Iranian Phosphate Rocks and Their Usage as Phosphate Fertilizers in Zeoponic Culture

Increasing in application of phosphate fertilizers and their expensiveness are reasons to seek a way to use phosphate rocks directly in agriculture. Zeoponic substrates are new approach for using phosphate rocks (apatite) in plant production. This study was carried out to determine phosphate rocks efficiency in zeoponic substrate in greenhouse rose culture in Tehran University, Faculty of Agriculture in 2004-2005. Two different kinds of Iran’s apatite rocks with different characteristics were used in five substrates as main-plots and five different nutrient solutions for nourishing the plant were used as sub-plots in a split-plot arrangement-using randomized complete block design with three replications. Apatite content in substrats, solutions concentration and phosphorous element varied in this investigation. Results showed that root growth and root dry weight in substrates without apatite or of low amount of apatite, were greatr than other treatments. Different nutrient solutions had no significant effect on root growth, however, root dry matter production reduced when solution concentration reduced and phosphorous was eliminted from the nutrient solutions. Phosphorus content of roots in substrates that had low amount of apatite was greater than other substates including control, however, this differences were not significant. Solutions that contained high concentration and phosphorous element resulted in high phosphorous content in roots in comparison with solutions contained low concentration and without phosphorous element, but the differences were not significant.