Nutrient demand and uptake by pickling cucumber under drip irrigation in a northern climate.

摘要

A study was conducted in Finland during 2001-03 to develop a fertilizer application programme for pickling cucumbers when grown using a drip irrigation system. The specific objectives were to determine: (1) which nutrients are needed in fertigation (N and K vs. all nutrients), (2) the optimal level of N in pre-planting fertilizer application and fertigation, (3) whether it is useful to provide a starter fertilizer high in P, and (4) how much N, P and K is taken up by the plants. The cucumber cultivar used was Carine. A relatively low N level (120-140 kg/ha) was sufficient for a good yield under Finnish conditions. A higher N level may give a small increase in fruit yield, but only under warmer growing conditions. Moreover, 50-70% of fertilizer N and K should be added by fertigation, whereas other nutrients can be provided during pre-planting fertilizer application. Moderate pre-planting application is suggested because it enables a more flexible optimization of N application later in the season depending on other growth factors. Fertigation is not needed during the first 3-4 weeks after planting when nutrient uptake is still low. Addition of only N and K by fertigation was found to be sufficient if other nutrients were provided by pre-planting application and soil nutrient contents follow the recommendations. A starter fertilizer high in P is unlikely to be needed since cucumbers are usually planted in warm soil, which is kept moist. The N, P and K uptake per tonne of fruit was 1.2-1.4, 0.28-0.35 and 2.2 g, respectively, which were slightly lower than reported in earlier studies..