Thursday, October 3, 2013

Fall Tillage Management

This article was originally written for and distributed to farmers and other members of the agricultural industry in western New York.

As the crops come off the fields, many tillage operations will take place this month across western New York. Fall tillage operations are often needed to manage residue, smooth out ruts in the field, dry out the soil, in addition to incorporating lime, fertilizer, and manure. A number of best management practices can be used to greatly reduce the risk of soil erosion.

Plant a Cover Crop
In October winter rye is the only reliable crop that will provide some cover over the winter. Many farmers in the region have successfully planted this crop after their fall tillage operations. Very few growing degree days are left so plant as soon as possible with a drill and increase the seeding rate from 2 bu/A to 3 bu/A. Timely spraying or spring tillage will be necessary to effectively control this cover crop. With warmer weather during the early part of the month, plantings of winter triticale and winter barley have a better chance of establishment before the winter.

Increase Surface Residue
Increasing the surface residue to 30% ground coverage from 0% results in a 50% decrease in soil erosion, Figure 1. Smaller decreases in soil erosion occur as more residue is left in the field. Managing low residue levels is easier than large amounts of corn stalks, straw, and other material in the spring while greatly reducing soil loss.

Figure 1: Effect of residue cover on soil erosion, expressed as the percent of that occurring relative to that for a bare surface. 
Adapted from Laflen and Colvin (1981).

Till on a Contour
If ground must left open over the winter without much residue or a cover crop, tilling on a contour perpendicular to the direction of run-off can reduce soil erosion, Figure 2. In some parts of western New York strips of crops are still planted on the hill contours to further prevent erosion losses. However there are still soil erosion losses during the tillage operations on the sides of hills. Adopting reduce tillage practices on the hill-slopes will further decrease soil losses.

Figure 2: Farming on the Contour

Changs Tillage Equipment
Every piece of tillage equipment has a different impact on soil erosion. Often there is another piece of iron that can meet your needs while reducing erosion. Check out the NRCS’s Tillage Guide (|7) for more information. Using shallow tillage at an angle across the field can fill in ruts from previous field operations while reducing the destruction of soil structure. Vertical tillage equipment has become popular in recent years due to their shallow tillage of the soil while preparing a desirable seedbed.  Soil with good structure is more resistant to erosion. This is due to root channels from previous crops, some residue on the soil surface, and high populations of earthworms (and other animals) that create channels for water to flow more quickly through the soil ultimately resulting in less soil erosion.

Bottom Line:
1. Farmers can minimize soil erosion caused by fall tillage by planting cover crops, leaving some residue, tilling/farming on a contour, and changing the piece of tillage equipment used. 

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