Purpose

The study aimed to determine the interactive effect of temperature with nutrients on maize residues decomposition in soil.

Materials and methods

We conducted an incubation of 87 days by applying maize straw (δ¹³C value of −11.2‰) to soil (δ¹³C value of −26.3‰) with low (N₀), medium (N_M), and high (N_H) level of nutrients addition, at two temperature levels of 5 °C (T_-L) and 25 °C (T_-H). We measured the cumulative CO₂-C efflux, residues decomposition, temperature sensitivity (Q₁₀), and extracellular enzyme activities.

Results and discussion

Increased temperature significantly increased cumulative CO₂ efflux and straw decomposition, with an enhanced rate of active (K_a) and slow (K_s) pools of soil and residues C. The mean values of Q₁₀ ranged from 1.4 to 1.6 for the total CO₂ efflux and 1.4 to 1.7 for maize straw decomposition. The outcome might be due to temperature-dependent microbial activation at 25 °C. The activities of β-glucosidase, α-glucosidase, cellobiohydrolase, and β-xylosidase enzymes were positively correlated with cumulative CO₂ emissions at 25 °C suggesting microbial regulation on SOM decomposition. We found a U-shaped pattern of nutrients regulation on the temperature sensitivity of maize straw decomposition, with the lowest Q10 under N_M.

Conclusions

Our findings suggest that nutrients regulated the temperature effects on residue C decomposition by adjusting microbial activity (extracellular enzyme activities). Consequently, it may lead to soil C sequestration under the current climate change scenario.

中文翻译：

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营养添加调节玉米秸秆矿化的温度敏感性

目的

该研究旨在确定温度与养分的相互作用对土壤中玉米残留物分解的影响。

材料和方法

我们通过将玉米秸秆（δ进行87天的温育¹³的-11.2‰C值）到土壤（δ ¹³的-26.3‰C值）低（N ₀），中（N_中号）和高（N在5°C（T _-L）和25°C（T _-H）的两个温度水平下添加营养素的_H）水平。我们测量了累积的CO ₂ -C外排，残留物分解，温度敏感性（Q ₁₀）和细胞外酶活性。

结果和讨论

温度升高显着增加了累积的CO ₂流出和秸秆分解，增加了土壤和残留物C的活性（K _a）速率和缓慢（K _s）库的速率。Q ₁₀的平均值在总CO的1.4至1.6范围内。₂流出，玉米秸秆分解为1.4到1.7。结果可能是由于25°C下依赖温度的微生物活化所致。β-葡萄糖苷酶，α-葡萄糖苷酶，纤维二糖水解酶和β-木糖苷酶的活性与累积CO ₂正相关。25°C时的二氧化碳排放表明微生物对SOM分解有调控作用。我们发现玉米秸秆分解的温度敏感性呈U型养分调节，在N _M下Q10最低_。

结论

我们的发现表明，营养物质通过调节微生物活性（细胞外酶活性）来调节温度对残留C分解的影响。因此，在当前的气候变化情景下，这可能导致土壤碳固存。