THE IMPACT OF DIFFERENT SOIL MOISTURE CONDITIONS AND NITROGEN RATES ON FORAGE GRASSES PRODUCTIVITY
Keywords:clover, timothy, drought, waterlogging, aboveground biomass, root biomass
The vegetation experiment was performed in 2020. February - June Vytautas Magnus University, Academy of Agriculture, Open Access Land and Forest Research Center, Greenhouse. A mixture of herbs was chosen for red clover (‘Vyčiai’) and forage timothy (‘Gintaras II’). The experiment consisted of two factors: Factor A: Soil moisture conditions: 1. Lack of moisture (drought imitation); 2. optimal humidity regime; 3. excess moisture (soaking imitation); Factor B: Nitrogen fertilizer rate: 1. N25P60K90 (background fertilization); 2. N25P60K90 (background fertilization) + N60; 3. N25P60K90 (background fertilization) + N120. The experiment was performed in 4 replicates. In the drought simulation, the aboveground dry matter biomass of the clover and timothy mixture was found to be significantly lower compared to the optimal conditions and the aboveground dry biomass of plants grown in the soaking simulation, from 36.3 to 44.1% and from 44.2 to 47.2%, respectively. In drought and excess moisture simulations, increasing the rate of fertilizer caused additional stress to the plants, resulting in a significant reduction in the biomass of the clover and timothy mixture. In drought and soak simulations, a decreasing trend of root dry biomass was observed with increasing nitrogen rate in plants fertilized with increasing nitrogen rate. As the nitrogen rate increased in the drought simulation, the content of crude protein and crude fiber in the aboveground biomass of clover and timothy increased, but not significantly, and the content of green ash decreased significantly (3.9%).