Integrated nutrient management (INM) is a widely recognized tool to ensure sustainable crop productivity while preserving soil fertility. The addition of organic manures in soil has been evidenced to improve soil characteristics, in addition to improving nutrient availability. The soil samples, with five treatment combinations of chemical fertilizers with farmyard manure (FYM), were collected from a 17-year-old field experiment conducted at PAU, Ludhiana to investigate the effect of INM on the buildup of organic carbon (OC), microbial community, soil nutrient status and improvement in soil physical properties under the maize–wheat cropping system. The INM technique enhanced the OC content (0.44 to 0.66%), available N (152.8 to 164.9 kg ha⁻¹), P (22.8 to 31.4 kg ha⁻¹) and K (140.6 to 168.0 kg ha⁻¹) after 17 years. The DTPA-extractable and total micronutrients (Zn, Cu, Fe, and Mn) status also improved significantly with FYM supplementation. The organic source, coupled with inorganic fertilizers, improved the water holding capacity, total porosity, soil respiration, microbial biomass C, microbial biomass N, and potentially mineralizable N. However, pH, EC, and bulk density of soil decreased with the addition of FYM, coupled with chemical fertilizers.

The impact of integrated nutrient management seems crucial for the sustainability of crop production as revealed by studies on long-term experiments. It provided the opportunity to monitor long-term variations in crop yields and associated factors. The impacts of various nutrient management strategies on yields and soil attributes in a rice-wheat system have been researched under a long-term experiment that has been running since 1983 at Punjab Agricultural University, Ludhiana. Further, a positive correlation has been observed between crop yields and soil properties such as soil organic carbon (SOC), nitrogen (N), phosphorus (P), potassium (K) and zinc (Zn). The negative correlation with K could be attributed to soil becoming deficient in K and necessitating the application of potassium fertilizer. The treatments receiving organic manures (green manure, farmyard manure and wheat cut straw) showed a better population of soil microorganisms in comparison to the treatments receiving chemical fertilizers, thereby proving as precursors of sustaining soil health. The best soil characteristics (water-soluble aggregates, exchangeable and non-exchangeable K, fixed and total K) after rice and wheat harvesting were found where 50 % of the recommended NPK was supplemented with farmyard manure (FYM). The build-up of trace elements particularly for Fe and Zn was also noticed. In crystalline Fe oxide bound fraction (CFeOX), Fe increased between 717.1 and 984.8 mg kg⁻¹, while Zn increased between 2.64 and 3.08 mg kg⁻¹. Furthermore, amorphous iron oxide (AFeOX), CFeOX, carbonate (CARB), organic matter (OM) bound and exchangeable (EXCH) Fe and Zn were higher in treatments where organic manures were supplemented with 50 and 25 % N. Farmyard manure showed an incremental trend, followed by wheat cut straw and green manure (GM). The incremental trend in soil quality was noticed with FYM followed by wheat cut straw and GM.

The scarcity of fertilizers and their rising costs are significant barriers to crop production, as the current agricultural situation in India has shown. In maize–potato–onion cropping systems, the impact of various organic treatments on crop yields and soil parameters has shown that organic treatments increased maize, potato and onion yields compared to chemical treatment (recommended dose of fertilizers) alone. Treatments with applications of different organic sources, each equivalent to 1/3 of the recommended N, along with intercropping of soybeans in maize, radishes in potatoes and coriander in onions, gave the highest yield of maize crops, and significant positive yield trends were observed in four treatments (T1, T2, T4 and T6). Interestingly, all treatments showed a positive effect on potato and onion yields, clearly summarizing potatoes and onions as being more stable crops than maize. Further, the best soil characteristics, viz., bulk density and soil resistance under organic treatment, were lower than those found in integrated and chemical treatments. In contrast, the soil’s water-holding capacity, stable aggregate and infiltration rate followed a reverse trend. The treatment (T3), in which soybeans were grown as an inter-row crop in maize, radishes in potatoes and coriander in onions, showed the highest energy-use efficiency, energy output efficiency and energy productivity.

Achieving an economically feasible and environmentally robust model in agriculture while satisfying the expanding population’s food demands is a global challenge. Hence, a three-year (2014–2017) study was conducted at Punjab Agricultural University, Ludhiana to design environmentally clean, energy-efficient, and profitable cropping systems. Twelve cropping systems viz., rice-wheat (CS₁), basmati rice-hayola (transplanted)-mung bean (CS₂), basmati rice-radish-maize (CS₃), maize-potato-maize (CS₄), maize + turmeric-barley + linseed (CS₅), maize + turmeric-wheat + linseed (CS₆), maize + radish-wheat + linseed-mung bean (CS₇), groundnut + pigeon pea (5:1)-wheat + sarson (9:1) (CS₈), maize + black gram-pea (bed) + celery (furrows) (CS₉),_: maize + pigeon pea-chickpea (bed) + gobhi sarson (furrows) (CS₁₀), maize (green cobs) + vegetable cowpea + dhaincha (Sesbania spp.)-chickpea + gobhi sarson (CS₁₁) and sorghum + cowpea (fodder)-wheat + gobhi sarson (9:1) (CS₁₂) were tested in a four-times-replicated randomized block design. CS₁₁ had the maximum system productivity (28.57 Mg ha⁻¹), production efficiency (78.27 Kg Day⁻¹ ha⁻¹), irrigation water use efficiency (2.38 kg m⁻³), system net returns (4413.3 US$ ha⁻¹), and benefit to cost (B:C) ratio (2.83) over others. In comparison to the CS₁ system, this cropping system required ~78% less irrigation water for a unit economic production. However, the cultivation of CS₁₂ registered the highest energy use efficiency (49.06%), net energy returns (6.46 × 10³ MJ ha⁻¹), and global warming potential (GWP) (Mg CO₂ e ha⁻¹) at spatial scale. Among all the intensified systems, CS₁₁ had the lowest GHGI (0.29 kg CO₂ e kg⁻¹). Furthermore, cultivation of CS₆ resulted in the maximum bacterial and actinomycetes population in the soil, while CS₅ yielded the highest fungal count (23.8 × 10³ cfu g⁻¹ dry soil) in soil. Our study suggests that the cultivation of CS₁₁ is a resource-efficient, economically viable, and environmentally clean production system and could be a potential alternative to rice-wheat systems for developing a green economy policy for agricultural development in the Indo-Gangetic Plains (IGP) of India.