关键词: 生境变化, 中红外光谱, 土壤理化因子, 凋落物, 秸秆

Abstract: This study proposes to simulate the habitat changes of “returning farmland to forest” and “reclamation of forest land” by the replacement of agricultural and forest soils, and to investigate their effects on the decomposition of plant residues. We established forest soil + forest litter (F+L) and forest soil + agricultural straw (F+S) treatments in temperate forest ecosystem, which were also transferred to agricultural ecosystem. Agricultural soil + agricultural straw (A+S) and agricultural soil + forest litter (A+L) were established in agricultural ecosystem, which were also transferred to forest ecosystem. We measured plant residue mass loss, TC, TN, midinfrared spectra and soil factors after one year decomposition. Our results showed that replacement of A+S into forest habitat stimulated mass loss by 20.0%, increased C/N and TC, but decreased rH_{1635 cm}-1/rH_{2920 cm}-1. Moving A+L replacement into forest habitat had no significant effect on mass loss, C/N, and rH_{1635 cm}-1/rH_{2920 cm}-1. Replacement of F+S into agricultural habitat resulted in a 34.3% reduction in mass loss, decreased C/N, TC, and TN, but increased rH_{1635 cm}-1/rH_{2920 cm}-1. Replacement of F+L into agricultural habitat reduced mass loss by 14.1%, but did not affect C/N and rH_{1635 cm}-1/rH_{2920 cm}-1. These results indicated that the replacement of agricultural soil into forest habitat improved the decomposition of the recalcitrant components of high-quality straw and enhanced the release of carbon and nutrients. While the replacement of forest soil into agricultural habitat reduces soil moisture and DOC, inhibiting the decomposition of straw and litter, slowing the release of carbon and nutrients from plant residues, high chemical stability of the remaining straw is not conducive to the input of carbon and nutrients into soil in the later stages of decomposition. Our study can provide the basis theory for nutrient management and sustainable management in agricultural and forest soils.

Key words: habitat change, mid-infrared spectroscopy, soil physicochemical factors, litter, straw