Phyto-availability of chromium to fluted pumpkin (Telfairia occidentalis Hook F.) in an ultisol

The present study was conducted to determine the influence of Cr on some agronomic characters of Telfairia occidentalis nutrient content and uptake and some chemical properties of soil. In the greenhouse trial, chromium nitrate [Cr(N03)2] was applied at rates of 0, 50, 100 and 200 mg per 5 kg sieved and air-dried soil obtained from a depth of 0-15cm. The rates of 0, 20, 40 and 80 kgha-1 equivalent to pot rates were used in the field trial. Results showed that the soil used was texturally sandy loam and an ultisol as revealed by its low base saturation. In the greenhouse the soil pH, N, K, Mg, Ca, Na, Fe, Mn, Zn, free Fe and Al oxides, organic carbon, effective cation exchange capacity, exchangeable acidity, amorphous Fe and Al oxides content of the soil decreased inconsistently at various levels of Cr treatments except available P, which appreciated inconsistently. With the exception of soil pH, organic carbon, available P and amorphous Fe oxide, which increased at various levels of Cr concentrations, all other soil chemical properties determined, declined inconsistently in the field trial. The amorphousAl oxide however remained stable in the field trial. The Cr content of the soil increased with the levels of Cr treatments when compared with the control in the trials. The N, P, K, Mg, Ca, Na, Fe, Mn and Zn content of shoot and root as well as their uptake also decreased consistently with increasing Cr treatments. In addition, the Cr content as well as uptake by the shoot and root also increased consistently with increased rates of the Cr applied in the trials with the minimum levels of the Cr content and uptake recorded at the control treatments. As the Cr concentration increased, the crude protein content of both shoot and root consistently decreased with highest crude protein content recorded in the shoot compared to the root. A decrease in the dry matter yield with increased Cr treatments in shoot and root was recorded in the trials. Results also showed that the Cr influenced the height, collar girth, leaf area and number of leaves with control treatments higher than other treatments at final harvest.