[The influence of differentiated nutrition with nitrogen and of forecrop on the productive and qualitative properties of string beans]

Investigation of the inluence of forecrops(FC) and N fertilizer (30,60,90 and 120 kg N/ha) on the productive properties of string beans was performed upon Wavero, Koralle, Harvester and Niagara 773 varieties. FC was pea or spring barley. All variants and control were fertilized with 90 kg P2O5/ha and 70 kg K2O/ha. The vegetation length (VL) depended on the variety, N dose, FC and weather conditions (WC). Varieties had longer VL after barley than after pea. Increased N doses and WC influenced notably VL and had very strong positive effects on the number of pods per plant. Pea was a better FC. Interaction of the year and variety was found in both FC. Pod mass depended on the variety, N dose, FC and WC and interaction of variety and year and of fertilization and year was found. N dose effect was very important. Specific variety qualities (SVO) concerning genetic yield potential were shown. The pod yield varied, depending on FC. Pea was a better FC and the yield differences were significant. Very important effect of increased N doses on the pod mass was found, influenced largely by WC. SVQ, regarding genetic yield potential were noted by the years, as well as by FC. Variations of pod yield were smaller with barley than with pea. Low N doses had a weak and too high ones a harmful effect on the yield increase. N had varied effects, depending on FC, being higher with barley. Increased N doses influenced notably the dry matter content which increased with higher N doses, being the highest with 120 kg N/ha. With increased N dose the relative protein content in pods and the protein yield per ha increased. Pea was a better forecrop for protein content. Regarding sugar content, no notable differences among fertilization variants were for cellulose content. Increased N doses did not have a notable effect and barley was a better FC. Vitamin C content varied, depending on the variety and year.