By Plant Prediction of corn grain yield, yield prediction, corn forage N uptake, corn nitrogen uptake

By Plant Prediction of Corn Grain Yield from In Season Measurements
Added Corn Research (click here)

Causes of Plant to Plant Variability in Yield within Corn Production Systems

Average USA corn yield: 130 bu/ac
Corn Acres Harvested: 69.1 million acres
Corn Production USA: 9.0 billion bushels

By-Plant Prediction of Corn Forage and Grain Yield Using NDVI and Plant Height at Various Growth Stage, Freeman et al. (2004)

By-Plant N Management and Delayed Emergence Trials

Corn Research (Mexico 2002, and Foliar UAN)

Nitrogen Uptake in Wheat and Corn

1. Estimating Corn Yield Losses from Uneven Plant Spacing (Carlson, Doerge, Clay)

2. Plant to Plant Variability in Corn Production (Agronomy Journal)

CV algorithm tested for variable N application in Winter Wheat

3. By-plant variability in corn grain yield (45 transects)

4. Use of Fixed Distances or Actual Distances to Compute By-Plant Corn Grain Yields, What is the Difference?

5. Causes of By-Plant Variability in Corn Production Systems

6. Spatial Variability of N, What is the Scale?

7. What are the Errors in Predicting Yield on a By-Plant Basis?

Corn yield prediction from NDVI sensor readings collected at V8 from locations in Mexico, Nebraska, Iowa, and Oklahoma where INSEY (in-season estimated yield) was NDVI divided by the cumulative growing degree days from planting to sensing.

The above graph shows results over 2 years (6 total sites in Oklahoma) where corn forage N uptake can be predicted from growth stages ranging from V8 to V10. However, it should be noted that this was from by-plant data (NDVI and N uptake determined by-plant).

Relationship between cotton lint yield and INSEY (NDVI divided by cumulative GDD)

Kent Martin employs our new shaft encoding GreenSeeker sensor combined with Sonar for height that allows for by-plant measurements in corn (variable rate technology). These results are being applied within the Nitrogen Fertilization Optimization Algorithm (NFOA) that is being tested in corn this spring in Oklahoma, Nebraska, and Iowa.

The relationship between INSEY and grain yield using 3 different approaches where predicted yield that can be achieved with added N fertilization is; a) yield potential multiplied times the response index, b) maximum yield can be achieved regardless of the response index (generally low CV's), and c) yield potential multiplied times the response index but as a function of CV.

Mean: 9496.17 kg/ha
Standard Deviation: 3737.60 kg/ha

Mean 9983.29 kg/ha
Standard Deviation: 4132.39

Lake Carl Blackwell, Oklahoma. Variability in by-plant corn yields over 15 m of row.

Shelton, NE, MSEA Site, USDA-ARS 2004. Work by Paul Hodgen, Kent Martin, and Kyle Freeman has shown that SPAD readings taken "by-plant" at V16 were highly correlated with final "by-plant" grain yields. This relationship would not have been observed unless the by-plant resolution had been used.

Reproducibility of NDVI readings over 16m using an on-board shaft encoder, with 50 corn plants sensed at the 7-leaf growth stage on May 23, 2003, Perkins, OK.

Average NDVI (by-plant) determined by collecting sensor readings from the sum of 1/2 the distance left and right to its neighboring plants. Similarly, by-plant yields were determined from the from the exact same area for which NDVI measurements were captured.

The NEW GreenSeeeker Variable rate applicator for corn and sorghum was completed on August 19, 2003, This is a modification of the version below whereby the valves and nozzles are all assembled on a shaft that travels just above the ground. Skids and a retractable arm allow for operator error.