Combined use of compound synthetic fertilizer, cattle manure, and frequency of leaf harvest on growth and yield of Butternut

ABSTRACT

There is limited knowledge on how frequency of leaf harvest and soil nutrient replenishment affects growth and yield of Butternut squash (Cucurbita moschata Duch. ex Poir). An experiment was conducted at the Agricultural Training Center Matuga-Mkongani, Kenya, to determine effects of a combination of synthetic compound fertilizer (NPK) and cattle manure, and frequency of leaf harvest on growth and yield of butternut. The synthetic fertilizer was applied at 250, 500, or 750 kg∙ha⁻¹, and manure at 2.5, 5.0, or 7.5 t∙ha⁻¹ in all combinations. Leaves were harvested at 2, 4, 6, or 8 week interval. Combining NPK fertilizer at 500 kg∙ha⁻¹ with cattle manure at 5.0 t∙ha⁻¹ increased number of branches, vine length, stomatal conductance, and resulted in better sex expression ratio than the rest of the treatments. Butternut leaf harvest frequency of at least 4 week interval was sufficient to maintain higher branch numbers. Combining 500 kg∙ha⁻¹ of NPK fertilizer with 2.5 t∙ha⁻¹ of cattle manure was sufficient to improve growth and fruit yield of butternut, even at 2 week leaf harvest frequency. Combined use of NPK fertilizer and cattle manure may benefit yield of butternut when harvesting leaves for consumption.

KEYWORDS:

• Cucurbita spp
• butternut squash
• plant nutrition
• soil fertility

Acknowledgments

This work was supported by Pwani University. We thank officials from the Agricultural Training Centre, Matuga-Mkongani, Kenya, for providing space to conduct the work. We thank Egerton University for providing equipment for data collection and laboratory analyses.