the effect of application of vermicompost on micronutrient concentrations in soil and lettuce plant

in order to study the effect of vermicompost individually and enriched with chemical fertilizer on soil micronutrient content and micronutrient concentration of lettuce (lactuca sativa l.), athree year experiment was conducted with randomized complete block design in two factors and three replications at the experimental farm of sari agricultural sciences and natural resources university in 2008. the main plot included six fertilizer treatments consisting of t1 )control(, t2) chemical fertilizers(, t3 (20 ton.ha-1 of vermicompost enriched with 50 percent chemical fertilizer), t4 (20 ton.ha-1 of vermicompost individually), t5 (40 ton.ha-1 of vermicompost enriched with 50 percent chemical fertilizer) and t6 (40 ton.ha-1 of vermicompost) individually. one – year (2006), two - year (2006-7) and three - year (2006-8) application of that fertilizer were considered as sub plots. the results showed that different treatments had significant effects on the available contant of  fe and zn of soil, root and shoots and also on cu and mn concentration of the lettuce roots. the result also showed that the concentration of the elements in soil and lettuce affected significantly by one year, two year and three year application of  these fertilizers. interaction of the two factors had significant effect on the avaiable fe an zn content of soil and zn concentration of root and shoot. totally, from 40 ton.ha-1 vermicompost enriched with 50 percent chemical fertilizers, the highest avaiable micronutrient content was obtained in the soil and the higest micronutrient concentration was obtained in root and shoot of lettuce.