Conservation Tillage Systems in the Southeast

March through May

Overview

With spring planting, March through May is the busiest time of year on conventional farms, but this is not the case in conservation tillage systems. The elimination of most soil preparation tasks—harrowing, bottom plowing and bedding—saves a tremendous amount of time. Essentially, springtime comes down to just a few operations: terminating the cover crop or harvesting the small grain crop, fertilizing unless it was done in the fall, planting the cash crop, and pest management.

Cover Crop Termination

Cover crops are usually terminated with organic or conventional herbicides, by rolling/crimping, or by a combination of the two methods. Rolling/crimping is an excellent method to control weeds that may be less costly than herbicides alone. A roller/crimper flattens the cover crop and crimps (breaks) the plants to prevent regrowth. Maximizing biomass left on the surface from a terminated cover crop will help to block sunlight and to inhibit weed growth. Rolling/crimping a cover crop alone will kill it if the cover crop is mature. If the cover crop is immature, rolling/crimping may not kill it, so herbicides are often used as well, usually at a reduced rate (see Chapter 9).

Cover crops are normally terminated three to four weeks before cash crop planting. This allows time for them to die and dry out, making it easier for strip-till or planting equipment to cut through the residue. It also allows time for spring rains to replenish soil moisture and helps prevent pests such as cutworms from attacking the newly germinating cash crop. Terminating cover crops too early may allow weeds to emerge before cash crop planting. To avoid competition during cash crop emergence, kill all weeds before planting.

Fertilize Cash Crop

After cover crops are killed, it is time to fertilize for the cash crop if needed. Remember, fertilizer is surface applied, so there is no need to harrow it in. Fertilizers are spread with spreader trucks or broadcast spreaders. Base application rates on soil test results and any credits for nutrient release from decomposing cover crops or for nutrient fixation.

In-Row Subsoiling

Some Southeastern soils, notably in the Southern Coastal Plain, naturally compact and require in-row subsoiling. This is done after the cover crop has dried out and before or during planting. Use a soil penetrometer to identify soils that need in-row subsoiling and the depth of the compacted layer (see Chapter 6). Subsoil only if necessary and only as deep as necessary.

Plant Cash Crop

Planting the cash crop in a conservation tillage system is not much different from planting in a conventional tillage system. More time may be needed for the soil to warm up to the recommended planting temperature if the cash crop residue and/or cover crop residue blanket the soil. Use a soil thermometer to make sure conditions are right for cash crop planting. Delay strip-tilling if the residue is wet from morning dew or rain. This helps prevent problems with residue management. For example, wet residue may wrap around and get stuck in row cleaners. The row cleaners may need to be raised in these situations. Otherwise, follow normal planting procedures.

Conservation tillage equipment can be set up to strip-till and plant in the same operation or to strip-till and then plant in a separate pass. For small-scale farmers, the trend is to strip-till and plant in one pass to save labor and fuel (Chapter 9). Many large-scale farmers prefer to lay off or mark the rows in the field and then plant along those rows. In this situation, in-row subsoiling is done ahead of time, which helps with faster planting of large acreages.

Scout for Pests

Scout for weeds, diseases and insects during the spring. Manage them before they become a problem. A heavy cover crop residue will suppress weeds. This is especially important before the cash crop canopy is established.

Summary

Successful conservation tillage systems require good management and planning. As with all farming operations, timely decisions and applications are important. Due to the use of cover crops and the presence of crop residue, timeliness may be more important with conservation tillage than with conventional tillage. The dates for planting and harvesting cash crops and cover crops are interrelated. The interrelationship is discussed in the following chapters. The impact of local conditions on decision-making is included in the discussion in chapters 17–20. With conservation tillage systems, it is never too early to make plans and get started.

Download the table from Chapter 4.

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