Open access publications in the SLU publication database

Abstract

Three long term plant nutrient experiments in the south of Sweden are reported.Two experiments were started in 1951 and one in 1959. Variants with straw incorporation, straw removal and straw burning were compared at different nutrient levels. Effects on yields, development of soil C content with time, amounts of crop residues produced, earthworms and pests were investigated. Undisturbed soil cores were sampled and soil bulk density and porosity were determined. There are annual yield data and analyses from 1951 and onwards. Yield differences between treatments where the straw was burnt and where it was incorporated were small. But compared with treatments where all straw was removed a positive yield effect was measured. Continous incorporation of straw resulted in minor increases of soil C content compared to treatments with all straw removed. The difference was less than 0.5 percentage units of C. Burning straw on the field did not depress the C content. Soil bulk density and porosity were correlated to the soil C differences. The higher the bulk density, the lower the soil C content. For the porosity the contrary was true. The number of earthworms were the highest in a mixed rotation with ley and arable crops and application of FYM. In rotations where the straw was burnt and where the straw was incorporated the number of earthworms were low. Rotational effects on the existence of pests were unclear. In rotations with FYM the number of springtails were the highest but the number was not high enough to cause measurable damages