Effects of treated rock phosphate on canola in greenhouse experiment.

Treatment of rock phosphate with organic matters and composting of it is a useful method for increase in solubility of rock phosphate. For determining efficiency of released phosphorus from treated rock phosphates, a green house and net house experiment was carried out in completely design as factorial with 3 replications in Karaj soil and water research institute. Experiment had 2 factors which first factor was different treatments of RP with mineral fertilizers and with manures, TSP fertilizer, Rock Phosphate and blank (without p). Second factor was rates of P2O5 (25 and 50 mg.kg-1). Planting was done on 8.5 kg soil per pot and the canola variety was RGS 003. Before elongation stage (before the decimal code of 58) plant sample was take from all of upper part and dry weight and P uptake in it was measured. P Olsen in soil sample was 5.8 mg.kg-1 before palnting. After ripening, pod and shoot weight, P concentration and P uptake was measured in upper part. Results were analyzed with SAS (9.1) software and separation of means was carried out with Duncan test. Based on results, in before flowering stage main effects of phosphorus rate and phosphorus kind on shoot dry weight was significant but main effect of phosphorus rate on shoot dry weight in maturity was no significant and on pod weight was significant. Main effects of phosphorus rate and phosphorus kind on p uptake in before flower stage were significant. Treatment of rock phosphate with phosphoric acid had furthest dry matter and p uptake and Treatment of rock phosphate with chicken manure had lowest dry mater. Correlation between p uptake and ca uptake and between total dry mater and p uptake was positive. Mineral acids had better effect on solubilising of RP than organic substances. Key words: Rock Phosphate, Canola, Organic acid, TSP, mineral acids