The experiment was laid out as a strip-plot design with four replications. Four cropping systems occupied the vertical axis: sole chickpea, and chickpea intercropped in 2:2 row proportions with coriander, linseed, or sorghum. The horizontal axis carried three nutrient strategies. The organic farming module supplied biofertilizers, vermicompost, and biopesticides. The natural farming module relied on the classic inputs of the movement — Ghanajeevamrith, Beejamrith, Jeevamrith, and Neemastra — fermented preparations built from cow dung, cow urine, jaggery, pulse flour, and local soil. The integrated module blended both approaches, combining vericompost and biofertilizers with Jeevamrith and Neemastra. All nutrient sources were applied on a nitrogen-equivalent basis so that each treatment received the recommended dose of nitrogen, phosphorus, and potassium for its crops, ensuring that differences in soil biology could be attributed to the quality of the inputs rather than the quantity of nutrients delivered.

When the researchers compared the two extreme treatment combinations, the contrast was dramatic. Sole chickpea under the integrated organic and natural module outperformed chickpea–sorghum intercropping under natural farming alone by 60 percent in plant nitrogen uptake, 100 percent in phosphorus, and 192 percent in potassium, measured per plant rather than per hectare to avoid the confounding effect of different plant densities. Fungal populations rose 78.0 percent, bacterial populations 85.4 percent, and actinomycetes 109.8 percent between those same two treatments. Soil microbial biomass carbon increased by 42.4 percent and microbial biomass nitrogen by 64.6 percent.

The enzyme story followed the same pattern. Urease, the nickel-containing metalloenzyme that hydrolyzes urea into ammonia and carbon dioxide, was 75.6 percent more active under the best treatment than the worst. Dehydrogenase, widely used as an integrative indicator of overall microbial oxidative activity because it transfers electrons and protons during organic matter oxidation, doubled — a full 100 percent increase. Acid phosphatase activity rose 116.8 percent and alkaline phosphatase 42.4 percent. Urease values spanned 36.34 to 75.58 micrograms of ammonium-nitrogen per kilogram of soil over two hours, while dehydrogenase ranged from 29.42 to 58.91 micrograms of triphenyl formazan per kilogram per day. Across the individual comparisons, the treatment ranking was consistent: the integrated module on sole chickpea came first, followed by integrated chickpea–coriander, organic sole chickpea, and integrated chickpea–linseed, with natural farming combined with chickpea–sorghum at the bottom in every case.

Why did the simplest cropping system beat the mixtures? The authors point to chickpea’s physiology. Its deep root system, nodulation, and the organic acids it releases — malate, malonate, and citrate — increase phosphatase activity and liberate organic phosphorus, encouraging phosphate-solubilizing bacteria such as Pseudomonas species. Root turnover and sloughed cells add carbon and nitrogen to the rhizosphere, feeding a nutrient-efficient microbial community. The root exudates of companion crops apparently diluted these benefits rather than amplifying them.

Sorghum, in particular, appears to have worked against the soil biota. Its root hairs exude sorgoleone, a lipophilic secondary benzoquinone with documented allelopathic properties that can restructure belowground microbial communities and suppress beneficial microorganisms and their enzymes. The chickpea–sorghum treatment under natural farming recorded the lowest values of every biological parameter: 33.84 million bacterial colony-forming units per gram, 4.03 × 10⁴ fungal units, 2.82 million actinomycetes, 173.42 micrograms per gram of microbial biomass carbon, and the weakest enzyme activities. Under the same natural farming module, sole chickpea supported 57.43 million bacteria and 6.58 × 10⁴ fungi per gram — nearly double the actinomycete count.

The integrated nutrient module itself deserves attention. Vermicompost, biofertilizers, Jeevamrith, and Neemastra together outperformed either approach alone across every measured biological variable. The authors attribute this to synergies among diverse nutrient sources: a balanced and sustained nutrient supply, improved soil organic carbon, better microbial habitat conditions, and enhanced aggregation and moisture retention. Natural farming inputs alone gave the weakest biological response of the three modules, with mean microbial biomass carbon of 204.80 micrograms per gram against 216.12 for organic farming and 226.43 for the integration. By contrast, the sole application of individual inputs, either organic or natural, may provide limited or short-term benefits due to nutrient imbalance, slower decomposition, or insufficient microbial stimulation, according to the authors.

Statistical analysis reinforced the picture. Principal component analysis showed the first dimension alone capturing 91.9 percent of the variance, separating the sole chickpea and chickpea–coriander treatments, which aligned with microbial groups and phosphatase activity, from the linseed and sorghum systems, which were more closely linked to dehydrogenase, urease, and nutrient availability. Correlation analysis found urease and alkaline phosphatase significantly associated with bacterial and fungal populations, while acid phosphatase correlated with all three microbial groups, underscoring the broad microbial mediation of phosphorus cycling. Clustered heat maps for the 2024 season grouped sole chickpea with all three nutrient modules at the highest enzymatic intensity.

The measurements themselves were rigorous. Microbial biomass carbon was determined by chloroform fumigation–extraction, with fumigated and unfumigated soils extracted in 0.5 M potassium sulfate and organic carbon oxidized and back-titrated. Microbial biomass nitrogen followed a parallel fumigation-digestion protocol. Urease was assayed by incubating soil with urea substrate in THAM buffer at 37 °C and quantifying released ammonium by steam distillation; dehydrogenase was measured from triphenyl formazan extracted with methanol and read spectrophotometrically at 485 nanometers; acid and alkaline phosphatase were quantified from p-nitrophenol released from p-nitrophenyl phosphate at pH 6.5 and 11.0 respectively. Bacteria, fungi, and actinomycetes were enumerated by serial dilution and spread plating on nutrient agar, Martin’s Rose Bengal agar, and Kenknight’s agar, with colony-forming units expressed on a dry soil basis. Rhizosphere samples were collected at flowering from chickpea roots and, in the intercrops, separately from both crop interfaces, then composited treatment-wise.

For the authors, the practical message is that sole chickpea or chickpea intercropped with coriander, fed by integrated organic and natural inputs, offers a promising route to restoring fertility in the Inceptisols of the Satpura foothills while reducing dependence on synthetic fertilizers. They caution, however, that the experiment covered a single location and two seasons under specific soil and climatic conditions; molecular characterization of the microbiome was beyond its scope, and long-term effects on carbon sequestration, nutrient dynamics, and system productivity remain untested. Multi-location, long-term trials with molecular and economic assessments are the recommended next step before these recommendations travel far beyond the black clay loams of Akola.

Subject of Research: Effects of organic, natural, and integrated nutrient management on soil microbial and enzymatic properties in chickpea-based cropping systems

Article Title: Microbial and enzymatic response of soil to organic and natural management practices in chickpea-based cropping systems at the Satpura foothills

Article References: Charitha, N., Paslawar, A. N., Kharche, V. K., Saikrishna, M., Ingle, Y. V., Singh, A., & Chorey, A. B. (2026). Microbial and enzymatic response of soil to organic and natural management practices in chickpea-based cropping systems at the Satpura foothills. Frontiers in Sustainable Food Systems, 10, Article 1814274. https://doi.org/10.3389/fsufs.2026.1814274

Image Credits: AI Generated

DOI: 10.3389/fsufs.2026.1814274

Keywords: soil health, chickpea, organic farming, natural farming, soil enzymes, microbial biomass, intercropping, urease, dehydrogenase, phosphatase, sorgoleone, Satpura foothills