Agronomy Notes

January 8, 1999

Contents

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SOIL TESTING

Dr. Keith Crouse

Maintaining soil levels for crops and pastures requires a regular soil testing program. Also, keeping acceptable soil pH ensures that calcium or magnesium will not be depleted by leaching, erosion, or crop removal from the soil. An acceptable pH level promotes better overall availability of essential nutrient for healthy crop growth; good pH levels increase the efficiency of fertilizers applied.

The availability of various plant nutrients is affected somewhat differently by changes in the soil pH. Macronutrients such as nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur will increase in availability with an increase in soil pH. Micronutrients such as iron, manganese, boron, copper, and zinc, with the exception of molybdenum, will decrease in availability.

There is still plenty of time to take a soil sample before planting a crop. A fertilizer recommendation is only as good as the soil sample submitted; therefore, a representative soil sample is important in any soil testing program.

SOYBEANS

Dr. Alan Blaine

It seems just yesterday it was mid-August... but the year is over. The growing seasons of 1998 were varied, but final yields statewide are better than most expected.

With many new options coming to the forefront (new varieties, transgenics, new herbicides, etc.), it is easy to overlook the basics of crop production. Although the basics are not glamorous, they should get a lot of attention.

I have little doubt that if a grower concentrates on a good soil testing program, choose varieties carefully, and practice crop rotation, the grower could increase profits. Do not underestimate these three inputs, all of which are in your control.

Groups IV, V, and VI of the Soybean Variety Trials are available in your county Extension office. I encourage you to pick up a copy and make your variety choices quickly. Varietal differences are real. Use the variety trials as a guide; they are by no means absolute. The best variety trial will always be the one conducted on your farm. When evaluating varieties, consider your specific problems or problem fields but above all, select those varieties with a consistently high yield potential.

Roundup Ready soybean crops have been big topics of conversation this fall; discussions range from yield to weed control. As producers enter the 1999 growing season, about as much confusion exists today as it did before 1997. Some excellent variety choices are available in Roundup Ready and conventional soybean seed, but many Roundup varieties have been quite variable over the last couple of years.

Review as much varietal information as you possibly can. Choose varieties adapted to your particular soil type and those that will address any potential disease problems. Select varieties that best meet your needs whether conventional or Roundup Ready.

After 2 years of large-scaled planting of Roundup Ready varieties, a lot of mixed emotions have surfaced. Although some good varieties are available, Roundup Ready varieties, as a whole, have been much more variable in yield and disease reaction.

As you look at the variety trials, it appears that not as much variability exists between Roundup Ready and conventional Group IV's; however, this is not the case when comparing the Group V's. Good high-yielding varieties are available, but you will need to be selective to stay on top of the best varieties. Nothing has changed regarding variety selection.

SUSTAINABLE AGRICULTURE

Dr. Malcolm Broome

A Perspective on Sustainable Agriculture Sustainable agriculture is defined in a number of different ways. A definition of functional use is food, fiber, and forest systems that are economically viable, socially acceptable, and ecologically sound.

So, what is sustainable agriculture? Some people believe it to be a movement, a rally, and cry for their perspectives of agriculture today or yesterday; a marketing tool used by insight for producers of products and programs in the areas of educational programs and research programs, or a concept and program itself. Certainly one of the concepts that has to do with sustainable agriculture as an agriculturist or an educator provides for a mixed concept or system, but certainly in today's agriculture in Mississippi, the profit motive has to be a component.

Sustainable agriculture is changing all the time. There is a history of sustainable agriculture being only the low-input sustainable agriculture program, or the organic program, or the conventional agriculture program. The comings and goings of various "buzz words" around sustainable agriculture such as "LISA," "organic," "high in-put conventional agriculture," and "ecosystem management" are components of a development of sustainable agriculture and can be positives or negatives regarding its adoption and understanding.

At any rate, sustainable agriculture should include forestry and all ranges of crop and livestock production areas. It is diverse with the best discussions and the best decisions on sustainable agriculture coming out of that diversity. Another characteristic of sustainable agriculture is that it is personal. Everybody has their own decided definition for sustainable agriculture. It is interconnected with the environment, the agriculture production systems, the market, and all the people involved. It is synergistic, which means the various parts of sustainable agriculture, when used and looked at collectively, provide more than the total of all of its parts. It is a describable system based on the individual or the group, or the status of agriculture in a given area.

Sustainable agriculture should be : * Operational - site specific. * Prescriptive - what needs to happen to be sustainable. * Progressive - a direction, not a destination. * Goal oriented - accountable, measurable, and analyzable. * Research and demonstration based if it is to have validity.

But what is new? Maybe it is becoming clearer now that sustainable agriculture fits an operational definition that shows imbalance for three major components: that of being socially responsible, economically viable, and ecologically sound. Farms and forests are not just producers of food and fiber, but are producers also of clean water, oxygen, green space, soil as a filter or a sink, and a detoxifier. Human beings are a part of agriculture. They are not extraneous; they are a part of it. First, every individual needs to find out where they fit in a definition of sustainable agriculture. What is it about your work that is sustainable? Try to enhance it. Try to find out whether a field, a farmstead, a farm, a community, a watershed, or a basin are sustainable. Look in terms of local site-specific first; move up to the state and the region. Evaluate it and begin to practice sustainable agriculture and see if progress is being made.

As we move into 1999 and beyond into a new century, any society that expects to last must manage its resources in harmony with the environment. How else could the production of food and fiber be assured for future generations?

FORAGES AND PASTURES

Dr. Lamar Kimbrough

Planning Your Forage Program - During this time of the year, some of your chores may have slowed somewhat and you may have a little extra time to do some planning on your forage program. Since some 80 percent of the feed for most cattle operations comes from forages, this also includes the largest amount of money spent for growing forage-consuming livestock.

         
         Usually no two livestock operations will have identical forage programs.    Resources on different farms may vary, as do the objectives and desires of different producers.  Many things, however, will be common to most good forage-production programs.  These things were true years ago when W.R. Thompson, Sr., was in the job I have today, and it will be true after I retire.  The autograph in my old "The Pasture Book" written by Mr. Thompson states, "Pastures will make money if fertilized, weeds controlled, and good management given.  Fertilizer is the answer to making profits."  This is probably even more true now than in Mr. Thompson's time, since some fields have had even more time to be robbed of these practices.  Unless attention is given to these practices, your forage program will never be what it could be.

Lime and Fertilizer - Experts have always emphasized the importance of soil testing followed by applying lime and fertilizer based on soil test results. If weeds are controlled, this practice will influence forage quality and quantity more than any other thing you can do. Most forage grasses need a soil pH of at least 6, and soils for forage legumes need a pH of 6.5 to 7.0. Forage grasses for hay usually require a 4-1-3 ratio of N-P-K and a 4-1-2 ratio for grazing. Nitrogen amounts may be reduced where good stands of legumes are present. On many sandy soils, producers are seeing the increasing need for sulfur to be added with these mixed fertilizers. The balance (ratio) of these plant nutrients is often more important than any one nutrient alone. The only sure way of knowing these needs is to take periodic soil samples and apply what is recommended.

Weed Control - Many troublesome broadleaf weeds compete for nutrients, water, light, and space to grow. If given a choice, cattle will not eat many of these weeds, and some weeds may even be toxic. For sure, most contain more added fertilizer nutrients than the desired forage and in doing so, rob you of lime and fertilizer money.

Clipping may help, but many times, chemical weed control is the most practical way to control many troublesome broadleaf weeds. At present, producers have several safe research-proven chemicals and/or mixtures for controlling weeds. By killing these, you are returning the nutrients in the weeds back to the soil, saving and supplying these nutrients for your desired plants, and at the same time, improving you quality and quantity of pasture and/or hay.

Management - Management is a big word and can include any practice you do with your forage program. With other practices being done, grazing and/or harvesting management is a main concern. Unless it is properly used, there is no need to grow the forage. Whether grazed or harvested for hay, the main thing is to get it when young and of high quality and try not to let it become overmature and low in quality. More than one cross-fence and/or more frequent hay harvests may be needed.

Another big management factor, especially with hay, is not to waste it at or after harvest. A bale wrap, on the new roll baler you plan to buy, or a new pole barn for inside storage may be what you need before next harvest season.

If you have questions concerning your forage program, check with your local county Extension agent, who can supply you with soil sample boxes and written information on specific forages and management practices.

CORN

Dr. Erick Larson

Aflatoxin carryover? - Some misinformation is circulating about the threat of aflatoxin carryover to the 1999 growing season. The philosophy that excessive overwintering inoculum will create a significant problem next year, even in the presence of mild drought stress, is unfounded.

Aflatoxin is not a fungus, but rather, it is a chemical by-product of the Aspergillus flavus fungus. This fungus is abundant in the Midsouth nearly every year. The limiting factor responsible for triggering aflatoxin production in corn is environmental conditions known to stress kernel development and promote fungal infection within the ear. Conditions stressing kernel development linked to aflatoxin include water stress, heat stress, insect damage, disease pressure, inadequate fertility, excessive plant population, and weed pressure. Insect damage on ears also promotes aflatoxin production by encouraging fungal infection and damaging kernels. Southwestern corn borers and corn earworms can damage corn ears in this manner; thus, aflatoxin contamination may be improved by managing these potential sources of stress.

Hybrid Selection - The new Mississippi State University Corn for Grain Variety Trials bulletin is available. This publication provides useful data for selecting hybrids to plant in 1999. I recommend growers plant several hybrids based upon three primary criteria - grain yield, stalk strength, and maturity. High-grain yield is obviously a primary consideration because grain is sold on a weight basis; however, variety trials may not reflect harvestable yield in a field situation unless stalk strength is considered. Leaning or broken stalks can lead to significantly reduced harvest efficiency in terms of harvest loss, time and fuel.

Hybrid maturity influences harvest date and can impact profit through its effect on grain moisture. Hybrids grown may differ in maturity by as much as 2 weeks. Producers who market their grains at harvest may benefit from growing early maturing hybrids because markets usually decline through harvest.

Aflatoxin resistant hybrids? - More than 50 commercial hybrids were evaluated for aflatoxin content in Mississippi during 1998. Results indicated no hybrids were aflatoxin resistant; however, some hybrids were more susceptible than others. Susceptibility seemed to be correlated to lack of drought resistance. This information will be published in the near future.

SOIL AND NUTRIENT MANAGEMENT

Dr. Larry Oldham

Winter is the time to assess your total farm management system. I'm sure there are some lenders in Mississippi who are especially watchful this year. The strangest rationale for tillage operations I have ever heard was that the help needed something to do. I don't think this qualifies as good agronomy or as good business management.

I hear more diesel fuel was burned in Mississippi this fall than ever, but producers are learning that tillage should be a site-specific decision. There is no perfect soil management system for a region, county, or farm. Soil characteristics vary widely, and thus tillage responses vary widely.

Do not use subsoiling to compensate for poor management; it is not an universal best management practice. In many cases, it is needed because tillage pans formed when traffic was not controlled on wet soils. There are some soils that are prone to natural compaction. Other soils such as Tunica clay offer drainage challenges. But the bottom line is unnecessary subsoiling wastes time, fuel, labor, and other real cost resources. It is more cost effective to manage better than to try and erase mistakes.

Aflatoxin has taken the bloom off Freedom-to-Farm in Mississippi. This is a winter of economists, risk management, cash flow projections, and auctions. I think common sense dictates a cold, hard evaluation of each trip over a field. What is the agronomic justification? What are the costs? Are the returns justifiable?

COTTON

Dr. Will McCarty

According to the November, 1998 Crop Report, Mississippi was to pick 915,000 acres and yield 776 pounds per acre. That is not bad considering the growing season. .

The 1998 crop averaged 34.62 staple, 27.71 grams per tex HVI strength, an average mike of 4.58 with 12.2 percent of the bales having mike of 5.0 or better. Overall the crop produced a slightly shorter fiber with a slightly higher mike than the 1997 crop.

Fall Practices Are Important - 1998 is almost over, and we must continue planning for 1999. As soon as possible after harvest, stalks should be cut and fall tillage performed. Fall tillage can range from sub-soiling to rowing up and planting cover crops. If soils are wet, delay tillage until soils are dry.

Many Soils need Sub-soiling - Sub-soiling to break up compaction is a very important step toward preparing soils for cotton planting. This maybe done at the conventional 45 degrees or accomplished down the row with a para plow or ripper-hipper. The use of a para plow with a buster unit in the fall followed by ripping the non-traffic or alternate middles in the spring has been used by many growers with promising results.

Control Traffic Systems - A system that controls traffic or confines traffic to a particular set of rows, has shown tremendous promise in research and demonstrational. Confining all trips across the field to the same middle, coupled with down the row sub-soiling, and ripping non-traffic middles is a system that can reduce trips across the field while maintaining or increasing yields.

Row Up Clay Soils in Fall or Winter - For those that farm cotton on soils with high clay content, rowing up in fall and planting on a stale seedbed is the preferred option. It can mean the difference in planting on time or very late.

Taking a Representative Soil Sample - Soil testing is another important practice for fall. Soil fertility is not an area that can be neglected if you want a profitable cotton production program.

Sampling When Bands Locations are Known - To insure an average sample for the field when the band locations are know, the number of cores to be taken between the bands for every core taken in-the-band are equal to 8 times the band spacing. Example, if the band spacing is 30 inches, 20 cores (2.5 feet X 8) should be taken between the bands for every sample taken in the band.

When Band Locations Are Not Known - Where the band locations are not known, pair sampling when the first sample is taken at random and the second sample of the pair is taken at 50 percent of the band spacing from the first sample and perpendicular to the band direction. These guidelines were developed from phosphorous use but probably are also valid for potassium and/or mixed fertilizers as well.

Fall Fertilizer Applications - The application of potassium and phosphate in the fall is an acceptable practice. Potassium is a little more mobile in the soil than the phosphates but not enough to present a leaching problem. On sandy soils that have a CEC of 7 or less, delay potassium application until spring. It is not a bad practice to split the total potassium needs into more than one application. Research has shown an advantage in combining broadcast and band applications. The band application can be made before, at, or after planting as apart of the sidedress nitrogen application. Regardless of the fertility program used, the heart of that fertility program is a sound soil testing program.

Know Nematode Populations - Soil testing for nematodes should also be part of your program. Nematodes are stealing yields in many fields. Research and demonstrations in 1994 showed tremendous response to the application of Termik at the recommended nematode control rates. Take soil samples and test for nematodes.

Book Cotton Seed Early - Results of variety testing will be available soon. Pick your varieties based on proven performance on your farm and on your soil types. Yield, yield and yield followed by value added traits should be the considerations for variety selection. It is important to plant the bulk of your acreage in varieties that have a stable yield over time. That is, a variety that has yielded well over a several year period demonstration an ability to produce within a range of consistency.

Value added traits should be selected based on need and not what you have heard or read. Bt is an excellent tool to manage tobacco budworm and should be a consideration. When considering herbicide tolerate varieties be sure you know your weed problems and the strengths and weaknesses of the herbicides involved. If you have been doing an excellent job with weed control, do you need a herbicide tolerate variety? More on this topic in the next edition.

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