Soil movement and manure placement from liquid manure injection tools

Knowledge of soil movement, manure distribution in soil, and soil surface profile from liquid manure injection tools is important for modifying tool design and selecting the most effective tool to minimize agronomic and environmental concerns associated with liquid manure injection. In this research, both laboratory and field studies were conducted. A mathematical model was developed for manure distribution in soil for different manure delivery modes and micro-application rates. The predicted values were compared with the experimental results from the field study.;Field studies were conducted in clay soil to investigate manure distribution in soil, manure exposure to the surface, and odour emissions following injection. The same micro-rates as in the laboratory study and two different injection tools (furrower and disc) were used under field condition over two years and a manually tracing method was used for manure distribution measurement. Manure exposure study was conducted with one commercially available injection unit at three application rates (R1 = 28, R2 = 56, and R3 = 112 m3 ha-1) and two injection depths (D1 = 50 and D2 = 100 mm). The line-transect (LT) and image analysis (IA) methods were used to quantify manure exposure to the air. A wind tunnel and vacuum pump were used to collect odorous air samples in a 10 L Tedlar bags and odour concentration was determined by a dynamic dilution Olfactometer with six panellists within 24 h of sample collection.;Average soil forward movement increased significantly with injection depth and tool forward speed, but not with soil moisture content. Soil upward movement increased significantly with increased injection depth and soil moisture content, but not with tool forward speed. Lateral movement of soil increased significantly with tool forward speed only.;Both application rate and injection depth had significant effects on manure exposure. As the application rate increased from 28 to 56 and 56 to 112 m3 ha-1, manure exposure increased by 50 and 87%, respectively. In contrast, as the injection depth increased from to 150 mm, manure exposure decreased by 25%. Odour emission increased significantly with injection depth.;The low pressure soil aggregates delivery mode modelling efforts were only moderately successful in predicting manure distribution in soil. The results, however, can be used for selecting tool spacing to ensure the even distribution of manure. (Abstract shortened by UMI.).