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依托于2001年布设在陇中黄土高原半干旱雨养农业区的保护性耕作定位试验,于2014年测定了5种保护性耕作(免耕+秸秆覆盖NTS、免耕NT、传统耕作+秸秆翻埋TS、传统耕作+地膜覆盖TP和免耕+地膜覆盖NTP)和传统耕作T处理下小麦-豌豆双序列轮作中表层土壤(0~5、5~10、10~30 cm)总有机碳(SOC)和轻组有机碳(LFOC)在作物生育期前后的变化。结果表明:土壤总有机碳和轻组有机碳在土壤剖面上均随着土层深度的增加而降低;相比传统耕作T,NTS和TS处理能显著提高0~30 cm土层中SOC、LFOC的含量,在作物播种前较T分别提高了19.51%、64.58%和13.36%、42.08%,在收获后分别提高了28.00%、85.37%和18.61%、77.82%,而SOC、LFOC含量NT和TP处理与T处理间差异不显著;从作物播种前至收获后,各处理下0~30 cm土层SOC含量均有减小趋势,其中NTS和TS处理变化量最小,NT和TP处理加大了作物生育期间SOC和LFOC的消耗;LFOC可以灵敏地反应出土壤有机碳的变化。因此,在该区推行以免耕、秸秆覆盖为主的保护性耕作措施更有利于碳的积累和土壤质量的改善,促进该区农业的可持续发展。
Relying on the conservation tillage experiment conducted in the semi-arid rainfed farming area in the Longzhong Loess Plateau in 2001, five conservation tillage (no-tillage + straw mulching NTS, no tillage NT, conventional tillage + straw tipping (0 ~ 5, 5 ~ 10, 10 ~ 30 cm) total organic carbon (TOC) in the double sequence rotation of wheat-pea under the traditional tillage + plastic film mulch TP and no tillage + plastic film mulching NTP) SOC) and light organic carbon (LFOC) before and after crop growth period. The results showed that total organic carbon (TOC) and light organic carbon (TOC) decreased with the increase of soil depth in soil profiles. Compared with conventional tillage treatments, NTS and TS treatments significantly increased SOC and LFOC , Increased by 19.51%, 64.58% and 13.36% and 42.08% respectively compared with T before sowing, and increased by 28.00%, 85.37% and 18.61% and 77.82% respectively after harvest, while SOC and LFOC contents of NT and TP There was no significant difference between treatment and T treatment. From before sowing to harvesting, the SOC content of 0-30 cm soil layer tended to decrease, and the change of NTS and TS was the smallest, while the NT and TP treatments increased The consumption of SOC and LFOC during crop growth; LFOC can sensitively reflect the changes of soil organic carbon. Therefore, the implementation of conservation tillage practices such as no-tillage and straw mulching in this area is more conducive to carbon accumulation and soil quality improvement, and promotes the sustainable development of agriculture in this area.