The influence of zinc on early growth and nutrient uptake by pumpkin (Telfairia occidentalis Hook F) in an ultisol

Abstract

The study investigated the influence of zinc on some growth parameters of Telfairia occidentalis as well as its effect on some soil chemical properties in field experiment carried out at the experimental farm of Faculty of Agriculture, University of Benin, Benin City, Nigeria. Four levels of treatment namely 0, 20, 40 and 80kg ZnSO4 ha-1 were used in an experiment laid out in a randomized complete block design with 3 replicates. Results showed that the soil Zn, N, P, K, Mg, exchangeable acidity, increased inconsistently from 0.002 mgkg-1, 0.60 gkg-1, 2.70 mgkg-1, 0.09 cmolkg-1, 0.30 cmolkg-1, 2.40 cmolkg-1 to 154.18 mgkg-1, in 80 kgZnha-1, 0.63 gkg-1 in 0 kgZnha-1, 3.86 mgkg-1 in 0 kgZnha-1, 0.12 cmolkg-1 in 80 kgZnha-1, 0.41 cmolkg-1 in 0 kgZnha-1, 2.50 cmolkg-1 in 80 kgZnha-1 respectively. The free Fe oxide, free Al oxide, amorphous Fe oxide and amorphous Al oxide also increased from 5.92%, 0.74%, 0.07%, 0.03% to 6.18% in 0 kgZnha-1, 1.98% in 80 kgZnha-1, 0.74% in 80 kgZnha-1, 0.35% in 80 kgZnha-1 respectively. While the soil pH, organic carbon, Ca and Na also inconsistently decreased from 5.70, 10.70 gkg-1, 1.60 cmolkg-1, and 0.06 cmolkg-1 to 5.09 in 20 kgZnha-1, 10.30 gkg-1 in 20 kgZnha-1, 0.36 cmolkg-1 in 80 kgZnha-1 and 0.041 cmolkg-1 in 20 kgZnha-1 respectively. The K, Mg and Zn content of the root increased with increase in Zn treatment whereas the Na decreased with increase in Zn application. The root Ca and P were however not consistent. In the shoot, the Mg, N, K, Ca, Na and Zn minerals also increased with increase in Zn application. The P content of the shoot was however not consistent. With the exception of Na uptake by the root, which decreased with Zn treatment, the entire nutrients uptake, plant height, number of leaves and the dry matter yield increased with increased Zn treatments. The leaf area and stem girth were however not consistent with increase in Zn application.