摘要：

为明确长期施肥对山东潮土固碳潜力和作物产量的影响,以冬小麦-夏玉米轮作体系为研究对象,通过28 a定位施肥试验研究长期施肥下潮土固碳特征及其作物产量效应,提出不同肥力水平山东潮土有机碳提升策略。试验采用裂区设计,包括单施化肥和有机无机肥配施两大主处理,化肥区处理分别为不施肥、氮、氮磷、氮钾、磷钾、氮磷钾、减量氮磷钾、增量氮磷钾;有机肥区处理为化肥区处理基础上分别增加等量有机肥。结果表明,有机肥处理土壤累积碳投入量和固碳速率分别比化肥处理高2.47,4.29倍。有机肥处理土壤有机碳投入量为155.6~193.2 t/hm²,固碳速率为0.25~2.18 t/(hm²·a),化肥处理土壤有机碳投入量为39.5~100.5 t/hm²,固碳速率为4.15~5.49 t/(hm²·a)。其中,化肥区和有机肥区均是增量氮磷钾处理碳储量最高、固碳速率最快。随着外源碳的累积投入量增加,土壤有机碳呈线性增加,当投入量小于120 t/hm²时,土壤有机碳的存储能力为18.4%~20.6%;当投入量在120~200 t/hm²时,土壤有机碳的存储能力为11.5%。外源碳累积投入量小于100 t/hm²时,土壤固碳效率为11.7%;外源碳累积投入量100~200 t/hm²时,土壤固碳效率为4.3%。土壤有机碳含量与小麦和玉米产量之间均呈极显著相关关系,潮土土壤有机碳提升1 g/kg,作物总产量可增加414.5 kg/hm²(小麦和玉米产量可分别增加208.4,184.8 kg/hm²)。在保证土壤肥力和作物产量条件下,建议山东潮土累积有机碳投入量为150 t/hm²较为合适。

关键词: 潮土, 长期施肥, 有机碳, 固碳效率, 产量效应

Abstract:

To reveal the effects of long-term fertilization on carbon sequestration potential and crop yield of fluvo-aquic soil in Shandong Province,taking the winter wheat-summer maize rotation system as the research object,carbon sequestration characteristic and its yield effect of fluvo-aquic soil were explored by long-term fertilization of 28 a.The experiment adopted split-zone design.The main treatments included single inorganic fertilizer treatment and organic and inorganic fertilizer treatment.The treatments in the fertilizer area were CK,N,NP,NK,PK,NPK,N₁₅PK,N₂₅PK.The treatment in the organic fertilizer area was based on the treatment in the chemical fertilizer area,and the same amount of organic fertilizer was added respectively.The results showed that the cumulative carbon input and carbon sequestration rate of the organic fertilizer treatment were 2.47,4.29 times higher than those of the chemical fertilizer treatment,respectively.Soil organic carbon(SOC)storage in the organic fertilizer treatment was 155.6-193.2 t/ha,and the carbon sequestration rate was 0.25-2.18 t/(ha·a).SOC storage in the chemical fertilizer treatment was 39.5-100.5 t/ha,and the carbon sequestration rate was 4.15-5.49 t/(ha·a).Both the chemical fertilizer area and the organic fertilizer area had the highest carbon storage and the fastest carbon sequestration rate in the increment NPK treatment.SOC increased linearly with the input of exogenous accumulated carbon.The storage capacity of SOC was 18.4%-20.6% when the input amount of exogenous carbon was less than 120 t/ha.The storage capacity of SOC was 11.5% when the input amount was 120-200 t/ha.The soil carbon sequestration efficiency was 11.7% when the cumulative input of exogenous carbon was less than 100 t/ha.The soil carbon sequestration efficiency was 4.3% when the cumulative input of exogenous carbon was 100-200 t/ha.There was a very significant correlation between SOC content and wheat and maize yields.When soil organic carbon is increased by 1 g/kg in fluvo-aquic soil,the yield of wheat and maize can be increased by 208.4,184.8 kg/ha,respectively,and the total crop yield can be increased by 414.5 kg/ha.It is recommended that the cumulative organic carbon input amount was 150 t/ha under the condition of ensuring soil fertility and crop yield.

Key words: Fluvo-aquic soil, Long-term fertilization, Organic carbon, Carbon sequestration efficiency, Yield effect