Northeast Ohio Agronomic Crop Report

Coming back from the Farm Science Review on Wednesday it was apparent the summer is over and fall is here. This event always marks the end of summer for me. The day after FSR is also one that wheat producers should have marked on their calendar. It is the Hessian Fly Free Date for this area of the state. Let the wheat planting begin. Well almost, it will have to dry out before any wheat can be planted in this corner of the state. This may be a good thing, because some very important mistakes will be avoided. What it amounts to is that wheat will not be planted this fall, on fields that are not good for wheat production. Last fall due to the dry conditions many growers planted wheat on fields that are perennially wet. The result was inability to apply spring fertilizer and herbicides as well as fungicides. The result was some very poor wheat yields. A wise farmer once said “how can you expect to grow a crop requiring 9 months on a field where you struggle to plant and harvest a crop in 4 months. Point well taken! You need to plant wheat on your best well drained fields and you need to take care of it with an intensive level of management. All of this is required to achieve a yield that will be financially competitive with corn and soybeans. Here are the recommendations for accomplishing this from the specialist from OSU Extension & OARDC.

Important Wheat Management Guidelines: A 2011 Update
•Ron Hammond,
•Ed Lentz,
•Andy Michel,
•Pierce Paul

The 2011/2012 winter wheat season is fast approaching and as growers make preparations for planting, we would like to remind them of a few management decisions that are important for a successful crop. Nearly every farm in Ohio has a field or two that could benefit from planting wheat, if for no other reason than to help reduce problems associated with continuous planting of soybeans and corn. Consistent high yields can be achieved by following a few important management guidelines. Below are listed the most important management decisions that Ohio wheat producers need to make at fall planting time to produce a crop with satisfactory economic returns. Here we also address several issues related to late-planted wheat.

Variety and Seed Selection.
Select high-yielding varieties with high test weight, good straw strength and adequate disease resistance. Do not jeopardize your investment by planting poor quality seeds or by planting anything but the best yielding varieties that also have resistance to the important diseases in your area. Depending on your area of the state, you may need good resistance to powdery mildew, Stagonospora leaf blotch, head scab, and/or leaf rust. Plant healthy, wholesome, clean (remove shriveled kernels), and disease-free seeds, and make sure that the entire seed lot is treated, whether or not the seeds appear to be diseased. In Ohio, seed-borne wheat diseases such as common bunt and loose smut are rarely ever major concerns because growers routinely plant seeds treated with fungicides. Problems with these diseases usually appear in isolated areas where poorly treated, bin run seeds are planted. Seed treatments can play an important role in achieving uniform seedling emergence and giving seedlings a good head start under certain conditions. In addition, the selective use of seed treatments can protect seeds or seedlings from early-season diseases. More information on seed treatments can be found on the field crops disease website: http://www.oardc.ohio-state.edu/ohiofieldcropdisease/.
Avoid varieties with susceptibility to Fusarium head scab. Unlike foliar diseases that are relatively easy to effectively control with a single foliar fungicide application, fungicide alone will not provide adequate control of head scab and vomitoxin if the variety is highly susceptible. A fungicide application at flowering must be combined with variety resistance to achieve the best results in terms of scab and vomitoxin reduction. Therefore one of the very first, and probably the most important, steps in a scab management plan is variety selection. In the past, producers have been reluctant to plant scab resistant varieties because some of the varieties did not yield as well as some of the more susceptible varieties. However, we now have scab resistant varieties with very good yield potential to choose from. A list of these varieties can be found in the 2011 Ohio Wheat Performance Trial (http://oardc.osu.edu/wheattrials).

Rotate wheat with Soybean.
Wheat should be planted after soybean not after wheat or corn. However, with soybean harvest likely to be late again this year, many producers are considering planting wheat after wheat to avoid having to plant late. Indeed, timely planting is critical for good stand establishment (more tillers per foot of row) and to reduce the risk of winter kill, however, planting wheat after wheat has several disadvantages.
Diseases are a big concern in wheat after wheat. One such disease, and by far one of the most important, is head scab. The head scab fungus survives in wheat stubble left in the field after harvest. Wheat planted into this stubble is more likely to have head scab and vomitoxin problems next year. This is especially true if late-spring, early-summer conditions are wet and humid. Our studies have shown that when wheat (or corn) residue is abundant (more spores of the fungus present), only a few days of wet and humid conditions during flowering are needed for head scab to develop and vomitoxin to exceed critical marketing thresholds (2 ppm). For the same reasons, planting wheat after corn is just as bad as planting wheat after wheat. The scab fungus survives equally well in both corn and wheat stubble.
In addition, growers who plant wheat after wheat usually have more problems with diseases such as Cephalosporium stripe and Take-all root rot. Plants severely infected in the fall and winter will become weak and discolored in the spring and often die prematurely without producing grain. In addition, foliar diseases such as Stagonospora leaf blotch, Septoria leaf blotch, powdery mildew, and tan spot become more problematic when wheat follows wheat. These diseases are all caused by fungi that survive in wheat stubble left in the field, and as such, can readily attack the new crop and spread shortly after germination or early in the spring. When diseases become established early, growers are more likely to suffer higher yield and quality losses

Planting Date.
Plant after the Hessian Fly Safe date for your county. The Hessian fly free dates can be found at (http://ohioline.osu.edu/iwy/flydates.html). These dates vary between September 22 for northern counties and October 5 for the southern-most counties. Planting within the first 10 days after the recommended fly-safe date minimizes the risk of serious problems with the Hessian fly. This is because on the dates indicated on the map, the weather conditions, especially temperature, are unfavorable for the Hessian fly. As a result, damage caused by this insect will likely be less if wheat is planted after the specific date. However, in Ohio the Hessian fly-safe date is not only about the Hessian fly. Another excellent reason to plant wheat after the fly-safe date is to minimize problems with diseases, especially barley yellow dwarf virus (BYDV). BYDV is transmitted by aphids and tends to be most severe when transmission occurs in the fall. Research has shown that due to unfavorable weather conditions, the aphid population tends to crash after the fly safe date, leading to fewer problems with BYDV. Planting date studies conducted here at OSU a few years ago showed that BYDV problems and yield loss associated with this disease are much higher when wheat is planted well before the fly-safe date. Planting after the fly-safe date also minimizes early establishment of other diseases such as Stagonospora blotch and leaf rust.
However, planting too early may not be a concern this year. From all indications, soybean harvest will likely be late again this year in most areas. As a result, some producers may not have the option of planting early. In fact, some may be forced to plant late, well after the Hessian fly-safe date, which is also a concern. Planting late (generally after Oct 20 in northern Ohio) can reduce the number of primary tillers that develop in the fall and increases the risk of cold temperature injury. If planting is delayed by more than three weeks after the Fly-Free date, the seeding rate should be increased to 24-26 seeds per foot of row, which is 1.75 million seeds per acre) to compensate for fewer tillers developing in late-planted wheat.

Seeding Rate and Planting Depth.
Optimum seeding rates are between 1.2 and 1.6 million seeds per acre. For drills with 7.5 inch row spacing, this is about 18 to 24 seeds per foot of row with normal sized seed. When wheat is planted on time, actual seeding rate has little effect on yield, but high seeding rates (above 30 seeds per foot of row) can increase lodging. There is no evidence that more seed is better, it only costs more money. However, as mentioned above, seeding rate should be increased if the crop is planted well after the fly-safe date. Seed size (the number of seeds per pound) and germination rates are critical for determining the proper seeding rate and drill calibrated. That information should be listed on the bag of seed. The table below shows the pounds of seed needed per acre to accomplish various seeding rates using different sizes of seed.
Pounds of Seed Needed to Plant from 1.2 Million to 2.0 Million Seeds Per Acre with Different Size Wheat Seed
---Millions of Seed Per Acre----
Seeds per Pound 1.2 1.4 1.6 1.8 2.0
10,000 120 140 160 180 200
11,000 109 127 145 164 182
12,000 100 116 133 150 167
13,000 92 108 123 138 154
14,000 85 100 114 129 143
15,000 80 93 107 120 133
16,000 75 88 100 113 125
17,000 71 82 94 106 118
18,000 66 77 89 100 111
Planting depth is critical for tiller development and winter survival. Plant seed between 1 and 1.5 inches deep and make sure planting depth is uniform across the field. No-till wheat into soybean stubble is ideal, but make sure the soybean residue is uniformly spread over the surface of the ground. Shallow planting is the main cause of low tiller numbers and poor over-winter survival due to heaving and freezing injury. Planting depth is even more important in late planted wheat. Late planting results in plants that smaller than normal when entering dormancy, with smaller and more shallow root systems than normal, making them more susceptible to heaving next March.

Fertilizer Application.
Apply 20 to 30 lb of actual nitrogen per acre at planting to promote fall tiller development. Wheat also requires at least 45 ppm of available phosphorus per acre in the soil to produce really good grain yields. If the soil test indicates less than 40 ppm, then apply 80 to 100 pounds of P2O5 at planting. Soil potassium should be maintained at levels of 135, 165 and 185 ppm for soils with cation exchange capacities for 10, 20, or 30, respectively. If potassium levels are low, apply 60 to 100 pounds of K2O at planting. In Ohio, limed soils usually have adequate calcium, magnesium and sulfur for wheat. Soil pH should be between 6.5 and 7.0.
The key to a successful wheat crop is adequate and timely management. The above recommendations are guidelines that may be fine-tuned by you to fit your farming operation, soils, and planting conditions. They also assume that you are planting wheat in fields that are adequately drained.