Browsing by Author "Asikainen, Aava"

Research on phosphorus (P) fertilization of white cabbage has been limited even though white cabbage is an important field vegetable in Finland. The quantities of phosphorus recommended in Finland when cultivating white cabbage are relatively large and excessive fertilization increases the risk of runoff to water systems. Scientific research is needed to determine fertilization levels that ensure good yields while reducing risks to the environment. The effects of P fertilization on yield, phosphorus uptake and phosphorus balance of white cabbage were studied in two soils of different P status in Piikkiö, Finland. The experiment on soil with loamy sand texture and high P status consisted of four fertilization treatments between 0-32 kg P ha-1 while the experiment on clay parcel with relatively low P status consisted of five treatments between 0-100 kg P ha-1, including a starter treatment. Yield, plant P content and P uptake were unaffected by the treatments. Yield was 83-87 t ha-1 on high P soil and 66-69 t ha-1 on low P soil. In high P soil, uptake of P by the plants was 50 kg ha-1 and field P balance was negative in all treatments. In low P soil, uptake was 40-45 kg ha-1 and P balance was positive starting from treatment level 30 kg P ha-1. It is likely that P fertilization levels based on the maximum limits set by the national Agri-environmental Programme are unnecessarily high for white cabbage. A level of fertilization equaling the P uptake of the yield can be recommended.