利用meta分析研究水田土地利用方式下化肥对土壤有机碳含量的影响。结果显示:长期施用化肥处理的表层水稻土土壤有机碳含量较不施肥处理显著提高1.00±0.23 g kg-1,是不施肥处理的1.06倍±1.01倍。分析认为施肥处理下,较高的根...利用meta分析研究水田土地利用方式下化肥对土壤有机碳含量的影响。结果显示:长期施用化肥处理的表层水稻土土壤有机碳含量较不施肥处理显著提高1.00±0.23 g kg-1,是不施肥处理的1.06倍±1.01倍。分析认为施肥处理下,较高的根系生物量导致较高的碳输入水平,另外相对充足的养分供应提高土壤固碳效率,这是施肥处理下土壤具有较高有机碳含量的两个原因。但不同轮作制度下,化肥对有机碳含量提升作用有差异:稻-稻-旱轮作制下化肥的作用不显著,而稻-旱轮作与稻-稻轮作制度下化肥对有机碳含量的提升作用显著。方差分析发现相同施肥措施下,稻-稻-旱轮作体系下土壤有机碳含量在三种轮作制度中最高,而稻-旱轮作与稻-稻轮作没有显著差异。尽管施用化肥能增加土壤有机碳含量,但评价施用化肥对温室效应的影响还需要综合考虑化肥生产、运输与施用过程中的温室气体排放三要素。展开更多
The accelerated expansion of swine production in Brazil has increased the generation of liquid wastes, which are usually applied to agricultural soils after a simplified treatment and pose potential environmental impa...The accelerated expansion of swine production in Brazil has increased the generation of liquid wastes, which are usually applied to agricultural soils after a simplified treatment and pose potential environmental impacts. The objective of this study was to assess the agronomic and environmental impacts of long-term application of swine slurry(SS) on soil and stream water properties in watersheds dominated by Oxisols in Quinze de Novembro of Southern Brazil. Soil samples(0–30 cm) were collected from farms with continuous application of SS since 1990 at low(40–80 m3 SS ha-1year-1) and high(120–300 m3 SS ha-1year-1) rates of SS. Surface water samples were collected from streams adjacent to the farm fields. Long-term SS application did not change total organic C and particulate organic C compared to cropland and woodland soils without SS application. The high rates of SS increased total N, P, Cu,and Zn and available P and Cu in the topsoil(0–10 cm) compared to woodland and cropland soils without SS application. Surface water analyses showed that fecal coliform bacteria and biological oxygen demand exceeded the legal limits for high quality water(Class 1). Other water parameters(such as NO-3, phosphate and total suspended solids) were within the acceptable limits. Long-term disposal of SS in cropland under no-tillage had impaired water quality in Quinze de Novembro, especially biological parameters. Some best management practices should be adopted, including more rigorous control of SS application to cropland as well as requiring edge-of-field and riparian vegetative buffers.展开更多
文摘利用meta分析研究水田土地利用方式下化肥对土壤有机碳含量的影响。结果显示:长期施用化肥处理的表层水稻土土壤有机碳含量较不施肥处理显著提高1.00±0.23 g kg-1,是不施肥处理的1.06倍±1.01倍。分析认为施肥处理下,较高的根系生物量导致较高的碳输入水平,另外相对充足的养分供应提高土壤固碳效率,这是施肥处理下土壤具有较高有机碳含量的两个原因。但不同轮作制度下,化肥对有机碳含量提升作用有差异:稻-稻-旱轮作制下化肥的作用不显著,而稻-旱轮作与稻-稻轮作制度下化肥对有机碳含量的提升作用显著。方差分析发现相同施肥措施下,稻-稻-旱轮作体系下土壤有机碳含量在三种轮作制度中最高,而稻-旱轮作与稻-稻轮作没有显著差异。尽管施用化肥能增加土壤有机碳含量,但评价施用化肥对温室效应的影响还需要综合考虑化肥生产、运输与施用过程中的温室气体排放三要素。
基金Support by the National Research Council of Brazil(No.482029/2010)
文摘The accelerated expansion of swine production in Brazil has increased the generation of liquid wastes, which are usually applied to agricultural soils after a simplified treatment and pose potential environmental impacts. The objective of this study was to assess the agronomic and environmental impacts of long-term application of swine slurry(SS) on soil and stream water properties in watersheds dominated by Oxisols in Quinze de Novembro of Southern Brazil. Soil samples(0–30 cm) were collected from farms with continuous application of SS since 1990 at low(40–80 m3 SS ha-1year-1) and high(120–300 m3 SS ha-1year-1) rates of SS. Surface water samples were collected from streams adjacent to the farm fields. Long-term SS application did not change total organic C and particulate organic C compared to cropland and woodland soils without SS application. The high rates of SS increased total N, P, Cu,and Zn and available P and Cu in the topsoil(0–10 cm) compared to woodland and cropland soils without SS application. Surface water analyses showed that fecal coliform bacteria and biological oxygen demand exceeded the legal limits for high quality water(Class 1). Other water parameters(such as NO-3, phosphate and total suspended solids) were within the acceptable limits. Long-term disposal of SS in cropland under no-tillage had impaired water quality in Quinze de Novembro, especially biological parameters. Some best management practices should be adopted, including more rigorous control of SS application to cropland as well as requiring edge-of-field and riparian vegetative buffers.
