Investigation into the Short-term Effects of Chipped Branch Wood (CBW) on Soil Fertility, Plant Growth and Soil Microbiology in an Agricultural Context
The principal objective of this project was to evaluate the short-term effects of CBW incorporation into soil in terms of soil fertility, plant growth and soil microbiology. Treatments consisted of a control, standard woodchip treatment (incorporation rate of 150m3/ha), woodchip + woodland litter incorporation treatment (woodland litter incorporation of 10-20g/m2), woodchip + fertiliser treatment (KNO3 applied at 50kgN/ha at start and a continuous fertiliser application treatment) and double woodchip treatment. Standard soil NO-3 tests were conducted to determine soil fertility. To assess plant growth and development, plant DW, S:R DW and plant K levels were measured Finally, microbiological analyses were carried out through serial dilutions and plate counts, with in-depth microscopy. Results indicated that there were obvious differences between treatments throughout the study period. In all measurements, woodchip treatments were found to have significantly lower values than the control. The exception to the rule was the WC + fertiliser treatment (continuous complete nutrient fertiliser application), which showed comparable results with the control. The addition of woodland litter did not seem to affect any of the soil fertility, plant growth or microbial measurements. The differences between the unfertilised woodchip treatments and the control were explained by a general nutrient deficiency resulting from a ‘dilution effect’ to soil nutrients by adding woodchips. This was further exacerbated by immobilisation of nutrients from the micro-organisms in the soil.