Effect of individual versus integrated use of phosphatic fertilizers onP uptake and yield of maize and wheat

Industrial by products, filter cake (FC), poultry waste (PW) anddicalcium phosphate (DCP) were applied individually or after integrationand evaluated against chemical fertilizers (SSP and DAP) as a P fertilizersource by growing maize and wheat in pots. Phosphorus was applied at therate of 75 mg P kg 7l to maize (cv. Double Cross-Top) and also to followingwheat. Maize was grown for 40 days while wheat was grown up to maturity.Application of DCP or FC produced dry matter yield (DMY) of maizeequivalent to that obtained with SSP or DAP, while application of PWproduced 34 and 19 percent higher DMY than SSP or DAP alone. Integrateduse of FC and DCP in 2:1 P ratio or FC, PW and SSP in 1:13 P ratioproduced 51 and 36 percent higher DMY, and improved P uptake by 39 and27 percent over SSP alone. These combinations showed 57 and 40 percenthigher P fertilizer efficiency and 83 and 58 percent higher agronomicefficiency over SSP alone. Assessment of residual plus applied fertilizereffect on following wheat (cv. Punjab-96) showed that except FC, all the Psources, individually or their integrated use, increased straw and grainyield as well as P uptake over control. Phosphorus applied as DAP, DCP orSSP produced equivalent grain yield but PW produced 18 percent highergrain yield than SSP. Integrating FC and SSP, DAP or DCP in 2:1 P ratioproduced equivalent grain but significantly lower straw yield than SSP orDAP. Integrated use of FC, PW and SSP in 1:1:1 P ratio, however, produced28 percent higher grain yield than SSP alone. Thus it may be concludedthat as a P fertilizer source FC was inferior while DCP and PW weresuperior and equivalent to chemical fertilizers for the maize-wheat rotationsystem. However, their integrated use may minimize the cost of fertilizer,increase crop yield and improve soil productivity.