Some consequences of carbon sequestration in Luvisol, loam soil owing to long-term conservation tillage use

摘要

Contemporary farming practices deplete soil carbon, which in turn degrades soil quality, reduces productivity, and results in the need for more fertilization, irrigation, and pesticides. Conservation tillage farming with residue mulching, cover cropping, and other means of organic matter management would reverse these harmful effects (Franzluebbers, 2002). A thirteen-year field experiment has been running in a temperate semiarid climate, 338 m above sea level, with an mean annual air temperature of 8.2°C, and mean annual precipitation of 477 mm. The field site has a soil of clay-loam texture (Orthic Luvisol, FAO Taxonomy). In this field trial, winter wheat, spring barely, and pea are grown in short crop rotation. The stands of these crops are established by classic plough technology (PL), shallow tillage with chopped straw incorporation (ST) and direct drilling into non-tilled soil (NT), as well as direct drilling with mulch soil covering (NTM). After the harvest in the winter wheat plots, soil samples were taken for analyses. Before analysing the soil, these samples were adjusted by sieving and air-drying. Total carbon (TC) and total nitrogen (TN) hi the air-dried soil samples were determined on a VARIO MAX CMS analyzer. The aggregate stabilitywas determined using the Kemper & Koch method (1966).