长期不同施肥模式下南方水稻土有机碳的平衡特征

Balance characteristics of soil organic carbon under different long-term fertilization models in rice soil in South China

以水稻土长期定位试验为依托,设置8个施肥处理:CK(不施肥),N(施N 375 kg·hm^(-2)),NP(施N375 kg·hm^(-2)、P_2O_5187.5 kg·hm^(-2)),NK(施N 375 kg·hm^(-2)、K_2O 187.5 kg·hm^(-2)),NPK(施N 375 kg·hm^(-2)、P_2O_5187.5 kg·hm^(-2)、K_2O 187.5 kg·hm^(-2)),M(施有机肥22 500 kg·hm^(-2)),M+NPK(施有机肥22 500 kg·hm^(-2)、N 375 kg·hm^(-2)、P_2O_5187.5 kg·hm^(-2)、K_2O 187.5 kg·hm^(-2)),M+1.3NPK(施有机肥22 500 kg·hm^(-2)、N487.5 kg·hm^(-2)、P_2O_5243.75 kg·hm^(-2)、K_2O 243.75 kg·hm^(-2)),研究不同施肥处理12 a间土壤有机质的动态变化、有机碳的平衡、碳的固定与转化速率,以及土壤有机质与作物产量的关系。结果表明,不同施肥处理下,土壤有机质含量随时间推进整体呈上升趋势,有机无机肥料配施(M+NPK、M+1.3NPK)可显著(P<0.05)提高土壤有机质含量,M+NPK、M+1.3NPK处理的土壤有机质含量较CK分别提高17.9%和23.3%。各施肥处理下,土壤有机碳平衡均表现为盈余,有机碳平衡和有机碳投入呈线性相关,试验点有机碳平衡每年所需的最低有机碳投入量为1 660 kg·hm^(-2)。有机无机肥料配施能提高土壤有机碳的固定速率,且以M+1.3NPK处理下碳的固定速率最高。作物产量与土壤有机质含量表现为线性相关。以上结果表明,有机无机肥料配施可有效提高水稻土有机碳含量及其固定速率,并有利于作物产量提高,其中,以M+1.3NPK施肥方式效果最佳。

Based on the long-term fertilization experiment on rice soil,8 fertilization treatments were set,including CK(no fertilization),N(application of 375 kg·hm^-2 N),NP(application of 375 kg·hm^-2 N,187.5 kg·hm^-2 P 2O 5),NK(application of 375 kg·hm^-2 N,187.5 kg·hm^-2 K 2O),NPK(application of 375 kg·hm^-2 N,187.5 kg·hm^-2 P 2O 5,187.5 kg·hm^-2 K 2O),M(application of 22 500 kg·hm^-2 manure),M+NPK(application of 22 500 kg·hm^-2 manure,375 kg·hm^-2 N,187.5 kg·hm^-2 P 2O 5,187.5 kg·hm^-2 K 2O),M+1.3NPK(application of 22 500 kg·hm^-2 manure,487.5 kg·hm^-2 N,243.75 kg·hm^-2 P 2O 5,243.75 kg·hm^-2 K 2O).The dynamic changes of soil organic matter,soil organic carbon surplus,sequestration and transformation rate of soil organic carbon,the relationship between soil organic matter and crops yields in 12 years were investigated.It was shown that the content of soil organic matter under different fertilization treatments increased gradually in 12 years.The soil organic matter content in the treatments with both organic manure and chemical fertilizers were significantly(P<0.05)increased.The organic matter content of M+NPK and M+1.3NPK was increased by 17.9%and 23.3%,respectively,as compared with CK.Soil organic carbon surplus was positive under all fertilization treatments.There was a strong positive linear relationship between carbon input and carbon surplus,and the minimum annual carbon input was 1 660 kg·hm^-2 in the experiment site.The treatments with both organic manure and chemical fertilizers improved the annual carbon sequestration rate,and the treatment of M+1.3NPK showed the highest carbon sequestration rate.There was a positive linear correlation between crops yields and the soil organic matter contents in all treatments.It was concluded that fertilization with both organic manure and chemical fertilizers could increase soil carbon content and sequestration rate,and benefit the crop yield.M+1.3NPK was the best fertilization mode under the experiment conditions.