Effect of phosphorus sources, solubilizers and bioregulators on growth, yield and phosphorus uptake by pigeonpea (Cajanus cajan)

An experiment was conducted during the rainy (kharif) seasons of 2001 and 2002 on clay loam soil of Udaipur, Rajasthan. Among phosphorus sources, application of rockphosphate 34% P₂O₆/74 microns (RP 34/74) + farmyard manure (FYM) in ratio of 1:3 + elemental sulphur (ES) at 25 kg/ha significantly improved plant height, primary and secondary branches/plant, pods/plant, seeds/pod, seed index, yield and P uptake by pigeonpea [Cajanus cajan (L.) Millsp.] over other treatments. However, it was statistically at par with diammonium phosphate (DAP) and RP 34/74 + FYM in ratio of 1:3 phosphate-solubilizing bacteria (PSB) at 2 kg/ha. Significant improvement in primary branches/plant, pods/plant, seeds/pod, seed index, seed yield, stover yield and P uptake by crop was recorded by foliar spray of thiourea over water spray and 2,3,5-tri-iodobenzoic acid (TIBA). However, foliar spray of TIBA significantly reduced plant height at harvest over water spray and thiourea.