长期施肥下石灰性潮土有机碳变化的DNDC模型预测

为探讨长期不同施肥条件下土壤有机碳的变化规律及DNDC模型的应用,利用封丘石灰性潮土不同施肥措施下的长期定位试验数据,选取CK、NPK、1/2NPK+1/2OM、OM4个处理,分析了15年来作物产量及土壤有机碳(SOC)的变化特征,并用DNDC模型预测了试验地近100年(2000~2099)的SOC变化趋势。结果表明,各施肥处理的多年产量平均值和对照处理差异显著;施用化肥(NPK和1/2NPK+1/2OM)处理和有机肥(OM)处理间也有显著差异;产量最高为NPK处理,达10811 kg/ha,CK处理最低,但1/2NPK+1/2OM处理产量与NPK处理无显著性差异。15年来土壤耕层(0—20cm)有机碳平均值,以OM处理最高,达到7.90 g/kg,显著高于1/2NPK+1/2OM、NPK处理;而CK处理仅为4.15 g/kg。从15年来有机碳的变化看出,CK处理略有下降,NPK处理较为平稳,而1/2NPK+1/2OM和OM处理呈现不断上升趋势,OM处理上升幅度较1/2NPK+1/2OM处理大。对试验地SOC变化趋势长期(100a)的模拟结果显示,与初始土壤SOC含量相比,100a后不施肥处理(CK)土壤有机碳含量下降了52%,化肥(NPK)处理土壤SOC含量较为稳定,而1/2NPK+1/2OM处理和OM处理土壤有机碳增加明显,大约25a后基本上稳定,100a后分别较2000年增加了24%和25%。从实测数据的分析和DNDC模型模拟分析可以看出,有机肥和化肥配施能获得较高作物产量,并能有效地增加土壤SOC含量,从而提高土壤的可持续利用能力。

Simulating trends in soil organic carbon of in calcareous fluvo-aquic soil under long-term fertilization using the DNDC model

The objectives of this paper were to study the variation of soil organic carbon and the application of DNDC model under the long-term different fertilization. Based on the data available of pre-set long-term experiment, four treatments (CK、NPK、1/2NPK+1/2OM、OM) were chosen to study the characteristics of crop yield and content of soil organic carbon(SOC) variation. The trend of SOC in Fengqiu was also simulated by DNDC model with a time scale from 2000 to 2099. The results were as follows: there was a significant difference on average production between fertilization treatments and control. Application of chemical fertilizer (NPK、1/2NPK+1/2OM) increased yield compared to single application of manure, with the highest yield was observed for NPK (10811 kg/ha); However, no significant difference between NPK and 1/2NPK+1/2OM, and the lowest occurred in CK was observed. The content of average SOC in OM was the highest (7.90 g/kg), followed by NPK and 1/2NPK+1/2OM. The lowest SOC was found in CK being 4.15 g/kg. With a time frame of 15 years, the content of SOC in CK decreased slightly, kept constant in NPK, while kept increasing in 1/2NPK +1/2OM and OM. The simulated results of SOC trend in Fengqiu with a time scale of 100 years showed that the content of SOC under CK decreased by 52% compared to initial content. Application of chemical fertilizer uniquely (NPK) could maintain constant, while it rose significantly under 1/2NPK +1/2OM and OM treatment in the first 25 year, then it kept stable. The content of SOC increased by 24% and 25% compared to that in 2000 year, respectively. It could concluded that combined application of manure and chemical fertilizer could increased yield and SOC content in the soil, hence, improve the sustainable utilization of soils.