and Jinja, there were high significant differences at p≤0.001 in performance of vegetables crops grown on Premium Influenced Land Agro-usage Structure compared to flat beds, in yield and height (Premium Influenced Land Agro-usage Structure yield (kg/ha) was 42254 versus 27772 for flat beds, Premium Influenced Land Agro-usage Structure height in (cm) was 14.8 versus 10.8 for flat beds). Comparisons in vegetable performance between seasons showed better performance of vegetable crops in the Long Rains than the Short Rains seasons for both sites with significant difference (p=0.001) as shown by the means of the following agronomic appeal attributes; mean yield (kg/ha) for the Long Rain (LR) was 36064 xviii against 33962 for the Short Rain (SR). Also significant differences in vegetable performance were detected between Vihiga and Jinja in the following agronomic appeal attributes height and yield; mean yield (kg/ha) for Vihiga was 34962 and 36064 for Jinja, mean height (cm) for Vihiga was 12.8 and 16.6 for Jinja. The Premium Influenced Land Agro-usage Structure had high Net Present Value (KSHS191390) compared to the flats beds (KSH122087). Further analysis showed the Premium Influenced Land Agro-usage Structure having a Satisfaction Index of 61.8%. The farmers were somehow satisfied with the Premium Influenced Land Agro-usage Structure introduction. The higher incidence of phyto-diversity at the Near house illustrates the nutrition and bio-economic benefits likely to be derived from growing vegetables at the Near House and Mid farm patterns. The indigenous leafy vegetables being superior to exotic ones in MiMi content suggests a justification for niching them in a specially constructed Premium Influenced Land Agro-usage Structure structure also as a way of increasing their production for a marketable value. Even though performance of vegetable crops on Premium Influenced Land Agro-usage Structure was better than on flats, the costs of construction of the former were high. The next phase of study is necessary to target measures for increasing the longevity of the Premium Influenced Land Agro-usage Structure and reducing associated costs of construction for increased viability.