Integrated potassium management through composted straws and inorganic fertilizer in maize

Using organic and inorganic fertilizers concurrently may not only quench the crop nutritive demands but also been proved an eco-friendly nutrient source. In order to evaluate the effect of potassium (K) application from only inorganic, integrated organic and inorganic sources of fertilizers on maize, a field study was conducted during 2008 and 2009 following randomized complete block design (RCBD) with three replications at Agronomic Research Area, University of Agriculture, Faisalabad, Pakistan. In this study composted wheat and rice straws were integrated with the sulphate of potash (SOP) as K source. Regarding application of K from the integrated sources, treatment containing 25% composted rice straw + 75% SOP provided highest leaf area index (LAI; 5.13 and 5.11), eaf area duration (LAD; 217.33 and 219.65 days), crop growth rate (CGR; 28.94 and 29.08 g m(-2) d(-1)), total dry matter (TDM; 1,925.03 and 1,931.32 g m(-2)), and gave prominent plant height (215.50 and 218.63 cm), 1,000-grain weight (262.87 and 266.63 g), grain yield (7.02 and 7.38 t ha(-1)), biological yield (16.63 and 17.37 t ha(-1)) and harvest index (42.22 and 42.49%) during both the years (2008-09), respectively. Moreover, given years, the integrated use of 25% composted rice straw + 75% SOP earned maximum benefit cost ratio of 2.12 and Rs. 2.22, respectively. Conclusively, integrated use of organic amendments of K with inorganic source might be a better technique over separate application of inorganic source.