| Popis: |
This thesis observed the effects of simulated winter warming, and cover crops planted between growing seasons on agricultural nitrate (NO3-) leaching. In a field study, using monolithic soil column weighing lysimeters with lower boundary controls to directly measure drainage, two soils to broaden the scope of this research, and soil solution NO3- concentrations from below the root zone were used to determine NO3- leached during the study period. NO3- leaching was significantly reduced by planting cover crops after harvesting the main crop by 69-77% depending on soil-type. Heaters were used to simulate warmer winters, which increased drainage, and soil NO3- concentrations below the root zone; however, the increase in drainage, and the increase in soil NO3- concentrations was separated temporally and did not have a significant effect on NO3- leaching. Observed effects of cover crops and warming on drainage, NO3- concentrations, and NO3- leaching are reported based on seasonal climatic variations. |
