Effects of sulfur granular compost and nitrogen on yield and yield components of two wheat cultivars, Darya and N8019

Application of various composts has been intensified in agriculture, due to manifestation of negative effects of chemical fertilizers on environment and soil fertility. However, their usage should be accompanied by environmental and nutritional studies. To study the effects of sulfur granular compost on yield and yield components of two wheat cultivars, a pot experiment was conducted in a completely randomized factorial design with four replications. The first factor was consisted of three levels of nitrogen (0, 25 and 50 mg/kg of soil as urea), the second one was four levels of compost (0, 5, 10 and 15 g/kg of soil) and the third one was cultivars (Darya and N8019). Results showed that the maximum number of grains per spike, spike weight, 100-kernel weight, straw yield and biological yield were obtained in 25 mg N/kg of soil treatment. The greatest grain yield, dry weight, and harvest index were achieved with 50 mg/kg nitrogen. Negative effects were observed in the compost-treated plots, so that the maximum spike length and weight shoot dry weight, straw and biological yield were found in the zero level of compost (control) which showed a decreasing in the mentioned variables with increasing the compost level. Negative response of wheat to the compost is likely related to the C/N ratio and probably to increase the solubility of heavy metals and/or toxic compounds that resulted in reduce or prevent soil biological activities. Both cultivars showed a positive response to the nitrogen treatment. N8019, however, was significantly superior to Darya.