|
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
 |
||
|
|
|
|
|||||||||||||||||||||||||||||||||||
 |
|||||||||||||||||||||||||||||||||||||
|
Wheat Yields are a Function of a Combination of Factors 1. Plant population: which affects tillering and number of heads 2. Head size: the number of spikelets per head 3. Number of kernels per spikelet 4. Size of the kernels. Remember the Feekes scale? Well, here is where the Feekes scale becomes important: The amount of nitrogen available to the plant through Feekes stage 6 is critical to determining the number of tillers formed, unless water or some other factor becomes limiting. Feekes stage 6 is when the first node of the stem becomes visible. The number of tillers that will form a head is determined by Feekes stage 6. The factors that affect head size are most significant from mid-to-late tillering, which corresponds with Feekes stage 3 for winter wheat (this occurs by the time the main stem has five or six leaves in spring wheat). Number of kernels per spikelet is determined at late jointing - Feekes stages 5 to 6, while the maturing process occurs during the period between boot and early heading (stages 10 to 10.5). Management practices starting at stage 8 can have a significant effect on kernel size. The key is to keep the flag leaf healthy as long as possible and to provide enough water and nutrients for maximum grain fill. —Jim Bauder, Montana State University extension soil and water quality specialist Determining Yield Probability Based On Soil Moisture Studies at NDSU have indicated that five inches of water is needed by wheat to reach the heading growth stage. After this requirement is met, each additional inch of water will produce 4-7 bushels of wheat. The water can be provided by soil or rainfall. Sandy soils hold about 1 inch of plant available water, clay soils about 2 inches and loam soils 2.25 inches per foot of soil at field capacity. Average May, June, July rainfall in N.D. is about 8 inches. Rainfall depending on crop growth stage, is more efficiently used in June than in other months, which may provide increased yields above predicted yields.
|
|||||||||||||||||||||||||||||||||||||