不同覆盖方式对旱作农田土壤碳氮含量及玉米产量的影响

设置垄膜沟播(R)、平作全覆膜(P)和平作秸秆覆盖(S)3种不同覆盖栽培模式,以传统平作(CK)为对照,通过3 a大田定位试验,研究不同覆盖方式对农田土壤碳氮及其组分变化、玉米干物质积累和籽粒产量的影响。结果表明:连续覆盖3 a后,R和P处理土壤有机碳和全氮含量及储量均呈逐渐下降趋势,而S处理则呈上升趋势且每年的增幅逐渐增大;各处理0～40 cm土层土壤有机碳储量均表现为S>R>P>CK,全氮储量表现为S>CK>R>P,S处理有机碳和全氮储量分别较CK提高3.4%和7.5%;与CK相比,R和P处理可提高土壤碳氮比,在0～20 cm土层平均分别提高7.9%和9.6%(P<0.05),而S处理0～20 cm土层土壤碳氮比平均降低了9.9%(P<0.05);各覆膜处理(R和P)均较CK显著降低了0～40 cm土层土壤可溶性有机碳(DOC)和土壤可溶性有机氮(DON)含量,而S处理较CK处理0～60 cm土层DOC和DON含量2 a平均均提高6.2%;各处理收获期硝态氮含量在0～100 cm剖面中的垂直分布与CK无明显差异;各处理土壤铵态氮含量均...

Effects of different mulching methods on soil carbon and nitrogen content and maize yield in semiarid farmland

A 3-years located experiment with four mulching patterns (R, ridge\|furrow with film mulching planting; P, flat planting with full plastic\|film mulching; S, straw mulching; and CK, conventional tillage without mulching) during the whole season were carried out.The effects of different mulching patterns on the change of farmland soil carbon and nitrogen and its components, the influence of the dry matter accumulation and grain yield of maize were studied to identify the effects of different mulching methods on regulating soil carbon.After 3-years, the content and storage of soil organic carbon (SOC) and total nitrogen (TN) showed a gradual decline trend under R and P, while S treatment showed an upward trend with an accelerating rate each year. The SOC storage in 0~40 cm soil layer of each treatment was S>CK>R>P, while the TN storage was S>CK>R>P. Compared with CK, S increased SOC and TN storage by 3.4% and 7.5%, respectively. Compared with CK, soil C/ N ratio increased by 7.9% (P<0.05) and 9.6% (P<0.05) in 0~20 cm soil layer under R and P, respectively.The C/N ratio of 0~20 cm soil layer was decreased by 9.9% (P<0.05) under S. Compared with CK, film mulching treatments (R and P) significantly reduced the contents of dissolved organic carbon (DOC) and dissolved organic nitrogen (DON) in 0~40 cm soil layer, while S treatment increased the contents of DOC and DON by 6.2% in two years. There was no significant difference in the vertical distribution of nitrate nitrogen (NO⁺₃-N) content in the 0~100 cm profile between all treatments and CK. The content of NH⁺₄-N in soil was lower than that of NO⁺₃-N under different treatments, and the variation was small in different soil layers. The content of NH⁺₄-N in deep soil (60~100 cm) increased significantly by 30.4% and 32.4% (P<0.05) under R and P, respectively. Film mulching treatments (R and P) significantly increased dry matter accumulation and grain yield, averagely increased by 17.4% (P<0.05) and 17.9% (P<0.05) under film mulching treatments (R and P) respectivelywhen compared with CK.In general, plastic film mulching (especially P) significantly promoted the grain yield, and straw mulching had a positive effect on improving soil carbon and nitrogen accumulation and maintaining soil sustainability.