Research and Extension of Ag-lime Application in Sichuan

Acidification of vegetable-producing soils is a common problem world-wide and generally is the result of prolonged reliance on heavy dressings of nitrogen (N) fertilizers. Clubroot disease, a common problem in crucifer vegetables, is attributed to soil acidity. The disease is widespread in the Chengdu vegetable production region and is especially destructive for some crop species (e.g. mustard) and can be corrected through the application of optimal rates of agime which, in combination with balanced fertilizer use, will improve crop profitability. This is the goal of field research at Peng County.

Soil pH 6.0 provided the most ideal environment for clubroot development in cabbage. Soils with pH levels adjusted above 6.5 showed significantly less disease incidence. Significantly higher cabbage yields were obtained with 1.5 t/ha of calcite limestone alone. Aglime use in combination with N, phosphorus (P), potassium (K)...180-90-150 kg N-P₂O₅-K₂O/ha...increased cabbage yields by 35 to 46% (105 to 126 t/ha) compared to yields obtained with typical farmer practices (68 t/ha).

Harvest field days and news media coverage have provided the local government and farmers with a better understanding of the problem and, as a result, they are promoting this technology to farmers and recommending its use in their vegetable fields. This technology is applicable to large areas of acid soils in southwest China including Sichuan, Chongqing, Yunnan, and Guizhou. The potential for better vegetable yields is tremendous. Sichuan-15