Managing clubroot disease (caused byPlasmodiophora brassicaeWor.) by exploiting the interactions between calcium cyanamide fertilizer and soil microorganisms

Abstract

SUMMARYCalcium cyanamide is a nitrogenous fertilizer used predominantly for over a century in field and glasshouse vegetable and salad production. The current review draws together, for the first time, knowledge concerning the biological properties of the compound that benefit crop production by encouraging sustainable soil health and quality. This is achieved through the increase of microorganisms antagonistic to plant pathogens. The review also reports on the natural occurence and degradation of cyanamide. The literature survey provides a perspective of research from the early 1900s to current studies. This identifies that nitrogen is released steadily into the rhizosphere from this fertilizer. Calcium is also readily available for plant roots and promotes the alkaline soil conditions beneficial to benign microorganisms. Consequently, soil suppressiveness towards organisms such asPlasmodiophora brassicae, the cause of clubroot disease in brassicas, develops. The effects of calcium and accompanying changes in soil pH values are discussed in relation to the life-cycle stages ofP. brassicaeand the development of clubroot disease. Formulations of calcium cyanamide contain the dimeric form, dicyandiamide. This compound slows soil nitrification and subsequent nitrate leaching into ground waters, reducing potential pollution. Calcium cyanamide is normally used for growing specialized fresh produce and is not available in quantities comparable with ammoniacal fertilizers. It is contended, however, that it has properties deserving wider assessment because of their implications for sustainable cropping.

Trichoderma harzianum Inoculation Reduces the Incidence of Clubroot Disease in Chinese Cabbage by Regulating the Rhizosphere Microbial Community

“…Current methods to control P. brassicae include crop rotation [ 10 , 11 ], liming [ 12 ], and agricultural chemicals such as quintozene, chlorothalonil, flusulfamide and fluazinam [ 13 , 14 , 15 ]. Although chemical methods can be effective, they have drawbacks associated with fungicide resistance, chemical pollution and impacts on food quality [ 16 ].…”

Control Strategies of Clubroot Disease Caused by Plasmodiophora brassicae

“…One reason is that the term “liming” means the application of different formulations of lime. Mostly lime with varying proportions of calcium carbonate (often mixed with Mg 2+ ) [ 50 , 51 ] cyanamide [ 33 , 48 , 52 ] is used. Moreover, a combination of calcium carbonate and calcium sulfate [ 53 ] or calcium hydroxide [ 48 ] is applied.…”

Core and Differentially Abundant Bacterial Taxa in the Rhizosphere of Field Grown Brassica napus Genotypes: Implications for Canola Breeding

“…Core bacteria with such antagonistic effects toward pathogens can be targets to enhance suppressive conditions in the rhizosphere. For instance, a suppressive environment in the rhizosphere can contribute to the failure of invasion and disease development by Plasmodiophora brassicae, the causative agent of clubroot disease (Mattey and Dixon, 2015;Dixon, 2017). Focusing on potentially coevolved core bacterial taxa with both antagonistic potential and a competitive advantage in the B. napus rhizosphere could be a strategy to boost the suppressive potential of the rhizosphere to provide a control approach for clubroot or other diseases.…”