Impacts of nine-years of conservation tillage and precise nutrient management on equivalent yields, soil microbial dynamics, and water-energy footprints of the maizemustard rotation

Vijay Pooniya ^1* K K Lakhena ¹ Dr. Niraj BISWAKARMA ^1* R RUSTUM ZHIIPAO ^1* Dinesh Kumar ¹ Yashbir Singh Shivay ¹ Nilutpal Sakia ¹ Anchal Dass ¹ Prabhu Govindasamy ¹ Sanjay Singh Rathore ¹ Pravin Kumar Upadhyay ¹ Anamika Barman ¹ Prakash Chand Ghasal ² Jairam Choudhary ² Karivaradharajan Swarnalakshmi ¹ R D Jat ³ Srinivasan R ⁴ Mahendra Prasad ⁴ Shankar Lal Jat ⁵ Rajkumar D Jat ⁶

• ¹ Indian Agricultural Research Institute (ICAR), New Delhi, India
• ² Indian Institute of Farming Systems Research (ICAR), Modipuram, Uttar Pradesh, India
• ³ Chaudhary Charan Singh Haryana Agricultural University, Hisar, Haryana, India
• ⁴ Indian Grassland and Fodder Research Institute (ICAR), Jhānsi, Uttar Pradesh, India
• ⁵ Indian Institute of Maize Research, Indian Institute of Agricultural Biotechnology (ICAR), Ludhiana, Punjab, India
• ⁶ Borlaug Institute for South Asia (BISA), Ludhiana, Punjab, India

In South Asian regions, the traditional maize-mustard rotation (MMR) has become less profitable and unsustainable due to inappropriate fertilization and deteriorating soil properties. Thus, climate-smart vis-à-vis sustainable farm practices are necessary to overcome production risks and ensure consistent or improved soil properties. This study evaluated the long-term impact of conservation tillage and nutrient management on equivalent yields, soil microbial properties, and water-energy savings. A long-term field study was initiated 9-years back in a fixed plot using the split-plot design to evaluate the three-conservation tillage (CA)-based crop establishment practices i.e., zero-(ZT) and conventional-(CT) tillage, permanent beds (PNB), accompanied by the recommended dose of fertilizer (RDF), improved RDF (RDF I ), and nutrient expert-guided (NE I ) fertilization.CA-based tillage (ZT or PNB) gave 24.4-25.2%, greater maize grain equivalent yields (EY) than to the CT, while the NE I and RDF I produced statistically (p=0.05) identical EY, being 26.6-30.3% greater than the RDF. These practices substantially reduced the water footprints, besides 11.9-12.9%, and 23.4-26.6% (9-yrs av.) greater water productivity compared to the CT, and RDF, respectively. In fact, at 0-45 cm soil depth, residue retained ZT or PNB had 31.9-42.2%, 56.5-67.2% and 16.5-18.3% more bacterial (10 7 ), fungi (10 4 ) and actinomycetes (10 4 ) populations, respectively. Across soil depths, ZT or PNB recorded 7.65-11% and 23.2-31.9% greater soil microbial biomass-C and -P, respectively. Compared to CT-based practices, these practices also improved soil mineralizable N (NO 3 -N / NH 4 + N). The conventionally tilled plots consumed greater direct, and indirect non-renewable energy than the CA-based residue retained practices. By virtue of the residue retention, the PNB and ZT had ~108% greater energy input (E I ) than the CT, while it was vice-versa in terms of the energy output (E O ). The NE I registered a 7.6-28.7% higher E O over the RDF I and RDF. This long-term field studies demonstrated that adopting CA-based ZT, or PNB, in combination with precise nutrient management would enhance equivalent yields and soil microbial dynamics, besides improving water-energy footprints in maize-mustard growing ecologies.