Tillage and crop residue management practices on crop productivity, phosphorus uptake and forms in wheat (Triticum aestivum)-based cropping systems.

摘要

This study was conducted to investigate the effect of crops and tillage (conventional and zero) and crops residue management (TCRM) practices on crops yield, P uptake and P forms. The experiment was laid out in split-plot design in which pigeonpea, cotton, soybean, maize and groundnut constituted the main plot treatments and combination of TCRM, viz zero tillage with residue (ZT+R), zero tillage without residue (ZT-R), conventional tillage with residue (CT+R) and conventional tillage without residue (CT-R) constituted sub-plot treatments. Conventional tillage with crop residue (CT+R) was found suitable for higher yields of maize, pigeonpea, soybean and groundnut, and for cotton lint yields it was zero tillage with residue (ZT+R). Crops and tillage systems did not affect the total soil P content; however, Olsen's, inorganic and organic fractions changed significantly due to application of crop residue in both zero and conventional tillage systems. Organic phosphorus content significantly increased in zero tillage system as compare to conventional tillage irrespective of crop residue application, whereas reverse trend was observed for inorganic P fraction. Crop residue increased Olsen's P content in both convention and zero tillage systems; however, tillage systems without crop residue had no effect on Olsen's P content. Different crops affected only soil Olsen's P fraction and appreciable build-up had been observed under all the crops on application of recommended doses of P and crop residue man initial soil Olsen's P content (9.9 kg/ha) but contents were still below the critical level of sufficiency (20 mg P/kg) in soil for all the crops after completion of three cropping cycles. Irrespective of crops and TCRM treatments, all P fractions increased in surface soil than their initial content due to fertilizer and residue application except under cotton, whereas appreciable decrease in inorganic P content and no change in total P content had been observed. This trend indicated that adaptation of zero tillage and crop residue addition for longer duration may require gradual adjustment in recommended doses of P application. From the results of this study, it may be concluded that soil phosphorus management decisions may differ according to the nature of cropping system and tillage and crop residue management practices.