effect of manure application on reduced nitrogen fertilizer consumptionin potato cv.agria

objective: an experiment was performed in ardabil (2012) to investigate the effects of manure consumption in different amounts on reducing nitrogen fertilizer consumption in potato cv. agria. methods: this research was conducted in factorial design based on randomized completely blocks design in three replication  in which two manure factors in three levels (control, 30 and 60 tons/h) and nitrogen fertilizer in 4 levels (25%, 50%, 75% and 100% recommended) were investigated. results: results showed that increased manure usage led to increased tuber yield, and the most yields were obtained from 60 tons/h manure usage. manure causes increased tuber’s average weight per plant, number of tubers per plant, tubers average weight, plant’s wet and dry weight, plant height and tuber’s nitrate. also, nitrogen fertilizer caused increased potato tuber yield in which the most yields were obtained from nitrogen fertilizer up to 100% recommended, and it also caused other properties increase. significantly, increased nitrogen usage increased tubers nitrate and tubers nitrate obtained from nitrogen fertilizer up to 100% recommended. results from variance analysis showed that manure-nitrogen fertilizer interaction in growth properties was not significant but, in 1% probability level it was statistically significant in tuber and nitrate yield components properties. increased manure usage from recommended 30 to 60 tons/h and nitrogen from 50 to75 percent have had better effects on total properties, especially in terms of nitrate accumulation. so, the highest yields were obtained from manure usage up to 60 tons/h.