GreenSeeker Sensor Results, Mexico 2002

Mexico Sensor Results,
Growth Stage where Differences are best detected, use of the CV

CV = standard deviation / mean CV = square root of the MSE / mean (coefficient of variation, %)

Influence of Residue on NDVI in wheat

1. Analysis of Wet vs Dry Soil Readings (follow this link)
RICE, flooded

2. Foliar Application of UAN in Corn

3. INSEY Equation for Spring Wheat (Ciudad Obregon)

4. Predicting Durum Wheat Grain Yields (Rust Breeding Nursery), El Batan

Figure X. Coefficient of variation from NDVI readings taken over time from 4 different corn rows, 27 m in length, Texcoco, MX. The average number of sensor readings per meter is 18.

The date where CV's start to decrease coincide with the physiological stage where the in-row canopy begins to close. Recognition of the point where the maximum amount of variability is expressed might also be the time where variable rate treatments will have the greatest benefit.

September 6th, 2002, Corn Sensor Readings

Fine-silty, mixed, Fluventic Hapludoll (click here to see the profiles, El Batan)

Single row (27 m in length, 125 individual corn plants) NDVI readings collected at different stages of growth, beginning on the 12th of August, 2002 (V4), to August 28th (V7).

When does a corn plant in monoculture corn become a weed?

By plant NDVI readings from corn, V12, Texcoco Mexico (above) and picture of the same corn row below

Data collected by Paul Hodgen, Ken Sayre, and Matthew Reynolds in Ciudad Obregon, MX shows a trend for improved prediction of yield using Green NDVI (versus Red NDVI) for data below that included 48 genotypes and 3 N rates.

The chart above plots cumulative distance (actual location of plants) and NDVI. We will use some of this information to predict distance between plants using sensor readings.

Foliar P Experiment, Ciudad Obregon, Spring Wheat, 2002

Table 1. Treatment structure including preplant and foliar applications of KH2PO4
for spring wheat production, Ciudad Obregon, Sonora, MX

Trt	Preplant P	Method	Foliar P	Growth Stage	Grain Yield	Grain P	Grain N
	kg/ha		kg/ha		kg/ha	kg/ha	kg/ha

1	0	-	0	-	6650	10.4	109
2	0	-	2.5	Feekes 6	6470	11.4	104.7
3	0	-	5	Feekes 6	6954	12.3	116.3
4	0	-	10	Feekes 6	6750	11	111
5	60	BRP	0	-	7332	14.3	125.3
6	60	BRP	2.5	Feekes 6	7372	14.3	124
7	60	BRP	5	Feekes 6	7754	14.9	132.7
8	60	BRP	10	Feekes 6	7475	14	127.3
9	0	-	5	Feekes 10	6897	12	116.3
10	60	BRP	5	Feekes 10	7448	13.8	125
11	0	-	5	Feekes 10.5	6903	12.4	115.7
12	60	BRP	5	Feekes 10.5	7842	15.3	135.3
13	60	BA	0	-	7206	12.4	119.7
14	60	BA	5	Feekes 6	7091	13.2	120

SED					154	0.8	4.6

BRP, P applied broadcast preplant as 0-20-0 (N-P-K)
BA, P band applied at planting as 0-20-0 (N-P-K)

A significant and consistent trend for increased wheat grain yields was noted for the 5 kg/ha foliar P application both at the 0 and 60 kg P/ha preplant rate. At the higher 10 kg/ha foliar P rate, no differences were observed.

Trimble Pocket Sensor, Greenseeker, NDVI, nitrogen