|Douglas Jr, Clyde|
Submitted to: Pendleton Station Field Day
Publication Type: Experiment Station
Publication Acceptance Date: 5/1/1997
Publication Date: N/A
Interpretive Summary: Soil erosion in the dryland wheat land of the Pacific Northwest is a serious problem. Approximately 4.5 million acres are planted to winter wheat and an equal number of acres are left fallow each year. Land growing winter wheat has little cover to protect against soil erosion by water. To help protect our soil resource, we developed and tested a new method for farming wheat. It is the mow-plow sytstem. With it, we make use of the wheat straw that remaining from the previous harvest. Instead of plowing it under in preparation for fall seeding, it is cut with a header on the front of a tractor and moved to the soil surface to the side. The same tractor plows the soil as the residue is cut. Thus, the residue from one pass covers the soil that was plowed in the previous pass. To test the soil protection by this system, we artificially rained on plots with this farming method and two additional farming methods. The other methods are a current conservation farming practice and a traditional farming practice. We compared the amount of soil that washed from each. The mow-plow method was nearly as effective as the conservation farming method for controlling erosion. However, we found that straw on the soil surface alone does not guarantee soil erosion will be checked. The plant roots and crowns in the conservation method provide additional soil erosion control. If enough straw was used in the mow-plow system, it would become mixed in the soil, and act nearly as effectively as the roots and crowns in the conservation method. The mow-plow method will be a useful tool for farmers to use in there effort to control soil erosion.
Technical Abstract: Erosion in the dryland cropping areas of the Pacific Northwest (USA) occurs during low intensity rainfall on frozen soil. The problem is greatest in fields planted to winter wheat following summer fallow, of which there are approximately 4.5 million acres. We developed the mow- plow system help reduce erosion in these fields. A harvester-header is mounted on the front of a tractor to cut an sidecast residue onto adjacent moldboard plowed surfaces. The moldboard plow is pulled behind the same tractor. With each circuit of the field, residue is placed on the moldboard pass as a new ground is plowed. The purpose of this research was to evaluate mow-plow soil and water conservation. Rainfall was simulated onto four treatments, chisel plow (CP), moldboard plow (MB), mow-plow light residue (l)(Mpl), and mow-plow heavy residue (h)(MPh) after the soil had frozen to a depth of at least 6 inches and just beginning to thaw. Runoff samples were collected in 10 minute intervals for 90 minutes after runoff began. Runoff rates were not different between treatments. Erosion was highest in the MB and lowest in the CP treatments. Erosion rates in the MPh were only slightly higher than those of the CP. Erosion rates from the MPl were indistinguishable from either of the three treatments. The crowns and root structure left by CP appears to provided the most consistent erosion control. Residue in the Mph, incorporated by secondary tillage, provides better erosion control than either the MB or Mpl. We propose that the MPh be considered an alternative residue management system for erosion control.