Sole- or Dual-Crop Basis Residue Mulching and Zn Fertilization Lead to Improved Productivity, Rhizo-modulation and Soil Health in Zero-Tilled Pigeonpea–Wheat Cropping System

Conventional tillage has led to deteriorated soil health in semi-arid ecologies of south Asia. Sole- and dual-crop basis residue mulching in a predominant pigeonpea-wheat cropping system (PWCS) of the region may boost crop productivity and soil health. Widespread Zn deficiency also invokes for developing sound Zn fertilization practices (ZFPs) for improved Zn bioavailability and crop productivity. We assessed the comparative performance of single- and double-crop basis residue mulching + hydrogel in main plots, and the ZFPs in sub-plots in split-plot design under a zero-tilled PWCS in semi-arid agro-ecology. Dual-crop basis residue mulching + hydrogel exhibited ~ 17.1–22.3% higher system productivity with improved rhizo-modulation and soil health over sole-crop residue mulching and no-residue mulchings in a zero-tilled PWCS. Dual-crop basis residue mulching (8 t ha −1 year −1 ) + hydrogel (2.5 kg ha −1 ) maintained significantly higher soil organic carbon (4.4 g kg −1 ); soil organic carbon stock (9.06 t ha −1 ); nitrogen, phosphorus, potassium and micronutrients; and soil biological parameters compared to sole-crop residue mulching (4 t ha −1 year −1 ). Interestingly, soil physico-chemical and biological properties and carbon stock showed an improvement while enhancing residue covering from 4 to 8 t ha −1 year −1 compared to no residues. Among ZFPs, 5 kg Zn ha −1 + Zn solubilizer ( Bacillus endophyticus ) exhibited 7.4–13% higher system productivity and soil health. Correlation analysis exhibited significant positive correlation ( p < 0.01) amongst system-productivity and soil-health parameters. Double-crop basis residue mulching + hydrogel along with 5 kg Zn ha −1 + Zn solubilizer improved the soil health with optimized root development and hence harnessed higher system productivity in PWCS. Likewise, pigeonpea residue mulching proved more beneficial than wheat residue mulching in succeeding crops in realizing higher system productivity and soil health, where otherwise livestock inevitably need crop residues as quality fodder in semi-arid agro-ecologies.