Phytopathology. 1998 Apr;88(4):300-5. doi: 10.1094/PHYTO.1998.88.4.300.
ABSTRACT The effect of a soil amendment (SA) composed of urea (200 kg of N per ha) and CaO (5,000 kg/ha) on the survival of Ralstonia solanacearum in four Philippine soils was investigated in a series of laboratory experiments. Within 3 weeks after application, the SA either caused an initial decrease, a final decline, or no change in the pathogen population, depending on the particular soil type. An initial decrease occurred in a soil with a basic pH and resulted in a significantly (P < 0.001) lower pathogen population immediately and at 1 week after amending the soil. This decrease was probably due to the high pH in the soil during urea hydrolysis. A final decline in the R. solanacearum population after 3 weeks occurred in two soils in which nitrite accumulated after 1 week. In these soils, no decline in bacterial levels occurred when nitrite formation was inhibited by 2-chloro-6-trichloromethylpyridine. In the soil with low pH, no nitrite accumulated and the R. solanacearum population did not decline. The suppressive effects of pH and nitrite on R. solanacearum growth were confirmed by in vitro experiments. Ammonium reduced the growth of R. solanacearum, but was not suppressive. Interactions of pH with ammonium and nitrite also occurred, whereby ammonium reduced growth of R. solanacearum only at pH 9 and nitrite was suppressive only at pH 5. Nitrate had no effect on R. solanacearum growth in vitro.
本研究通过一系列实验室实验，调查了由尿素（每公顷 200 公斤 N）和 CaO（每公顷 5000 公斤）组成的土壤改良剂（SA）对菲律宾四种土壤中青枯菌存活的影响。在施用后 3 周内，SA 要么导致初始减少，要么导致最终减少，要么不改变病原体种群，这取决于特定的土壤类型。在 pH 值较高的土壤中，初始减少发生，并且在土壤改良后立即和 1 周后，病原体种群明显（P < 0.001）降低。这种减少可能是由于尿素水解过程中土壤的高 pH 值所致。在两种土壤中，一周后亚硝酸盐积累，三周后青枯菌种群最终下降。在这些土壤中，当通过 2-氯-6-三氯甲基吡啶抑制亚硝酸盐形成时，细菌水平没有下降。在 pH 值较低的土壤中，没有亚硝酸盐积累，青枯菌种群也没有下降。pH 值和亚硝酸盐对青枯菌生长的抑制作用通过体外实验得到了证实。铵减少了青枯菌的生长，但没有抑制作用。pH 值与铵和亚硝酸盐之间也存在相互作用，只有在 pH 值为 9 时，铵才会减少青枯菌的生长，只有在 pH 值为 5 时，亚硝酸盐才具有抑制作用。硝酸盐对青枯菌的体外生长没有影响。
