For cucumber grown in perlite, the 7:8 N:K ration proved to be the most efficient in terms of N use

In the present work, the effect of the N:K ration (expressed in mmol L-1) in the nutrient solution supplied on the nutrients absorption and bioproductivity of a cucumber (Cucumis sativus) crop cv. Borja growin in perlite in a greenhouse has been evaluated. The modification of the N:K ratio was performed when the crop had already reached a vegetative development with a LAI of 3.5, coinciding with the initiation of the harvest. Therefore, until 52 days after sawing, the N:K ratio in the supplied nutrient solution was 15:8 and from there on until the end of the crop cycle four different ratios were established: 14:8, 10:8, 7:8 and 10:6. Statistically significant differences were obtained both in fruit yield as well as in total fresh and dry matter production. The 10:8 and 7:8 N:K ratios provided a higher fruit production than the 14:8 and 10:6 ratios. As the N and K supply were decreased the use efficiency of these nutrients increased in terms of fruit production. The 10:8 N:K ratio contributed to a higher total dry and fresh matter production. The N absorption concentration (mmol of N absorbed per L of water consumed) was not affected when the N supply decreased from 14 to 10 mmol L-1 and was lower when supply was decreased to 7 mmol L-1. The K absorption concentration (mmol L-1) was decreased from 6.5 to 5.6 as the supply was decreased from 8 to 6 mmol L-1. These results indicate that the N reduction in the generative stage of the crop favours the fruit production. On the other hand, the reduction in the supply of K negatively affects the fruit production. The 7:8 N:K ration proved to be the most efficient in terms of N use and could be a good strategy contributing to a reduction in the use of N and its loss by lixiviation. ? Original title, authors and sourcesRespuesta del cultivo de pepino en sustrato a la relaci?n N:K en t?rminos de bioproductividad y eficiencia Evangelina Medrano; Pilar Lorenzo; M? Cruz S?nchez-guerrero; M? Luisa Garc?a; Iban Caparr?s; Francisco Jes?s Alonso VII Congreso Ib?rico de Agroingenier?a y Ciencias Hort?colas, Madrid, 26-29 agosto 2013 The picture is by www.scoop.it Key wordsPepino?? ?pepinillo?? ?cucumber?? ?komkommer?? ??????? ????? ?kukumo?? ?concombre?? ?????????? ???????? ??? ?cetriolo?? ?og?rek?? ??? ????????? ?salatal?k?? ??????? ?gurke?? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ??? ????