This dataset concerns a field experiment conducted at the Crop Research Unit of the University of Reading in UK  in 2019. Wheat plants were grown in field plots of 1.6 m2, and mulch of diverse plant residues of whole plants were applied. The purpose of the experiment was to assess the effect of quality, and diversity of plant residue mulch on N mineralization and on soil microbial biomass at later stages of decomposition, on crop plant quality, and on the quality of the crop residues at the end of the growing season. There were five different types of plant residues: i) Perennial rye grass (P) (1 plant species), ii) Smart grass (S) (6 plant species), iii) Biomix (B) (12 plant species), iv) Herbal mix (H) (17 plant species), and Wood chips (W), and there was also a Control treatment with no residues. Therefore, there were 6 different treatments in total in 5 replicates. Soil samples were collected on days 25, 52, and 90 after mulch application. The dataset consists of 3 parts: 1)	data relevant to the plant residues that were applied as mulch on the field plots, 2)	data relevant to the field soil, and 3)	data relevant to the wheat plants which were cultivated in the field plots.