Effects of soil compaction on soil physical properties and nitrogen, phosphorus, potassium uptake in wheat plants

The field experiments were conducted in 2006 and repeated in 2007. The effects of soil compaction on physical properties and nutrient uptake in plants were studied. In the experiments, soil was tilled by rotary tiller at the depth of 10 cm, and compacted by holder/ walking tractor, wheel tractor and crawler tractor in one pass (T1), two passes (T2) and four passes (T3), while no compaction (T4) was applied as control. The topsoil (0～5 cm) was re-tilled by rotary tiller; and Nanjing-601 was sown by grain drill. Compaction of the subsurface soil significantly affects subsurface soil bulk density, soil porosity, grain protein content, content of N, P, K in plants (%). The maximum values of above parameters were recorded by T4 and the minimum ones by T3 except subsurface soil bulk density which the maximum value was recorded by T3 and the minimum by T4. Almost all parameters except bulk density of showed a decreasing trend with the increasing of subsurface soil compaction. However, slightly higher values were observed during the second year of experiment as compared to the first year. In a word, soil compaction badly affects the soil structure and unfavorable to nutrient uptake in wheat plants.