The studies were conducted from 2012 to 2015 at the National Institute of Horticultural Research in Skierniewice, Poland. The aim of the research was to determine the yield of Chinese cabbage, its storage ability and nutritional value, depending on weed management methods used during cultivation. In the field experiments the following methods were compared: mechanical treatments, mechanical treatments + growth stimulators, soil mulching with black polypropylene, black polyethylene and biodegradable foil and hand weeding. After harvest the Chinese cabbage was stored at 0–2°C for 125–126 days depending on the year and after storage marketable and rotten heads were sorted. The percent of yellowed, rotten leaves in the total mass of the stored heads was also determined, as well as the natural weight loss. The chemical composition of Chinese cabbage was analyzed after harvest and after storage. The analyses included: dry matter, total sugars, vitamin C and soluble phenol content. After harvest the highest yield of Chinese cabbage grown in black polyethylene mulch was obtained. After storage the highest yield of marketable heads from cabbage mechanically weeded with additional application of biostimulator AlfaMax during cultivation was obtained. Chemical analyses showed that after harvest the highest dry matter, total sugars and vitamin C content were found in Chinese cabbage mechanically weeded and soluble phenols were the highest in non-weeded Chinese cabbage. After storage the highest content of dry matter was recorded in non-weeded Chinese cabbage, while total sugars were the highest in cabbage mulched with black polyethylene and biodegradable foil. Vitamin C was the highest in mechanically weeded and soluble phenols were the highest in hand-weeded cabbage.

The content of structural carbohydrates and lignin are important assessment criteria of the feed value of meadow plants. It is affected by many independent factors, including among others its development stage during the harvest as well as climatic conditions, especially the amount of rainfall. During the years 2014–2016, plant samples were harvested at weekly intervals, respectively five times from late April to late May. The effect of harvest date on cellulose, hemicelluloses and lignin contents was evaluated. The chemical composition of plants was varied, depending not only on harvest date but also on the year of study. Regardless of the course of meteorological conditions in subsequent growing seasons, the increase of cellulose (from 236.5 to 297.9 g∙kg–1 DM), hemicelluloses (from 159.3 to 210.8 g∙kg–1 DM), and lignin (from 31.5 to 43.1 g∙kg–1 DM) in the following dates of harvest were observed. These parameters were also positively correlated with the total rainfall from the begging of vegetation season to the date of plants sampling (R2 = 0.65, 0.12 and 0.44 for cellulose, hemicelluloses and lignin, respectively), and with the average daily air temperature in the moment of harvest (R2 = 0.66, 0.32 and 0.52 for cellulose, hemicelluloses and lignin, respectively). The cellulose and lignin content, regardless of the harvest date, were significantly higher in the first year of the study (2014), when moisture conditions for plant development were optimal.