Showing posts from September, 2021

Reading Weeds

Weeds often tell a story about how a farm is managed. Most weeds grow really well in soils low in calcium with low humus. Often potassium and/or magnesium levels are high, but not always. Many weeds act as collectors of minerals that are deficient in the soil. When weeds die, they often improve the mineral nutrition of the soil. If farmers can understand what the weeds are telling them, they can change their management to reduce weed populations. Two problem weeds are giant foxtail and Canada thistle. Both these weeds thrive in soils that are highly saturated, poorly drained, have low porosity, and have low humus. These soils have low oxygen levels and contain anaerobic bacteria which are generally harmful to crop health. Low calcium and phosphorus are common problems in these soils. For Canada thistle, copper is also often low. Thistle roots can grow 20 feet deep and are a perennial plant, so they are trying to add humus and get oxygen deep into the soil. Foxtail roots have shallow fi

Corn Brace Roost: What Do They Tell Us?

  The 2021 crop year has been quite variable. A dry winter/spring followed by periods of excess rain and dry hot weather has caused considerable plant stress. Corn plants typically give us many tell-tale signs of soil conditions. One current debate is about the purpose of corn brace roots. Corn brace roots help keep the plant upright and also help with nutrient, water, and gas exchange. Shallow planted corn utilizes brace roots to prevent the corn from lodging. So, brace roots are at least beneficial for maintaining corn yields.  When corn with brace roots is dissected, however; a different story may emerge. Cut across the and stalk at the first leaf and then down through the center of the stalk to the root tip. Observe the lower part of the corn roots. Often the root tip up to the first brace root is brown and hard with few root hairs which is an unhealthy sign. Healthy corn plants without brace roots are typically white. The corn’s vascular system or plumbing for moving nutrients is

Improving Photosynthetic Potential

  Farmers do not often think about how their management practices can influence the rate of photosynthesis. Photosynthesis has always been assumed to be constant, but it is not. Photosynthesis does not occur at a constant rate, it varies each second, depending on light, carbon dioxide (CO2), water availability, temperature, leaf chlorophyll content, microbial impact on plant nutrient availability, and genetics. Some factors can be manipulated directly, others indirectly. Farmers can manage many of these factors, but not all, to improve yields. In a given year, water may be either limited or in excess supply while temperatures can also be extreme, either too cold or too hot. These factors often reduce nutrient cycling, resulting in reduced plant growth and yield. Soil compaction and poor soil structure can have a direct impact on microbial activity plant nutrition, water availability, soil temperature, and CO2 storage. Fall tillage is a major disrupter of the carbon and water cycle. Eve

Soybean Pests

  Many pests and diseases are rearing their ugly head this year. Fall armyworm, aphids, soybean cyst nematodes (SCN), sudden death syndrome (SDS), and white mold are common problems. Weather and management play a key role in the severity of these pests. Fall armyworm blow in from the south, most likely on tropical storms. Each female moth lays 10-20 eggs up t 100 eggs which hatch in 5-7 days and live 7-21 days. Eggs have been observed on fence posts, lawns, hayfields, corn, soybeans, and vegetable crops. The eggs hatch and the hungry larvae or caterpillars tend to move in waves, consuming everything in sight, even sometimes their own kind. There are two natural predator wasps that help control fall armyworm. Other options include bacillus thuringiensis (Bt) which is a natural control, neem oil, and pyrethrin insecticides. Aphids in soybeans are a problem especially during the reproductive stage (R5-R6) with an aphid threshold of 250 per soybean plant. Check 5 plants in 10 locations at