Phosphorus Use Efficiency and Yield of Direct Seeded Rice and Wheat Influenced by Residues Incorporation and Phosphorus Application under Saline Soil

Abstract

A two years field study according to split plot design was conducted to investigate the impactof crop residue (CR) incorporation and P application (0, 40, 80, 120 kg P2O5/ha) on P use efficiency andyield of direct seeded rice (DSR) and wheat grown under saline soil (ECe = 4.59 dS/m; pHs = 8.38;SAR = 6.57 (mmolc/L)1/2; extractable P = 4.07 mg/kg; texture = sandy clay loam), during the years 2011and 2012. Planting of DSR (with and without crop residue incorporation @ 2 tonnes/ha) were placed inmain plots and P application was in sub plots. Data on tillering, plant height, panicle length, 1000 grainweight, paddy and straw yields were collected. On an average of two years, maximum tillers (18), paniclelength (33), grain/panicle (121) and paddy yield (3.26 t/ha) were produced with P application @ 80 kgP2O5/ha along with CR incorporation. Similarly in case of wheat grown after DSR, maximum tillers (17),spike length (17), grains/panicle (66) and grain yield (3.56 t/ha) were produced with P application @ 80 kgP2O5/ha along with CR incorporation. Although, the growth and yield contributing parameters with thistreatment (80 kg P2O5/ha + CR) performed statistically equal to 120 kg P2O5/ha without CR incorporationduring both the years, but on an average of two years, grain yield of DSR and wheat was significantlysuperior (22 and 24%, respectively) than that of higher P rate (120 kg/ha) without CR. Overall, continuoustwo years CR incorporation further increased (17%) paddy yields during the follow up year of crop harvest.Higher P use efficiency and concentrations of P, K+ and Ca2+ in both DSR and wheat plant tissues wasfound where 80 kg P2O5/ha was applied along with CR incorporation or 120 kg P2O5/ha alone while Na+and Mg2+ concentration decreased with CR incorporation and increasing P rate. An increasing trend inDSR paddy and wheat grain yields was observed with increasing the rate of P application without CRincorporation, however, it was not as much as that of 80 kg P2O5/ha application with CR incorporationand found to be superior than rest of the treatments during both study years.