Ecophysiological Responses of White Clover - Hybrid Ryegrass Mixture to Foliar Fertilisation

Abstract

The rationale of the study was to check whether the association of hybrid ryegrass with white clover owing a moderate competition capacity, and optimal foliar fertilization will provide high and stable yields by reducing conventional fertilization rates. The experiment was carried out during two years of cropping with six growth cycles in a randomized block design with three replicates in Targoviste Piedmont Plain, South of Romania. In the first year, the plots received no nitrogen fertilisers in order to allow the biological potential development. In the second year, foliar fertilisation was applied six times in the fertilised variants during the vegetation season. The comparison between the six growth cycles showed that the biological potential of white clover in pure stand without foliar fertilisation was higher in the first cropping year than in the second one. Application of foliar fertilisation treatments enhanced the competition capacity of the hybrid ryegrass in the first production cycle of the second year. In white clover pure stand, the fertilisation increased the assimilatory areas from 3.6 to 4.8 (p<0.05). The contribution of hybrid ryegrass to the cumulative Leaf Area Index of species in the binary mixture was significant (4.7 no fertilisation; 4.9 foliar fertilisation), which revealed a low competition capacity of white clover in mixture (0.69 no fertilisation; 1.03 foliar fertilisation). In white clover-hybrid ryegrass mixtures, foliar fertilisation showed benefits in the first two growth cycles according to the phenophase particularities and weather conditions.