Abstract:

To explore the suitable fertilizer management mode under the condition of water and fertilizer integrated drip irrigation and to improve the yield and quality of leafy green vegetables in southern Jiangsu, taking conventional application of compound fertilizer as control, a pot experiment was conducted in 2020, and the effects of water-soluble fertilizer type and topdressing amount (450, 300, and 150 kg/hm²) on the growth, yield and quality of Brassica campestris ssp. chinensis var. rosularis were studied. Compared with the conventional application, water and fertilizer integrated drip irrigation under the same topdressing amount increased the leaf area of single leaf by 12.12%-20.40%, the chlorophyll content by 3.55%-4.82%, and the maximum root length by 9.67%. There was no significant difference in the average root diameter, and the yield increase could reach 39.8%. Under water and fertilizer integrated drip irrigation, the leaf area of single leaf and the maximum root length of B. campestris ssp. chinensis var. rosularis increased obviously with the increase of topdressing amount, the chlorophyll content, average root diameter, yield, dry matter weight and soluble solid content increased with the growth process, and tended to be stable in the later period, while the content of titratable acid showed an increasing trend, and the content of reducing sugar increased first and then decreased. Under water and fertilizer integrated drip irrigation, Qingshang water-soluble fertilizer was the most suitable for the growth of B. campestris ssp. chinensis var. rosularis, the leaf area of single leaf, the maximum root length and the yield index were all at the highest level, which were 66.07 cm², 31.3 mm and 475 g/plant, respectively. The water and fertilizer integrated drip irrigation could improve water and fertilizer use efficiency obviously, and guarantee plant quality and yield. Considering factors such as cost, quality and yield, applying 300 kg/hm² of water-soluble fertilizer Qingshang as topdressing was a suitable fertilizer management strategy for B. campestris ssp. chinensis var. rosularis.

Key words: water and fertilizer integration, Brassica campestris ssp. chinensis var. rosularis, topdressing amount, water-soluble fertilizer, yield, quality