耕地质量的概念和评价与管理对策

ttttt目的ttttt研究化肥减量配施有机肥(OF，80%化肥+有机肥)和生物有机肥(BIO，80%化肥+生物有机肥)对植烟土壤酶活性的影响。ttttttttttttt方法ttttt通过连续4年田间小区定位试验，采用归一化酶活性值探讨植烟土壤酶活性与土壤速效养分和活性有机碳的关系。ttttttttttttt结果ttttt在连续4年化肥减量20%条件下，化肥减量配施有机肥可明显增加烤烟产量，显著提高烟叶质量和产值，提高植烟土壤有机质和活性有机碳含量，显著提高植烟土壤酶活性。与常规施肥(CF，100%化肥)相比，OF处理的土壤脲酶活性、碱性磷酸酶活、脱氢酶活性和蔗糖酶活性分别显著提高了27.72%、11.11%、51.39%和14.12%；BIO处理的土壤脲酶活性、碱性磷酸酶活性、脱氢酶活性和蔗糖酶活性分别显著提高了27.72%、27.78%、58.51%和26.52%。
OF和BIO较CF相比归一化酶活性分别显著提高了 11.88%和19.88%。而BIO较OF 相比，归一化酶活性显著提高7.15%。相关分析表明：植烟土壤归一化酶活性与土壤速效养分和有机碳组分呈极显著正相关(P<0.01)。tttttttttttttttttt结论ttttt化肥减量20%配施生物有机肥对烤烟提质增效、改良植烟土壤结构效果较好。tttt

Soil organic C,nutrients, microbial biomass,and grain yield of rice (Oryza sativa L.) after 18 years of fertilizer application to an infertile paddy soil

tttttPurposetttttTo study the effects of different organic fertilizers (OF, organic fertilizer or BIO, bio-organic fertilizer) on the soil enzymes activity of flue-cured tobacco under chemical fertilizers reduction.tttttttttttttMethodtttttThrough four years field experiment, the normalized enzyme activity was used to discuss the relationship between soil enzyme activity and the soil available nutrient and between soil enzyme activity and soil organic carbon.tttttttttttttResulttttttUnder 4-years chemical fertilizer 20% reduction, combined application with different organic fertilizers could increase the yield and the quality of flue-cured tobacco, the soil organic matter, soil labile organic carbon and soil enzymes activity significantly. In comparison with the conventional fertilization (CF, 100% chemical fertilizer), the activities of soil urease, alkaline phosphatase, dehydrogenase and invertase of OF treatment increased by 27.72%, 11.11%, 51.39% and 14.12%, respectively. The activities of soil urease, alkaline phosphatase, dehydrogenase and invertase of BIO treatment increased by 27.72%, 27.
78%, 58.51% and 26.52% respectively. The normalized enzyme activities of OF and BIO increased by 11.88% and 19.88% respectively. The normalized enzyme activity of BIO was 7.15% higher than that of OF. Pearson correlation analysis showed that the soil normalized enzyme activity of flue-cured tobacco was extremely significantly related with soil available nutrient and soil organic carbon.tttttttttttttConclusionttttt20% chemical fertilizer reduction combined with bio-organic fertilizer is a better practice for improving soil fertility, yield and quality of flue-cured tobacco．tttt