AERIAL PHOTOGRAPHY FOR AGRICULTURE

Created: 9/1/1967

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INTELLIGENCE

A collection ol articles on the historical, operational, doctrinal, and theoretical aspects ol intelligence.

All siatements of laci. opinion or analysis expressed in Studies in Intelligence are those of the authors. They do not necessarily reflect official positions or views of the Central Inielhgence Agency or any other US Government entity, past or present. Nothing in the contcnis should be construed as asserting or implying US Government endorsement of an article's factual statements and interpretations.

The potential application of overhead reconnaissance techniques to crop

AERIAL PHOTOGRAPHY FOR ACRICULTUItE VVOlUm R. Cawer

Aerial photography has been used in the United State* tor several decades to obtain useful Information on agncultural feaourccs, and in recent years intelligence analysts have taken increasing advantage of ft for help in estimating crops and identifying troublehe agricultural sector of Communist countries.ource ofon the agricultureoreign power it is still in its infancy, but it shows promise ofaluable aid.

Stagnation in Communist Agriculture

Communist leaders have revealed an increasing awareness that the provision of an adequate supply of food is one of their most critical problems. In nearly all Communist countries stagnation inhas seriously damped economic growth. Because of thisin the face of continued increases in population, they have had to spend an average of more thanillion annually during recent years to purchase grain from the West, while by way of contrast the United States earns aboutillion annually from sales of grain abroad. These purchases of grain haveevere strain on Communist reserves of gold and foreign exchange. For the USSR and particularly China, grain imports haveacrifice in the acquisition of badly needed machinery and equipment

The Communist leaders now realize that agriculture must bea higher priority than in the past, even though this maysome diversion of investment funds from defense and heavy industry, the traditional priority sectors. Emphasis is befog given to agriculturalhigher yields per acre. Increased supplies of mineral fertilizers, pesticidei, and improved seeds have been promised, along with eipanded irrigation and higher iiKerjtives for farm workers and managers. The USSR's record crops6 reflect in part this greater priority. But to what extent theeffort can mitigate the serious agricultural problems that stem

largely from the nature of the systemritical question before the economic intelligence analyst

Crop Estimation Procedures

The analyst attempting to evaluate the current agriculturalin the Communist countriesery difficult task. Inadequate sources of information make the estimating process much less refined than be would like. He is envious of. Department ofStatistical Reporting Service, which in estimating US. crop production has available tbe periodicoreolunteer crop and livestock reporter! scattered throughout theHe himself has to build up his estimate of the early summer condition or the final harvestommunist crop from scattered bits and pieces of evidence.

In trying to determine, say, the actual amount of grain harvested in the Soviet Unioniven year be begins with an estimate of sown acreage by region and by kind of grain. Yields per sown acre by crop are estimated from widely variantweather information provided byir Force, reports from the press and Western travelers describing the condition of the crop at various times during the season, the reported progress in seeding and harvesting, data on grain procurement in various administrativegeneral statements made by Soviet officials, data on inputs such as machinery, fertilizer, and seed. These estimated yields per acre arc checked against tbe figures obtained for earlier years when crop and weather conditions were simitar in the respective regions. Then they are multiplied by the estimated sown acreage to give the production of each kind of grain and the total grain harvest

In the past few years aerial photography has become an important new source in this process, primarily, thus far, as applied to China and North Vietnam. Here its supporting role has been considerable because of the paucity of data on these countries. In thehotography over China partially filled die almost completeof information on agricultural production. During the springor example, weather information and Chinese press and radio reports indicated the possibilityather severe drought in south China. Chance availabilityhotography over south and central China at various times from January to June providedin the form of drted-up river beds and reservoirs as far north as Hunan province. Similarly, to the late summer and autumn

3 the Chinese press and travelers reported severe flooding in the north China plain. Weather data also showed above-average rainfall for the period March-July, followed by very heavy rains over large areas in the first ten days oftonches in the area of maximumhotography to September and3 revealed that large areas of the plain were still covered by water.

More basically than In this verification of moisture conditionscrop production, the photography of North Vietnam and China has been valuable for. purposes of farniliarization with agricultural rmocesses and projects"in the two countries. From'^recormaissance photography over North Vietnam the photointerpreterj have bsen able to tell what state of preparation fields are in for rice culture and then the crop's stage ofseedlings to fully mature rice beingumber of farming operations such astransplanting, and harvesting were readily identified. It has also been possible to spot certain conditions that, depending on severity and time of occurrence, could significantly affect crop yields, such as lodging (grain flattened by wind or rain) and flooding. Photography of China has been particularly helpful in evaluating the success of programs to reclaim land and develop irrigation. Large areas of reclaimed land in northern Heilungkiang province appeared to have been abandoned. In other areas, particularly in the north, many canals dug during the Leap Forward were subsequently refilled and the land returned to cultivation.

Potential Refinement

Esperts in the development of remote-sensing devices believe that satellite-mounted remote sensors have great potential as an aid to estimating crop production worldwide. Wemher von Braun, asked about the possibility of directing some of the "technological spin-off* from our moon program toward solving the world's hunger problem, replied:

It ha* been demonstratedp line Sights, usingsophisticated photographic equipment and remote sensors, that from high altitudes you can distinguish very dearly rye from barley, soybeans tramoreover, you can distinguish healthy crops from sick ones. You can, for example, distinguish com afflxflcd by black stain rust from healthy com You can also find out whether the proper (erttlixer has been applied, whether there Is loo much salinity In the loiL

By continuously surveying and re-turveylng ibo tilled areas of thoby keeping tuck of each patch of land a* it develops from (be planting season io the spring to the harvesnng season in thecan predict very well the crop expectationslobal scale- When drought bits an area, you wiDocal setback. If some crop has boco damaged or destroyed byyou* latellite-uiounted remote seusors wiD End It

A* you get closer to the harvesting period you can, by feeding aD that inform* Looomputer, predict just how touchrop to expect, and what land, aod when and where.

Of course, you would need plenty of correlation data before thebyatellite system would be reliable. You get thislimply by comparing the "groundr the, facts detonuDed bywaitingield, with what the satellite equlpusent'sentsame

Well fn advance of this suggestion from Von Braun, CIA'sand development organization had begun intensiveof the feasibility of deterrruning yields of rice, wheat, and sugar cane from high-altitude photography, and the preliminary results werelights were made with cameras of such focal lengths as to simulate from several conventional altitudes the corresponding high-altitudeew flights were madeltitudes for purposes of correlation. Fltotography was also takenoot tower to permit large-scale sequential photography of test crops planted adjacent to the tower. Various filters were tried inwith black-and-white, color, and infrared film. Ektachrome infrared seemed best for rapid monitoringrop's health, but once yield-reducing factors were suspected the black-and-white was better able to discriminate amoDg these factors.

In thesereliminary photointerpretatlon to establish parameters was conducted during the early stages of each crop, and then its further growth was followed by photouiterpretation at various stages. The procedure used in estimating yield was toheoretical maximum potential yield It was assumed that, given seed typical of the variety grown with success in the study areauitable plot oferfect crop of known yield would result except for the action of yieU-lirniting factors which may become operative from the day the seed is sown. These degrading factors

' US. rVeuu and World Repot,

' "Invc*ligation on (be Feasibility of Determining Yield of Rico, Wheat and Sugar Cane by Means of High Altitude Aortalols. I. II, and HI, Final Report

III* .I1 I. I

may be classified as physical that is the absence of crop-producing plants in any part of the field or less than ideal plant density, ordisease, drought. Or other operants against the vigor and hence the yield of the plants. These factors may affect yield ia decidedly different ways depending upon the severity of their manifestation and the stage of growth at which they appear.

Statistical analyses were performed on the results of the photointcr-pretatioo as the yield estimates so reached were correlated with ground-truth yields obtained after harvest. Sources of error were evaluated with respect to each of the photographic scales, film-filter combinations, and photo dates. It was foundumber of the 'yield-reducinginsects, weeds, drought, flood,mineral deficiencies,be assessed on aerialFor an accurate assessment of the degree to which these will affect yields, however, the photography must be taken according to specifications tailored to each factor so as to detect the extent and severity of its manifestations. It must be taken In the spectral bands that give the best tone values for the factor in question. It must also be taken at the right times during the growing season.

The contractor who carried out this investigation is testing the techniquearger scale during7 growing season byto estimate the yield per acre and total production of wheat for the state of Northorth Dakota, the leading US. spring-wheat-producing state, is in many ways climatically analogous to die new lands area of theive-mission scheduleircraft was carried out during the June-September period, each mission making three north-south flights across the state. Thetaken by multispcctral filtration, is still undergoing analysis at time of writing.

One of the difficulties in analyzing the output of photographicis the tremendous volume of imagery that must be scanned. The problem becomes particularly acute when the target isproduction, with scattered fields of different types of cropshundreds of square miles. Its solution may lie in sophisticated sampling procedures, origh degree of automation in theof the plntography, orombination of both. An ultimate goal is the development of remote sensing systems that require little or no human participation to reduce their raw data to the

'"Technical Ptoposal7 Clutter Program" .

desired end tnfoimation. One system now under investigation records tbe relative amplitude of spectral components of theource and applies automatic pattern recognitionto identify designated characteristics so revealed. Thisnow under way at Purdue University. Department of Agriculture and NASA contracts, assumes that various crops can be differentiated on the basis of mullispectraj response "signatures* at various times during the growing season and that for any particular crop it will lie possible to determine what variations in tho response signatures, are caused by yield -influencing factors and so, distinguish, these. In Initial tests die computer outputtrip of Indiana farmland one mile wide ana Eve miles long, plotting the major vegetative patterns on it. Tba operational stage of automated scanning and data reduction fa unlikeh/ to be "just around theowever.

Outlook

The results of developmental research to date in aerial photo estimation of crop yields maVo it seem likely that this technique will become an increasingly important tool for the intelligence analyst estimating Communist agricultural production. For the foreseeable future, however, it will probably supplement rather than replace present methods. And pending further development and refinement of techniques for computerized estimation from photographic patterns, the intelligence community will continue to rely on tbe skills of specialists In pbotointcrprctation for qualitative evaluation ofconditions in problem areas where photo coverage is

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