One acre of soybeans=82,368 crayons
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When is the best time to plant soybeans?
What is the ideal soil for growing soybeans?
Ideal soil for optimum soybean production is a loose, well-drained loam. Many fields have tight, high clay soil that becomes waterlogged when it rains. When the soil dries out, a hard crust surface may form which is a barrier to emerging seedlings. These high clay soils are low in humus and may have imbalance in mineral nutrients. Also, these soils may have few beneficial soil organisms (bacteria, fungi, algae, protozoa, earthworms and others). High clay soils may be amended with peat moss, sphagnum, organic mulch to increase the humus content. Sand may be added to loosen and aerate the soil and allow better drainage.
The advantages of loose, well-aerated soil include (1) movement of air to roots and nitrogen-fixing root nodules, (2) increased water-holding capacity with adequate drainage, (3) reduced erosion, (4) reduced weed populations, (5) maintenance of steady and balanced nutrients to roots and balance pH, and (6) increased potential to protect roots from harmful nematodes, insects pests, and pathogens.
How should the seedbed be prepared?
If soybeans have not been grown in a particular location for three to five years, it is best to inoculate the seed with the proper strain of nitrogen-fixing bacteria (Rhizobium). Some strains are more effective nitrogen fixers than others. Both seed and soil inoculum are available.
What happens during germination and emergence?
About five to ten days after planting, the new seedling arches through the soil surface (this is called emergence). The hypocotyl ‘hook’ (the emerging portion just below the cotyledons) begins to lengthen pulling the remainder of the seed upward, and the oval seed leaves (called cotyledons) open up. The cotyledons provide the seedling with a temporary source of food (plant useable nutrients originally stored as the seed was formed). The cotyledons quickly turn green and begin making additional food by photosynthesis. Shortly after the first set of true photosynthetic leaves is formed, the cotyledons drop off.
Seed germination and emergence is a critical period in the life of a soybean because poor emergence due to low temperatures, a soil crust, or seed planted too deeply allows seedling pests or diseases to drastically reduce yield.
What are the optimum planting depth, row width, and plant density for soybeans?
Plant density/population. Plant population varies depending on row spacing and environmental factors. A final plant population may range from 70,000 to 180,000. Typically, 150,000 is a good target for wide rows and 175,000 for narrow rows. Planting an excessive population may result in increased lodging, but an inadequate or uninformed stand may lead to higher weed populations. At lower populations, plants branch more and lodge less, while at high populations the opposite is true. Pods form higher on the plant in high populations. Weeds are more of a problem in low populations. Populations should be adjusted to reduce lodging and keep pods high on the plant. Populations can be increased when growing determinate, semi-dwarf and non-branching varieties. Additionally, the local soil type, environment, and seed quality can influence plant density.
Row width. An important goal is stand uniformity. In general, if weeds are controlled, soybeans will yield more in narrow rows than in 30 inch rows. Benefits from narrowing the row width will depend on location, soil conditions, weather conditions, planting date, and variety. In northern and central regions of the U.S., soybeans grown in narrow rows yield more than those grown in corn-width rows. In southern areas, there is a similar trend toward narrower rows and higher yield if good weed control is achieved. The ‘rule of thumb’ is that the soybean canopy should completely close (cover and shade the space between rows) by flowering time. The faster the soybean canopy closes, the fewer the number of weeds will grow. In narrow rows, weeds can not be cultivated easily.
Should fungicide treated seed be used?
What is the growth rate of soybeans?
What is the vegetative growth stage?
The first two leaves that develop are called unifoliolates, one simple leaf or blade supported by a petiole. The remaining leaves are compound leaves composed of three leaflets and are called trifoliolates. The cotyledons, unifoliolates, and trifoliolates are attached to the main stem at regions called nodes. Later, flowers will develop at the nodes between the petiole and stem, and branches also grow out from node regions. Newly formed upper leaves will shade older, lower leaves which may turn yellow and fall off.
How does the root system develop?
The young roots will develop root nodules within a week after emergence. The nitrogen-fixing bacteria, called Rhizobium, enter the nodules and after ten to fourteen days are able to supply most of the plant's nitrogen needs. In favorable soil conditions, about two dozen nodules will develop on the upper roots of a plant. Healthy nodules are pink or reddish inside.
What happens during the flowering stage?
Regarding flower development, soybean plants can be grouped by two main types: determinate and indeterminate. Indeterminate plants continue growing upward at the tip of the stem for several weeks after flowering begins lower on the stem. Upper nodes will not flower until later. Most commercial varieties are indeterminate. They typically grow taller and do well in short growing seasons. Determinate plants complete their growth in height and then produce all the flowers at about the same time. They are usually one-half to two-thirds as tall as indeterminate varieties.
The flowers of soybean are very small (1/4 inch) and are white, pink, or purple. They resemble the flowers of pea or clover, since the soybean is also in the legume plant family. Only about 50 to 80% of the total flowers actually produce pods.
What happens during pod development?
When should soybean be harvested?
What soybean varieties are available?
Most of soybean varieties grown commercially today are yellow-seeded field varieties used for animal feed and oil production (for food processing and industrial uses). Other varieties can be obtained for special uses: forage and hay (with an abundance of stems and leaves) and human food (large-seeded, various colored varieties).
Are soybean hybrids available?
How important is the soybean ‘MATURITY GROUP’?
Nitrogen (abbreviated N) is a macronutrient and needed by the plant for certain enzyme functions, to make proteins, and as a necessary part of chlorophyll, nucleic acids, vitamins and several other substances. Soybeans can obtain all the nitrogen they need from root nodule nitrogen-fixing bacteria. Soybean is a legume and which normally provides itself with adequate nitrogen through a symbiotic relationship with N-fixing bacteria of the species Bradyrhizobium japonicum. In this symbiotic relationship, carbohydrates and minerals are supplied to the bacteria by the plant, and the bacteria transform nitrogen gas from the atmosphere into ammonium-N for use by the plant. In fact, in tests where fertilizer nitrogen was added to soil, no yield increase occurred, plus the root nodules fixed less nitrogen.
Phosphorus (abbreviated P) is a macronutrient and is needed for general growth and metabolism and for photosynthesis. It carries energy from one part of a cell to another and helps transport food from one part of the plant to another. It also makes up part of cell membranes, nucleic acids and other components. It is necessary for growing really high quality crops. Young seedlings especially need phosphorus. The most efficient and economical way to get phosphorus to crop plants is to maintain soil with adequate levels of humus/organic material and beneficial soil microbes which decompose organic matter to release phosphorus and nutrients to plants.
Potassium (abbreviated K) is a macronutrient and is needed for the plant's enzyme functions, food transport, protein and chlorophyll production, and in regulating water balance, potassium is needed by soybeans in fairly large amounts. Most soils contain large amounts of potassium which are tied up and not available to plants. Soil microbes function to release potassium and other nutrients to plants.
If the soil is very low in potassium, a suggestion for an overall fertilizer source is potassium sulfate (0-0-50). Avoid using fertilizer formulations with chloride because the chloride ion can injure soil microbes as well as soybeans themselves if present in high amounts. Potassium sulfate is more expensive than potassium chloride, but only about one-half as much is needed, and the extra sulfur is usually beneficial.
Calcium (abbreviated Ca) is a macronutrient and is very important for growing high quality soybeans. Calcium is critically important for cell division, root hair growth, enzyme functions, and production of normal cell walls. Calcium improves plant's resistance to disease and gives higher quality, more nutritious crops.
In the soil, calcium and magnesium "compete" for plant absorption. Too much magnesium disrupts the plant's uptake of calcium and potassium, causing low quality crops. Additionally, excess magnesium causes soil to develop hard, crusty conditions. Most soils should have adequate magnesium. In general, soils in the western two-thirds of the U.S. have adequate calcium, while those in the eastern one-third may be deficient.
The best source of calcium is high-calcium lime (calcium carbonate) which has low magnesium and dissolves quickly in water. In alkaline soil, gypsum (calcium sulfate) is the best source of calcium.
Sulfur (abbreviated S) is a macronutrient and is needed to build proteins and assist enzyme functions. Many soils have adequate sulfur because of air pollution from burning high-sulfur coal, but some soils are deficient.
If sulfur is needed for healthy soil, the most readily available source is sulfate-containing fertilizers (calcium sulfate, potassium sulfate). Elemental sulfur (flowers of sulfur) is slow to release and become available.
Micronutrients are required by plants in small amounts and include iron (Fe), zinc (Zn), copper (Cu), boron (B), manganese (Mn), molybdenum (Mo), cobalt (Co) and chlorine (Cl). Molybdenum is needed by nitrogen fixing bacteria. In soybeans, the most frequent micronutrient deficiencies are for iron, zinc, manganese and molybdenum. But such deficiencies usually occur in poor, weathered or sandy soils, or in soils that are very alkaline or excessively high in organic matter (mucks and peats). A loamy soil with adequate humus and soil life should not have micronutrient deficiencies. If a micronutrient is deficient in your soil, only that element should be added. Too much of some micronutrients will be toxic.
Nutrient Balance and pH. For healthy crops and high quality yields, nutrients must be available to the plants in the proper amounts and in the right balance. The soil pH (acidity or alkalinity) affects the availability of soil nutrients to plants. The pH scale is expressed as a numerical scale ranging from 0 (most acid) to 14 (most alkaline), with a 7 being neutral. Soybeans grow best in slightly acid soil but can tolerate a wide range of pH (pH 5.8 to 7.0). Soil pH also affects the types and ability of soil organisms to live, including nitrogen-fixing bacteria. Humus in soil will buffer extremes in pH, and lime can be added to amend soil and counteract acid soil.