ECOPHYSIOLOGICAL RESPONSES OF POTATO (Solanum tuberosum) TO SALINITY AND NITROGEN FERTILIZATION IN SCREENHOUSE, CAMEROON

Abstract

Irrigated agriculture under fertilization is a practice that can ensure food security but has the unintended consequence of secondary salinization of arable land. There is the need to forecast production in this increasingly saline environment. An experiment of 4x4 factorial was carried out in screenhouse in Cameroon, to test the responses of potato to salinity under nitrogen fertilization. Plants were grown over two months and standard growth and physiological measurements taken and analysed. Results showed that in conditions of increased sediment salinity up to 12 ppt, tuber yields were greatly suppressed, and did not respond to fertilization. Plants grown under freshwater irrigation had higher root:shoot ratio and tuber development. Plants irrigated with freshwater had higher water use efficiency (WUE), irrespective of whether they were fertilized or not; WUE decreased as salinity increased. Photosynthetic efficiency dropped in all treatments. Under freshwater conditions, potato plants present a more efficient physiology that ultimately results in better growth and tuber development. Our results are significant for future potato farming under increasing sediment salinity. In areas where potato is produced, measures should be taken to prevent or reduce the rate of sediment salinization. If this is not done, in future alternate farmlands would be needed, but arable land is already very limited globally.