Friday, July 8, 2011

Cover Crops

I am already thinking about my cover crop needs at harvest. I want to have the seed on hand and ready to plant right behind the combine this fall.

It's going to be a late harvest so my best bet is rye again or maybe triticale. Triticale seed is high priced because it's in high demand for dairy operations and makes good green chop.

The cover crops really helped my soil this winter and kept the beneficial mycorhizae fungi alive and good bacteria compared to the barren fields that got flooded and eroded. It's and extra cost and a lot of work but I see the benefit in it.

I had 110 acres of headed out rye but it was pretty sparse in places and we didn't have time to run the combine over it and I didn't want to wait to plant the soybeans into to for it to fully mature.

I like it even more when you can harvest it like the picture but double cropping is hard to do and a little risky. It helps me keep the soil covered while generating as much gross income as one crop.

No wonder I saw the benefit of T-22 trychaderma fungus all these years and use the latest version called SabrEx today. Radishes in my wheat increased yield 9.6 bu in trials and SabrEx increased yield 12.3 bu.

I really see the benefit of keeping my fields green all the time as the soil is healthier and it takes less fertilizer and chemical to raise a good crop. I haven't seen the need for fungicide except for on the seed, when it is most vulnerable.

Vern Grubinger has a good sheet on rye in Vermont. "WINTER RYE: A RELIABLE COVER CROP."
Why Rye? Cereal rye is an excellent winter cover crop because it rapidly produces a ground cover that holds soil in place against the forces of wind and water. Rye’s deep roots help prevent compaction in annually tilled fields, and because its roots are quite extensive, rye also has a positive effect on soil tilth.

Compared to other cereal grains, rye grows faster in the fall and produces more dry matter the following spring--up to 10,000 pounds per acre, although 2 tons is more typical in the Northeast. Rye is the most winter-hardy of all cereal grains, tolerating temperatures as low as -30°F once it is well established. It can germinate and grow at temperatures as low as 33°F, but it sure won’t grow very much when it’s that cold.

When sown in late fall, around the time of the first light frost, winter rye is still able to put on just enough growth to provide some protection against soil erosion over the winter. High seeding rates should be used for late-sown winter covers to assure a decent amount of ground cover, since individual plants will be small.

Growing Rye. Cereal rye thrives on well-drained loamy soils but it’s tolerant of both heavy clays and droughty, sandy soils. Rye can withstand drought better than other cereal grains, in part because of its prolific root system. It grows best with ample moisture, but excessive rainfall can suppresses subsequent vegetative growth and flooding can it. Rye can grow in low-fertility soils where other cereal grains may fail. Optimum soil pH is 5.0 ­ 7.0, but pH in the range of 4.5 ­ 8.0 is tolerated.

Suggested seeding rates are 1 to 2 bushes per acre if drilled, 1.5 to 3 bushes per acre if broadcast and lightly tilled in. A bushel of rye is said to weigh 56 pounds. It’s best to use seeding rates on the high side if planting into a rough seedbed, seeding late in the fall when growing time will be limited, or trying to establish rye on a field that has a high potential for erosion. Rye is more sensitive to seeding depth than some other cereals, and it should not be sown more than 2 inches deep.

Rye will often respond to a modest application of nitrogen (N) fertilizer, but when it follows corn and other crops that have been well-fertilized with N it seldom requires additional fertilizer. Rye has a good ability to scavenge residual soil N when it follows other crops, and it is commonly grown for this purpose. This reduces the potential for nitrate leaching into groundwater and it conserves N fertilizer inputs, which saves money.

Flowering in rye is induced by 14 hours of light in spring. Vegetative growth stops when reproduction begins. If allowed to grow to maturity, rye residues tend to have a high carbon to nitrogen ratio and high percentages of lignin and cellulose, so they can be slow to decompose.

Excessive amounts of spring residue produced by rye can delay cash crop planting and actually decrease the availability of N to subsequent crops as N is tied up or ‘immobilized’ by the decomposing residues.

Rye plus Legume. Winter rye can also be grown in mixtures with a legume such as hairy vetch and/or crimson clover. During the fall and winter, cereal rye protects the soil, scavenges soil-N, and acts as a nurse crop for the legume. In spring, rye provides structural support for the climbing legumes. The relatively high N content of legumes reduces the overall C:N ratio of the rye/legume mixtures, and increases the nitrogen available to the following crop.

Allelopathic Effects. Cereal rye produces several compounds in its plant tissues and releases root exudates that apparently inhibit germination and growth of weed seeds. These allelopathic effects, together with cereal rye's ability to smother other plants with cool weather growth, make it an ideal choice for weed control.

However, allelopathic compounds may suppress germination of small-seeded vegetable crops as well if they are planted shortly after the incorporation of cereal rye residue. Large-seeded crops and transplants rarely are affected. There is some evidence that the amount of allelopathic compounds in tillering plants is lower than in seedlings.

Rye for No-Till. Because it leaves a lot of residue on the soil surface, no-till rye can be an effective way to avoid erosion and help control weeds. Mowing or using a burn-down herbicide are two common methods of killing a rye cover crop for no-till plantings. To kill rye by mowing, it should be done at flowering when the anthers are extended, and pollen falls from the seed heads when shaken. If mowing is done earlier, the rye simply grows back. Studies are underway looking at rolling instead of mowing as a means of physically killing winter rye.

For no-till to be effective, it’s important to first grow a very good stand of rye before killing it. When rye is left as a surface mulch it is difficult if not impossible to manage escaped weeds with mechanical cultivation. Thus, a poor no-till cover may be worse than no mulch at all in terms of weed management.

Research at Penn State, Michigan State and elsewhere has looked at the use of a roller-crimper to mechanically kill winter rye for no-till crop production."

This is a pretty good review and the reason I am planning on rye again this fall.

We got a shower last night which is "pennies from heaven" in the old days and in today's economy it's dollars from heaven!

It's TGIF for the 8-5 work crowd but just another day on the farm here so either way, have a great weekend!


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