鸡粪与化肥配施对饲用小黑麦/玉米轮作土壤团聚体分形特征与碳库管理指数的影响

为探讨鸡粪与化肥配施对饲用小黑麦/玉米轮作土壤水稳性团聚体分形特征及碳库管理指数的影响,通过2010-2017年连续8年大田试验,研究了C_0N_0(不施肥,CK)、C_0N_(10)(鸡粪氮∶尿素氮=0∶10)、C_2N_8(鸡粪氮∶尿素氮=2∶8)、C_4N_6(鸡粪氮∶尿素氮=4∶6)和C_5N_5(鸡粪氮∶尿素氮=5∶5)5种不同处理对小黑麦/玉米轮作土壤水稳性团聚体组成及对土壤有机碳(SOC)、总有机碳(TOC)、活性有机碳(AOC)、土壤质量分形维数(D_m)和碳库管理指数(CPMI)的影响。结果表明:不同施肥处理对小黑麦/玉米轮作土壤水稳性团聚体组成具有显著影响。0-40cm土层水稳性团聚体组成均以0.25mm粒径为主,其含量表现为C_0N_0处理最高,C_0N_(10)、C_2N_8和C_5N_5处理次之,C_4N_6处理最低;与CK相比,各处理的团聚体SOC含量均显著增加(p0.05),增加幅度由大到小依次为C_4N_6C_5N_5C_2N_8C_0N_(10),且C_4N_6处理明显高于其他处理(p0.05);不同施肥处理下土壤水稳性团聚体D_m大小排序为C_0N_0C_0N_(10)C_2N_8C_5N_5C_4N_6;不同施肥处理下TOC、AOC和CPMI含量大小顺序为C_4N_6C_5N_5C_2N_8C_0N_(10)C_0N_0,且同一处理下TOC、AOC和CPMI含量均随着土层的加深而逐渐降低;Pearson相关性分析表明,D_m与TOC、AOC和CPMI和团聚体SOC基本呈极显著负相关(p0.01),而CPMI与TOC、AOC和团聚体SOC则基本呈极显著正相关(p0.01)。综合分析认为,在小黑麦/玉米轮作体系中鸡粪配施化肥不仅有利于提高土壤团聚体稳定性,还增强了土壤肥力,其中C_4N_6施肥处理效果最佳。

Effect of Combined Application of Chicken Manure with Fertilizer on Soil Aggregate Fractal Characteristics and Soil Carbon Pool Management Index in Triticale/Maize Rotation System

To investigate the effects of different proportions of chicken manure and nitrogen fertilizer on the fractal characteristics of soil water stable aggregates and the carbon pool management index in the forage triticale/maize rotation, a field experiment was conducted from 2010 to 2017 (successive eight years) with five treatments: C₀N₀ (no fertilizer, CK), C₀N₁₀ (chicken manure nitrogen:urea nitrogen=0:10), C₂N₈ (chicken manure nitrogen:urea nitrogen=2:8), C₄N₆ (chicken manure nitrogen:urea nitrogen=4:6), C₅N₅ (chicken manure nitrogen:urea nitrogen=5:5). Soil water stable aggregate composition and organic carbon (SOC), total organic carbon (TOC), active organic carbon (AOC), soil mass fractal dimension (D_m) and soil carbon management index (CPMI) were assayed in triticale/maize rotation. The results showed that different fertilization measures had significant influence on the composition of soil water stable aggregates in triticale/maize rotation. The soil water stable aggregate composition was less than 0.25 mm particle size, its content was the highest in C₀N₀ treatment, followed by C₀N₁₀, C₂N₈ and C₅N₅ treatments, and C₄N₆ treatment was the lowest. Compared with CK, aggregate SOC content of each treatment were significantly increased (p< 0.05), and the increase order from large to small was C₄N₆ > C₅N₅> C₂N₈ > C₀N₁₀, and SOC of C₄N₆ treatment was significantly higher than those of other treatments (p< 0.05), the D_m of soil water stable aggregates from large to small was C₀N₀ > C₀N₁₀ > C₂N₈ > C₅N₅ > C₄N₆. Soil TOC, AOC and CPMI of each treatment in order was C₄N₆ > C₅N₅ > C₂N₈ > C₀N₁₀ > C₀N₀, and the AOC, CPMI and TOC contents of the same treatment decreased gradually with the increasing soil depth. The pearson correlation analysis showed that D_m had a very significant negative correlation with TOC, AOC and aggregate SOC (p< 0.01), and CPMI was significantly positively correlated with TOC, AOC and aggregate SOC (p< 0.01). Comprehensively, the combined application of chicken manure with nitrogen fertilizer was not only beneficial to improving the stability of the soil structure, but also to enhancing soil fertility in triticale/maize rotation system, which C₄N₆ was the best treatment.