July 23, 2013
NASS to Start Surveying Fields for August Crop Report
This week NASS will start the process of conducting objective yield surveys in the principal corn and soybean producing states in the Midwest. Here is an outline of how the process works.
- The surveys are conducted in hundreds of fields across the Midwest.
- In a randomly chosen spot in the field, 20 feet of two adjacent rows are marked off.
- For the August Crop Report, the surveyors examine the first two feet of each row.
- For the September Crop Report, they examine foot number three and foot number four of the same two rows.
- In October they look at foot number five and foot number six. Once the crop is mature, the remaining portion of each row is harvested.
- For corn, the number of plants and ears are counted. If the ears are more fully developed, the length of the ears and the weight of the ears are determined.
- For soybeans, they count the number of plants, the number or nodes (this is where the leaf attaches to the stem), and the number of pods if they are present.
- This process is repeated for the September and October Crop Reports and maybe the November report if the field is extra late in maturing.
- After the field has been harvested by the farmer, they return to the same area and determine the harvest loss by counting the number of kernels or seeds on the ground in a defined area.
The objective yield surveys are then combined with the subjective yield estimates sent in by thousands of farmers. As you can imagine, the accuracy of both the objective and subjective surveys improves with each successive sampling. The surveys will be conducted during the last week of July and the first week of August and the yields are estimated as of August 1st.