Effects of the application of a special manure and a soil amendment on Club root disease [Plasmodiophora brassicae] of cruciferous species

The experiments were made to examine the effects of the application of a special manure: Green Rise, a fermented Tofu residue, and a soil amendment Carus NR-c, a fermented product of anaerobic bacteria on the occurrence of Club root disease caused by Plasmodiophora brassicae Woronia. Two cole plants Brassica oleracea L. var. gongylodes L. cv. Ground Duke and B. rapa L. cv. Narusawana were used and planted in 2-year and 3-year continuous cultivations, respectively. Treatments were designed in 6 plots as follows: 1) Control plot (CON) a compound fertilizer was applied at rate of 100 kg/10a, including 16, 17, and 17% of nitrogen, phosphorus, and potassium, respectively. 2) PCNB plot (PCNB); application of the fertilizer was the same as CON plot, except that fungicide PCNB was applied at a rate of 20 kg/10a. 3) Green Rise 300 kg plot (G300); green Rise was applied at the rate of 300 kg/10a in '90 and '91. However, a compound fertilizer was applied at the rate of 100 kg/10a in 1992. 4) Green Rise 500 kg plot (G500); the application was the same as that for G300 plot, except for the application of 500 kg/10a of Green Rise. 5) Carus NR-c 20 kg. plot (NR20); 20 kg of Carus was applied together with 2 tons of fresh compost (excrements from a pigsty) and 500 kg of chaffs in '90 and '91. However, the fertilizer was applied at the rate of 100 kg and 66 kg/10a in each case of B. oleracea and B. rapa in 1992, respectively. 6) Carus 30 kg plot (NR30); the application was the same as NR20 plot, except that it wa supplied at a rate of 30 kg and 3 t/10a of CArus and the compost, respectively. The results showed that the incidence of Club root disease was increased by the application of Green Rise and Carus NR-c for 3 years. However, there was no visible injury on the fifth crop of continuous cultivation of cruciferous crops. It is thought that this is due to high pH of each plot