Effect Of Biochar On Growth And Clubroot Of Brassica Campestris L.ssp. Pekinesis (Lour) Olsson

Clubroot has become one of the main soil-borne disesse. In recent years, the trend of the clubroot harmfulness in China was increasing year by year. Biochar used as a soil amendment, is beneficial to increase soil fertility and crop yield, due to physicochemical properties and the rich carbon product under anoxic and pyrolysis condition. There are research show that biochar play a positive role in controlling several soil-borne diseases, and probably could be the solution of the clubroot problem too. A pot experiment was carried out to study the effects of biochar on clubroot and seedling growth of Chinese cabbage [Brassica campestris L. ssp. pekinesis (Lour) Olsson] by using three cultivars and two kinds of biochar, through the indexes of substrate physicochemical properties, seedling growth and clubroot incidence. The main results as follow:1. Compared with conventional nursery substrate, additions of biochar significantly increased porosity, pH, total carbon, total potassium, available potassium by 42.06%,50.77%,265.7%,109.5% and 297.2%, respectively. It also decreased total phosphorus, alkali hydrolyzable nitrogen and available phosphorus by 51.77%, 44.79% and 53.48%.2. In the first part, peanut shell biochar mix with conventional nursery substrate at equal volume showed the greatest values in seedling height, stem diameter, chlorophyll content, fresh weight, dry weight and robust seedling index, but the lowest seedling emergence rate. In the second part, peanut shell biochar mix with conventional nursery substrate in a ratio of 3:7 showed the greatest values in all seedling growth indexes and clubroot incidence.3. Compared with conventional nursery substrate, additions of biochar decreased the seedling emergence rate, showed the greater values in contents of total nitrogen, total phosphorus and total potassium, leading to greater growth of the seedlings, but the lower seedling emergence rate.4.The growth-promoting effect of peanut shell biochar was much better than that of maize straw biochar. Peanut shell biochar also increased the contents of chlorophyll in seedlings, but could also decrase the seedling emergence rate.5. The additions of biochar had a certain effect to clubroot. It could decrease the disease plants rate and disease index by 60% and 91.29%. Disease index was decreased with the addition increased.