[目的]有机肥替代化肥可以改善黑土团聚体稳定性和土壤结构.基于长期定位试验,研究等氮量下不同比例有机肥氮替代化肥氮的效果,为吉林省黑土区土壤高效培肥提供科学依据.[方法]位于吉林省公主岭市的8年田间定位试验包括不施肥(CK)、单施化肥(M0)、25％有机肥氮替代化肥氮(M25)、50％有机肥氮替代化肥氮(M50)和100％有机肥氮替代化肥氮(M100)5个处理.在每个处理分别采集0-20和20-40 cm 土层原状土样,采用干筛法和湿筛法,研究等氮量下有机肥替代化肥不同比例下土壤团聚体粒级分布特征、稳定性及碳氮含量、碳氮比.[结果]干筛条件下,相比CK处理,M0处理降低了 0-20 cm 土层大团聚体比例(R＞0.25)和团聚体稳定性.相比M0处理,M25、M50和M100处理增加了 2～10mm粒级比例及R＞0.25,降低了0.25～2和＜0.25 mm粒级比例;增加了团聚体稳定性.在20-40 cm 土层,各处理7～10 mm团聚体比例较0-20 cm 土层降低了 3.56％～9.92％,5～0.5 mm各粒级比例有所增加,而5～7和＜0.5 mm团聚体的比例基本持平.与M0处理相比,M25和M50处理降低了R＞025,M100处理有所提高.湿筛条件下,相比CK处理,M0处理0-20 cm 土层R＞0.25增加了 0.13％,平均重量直径(MWD)、几何平均直径(GMD)和分形维数(D)均有所降低,水稳性团聚体有机碳含量下降了 3.4％,水稳性团聚体碳氮比(C/N)下降了 21.29％.相比M0处理,M25、M50和M100处理R＞0.25没有显著差异,但C/N分别增加了 6.85％、33.02％和34.97％;M25处理MWD和GMD有所降低,而M50和M100处理MWD和GMD有所提高;M25和M50处理团聚体有机碳含量分别增加了 9.18％和16.08％,M100却降低了 5.36％.所有施肥处理0-20 cm 土层土壤水稳性团聚体有机碳和全氮含量明显高于20-40cm 土层,＞2、1～2和0.5～1mm团聚体有机碳和全氮含量最高,0.053～0.25 mm团聚体有机碳和全氮含量最低.20-40 cm 土层,相比CK处理,M0处理R＞0.25下降约10个百分点,而0.053～0.25和＜0.053 mm团聚体均增加约2个百分点.相比M0处理,3个有机替代处理R＞0.25增加8.29～13.25个百分点,而0.053～0.25和＜0.053 mm团聚体分别降低1.26％～2.31和1.65％～2.34个百分点,3个有机替代处理间没有显著差异.相比M0处理,有机替代各处理团聚体稳定性均有不同程度的增加.0.25～0.5和0.053～0.25 mm两个粒级团聚体中有机碳含量随有机替代比例的增加而增加.[结论]长期以有机肥氮替代50％化肥氮可最有效改善0-40 cm 土层土壤＞0.25 mm团聚体的占比,提升大团聚体中有机碳与全氮的累积量,进而加速大团聚体形成与稳定,提升土壤固碳能力与肥力,是吉林黑土可持续利用及绿色农业发展的适宜有机肥施用比例.
Substitution of chemical nitrogen with 50％organic fertilizer nitrogen improves the aggregate status of the black soil in central Jilin Province
[Objectives]Organic fertilizer is effective in improving soil structure and carbon and nitrogen retention.We studied the suitable substitution proportions of organic fertilizer based on long-term experiment,aiming to provide scientific basis for soil fertility improvement in the black soil region of Jilin Province.[Methods]The 8-year positioning experiment located in Gongzhuling City,Jilin Province.Soil samples were collected without disturb from 0-20 cm and 20-40 cm soil layers in the treatment plots of no fertilizer(CK),only chemical fertilizer(M0),25％organic fertilizer nitrogen substitutes chemical nitrogen(M25),50％organic fertilizer nitrogen substitutes chemical nitrogen(M50),and 100％organic fertilizer nitrogen substitutes chemical nitrogen(M1 00).Dry sieving and wet sieving methods were employed to study the proportion of soil aggregates in different sizes,and the carbon and nitrogen content,the carbon-to-nitrogen ratio of each size soil aggregates.[Results]Compared to CK,M0 treatment reduced the proportion of macroaggregates(R＞0 25)and aggregate stability in 0-20 cm soil layer.Compared to M0 treatment,M25,M50,and M100 treatments increased the proportions of 2-10 mm aggregates and R＞025,and decreased the proportions of 0.25-2 mm and＜0.25 mm ones.The proportion of 7-10 mm aggregates in 20-40 cm soil layer was 3.56％to 9.92％lower than in the 0-20 cm soil layer,while the proportions of 0.5-5 mm aggregates were higher,and those of 5-7 mm and＜0.5 mm aggregates remained relatively stable.Compared to M0,the M25 and M50 treatments reduced the proportion of R＞0.25,M100 treatment increased.Compared to CK,the M0 treatment increased the proportion of R＞025 in 0-20 cm by 0.13％,decreasing the mean weight diameter(MWD),geometric mean diameter(GMD),fractal dimension(D),organic carbon content(3.4％)and the C/N(21.29％)of water-stable aggregates.Compared to the M0 treatment,M25,M50,and M100 treatments did not increase the proportion of R＞025 significantly,but enhanced the C/N ratio by 6.85％,33.02％,and 34.97％,respectively;M25 decreased the MWD and GMD,while M50 and M100 treatments were recorded higher MWD and GMD,and M25 and M50 treatments were recorded 9.18％and 16.08％higher organic carbon of aggregates than M0 respectively,while M100 was 5.36％lower.The organic carbon and total N content of water-stable aggregates in the 0-20 cm soil layer were significantly higher than in the 20-40 cm soil layer,with the highest content in the＞2 mm,1-2 mm,and 0.5-1 mm aggregates,and the lowest in the 0.053-0.25 mm aggregate.Compared to the CK treatment,M0 treatment decreased R＞0.25 by 10 percentage points,while increased 0.053-0.25 mm and＜0.053 mm aggregates by about 2 percentage points in the 20-40 cm soil layer.Compared to the M0 treatment,organic substitution treatments increased R＞0.25 by 8.29-13.25 percentage points,decreased the 0.053-0.25 mm and＜0.053 mm aggregates by 1.26-2.31 and 1.65-2.34 percentage points,respectively,and the increments in R＞025 were not significant different among treatments.Compared to the M0 treatment,organic substitution treatments increased aggregate stability to varying degrees.In the 0.25-0.5 mm and 0.053-0.25 mm aggregates,the organic carbon content increased with the increase of the organic substitution proportion.[Conclusions]Substitution of chemical fertilizer with 50％of organic fertilizer showed the best effects in improving soil structure,promoting the accumulation of organic carbon and total nitrogen throughout the soil profile,accelerating the formation and stability of macroaggregates,and enhancing soil carbon sequestration capacity and fertility,providing a core strategy for the sustainable use of black soil and the development of green agriculture.
organic fertilizer nitrogen substitutes chemical nitrogenblack soilaggregate distributionaggregate stabilityorganic carbontotal nitrogencarbon nitrogen ratio
万方数据
维普
