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It is very difficult to make top yields in a season where weather favors pests but not growth and development of the crop.

January 11, 2017

4 Min Read

Yields seemed too low for the money invested in the crop. Frustration among row-crop growers was high in 2016.  Disappointment with commodity prices, anxiety over unfavorable growing conditions and significant pest pressure left some wondering what, if anything else, could go wrong.

Occasionally this frustration was directed at those who sold the seed and chemicals and at those, like me, who provided advice and recommendations.  Sometimes the exchanges became personal, but more often than not, words were spoken from despair.

Growing a crop is not cheap.  Production includes significant expenses on purchase of seeds, chemicals, fuel, and irrigation.  Successful farmers must be good managers who carefully plan to achieve not only top yields but also profits as well.  Planning leads to an expectation among some that, “If I plant variety A, fertilize at a rate of B, use C, D, and E herbicides, insecticides and fungicides, and irrigate according to schedule F, then I should harvest X bushels, Y pounds or Z bales per acre at the end of the season.”   Problems arise when A+B+C+D+E+F doesn’t add up to X,Y, and Z.

Careful management, adoption of new varieties and innovative production practices and use of improved herbicides, fungicides, insecticides, etc., has allowed growers to realize significant increases in yield.  If A+B+C+D+E+F equaled X, Y, or Z in 2014 and 2015, then yields should be the same in 2016, right?  Where yields actually declined despite following a “proven” program, growers were justified in asking, “What went wrong?  What changed?”  At times, blame was placed on the seed- poor quality, poor disease resistance, etc.  Sometimes the blame was placed on the products applied, for example, “This fungicide doesn’t work as well as last season.”  And sometimes the blame was placed on lack of effective recommendations to manage new pest problems.

While harvesting cotton plots, I had the opportunity to share my thoughts with good friend and colleague Dr. Steve Brown, who was a long-time cotton specialist at the University of Georgia.  He listened patiently as I told him of growers’ frustrations with reduced yields and their struggles to understand the reasons.  As my shoulders sagged, Steve looked at me and said, “Bob, agriculture is biology; we’re not making screws.”   

That was it exactly!  Mass production of screws, or most anything else, involves processes where nearly every detail can be controlled.  Barring some human error, every screw is pretty much like the other screws.  But farming is different, and Steve was right, the difference is in the BIOLOGY!  In producing any crop, there are things that growers cannot control and one season is not exactly like another other.  Though pest pressure will vary from year to year, the most important factor that the grower can do little to control will be weather and its impact both on the crop and on pests.

Impact of weather on an agricultural system is huge and management of a crop during extreme wet or dry, hot or cold is a difficult challenge.  Temperature affects growth and development of a crop.  Too many cloudy days affects photosynthetic efficiency in crops, for example in corn.  The impact of too much or not enough rain is clear.  In the worst cases, irrigation may not be enough to offset drought.  Weather can have a significant impact on many  insect pests, to include thrips, white flies,  lesser corn stalk borers and spider mites later in the. 

Weather plays a huge impact on diseases as well.  Cool and wet conditions increase pressure from seedling diseases; hot conditions increase risks to Aspergillus crown and white mold on peanut; too little rain inhibits redistribution of fungicides and increases risk to soilborne diseases on peanut as well.  Too much rain not only creates conditions favorable for the development and spread of fungal and bacterial diseases, but keeps growers from making timely fungicide applications. Tropical storms and hurricanes can spread pathogens, like those that cause rust diseases, over great distances.

Advances in technology, for example larger sprayers, GPS-guided tractors, irrigation, improved varieties, and more effective agrichemicals, have helped growers to achieve better yield and increased profitability.  While these advances in technology and information provide safeguards to the negative impacts of extreme weather, they cannot fully protect the yields realized in a “gentler” year.  In 2016, growers were understandably frustrated by lower yields than they managed for.  But as my friend said, “We are not making screws.”  Unfortunately, conditions during the season meant that A+B+C+D+E+F just didn’t add up. 

Growers cannot control the weather, but climate can be predicted in advance and this can be used to make better management decisions.  The winter of 2015-2016 was defined by an extreme El Niño phenomenon and characterized by increased rainfall and cooler temperatures.  Currently our region is affected by La Niña resulting in drier and warmer conditions.  Warmer conditions could impact the 2017 season by prolonging the survival of southern corn and Asian soybean rust pathogens and also lead to more significant nematode problems. 

Despite best efforts, it is very difficult to make top yields in a season where weather favors pests but not growth and development of the crop.  However, an awareness of predicted climate conditions can help growers to modify production decisions and improve yields as a result.  We may not be making screws, but we may make a better crop.

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