中国农业科学

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最新录用:免耕结合覆盖措施对渭北旱塬黑垆土结构与团聚体有机碳含量的影响

周明星1,代子俊1,樊军1,2*,付威1,郝明德1,2
  

  1. 1西北农林科技大学/黄土高原土壤侵蚀与旱地农业国家重点实验室,陕西杨凌 712100;2中国科学院水利部水土保持研究所,陕西杨凌 712100
  • 发布日期:2022-10-12

Effect of No-Till Combined with Mulching on the Structure and Organic Carbon Content of Agglomerates in Heilu Soils of the Weibei Dry Plateau

ZHOU MingXing1, DAI ZiJun1, FAN Jun1, 2 *, FU Wei1, HAO MingDe1,2 #br#   

  1. 1 College of Natural Resources and Environment, Northwest A & F University/ State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Yangling 712100 , Shaanxi; 2 Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi 
  • Online:2022-10-12

摘要:

【目的】阐明长期免耕及覆盖措施对渭北旱塬田土壤团聚体结构和有机碳含量的影响,探索改善区域土壤的适宜耕作措施。【方法在连续16年的黑垆土田间定位试验中选择传统耕作(CT)、免耕无覆盖(NT)、免耕+秸秆覆盖(NS)、免耕+地膜覆盖(NP)、免耕+秸秆+地膜覆盖(NSP)等共5种田间管理措施,于2019年10月春玉米收获期采集0—40 cm土层环刀和剖面土样,测定容重、团聚体粒级分布及有机碳含量。【结果】(1)免耕及覆盖措施(NTNPNSNSP)影响了黑垆土容重和团聚体粒级分布。免耕及覆盖措施均提高了耕层土壤容重,其中010 cm土层显著提高6.8%17.8%,犁底层容重和孔隙度变化与耕层相反。耕层大团聚体比例显著提高、微团聚体比例显著降低,促进耕层微团聚体向大团聚体的转化。各粒级团聚体重量百分比在耕层(0—20 cm)分布为:较大团聚体0.252 mm>大团聚体(>2 mm)>微团聚体(0.053—0.25 mm)>粉黏粒组分(<0.053 mm),在犁底层(20—40 cm)为较大团聚体和粉黏粒组分显著高于大团聚体和微团聚体。(2)免耕及覆盖措施下有机碳含量随团聚体粒级增大而增加。040 cm土层,NT处理各粒级团聚体有机碳含量均显著低于CT处理,而NSNSP处理均显著高于CT处理。(3)团聚体粒级分布是引起团聚体养分贡献率变化的主导因素,耕层总有机碳累积以>0.25 mm团聚体为主,犁底层以粉黏粒组分和较大团聚体中有机碳为主。【结论】长期免耕及覆盖措施促进耕层微团聚体向大团聚体转化。与传统耕作相比,免耕和地膜覆盖分别降低了黑垆土0—40 cm土层各粒级团聚体有机碳含量。而免耕覆盖(NSNPNSP)比无覆盖(NT)均增加了各粒级团聚体有机碳含量,单独秸秆覆盖NS效果最优,且显著改善土壤容重和团聚体粒级分布,是最佳处理。

关键词: 免耕, 覆膜, 秸秆覆盖, 有机碳, 团聚体粒级, 渭北旱塬

Abstract: ObjectiveTo clarify the effects of long-term no-tillage and mulching measures on soil aggregate structure and organic carbon content in Weibei dry plateau farmland, and to explore suitable tillage measures to improve the regional soil.MethodOn the basis of continuous 16-year field positioning experiments, traditional tillage (CT), no-tillage and no mulch (NT), no-tillage + straw mulch (NS), no-tillage + plastic film mulching (NP), no-tillage + A total of 5 field management measures, including straw + plastic film mulching (NSP), were used. The 0-40 cm ring knife and profile soil samples were collected during the spring corn harvest in October 2019, and the bulk density, aggregate particle size distribution and organic carbon content were determined.Result(1) No-tillage and mulching measures (NT, NP, NS and NSP) affected the bulk density and aggregate size distribution of Heilu soil. No-tillage and mulching measures both increased the soil bulk density of the plough layer, of which 0-10 cm increased significantly (6.8%-17.8%). The changes of bulk density and porosity of the plough layer were opposite to those of the plough layer. The proportion of micro-aggregates was significantly reduced, which promoted the transformation of micro-aggregates into macro-aggregates. The weight percentage of aggregates of each particle size in the plough layer (0-20 cm) is distributed as follows: larger aggregates (0.25-2 mm) > large aggregates (>2 mm) > micro aggregates (0.053-0.25 mm) > powder. The clay fraction (<0.053 mm), the larger aggregates and silty clay fractions in the plow bottom layer (20-40 cm) were significantly higher than the macroaggregates and microaggregates. (2) Under no-tillage and mulching measures, the organic carbon content increased with the increase of aggregate particle size. In the 0-40 cm soil layer, the organic carbon content of the aggregates of each particle size in the NT treatment was significantly lower than that in the CT treatment, while the NS and NSP treatments were significantly higher than those in the CT treatment. (3) The particle size distribution of aggregates is the dominant factor causing the change of the nutrient contribution rate of aggregates. The total organic carbon accumulation in the plough layer is dominated by aggregates >0.25 mm, and the plough layer is mainly composed of silty clay components and organic carbon in larger aggregates main. ConclusionLong-term no-tillage and mulching measures promote the transformation of micro-aggregates into macro-aggregates in the plough layer. Compared with traditional tillage, no-tillage and plastic film mulching decreased the organic carbon content of aggregates of various particle sizes in Heilong soil and in the plough layer, respectively. However, no-tillage mulching (NS, NP and NSP) increased the organic carbon content of aggregates of each particle size compared with no mulching. Straw mulching alone had the best effect, and significantly improved the bulk density and aggregate particle size distribution, which was the best treatment.


Key words: no-tillage, coated, straw mulching, organic carbon, aggregate size, Weibei dry plateau