Nitrate accumulation in the soil profile: Long-term effects of tillage, rotation and N rate in a Mediterranean Vertisol

作者：Lopez Bellido Luis; Munoz Romero Veronica; Lopez Bellido Rafael J

来源：Soil and Tillage Research, 2013, 130: 18-23.

DOI：10.1016/j.still.2013.02.002

• No-tillage
• Wheat
• Faba-bean
• Chickpea
• Sunflower
• Rainfed

Excessive application of fertiliser in agriculture can have detrimental effects, one of which is diffuse contamination with nitrates. An 18-year field study was conducted on a typical rainfed Mediterranean Vertisol to determine the effects of the tillage system, crop rotation and N fertiliser rate on the long-term NO3--N content in the soil profile (0-90 cm). The experiment was designed as a randomised complete block with a split-split plot arrangement and 3 replications. The main plots tested the effects of the tillage system (no-tillage and conventional tillage); the subplots tested crop rotation, with 2-year rotations (wheat-wheat, wheat-fallow, wheat-chickpea, wheat-faba bean and wheat-sunflower); and the sub-subplots tested the N fertiliser rate (0, 50, 100 and 150 kg N ha(-1)). The nitrate content increased with time. The tillage system showed an inconsistent effect on nitrates, although, overall, nitrate levels were higher under conventional tillage than with no-tillage. The wheat-faba bean rotation induced a larger accumulation of soil nitrates. Nitrates usually accumulated to a greater extent in the 30-60-cm depth of soil. As a rule, farmers should know the amount of residual N existing in the soil prior to crop fertilisation in order to avoid over-fertilisation.

• 出版日期2013-6