Phosphorus affects storage root yield of cassava through root numbers

Abstract

The objective of this study was to determine the effect of phosphorus applied through fertigation on growth and root yield of cassava. This was achieved through a greenhouse pot-experiment consisting of 1, 4, 7, 10, 20 and 30 mg P L⁻¹. Increasing P from 1 to 30 mg P L⁻¹ realized a 57.1 and 150.0% increase in leaf blade P in 2014 and 2015, respectively. Similarly, chlorophyll content and shoot growth increased as P concentration in solution increased. However, leaf stomatal conductance and net photosynthesis reached a maximum in 7 and 20 mg P L⁻¹ in 2014 and 2015, respectively. This trend of stomatal conductance and net photosynthesis was consistent with that of dry root yield and storage roots numbers. Regressing dry root yield against storage root numbers showed that R² = 0.80. Phosphorus encourages formation of storage roots and the duration of cassava’s growth affects the amount of P required for maximum root yield.

Keywords:

• fertigation
• fertilizer
• irrigation
• macro-elements
• roots

Acknowledgments

The authors’ thank Ina Feingold and Yonatan Saroya who gave their support during laboratory analysis of plant samples and data collection.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors’ gratitude goes to the African Development Bank and Israel Chemical Limited for funding the work through International Institute of Tropical Agriculture, International Potash Institute and Center for Fertilization and Plant Nutrition.