Tang et al. 2024 - Spent mushroom residue, soil fertility, and soil metals

Tang and colleagues tested whether returning spent mushroom residues to a rice-wheat rotation field improved crop yield and soil fertility while changing soil Pb, Cd, and Cr accumulation. This is primary agronomic soil evidence, not crop-metal occurrence evidence: the paper reports rice and wheat grain yields, but heavy-metal concentrations are measured in soil and spent mushroom residues, not in harvested grain.

Key numbers

Field baseline and treatment design

The experiment began in 2020 at the Modern Agriculture Base of Sichuan Agricultural University in Qiquan village, Chongzhou, on clay loam soil in the Chengdu Basin. Baseline 0-20 cm soil characteristics included pH 6.6, SOC 18.7 g/kg, total N 2.0 g/kg, total P 1.0 g/kg, total K 8.7 g/kg, total Pb 40.5 mg/kg, total Cd 0.24 mg/kg, and total Cr 101.3 mg/kg.

Seven treatments were used: CK (no fertilizer), CF (mineral NPK: 330 kg/ha N, 165 kg/ha P2O5, 165 kg/ha K2O), and five 50% residue-substitution treatments in which spent mushroom residue supplied 50% of N input with chemical fertilizer supplying the other 50%. Field plots were 5 m x 4 m with buffer zones; the paper states treatments were replicated three times. Table 1 reports grain-yield summaries as mean +/- SD with n = 4.

Crop yield

The study reports yield as an agronomic outcome, not as a metals occurrence endpoint:

Relative to CK, the authors report grain-yield increases of 49.1% for CF, 66.1% for EMR50, 50.0% for OMR50, 84.4% for APR50, 82.2% for SMR50, and 78.0% for ABR50.

Soil metal outcomes

Figure 2 reports relative changes in post-harvest soil metals compared with CK:

The authors state that both total Cr and total Cd were highest under the mineral NPK treatment (CF), while cumulative ecological risk (RI) was highest under the oyster mushroom residue treatment (OMR50). Crop yield was positively correlated with SOC (r = 0.61, p < 0.01), TN (r = 0.47, p < 0.05), and TP (r = 0.58, p < 0.01). Cr and Pb were significantly correlated with TN (r = 0.48, p < 0.05).

Metal content of spent mushroom residues

Table 2 reports these metal concentrations in the spent mushroom residue materials:

Methods (brief)

Soil samples from 0-20 cm were randomly collected after crop harvest from the seven treatments in each plot. Composite soils were cleaned of plant roots and organic debris; fresh soil was gently fragmented and sieved, while analysis soil was air-dried, ground, and sieved to 0.25 mm. Soil Cd, Cr, and Pb were extracted from soil samples using HNO3-HCl (3:1) and measured by flame atomic absorption spectrophotometry. Heavy metals in spent mushroom residue were extracted with concentrated HNO3 and HClO4. Potential ecological risk used national background values of Cr 90 mg/kg, Cd 0.2 mg/kg, and Pb 35 mg/kg, with toxicity coefficients of Cd 30, Cr 2, and Pb 5.

Implications

Certification: Do not use this source in rice, wheat, grain, or food-product occurrence pools. It does not measure Pb, Cd, or Cr in edible grain. It is relevant as agronomic context for amendment-driven soil-metal changes and residue-metal inputs.

App: Context for mitigation and sourcing notes. Spent mushroom residues improved yield and soil fertility in this short-term field experiment, but they also changed soil metal accumulation and ecological risk, so residue metal content and application rate matter.

Courses: Useful for teaching why agronomic yield trials must be separated from food-contaminant occurrence evidence unless the harvested crop itself is analyzed for metals.

Wiki pages this source may touch

• agronomic
• remediation-evidence
• chromium
• cadmium
• lead
• index

Verification notes

This page was built from the full PDF, including the abstract, Table 1 yield values, Figure 1 soil-fertility summary, Figure 2 heavy-metal relative changes and RI index, Figure 3 correlations, field-design methods, Table 2 mushroom-residue properties and application rates, soil-sampling and analytical methods, conclusions, and data-availability statement. Products and ingredients are intentionally empty because the source measures soil metals and residue input metals only; it does not report rice-grain or wheat-grain metal concentrations. The PDF extraction duplicates some figure captions and the peer-review layout, so numeric values were checked against the raw text where possible.

Page history

The five most recent substantive edits to this page. The full version history lives in git; when DOI minting comes online (see schema docs), each entry below will also link to a version-pinned DataCite DOI.