Unit 2.1 Field Operations
- Determine what farm practices use the most energy for producing a crop.
- Describe farm equipment options for reducing energy use.
- Describe management options for reducing energy use.
The combustion engines of tractors or self-propelled equipment such as combines, forage harvesters, or sprayers account for most of the direct energy used during field operations. Transmitting engine power as efficiently as possible for a particular task (pulling implements through soil, cutting plants, pumping, etc.) can make a significant difference in the amount of energy used, and therefore, to the cost of operations.
Some seeding, harvest, and weed or pest control is nearly always necessary. However, the type and frequency of tillage operations to prepare or weed a seedbed can vary. Row crops such as corn or soybeans may be produced with one or no tillage passes prior to planting. Establishment of perennial alfalfa and small grains traditionally used primary and secondary tillage operations. New no-till seeders with better seed bed preparation and seed placement have resulted in yields equal to stands established using conventional tillage. Factors in choosing tillage operations include comfort with a specific manage-ment style along with local soil, crop, and weather conditions. Successful reduced and no-till operations are often found in the same neighborhood as fields with more aggressive tillage schemes suggesting that options to reduce tillage frequently exist. For example, although surface cornstalks from the previous year can appear daunting, no-till soybean yields are frequently equal to those of full-width tillage systems in yield trials. So, before investigating specific ways to increase energy efficiency, it is important to decide whether the field operation is necessary. Increased engine efficiency may save up to 20 percent in fuel costs, but leaving the tractor parked saves 100 percent.
Other cultural or production schemes that generally increase efficiency may also reduce energy use for the amount of crop harvested. Narrow corn rows can help stimulate vegetative growth and increase potential harvested yield, particularly in northern areas of the Corn Belt. A leguminous cover crop can supply nitrogen to a subsequent crop, reducing the need for fertilizer nitrogen and associated transportation and application costs.