Effect of soil and foliar application of zinc on fodder yield and nutritional quality of sorghum

Sorghum (Sorghum bicolor L.) ranks fifth in worldwide economic importance among cereal crops and it is one of the most important summer annual grass of Pakistan. Zinc (Zn), essentially required by plants and animals, is mostly found deficient in calcareous soils leading to one· of the widest abiotic stress to crop production. A possible way to reduce Zn deficiency in livestock is to fertilize the fodder fields with Zn. The objective of this pot study was to evaluate the effect of soil and foliar Zn application on yield and Zn concentration in sorghum fodder. Various treatments comprising of soil Zn rates (0, 4 and 8 mg Zn per kg soil) foliar Zn spray (distilled water, 0.02% Zn solution) and two sorghum cultivars (Noor and Faisalabad-08) were arranged in a factorial completely randomized design (CRD). Shoots of 50 days old plants harvested, dried and analyzed for Zn. There was a significant (P less than 0.05) main and interactive effect of soil Zn rates and cultivar on shoot dry matter of sorghum. Maximum increase in shoot dry matter was 8% for Noor and 20% for Faisalabad-08 when fertilized with soil Zn rates of 4 and 8 mg Zn soil per kg, respectively. There was a significant (P less than 0.05) main and interactive effect of soil Zn rate, foliar Zn spray and sorghum cultivars on concentration and uptake of Zn in plant shoots. Both soil and foliar Zn application significantly increased concentration and uptake of Zn in plant shoot. At various combinations of soil and foliar Zn rates, Zn concentration ranged from 25 to 85 mg Zn per kg for Noor and 26 to 98 mg Zn per kg for Faisalabad-08. It can be concluded from present study that soil and foliar application of Zn has great potential to increase yield and nutritional quality of sorghum fodder for livestock consumption.