Warm, wet springs make excellent conditions for devastating infestations of leaf diseases on cereal crops. Dirkwin wheat is one of the most susceptible varieties, and does not perform well under these conditions. Oats in general do not tolerate extended periods of wet feet, nor excessive amounts of lagoon water. Both Swan and Kanota oats can get rust. Of commercially available forage varieties, Gene wheat, Trical 2700 triticale and Ogle oat probably have the least susceptibility to leaf diseases. More detail on these and other varieties was given in the last issue of Stanislaus Forage Farmer.
|.||hgt||T/A wet||% moist||T/A 70%|
|Swan + 50% Languedoc Vetch||35.8||14.32||80.3||9.37 A|
|Swan + 2x Dundale Peas||37.3||12.80||80.4||8.32 AB|
|Swan+ 50% Dundale Peas||39.3||11.99||79.3||8.27 AB|
|Swan + 10% Common Vetch||35.0||9.49||77.4||7.20 BC|
|Swan + 10% Languedoc Vetch||31.5||8.64||78.0||6.35 BC|
|Swan + 10% Dundale Peas||31.8||6.99||77.0||5.42 C|
|Swan Oat||32.8||6.28||75.7||5.14 C|
Vetch traditionally does best in wet years. It is especially suited to situations where fertilization is not possible. In a trial conducted last season, vetch and peas were evaluated under conditions where no fertilizer was applied (this was not planned). A yield of over nine tons was obtained from a 120 pound seeding rate of a mix of Languedoc vetch planted at double the weight of Swan oat. These varieties of vetch and peas make much earlier growth than Common vetch and Austrian Winter peas and will have well formed pods by the time the Swan oat is in flower.
Many people plant forage mixes to minimize risk, in hopes that if one component of the mix fails, something else will do better. This can be an effective strategy with a good quality mix. Adding ryegrass to a mix may provide insurance in areas where waterlogging is expected to be severe because it will tolerate extremely wet conditions that will kill other species. However, under normal circumstances, it has poor yield potential in comparison to other options. Burseem clover is another species which will tolerate waterlogging, however, it must be planted during early fall to get established, and it may be ready to harvest before the ground is dry enough to get on. If you have a field that is at risk of being completely lost and expensive seed is not justified, Cayuse oat seed is inexpensive. In last year's trial, boot stage occurred during the normal harvest window, providing reasonable yield of good digestibility.
Winter cereals need most of their nitrogen during the period of rapid growth, during mid February through harvest in April. On sandy soils, most applied fertilizer nitrogen will wash away during winter storms. On heavy soils which waterlog, the nitrogen will be converted to gaseous nitrogen and go off into the atmosphere. The more rain we have, the more pronounced these losses become. On most soils, only enough nitrogen should be applied at planting to cover the growth expected before mid January. This will vary depending on how early you plant. Figure about 16 lbs of nitrogen are needed per ton of growth. If you will anticipate there will be the equivalent of 4 tons of silage before mid winter, then put down 4 times 16 or about 64 lbs of N fertilizer preplant. Very early planted forage which makes more growth in the fall will need more than that.
The remaining nitrogen should be applied about late January. An 17 ton crop of silage at 14% protein will use about 250 total units of nitrogen and about 16 pounds of sulfur. Sulfur, like nitrogen, will leach during a wet winter and will also need to be applied in early spring in many areas . Use only a sulfate form of sulfur; popcorn or elemental sulfur will not be available quickly enough and will contribute to soil acidity.
If your dairy lagoon has limited capacity, remember that rain water collected off roofs is fresh water and does not need to go into the pond. If you capture that water before it contacts any manure, you can redirect it to drains, fields, and possibly, by prior arrangement only, to canals. Applying fresh roof water to fields should be done in a way that avoids applying too much at one time to one area, causing water to stand.
On heavy ground, putting a cereal crop on beds which have furrows open to drains can really help in a wet year. If you have drains available, clean or repair them as necessary ahead of time. If we have an early, rainy fall, alfalfa which does not have a good start by the change of the season is not likely to produce a good stand. If you cannot have your alfalfa in by early to mid October, consider waiting until next season to plant.
November 5, 1999