Effect of no-tillage on nutrient content and organic matter of the soil.

摘要

In the long-term field trial "Oberacker" at Zollikofen (Switzerland) the content of organic matter and macro-nutrients in the soil was analysed to compare the effect of no-tillage without any soil disturbance to conventional tillage with mouldboardplough. The amount of nitrogen mineralised during the year was similar in both treatments. However, nitrogen mineralisation in spring was delayed due to lower soil temperature and higher soil water content in no-tillage plots. As a consequence, spring-planted crops showed a slower plant development during their early growth stages. Under these conditions an application of a starter fertiliser may help to promote early plant development, more so, as root growth may be also reduced due to the higher bulkdensity of no-tillage soils. In contrast, under winter cereals, soil content of mineral nitrogen in spring was almost the same for both treatments, implying that no special nitrogen fertilisation strategy is required. Five years after the start of the field trial, the amount of organic matter in the top-soil (0-20 cm) with no-tillage had increased by 6.8 t*ha-1 or 10% as compared to conventional tillage. This augmentation was mainly observed in the top 10 cm of the soil, whereas in the 10-20 cm soil layer, the content of soil organic matter in no-tillage did not increase. Nevertheless, there is still a lack of information whether the combined effects of increased content of organic matter and nitrogen in the soil result in a higher nitrogen mineralisation, which would allow a reduction of nitrogen fertilisation in no-tillage as compared to conventional tillage.