The objective of this study is to evaluate the use of Global Positioning Systems (GPS) in conjunction with a regular crop scouting program to pinpoint exact pest locations in these fields. Once documented, this data will then be used to make pesticide applications if needed. Fields will be divided into two equal parts. On one side the field will be farmed according to the producers normal production practices. On the other side GPS will be used to document exact pest location. With this data we will treat only portions of the field needing applications rather than the entire field.
Many farmers believe that SSM is to costly and thus have not added it to their operation. The results of this research will be used to develop a comprehensive economic and environmental analysis comparing SSM vs. normal production practices in an actual farm setting.
The entire field was scouted on a regular bi-weekly basis from mid-April through mid-October. The field scout was equipped with a Fijitsu handheld PDA and a Satlock differentially corrected global positioning satellite receiver. This equipment allowed the scout to record detailed field data showing weed species and exact weed location within the field. Weed data was recorded in areas where groupings of three or more species were observed in a radius of five feet or less.
Results:
Field data was used to make pesticide recommendations for this field using the following guidelines:
Plot A was treated with the farmers normal production practices.
Plot B was treated with recommendations from the scouting and GPS data.
Figure 1 shows field data including weed species and location one day prior to pesticide application. Weed pressure, was heavy throughout these plots. Figure 2 shows the herbicide application patterns for this field. In Plot A the farmer decided to spray the entire field based upon weed pressure and past experience. Roundup herbicide was applied at a rate of 1.5 Qt./A
In Plot B only the areas designated with heavy weed pressure received herbicide applications. Treatments were made to approximately 69% (25 out of 35 acres) of the area in Plot B. The boxes in Plot B indicate the areas of the field receiving herbicide applications. These areas received Roundup at a rate of 1.5 Qt./A.
Figure 3 shows the reduced weed pressure in each plot at three weeks after application. Adequate weed control was achieved in both areas of the field. With regular scouting and documentation of weed location herbicides were applied to approximately 69% of the acreage in Plot B. This resulted in a savings of $16.25 per acre (herbicide cost = $11.25 per acre and application cost = $5.00 per acre). The reduction in herbicide usage resulted no apparent impact on yield. Yield data analysis indicates no significant difference in the yield for these two plots. The yields in Plot A and Plot B were 59.7 and 61.2 respectively.
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