Thepresent researchwas conductedin November 2005to February 2006, at the Faculty of Agricultura Sciences atthe National University offrujillolocatedin the District offrujillo,Province offrujillo, La LibertadDepartment.The research work aimed at determining the "Effect of five levels of phosphorus and calcium carbonate in dry matter production, extraction of phosphorus in barley (HordeumvulgareL.) and its availability in the soil, under greenhouse conditions. Experimental design was used in a randomized complete block with factorial of 5 for 5 with 4 replications. The treatments used were interaction ofO, 4, 8, 16 and 32% calcium carbonate with O, 20, 40, 60 and 80 ppm of phosphorus, making a total of 25 treatments. Statistical analysis was analysis of varían ce and Duncan test of significance of 5%.The results showed that if there is an effect on the interaction of phosphorus and calciu...