Agronomy Notes

September, 2001

Contents:

SOYBEANS
FORAGES AND PASTURES
SOIL TESTING
COTTON
CORN
WHEAT

 

SOYBEANS
Dr. Alan Blaine

The Mississippi soybean crop has been projected at 28 bushels per acre. Unlike the previous three years, I feel this yield prediction will be easily attained. This crop has an excellent potential, but in recent weeks has experienced its share of problems.

Over the last couple of weeks we have observed several fields of soybeans that have been affected by Phomopois, a seed rot organism.

This problem was observed primarily in fields that were ready to harvest when the heavy rains hit.

The problem was not due to planting date but to the effect of moisture at/near harvest. This problem was not isolated on Roundup Ready varieties, but it did appear to be worse on gray pubescent beans versus tawny. Varieties that it has appeared to be the worst on were: Delta King 4868, DPL 4690, AP 4880 and DPL 3478.

We have never observed the problem this bad, ever before. This disease is not new, and was seen much more frequently when we used to plant later maturing varieties (VI's and VII's). When rains occurred late in the fall, this problem expressed itself. As a matter of fact, this is what brought about the large use of Vitavax. In a fall when this problem occurred, it was found that adding Vitavax to germinating seed improved gemination by 15-30 percent.

An indication that the problem is present at this time is the presence of brown to black blotches on the outside of the pods and flat pods. Earlier in the season flattened pods is a good indication that it is present in the field. We have observed this problem since 1996 but numerous attempts at a positive identification have been successful. It appears however, that in the presence of adequate moisture the organism/seed rot exploded.

Only a portion of this crop was exposed to this problem, but for that portion it is serious. Estimated yields at 50-55 bushels per acre actually cut about 20 bushels per acre once harvest was able to take place. Stink bugs appear to be involved by allowing the problem to progress faster.

We have observed fields or areas in fields where stink bug pressure was heavier, thus causing a much greater problem. I am not pointing this out to say Stink bugs caused it, but the observation that some areas are worse than others, leads me to feel this insect played a significant role.

Fungicides are every effective in treating this problem, but in several tests there was no difference in treated and untreated areas.

In one field where irrigation was terminated, this problem developed in less than two weeks. In the absence of sufficient moisture, this organism may not express itself. There appears to be varietal resistance present, and we hope to have this information available this winter.

We have applied fungicides on many acres and in the future when we experience above average rainfall more acres should be considered for an application. This is not the only disease problem popping up. Aerial Blight is occurring more widespread and further north than we have ever seen it before. Two other diseases Stem Canker and SDS have been observed widespread. Varietal residence is available and should be considered mainly in the case of Stem Canker.

In mid-August the Bureau of Plant Industry declared a crisis exception for the use of Intrepid on Salt Marsh caterpillars. This is an excellent worm material that offers a level of residual we have never had available before.

A recent test was applied where populations of salt marsh caterpillars and loopers were 90-100/25 sweeps. The 7 day count was zero larvae present at all rates. We will continue monitoring this test to determine the length of residual we can expect.

 

FORAGES AND PASTURES
Dr. Malcolm Broome

Why Consider Year-Round Grazing There are many factors that could be positive in trying to build a forage program that will allow grazing most of the year. In general, grazing forages cost only about 50% as much as stored feed because of the cost of producing hay or silage plus feeding cost. Extended grazing is being done where livestock managers become forage managers using livestock to harvest their production. Changing from the attitude of having animals on pasture to one of efficiently converting forages into meat or milk is the difference.

Mississippi, due to its climate, offers a real opportunity to increase the number of days on grazing, thus reducing the number of days requiring stored feed. A one size "fits all" plan is not available which could make forage production easy. Yet, reliable recommendations and planning assistance is available from several sources, especially university recommendations. Our Land-Grant Universities are in the business of conducting scientific research that is unbiased and it is difficult to accurately determine animal performance through on-farm observations.

To grow as much forage as the weather permits will require several factors be followed. First, use of forage varieties and species that are adapted locally within the state and even to the soils on the farm. To help determine soil types, a soils map, usually available from the Natural Resources Conservation Service, would be quite useful. Along with soils, comes the need for proper liming and fertilization which greatly influence forage amount and quality. The use of regular soil testing procedures will help provide this information.

The combining of the variety and soil information can best be done through use of a grazing plan to best utilize the forage grown. This will determine the most efficient and convenient way for the forage manager to utilize each pasture. This plan will attempt to graze forage at its peak growth or mechanically harvest an excess before it loses quality.

The following is an example of forages that can be used for thought and planning when trying to lengthen the number of days on grazing:

 

Scenario I: Farm Located on Vicksburg to Meridian line South to Gulf Coast

Consider Growing:

Grazing Period:

Rye, Wheat, and Ryegrass more days

November to May

Crimson or Arrowleaf Clover (if legume desired)

mid-January - May

Bahiagrass and Bermudagrass

April - October

.

Scenario II: North of Vicksburg-Meridian line to Tennessee border

Consider Growing:

Grazing Period:

Wheat, Tall Fescue(more days), Ryegrass (south half of this zone)

October - December and February to July

Alfalfa (site specific)

March - November

Ladino Clover and Arrowleaf (if desired)

March to July

Dallisgrass and Bermudagrass

April - October

Scenario I offers the best chance for a year-long forage grazing program due to climate.
Scenario II offers a good chance for 10 months - reducing stored feeding 30- 45 days.

Weather can change plans and often does. However, without a plan the weather will exact an even bigger toll.

 

SOIL TESTING
Dr. Keith Crouse

Early fall is a good time to improve pastures and hays fields. During the past few weeks we having been receiving soil samples that were cropped for cool season forages and soil acidity appears to be the major fertility problem for these fields. This can easily be taken care of by apply recommended lime. Most cool season grasses grow best at a pH level above 6.0.

Depending on the crops, approximately 30 lbs of potassium per ton hay removal and potassium removal from a soil could be even higher on the hybrid bermudagrass fields. Potassium roles in plants are to reduce lodging and increases winter hardiness and disease resistance; increases photosynthesis; carbohydrate metabolism and breakdowns and translocations starches; activates various enzymes; adjusts stomatal movement and water relations. Potassium fertilizer may need to be applied to our hay fields and fertilizer recommendations depend on the crop being grown. Therefore, to know what is needed, take a good random soil sample and have it tested.

Remember that you should always take the soil sample from a uniform area that is usually about 10 acres or less in size. Take enough separate cores within the soil area for a representative soil sample. Generally, this is about 15 to 20 cores. Take your soil cores from the surface to plow layer. Mix your soil cores thoroughly. Send a full soil box or a pint of soil for analysis.

COTTON
Dr. Will McCarty

The 2001 cotton crop production is fast drawing to a close. This crop had a pretty good start, fair conditions in June and generally good rains during late July and August. Fruit retention in 2001 is not quite as good as we would like to see, largely due to continuous pressure from plant bugs. Boll rot has taken a larger toll in 2001 than in recent years. Boll rot is generally a problem where you have good vegetative growth (an indication of good weather during the season), good soil moisture and high humidity (needed to finish off the top crop) and the presence of bolls. Take away any one of these and yields tend to suffer. A little boll rot in a Mississippi cotton crop is normal. Let's just hope it is arrested before damages is too great.

The USDA August crop report was somewhat bullish on our 2001 crop. This report estimated that we would pick some 1,680,000 acres and yield some 743 pounds of lint per acre. This would lead the state to produce 2,600,000 bales of cotton. First - I do not think we will pick 1,680,000 acres nor will we average 743 pounds per acre. However, our good cotton is very good and out not so good cotton is better than expected - so we will have a good crop. Lets think about the size of this crop for a moment - 2,600,000 million bales ---- the all time record crop was produced in 1937 - 2,692,000 bales. That 2,692,000 bales were produced from 3,421,000 harvested acres.

Anyway you want to look at it, the 2001 crop will be the second largest crop ever produced in Mississippi. This will put a strain on our ginning capacity, storage facilities and seed houses. I highly encourage you to use precaution in storage of modules. Monitor temperatures and gin hot modules as fast as possible. It is a good possibility that seed cotton will remain in modules longer this year than in the recent past. Be sure to build modules where they can be moved easily, cover them properly, move them ASAP and store them in very well drained areas. Cotton is very hygroscopic and quality will deteriorate if we have a wet fall.

Boll Counts for Yield Estimation - Generally speaking, counting bolls per acre will provide you a fairly accurate estimate of the number of bolls per acre in a field, not much else. Using boll counts to estimate yield can be variable depending on boll size variability, harvest efficiency and gin turnout. As a rough rule, it takes about 127,000 - 128,000 4.5 gram (seed cotton) bolls to produce a bale of cotton. That is at 38% turn out and no consideration for harvest efficiency. More realistically you are looking at about 150,000 bolls being required to produce a bale of lint. This may vary from variety to variety, from field to field, and from year to year. Therefore boll counts are perhaps better tan nothing at estimating yield, but not much.

Below are a few tips to consider as we finish this crop and prepare for next year:

Variety Selection - Post defoliation is an excellent time to make critical observations of all varieties in your area. Look very closely at your varieties and varieties planted in your area on similar soil types to your own. Look at plant height, node of first fruiting branch, fruit retention, boll size, boll integrity, presence of diseases such as vert wilt etc., root growth and crop uniformity. Make notes about each variety - so you want forget what you see - and then record yields of each variety after harvest

Tillage decisions - Interest in no-till, reduced till production has increased greatly. The main driving factor in this decision and movement is economics - (labor, machinery, time = money). Technology exist today to allow growers to produce cotton in reduced till systems. There are so many options to consider there is no way to address them here. If you are interested in no-till or reduced-till cotton production, give your local county agent a call and he will be glad to work with you in devising a system. Each time you can reduce a trip across a field it will allow you to either save money or work more cotton acreage for the same money. There are advantages and I feel that cotton production, on many soil types and soil resource areas, must move in that direction to remain sustainable.

Soil testing - fall is an excellent time to take soil samples. I suggest you do so as soon as possible. Getting samples pulled early may allow you sufficient time to incorporate lime or other needed nutrients during a tillage rotation. Observe fields closely and mark problem areas for separate sampling.

Nematode sampling - reniform nematodes have developed into a major pest in Mississippi cotton. I highly encourage each cotton grower to sample their fields for the presence of this pest. After confirmation of presence and levels of infestation, a control, or management strategy may be developed. In most cases, management of this pest will involve both crop rotation and nematicides. There are no resistant varieties and generally, for long term management, nematicides will need a crop rotation program to be very successful.

Final Reminder on Harvesting - move modules to the gin yard as fast as possible. Do not let modules set in fields until rains cause mud problems in moving them or results in grade reductions.

2001 COTTON SHORT COURSE

DATE: December 5 , 6 and 7, 2001
LOCATION: Bost Building, Mississippi State University
REGISTRATION FEE: $75.00 (This includes 2 lunches and coffee breaks.)

Last day ends by noon. Please call (662) 325-2701, or e-mail csimmons@pss.msstate.edu.
Make check to: MSU-ES Cotton Short Course and send before November 30 to:

Department of Plant and Soil Sciences %Charlotte Simmons
Box 9555
Mississippi State, MS 39762

Lodging accommodations available:
Best Western - 662-324-5555
Hampton Inn - 662-324-1333
Ramada Inn - 662-323-6161
Comfort Inn - 662-324-9595
Holiday Inn - Express 662-324-0076

 

CORN
Dr. Erick Larson

Will late harvest hurt? - Abnormally rainy, humid and cloudy August conditions have delayed corn harvest compared to past years. These conditions have primarily slowed harvest progress by reducing the corn grain field-drying rate. This could increase corn field loss before harvest and deteriorate grain quality and seed weight. Thus, many producers are wondering whether they should continue to wait or commence harvest, despite dockage incurred due to high moisture content. There is no simple answer to this question, but there are several important factors (besides the dockage rate) which will help your decision. The longer corn stays in the field, the greater the likelihood of substantial field losses. Stormy weather can potentially cause considerable lodging in unharvested fields. Furthermore, southwestern corn borers girdle stalks during August, which will begin to cause considerable stalk lodging in late August and early September. Abundant late-summer rainfall has also promoted morningglory growth in corn fields, which can greatly inhibit harvest efficiency. Each of these factors may cause substantial field loss, which would considerably outweigh moisture savings. Producers should also consider their harvest capability -- the longer it takes to complete harvest, the earlier you should start harvest. Growers seeking maximum profitability should always strive to finish harvest before grain moisture falls below 15%. Growers should harvest early maturing hybrids and those possessing below average stalk quality promptly and before other hybrids.

 

WHEAT
Dr. Erick Larson

Wheat Varieties - The 2001 MSU Wheat Variety Trials are now available at your county extension office or on the MSU-CARES website. Variety evaluation should be based primarily upon your area of the state, variety yield history, expected planting date, soil type and variety disease resistance. Suggested varieties (based upon above-average yield in the MSU Wheat Variety Trials) in north Mississippi and the Delta include: AgriPro Mallard, Patton, and Shelby; AGSouth Genetics AGS2000; Delta King 1551W; Genesis 9939; Northrup King Coker 9663; Pioneer 2684, 26R24, 26R38, and 26R46; Southern States 522W/FFR 522W; and Terral TV 8555.

In south Mississippi variety choices become more limited due to the warmer winter climate. This eliminates use of many Ohio-valley adapted varieties which need substantial cool temperatures to trigger seed head development (vernalization). The highest yielding varieties which meet these vernalization requirements for south Mississippi are AgriPro Shelby, NK Coker 9663, Pioneer 2684, and Terral LA422 Specific recommendations and variety characteristics are listed on the MSU- CARES Small Grains web site (www.msucares.com/crops/grain/index.html).

Department of Plant and Soil Sciences
Box 9555
Mississippi State, MS 39762

Will McCarty, Ph.D.
Extension Leader

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