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

Phosphorus Application for Rice Wheat Yield

Abstract

A two years field study according to split plot design was conducted to investigate the impact
of crop residue (CR) incorporation and P application (0, 40, 80, 120 kg P2O5/ha) on P use efficiency and
yield 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 2011
and 2012. Planting of DSR (with and without crop residue incorporation @ 2 tonnes/ha) were placed in
main plots and P application was in sub plots. Data on tillering, plant height, panicle length, 1000 grain
weight, paddy and straw yields were collected. On an average of two years, maximum tillers (18), panicle
length (33), grain/panicle (121) and paddy yield (3.26 t/ha) were produced with P application @ 80 kg
P2O5/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 kg
P2O5/ha along with CR incorporation. Although, the growth and yield contributing parameters with this
treatment (80 kg P2O5/ha + CR) performed statistically equal to 120 kg P2O5/ha without CR incorporation
during both the years, but on an average of two years, grain yield of DSR and wheat was significantly
superior (22 and 24%, respectively) than that of higher P rate (120 kg/ha) without CR. Overall, continuous
two 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 was
found 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 in
DSR paddy and wheat grain yields was observed with increasing the rate of P application without CR
incorporation, however, it was not as much as that of 80 kg P2O5/ha application with CR incorporation
and found to be superior than rest of the treatments during both study years.