稻壳及稻壳生物炭对土壤团聚体稳定性及有机碳分布的影响

【目的】长期种植雷竹(Phyllostachys praecox)会导致土壤酸化加剧，土壤结构破坏。我们比较了施用不同量稻壳和稻壳生物炭对土壤理化性状和团聚体组成的影响，以寻求实现雷竹的可持续生产的有效措施。【方法】采用盆栽方法进行雷竹幼苗试验，供试土壤长期种植雷竹，pH为5.3。设置分别施用稻壳、稻壳生物炭10 t/hm² (10H、10B)和30 t/hm² (30H、30B)处理，以不施稻壳和稻壳生物炭的处理为对照(CK)。雷竹幼苗生长262天后，采集土样测定土壤基本理化性质，采用湿筛法筛分不同粒级土壤团聚体，测定各粒级团聚体中有机碳和全氮含量。【结果】30H和30B处理均显著降低了<0.053 mm粒级团聚体含量，显著提高了水稳性团聚体的平均重量直径(MWD)、几何平均直径(GMD)以及>0.25 mm粒级团聚体(R0.25)含量；10H和10B处理对水稳性团聚体的MWD、GMD以及R0.25含量均无显著影响。30B处理显著增加了>2 mm、0.25～2 mm、0.053～0.25 mm粒级团聚体中有机碳含量，其中增...

Effects of rice husk and its derived biochar on soil properties and stability of aggregates

  【Objectives】  Long-term planting of Lei bamboo (Phyllostachys praecox) can destroy the soil structure and lead to acidification. Here, we compared the effects of applying rice husk and its biochar at different rates on soil physicochemical properties and aggregate fractions to promote sustainable Lei bamboo production.  【Methods】  A Lei bamboo pot experiment was conducted. The experimental soil samples were collected from a long-term cultivated Lei bamboo plantation with a pH of 5.3. This study had five treatments, including rice husk and its biochar at 10 t/hm2 (10H, 10B) and 30 t/hm2 (30H, 30B) and no rice husk and rice husk biochar as control (CK). Soil samples were collected 262 days after planting Lei bamboo to determine the basic physicochemical properties of soil. Soil aggregates were measured using the wet-sieving method, and the concentrations of organic carbon (OC) and total nitrogen (TN) in each aggregate fraction were also determined.  【Results】  The 30H and 30B treatments reduced the content of <0.053 mm aggregates compared to the CK (P<0.05). Mean weight diameter (MWD), geometric mean diameter (GMD) and >0.25 mm aggregate increased in 30H and 30B (R_0.25). However, 10H and 10B did not affect the MWD and GMD of the water-stable soil aggregates and R_0.25 (P>0.05). 30B increased the concentration of OC in >2 mm, 0.25–2 mm, and 0.053–0.25 mm aggregates (P<0.05) , and the highest increase was recorded for soil aggregates >2 mm. 10H and 30H increased the concentration of OC in <0.053 mm aggregates, but had no effect on the concentration of OC in other aggregate fractions compared with the CK (P>0.05).  【Conclusions】  Rice husk and its biochar applied at 30 t/hm2 enhanced the stability of soil structure. Compared with rice husk application, rice husk biochar increased the OC concentration in macro-aggregates to increase the soil organic carbon (SOC) concentration. Therefore, applying 30 t/hm2 of rice husk biochar instead of rice husk to Lei bamboo soil can improve the soil structure and increase soil carbon sequestration simultaneously.