Yield, nutritional and flavor quality of Chinese cabbage under different rates of chicken manure substituted for chemical fertilizer

Abstract

Combination of livestock manure (LM) with chemical fertilizer (CF) holds promise for obtaining high productivity. However, there is a relative lack of research on the impact of vegetable quality and its associated influences in the pursuit of high yields. The study aimed to investigate the effects of substituting chicken manure (CM) for CF on growth and quality (nutrition and flavor) of Chinese cabbage (Brassica rapa ssp. pekinensis) under the same nitrogen level. In general, CM substitution for CF recorded higher soil nutrients contents, head yield and phosphorus and molybdenum concentrations than sole application of CF. However, the concentrations of zinc, calcium, nickel, and lead decreased with CM application. Additionally, N concentration decreased by 47.1 % with sole CM application. Treatments had no significant effect on the concentrations of potassium, magnesium, iron, manganese, copper, boron, sodium, chromium, cobalt, arsenic, selenium, cadmium and on nutritional quality. We identified 454 volatiles, the primary percentages were esters (22.1 %), acids (14.3 %), and ketones (14.3 %). CM application inhibited the contents of total volatile and esters (especially isothiocyanates). When CM replaced CF at a rate of 2/3 and 3/3, the richness of volatiles dramatically increased. Furthermore, the Mantel test confirmed a strong correlation between volatile compound contents (VOCs) and soil C/N ratio, total nitrogen (TN), and available phosphorus (AP). Five volatiles (methanethiol, dimethyl disulphide (DMDS), 2-methyl-5-(1-methylethyl)-phenol, 1-propanethiol and dimethyl trisulfide) were collected as aroma compounds. With the CM application DMDS contents increased by 2.0–4.3-fold. Random forest model revealed a negative correlation between DMDS concentration and Ca level, possibly attributed to the decrease in allyl isothiocyanate content and the inhibition of TRPA1 transient receptor potential ion channel. In conclusion, precise adjustment of CM to CF substitution rates is essential for preserving Chinese cabbage yield and quality. This study could offer valuable insights for both nutraceutical and flavor purposes.