Monday, October 17, 2011
Has The Weather Caused You To Change The Way You Farm?
How have you changed your production practices over the years? Are you planting corn earlier? Are you harvesting beans after corn? Have you installed more drain tile? Are you farming with larger equipment because of shorter weather windows? Your practices have likely changed and weather may be a common denominator in all of those. While “global warming” has not been an issue that has riled most Cornbelt farmers, many are noticing changes in frequency and volume of precipitation, soil temperature trends, winds, cloudiness, and other weather phenomena that have an impact on crop production. And researchers who study weather changes verify your hunches.
Weather can be just as favorable as unfavorable to agriculture, say Natalia Rogovska and Richard Cruse of Iowa State University, whose recent newsletter indicates recent weather changes in Iowa have included the number of frost free days, annual and springtime precipitation, frequency of intense weather events, dew point temperature, and decreased precipitation in the fall. They work through many such changes over the past few years and show the impact on agriculture.
With the help of commercial fertilizer and better seed, yields have increased substantially, but the researchers say yields are still highly variable due to the weather. The trend is up, but highs are higher and lows are lower in recent years. They report that greater precipitation has helped yields, but excessive precipitation early in the growing season results in shallow root growth, nutrient deficiencies, and late season drought stress. Such excessive early season rains delays planting beyond optimum times and short seasons reduce yields.
This past summer high nighttime temperatures hurt corn yields by reducing pollen shed the next morning. The researchers report, “Iowa’s nighttime temperatures have been increasing more rapidly than daytime temperatures. In 2010, corn yield forecasts dropped from the previously projected 179 to 169 bushels per acre due to warm temperatures during the grain fill period.”
Nitrogen management is becoming more of a challenge because of changes in precipitation, and specifically greater spring rains have prevented timely application. Excessively wet soils have also lead to greater losses of nitrogen through leaching. Weather impact on the soil has frequently come from intense rainfall, and has increased erosion rates on topsoil. The researchers report a 20% increase in precipitation can increase erosion by 37%.
With increases in moisture and soil temperature, weed pressure is increasing and becoming more difficult to control. Weed pressures have been higher in recent years because of wetter springs, which in part, reduced the effectiveness of herbicides. The researcher say, “Weeds are more genetically diverse than crops, and therefore in the face of climate changes are more likely than crops to show enhanced growth and reproductive stability.” They report that with warming temperatures and higher levels of carbon dioxide, weeds are migrating northward, and with higher carbon dioxide levels, weeds will have less resistance to herbicides. “Current rainfall patterns also make mechanical cultivation more difficult. With increasing temperatures, harmful invasive species might pose new agricultural challenges, since many invasive weeds and plant pathogens can now overwinter in regions that were previously too cold for them.”
Greater need for tile drainage systems has resulted from increased precipitation and intensity of rainfall. Since 2000, rain has increased, and nitrate loss has increased from 5 to 50 pounds per acre. And with more rain, more tiling will be needed, increasing the potential for greater nitrate loss through streams.
Increases in temperature, humidity and soil moisture are contributing to greater disease impact on crops. Such a combination is blamed for more widespread occurrences of sudden death syndrome in soybeans. The combination is expected to generate more potential for the spread of Asian soybean rust. Subsequently, farmers have seen an increasing use of foliar fungicides the past few years.
Summary:
Weather conditions have been changing over the past few years with more rain, greater intensity of rain, higher humidity levels, and many other factors. As a result of such changes, increased erosion of soil has occurred and required more attention to soil conservation, there have been more acreage tiled, greater disease pressure has occurred, more weed control problems have occurred, and changes have occurred in farming that respond to changes in weather conditions.
Posted by Stu Ellis on 10/17 at 12:57 AM | Permalink