Title: Selected reading in agricultural applications of small-format aerial photography
Abstract: Processing: The present E-4 system with tanks in a controlled water bath is quite adequate since it will accommodate 200 pictures in one batch.It is absolutely essential that the process be done immediately after the flight.This enables the crop producer to have a very up-to-date service.Response of Producers: These observations are based on the results of a survey and following lengthly discussions with potato growers: That pictUres of potato fields should be done every 10 days during growing season.On a normal year June 30th should be the time to begin photography carrying on the 10 day cycle until harvest season• which would be early September.This would mean 6-8 separate sessions of photography during the season.Picture Angle: It was the opinion that more detail was shown from a picture taken straight do.wn as well as more consistant exposure.However, an oblique picture can often en• compass more area as weU as enabling the viewer to identirJ the particular field.Scale of Photography: Provided that the field was not too elongated it was felt that up to 80 acres in one view would show sufficient detail in the picture.Naturally this scale-, appro:::.(1:250,000},.would not show individual plants but does show areas of discoloration.In order to study seeding misses & germination var• iation an area of about 5 acres or less should be included in.one frame.Late Blight Identification: Since there was no late blight reported in Manitoba during 1975 we have no conclussive evidence.However, we were able to show definite variations within small areas of several fields.Tne majority of producers have indicated on their surveys that this technique would have illustrated the occurance of late blight.Commercial Service: Most of the growers involved with the service have indicated that they would like to have this service offered at a commercial level in 1976.Other benefits to Potato Growers: Again many of these ide3.soriginate with the producer after they studied the photographs.Soil variations: Due to the difference in reflectance shailow topsoil is ciearfy indicated.This is due tO the fact that clay or sand ts often mixed with the loam due to deep tillage practises.Having chis knowledge the producer• may alter the type or quantity of fertilizer or he may choose another variety of crop.Drainage Patterns: Since moist soil shows differently the low lying areas can be easily illustrated.This could be invaluable information if one were investing in 3.n irrigation system.The tecllnique of using color infrared aerial • photography to detect disease and stress in agricultural crops has been known for some time.In 1%7 Franklin E. Manzen of University of Maine clearly illustr3.tedhow both color and black and white infrared photography could be used to detect late bligbt in potato fields.While attending tbe 1975 ann•ual m~ng of P1ant Pathologists held in Houston, I was surprised to discover tbat ozily a handful of people are actively pursuing this technique.Most of tbe present efforts of developing this technique for practical use are still based with University research.Consequently, private industry has not yet arisen to the challenge of ~viding a commercial crop surveillance service using infrared aerial photography.Our technical research program of 1975 was intended to develop an aerial crop surveillance service in Manitoba.As well a.s developing the service to a very dependable level it was also necessary to acquaint the producers.with the benefits of this program.This often required taking sample views of his fields and helping him to determine the results.Throughout Manitoba~ from Winkler to Portage to Carberry we l.l11dertook to photo• graph 5.000 acres of potato fields on a weekly basis.The producers who joined the program were required to contribute S 1. 00/ acre.The rest of the expense was born by a F eden.! government grant •from Energy, Mines and Resources, as well as the business involved, McKinnon Photo, Glenboro.Manitoba.Following is an outline of some of the technical requirements and data of the pro• gram.