Optimizing production by varying leaf number and stem density in high-wire cucumber

As earlier leaf removal experiments in tomato had shown that this improved dry matter partitioning to the fruits and production, a pilot experiment with high-wire cucumber was conducted in the spring and summer of 2016 at the experimental research facilities of Wageningen UR Greenhouse Horticulture. The five treatments were combinations of 3 or 3.5 stems m^-2, and 0, 16 or 33% leaf removal in head of the crop. The combination 3.5/0% was lacking. The experimental data were analysed with the INTKAM crop growth model. The total number of fruits m^-2 was the most important factor for production, which is determined by the optimal combination of stem density and assimilate supply. It is therefore important to grow the crop such that the maximum number of fruits with sufficient weight can be realized. Leaf removal in itself led to a slightly higher abortion, a lower development rate and therefore less axils, and a lower LAI with less light interception, and therefore produced less fruits and kilos. This, however, can be compensated with a higher stem density. It results in a crop with a normal LAI and architecture, combined with more axils m^-2 that can bear fruits. Production and light use efficiency increase. On the other hand, labour and the risk to harvest small fruits will increase.