Precipitation Deficiency Research Articles

The Drought of 1934 and Its Effect on Trees in Kansas

The record-breaking temperatures, together with a pronounced shortage of moisture, made the year 1934 one of the most disastrous years ever known in Kansas for crops and vegetation in general. Several significant records are worthy of mention. According to the Weather Bureau at Topeka, Kan., the average temperature for the year, 58.5? F., was the highest since the establishment of the state-wide weather record service in 1887. July was the hottest month ever known to occur in Kansas, while the average temperature of the summer established a 48-year record. Extremely high temperatures began about the middle of June and continued with increasing intensity with scarcely a break until after the middle of August. Temperatuires of 105? to 111? were common throughout July and the first two weeks in August. The maximum at Manhattan was 115?, while 113? occurred on several occasions. On July 13 a reading of 119? was reported at Lincoln, Kan., which exceeded by 3? any other authentic high-temperature record ever reported in the state. Complete records for temperature and precipitation for March to September at Manhattan, Kan., are shown in table 1. The year 1934 began with a mild, dry January, with frequent dust storms. Snows in February offered some relief, but serious dust storms resulted from dry, windy weather throughout March and April. This was followed by the warmest May on record. June was warm and dry. It was the fifth successive year with a deficiency in precipitation, each year having a less amount of moisture than the preceding. The average for 1934 for the state as a whole was 20.02 inches, which is 6.77 inches less than normal, and the least on record except in 1910 and 1917. The meteorological conditions of 1934, coupled with greatly reduced subsoil moisture in 1932 and 1933, prepared the way for one of the severest tests on the survival of vegetation, not only on crops in general, but also on longestablished vegetation, as native trees and shrubs, both evergreen and deciduous. This unusual situation afforded an opportunity to make a definite record of the effect of the heat and drought on trees in Manhattan, Kan. The writers were interested in learning what effect the drought and excessive heat produced on the various species of trees which have long been established in their present locations. The same environmental conditions probably would not be encountered in other cities in Kansas; therefore, the first part

The Drought of 1930

Precipitation and run-off records indicate that droughts of major proportions, both in severity and in extent, have occurred at intervals of 15 to 20 years and that droughts of equal severity but of less extent have occurred at intervals of 3 to 6 years. The drought of 1930 was a major drought, in which some of the outstanding features were as follows: 1. The year 1930 began with water conditions in most States about normal. 2. The area affected and the deficiency of annual precipitation over this area were slightly greater than in any previously recorded major drought. Neither of these conditions, however, was materially worse than for the major droughts of 1894 and 1910. 3. In most of the areas affected the duration of the drought was much longer than that of any previous one. 4. The minimum annual precipitation records were broken in 18 States, and the monthly precipitation in many localities was below normal for 8 to 14 consecutive months. 5. In many of the areas affected the annual stream flow during the water year ending September 30, 1930, did not fall below previously established minima, and but few records of minimum daily flow were broken. On the other hand, for many streams the monthly flow and the annual flow on the basis of the calendar year reached new minima and for most streams all records of long-continued low flows were broken. 6. Ground-water levels were rapidly reduced to a point below which they did not fall appreciably and the later fall was very slow, indicating that the available ground-water supply for most river drainage basins is so great that it is adequate to maintain the stream This content downloaded from 157.55.39.104 on Thu, 01 Dec 2016 05:55:14 UTC All use subject to http://about.jstor.org/terms 1824 JOHN C. HOYT [j. A. W. W. A. flow at practically a fixed minimum without appreciable change for a considerable period of time and probably through any drought that may be expected. 7. Normal activities, both economic and social, were probably interfered with to a greater extent than during any previous drought, and the resulting losses were greater. The effects of previous droughts related primarily to economic and social activities The effects of the drought of 1930 were also an important factor in political activities. The drought emphasized the following needs: 1. The collection in more detail of the hydrologie data required in wise planning and use of our water resources. This should include a country-wide research into the quality and quantity of both surface and ground water supplies, and also the collection of information leading to the best methods of conservation of supplies for their highest ultimate use. 2. More adequate works for storage of both surface and ground water supplies. 3. More care in planning, so that development will be kept within the limits of available water supplies. 4. More adequate facilities for the disposal of sewage and industrial wastes, in the interests of health and social betterment. 5. More systematic planning and operation of agriculture, to the end that all farms shall produce food crops as well as money crops, in order that adequate food supplies will be insured during years when returns for money crops are small. In the studies leading to this report the following observations were made: 1. That a knowledge of the occurrence of ground water is essential in surface-water studies. 2. That the effects of vegetation are important factors in the consideration of water supplies during the growing period. 3. That precipitation data must be used with great caution in water-supply studies and that there is practically no relation between precipitation and low-water flows. 4. That conclusions drawn from precipitation or stream-flow data expressed as percentages of the mean may lead to erroneous conclusions. 5. That conditions in different drainage basins are so varying that estimates of low flow, based on comparison with adjacent areas or on precipitation data, can not be made with any degree of certainty. This content downloaded from 157.55.39.104 on Thu, 01 Dec 2016 05:55:14 UTC All use subject to http://about.jstor.org/terms VOL. 23, NO. Il] DROUGHT OF 193

Weather, a Factor in Outbreaks of the Hickory Bark Beetle

The contents of this paper indicates that weather has a marked effect on barkbeetle outbreaks. A hickory barkbeetle, Eccoptogaster quadrispinosus , outbreak occurred during the drought period of 1925 in North Carolina. The marked deficiency in precipitation weakened hickory trees by checking growth and rendered them attractive to beetle attacks, favoring brood development. An excess of precipitation during periods of beetle flight resulted in a partial mortality of the adults, thereby considerably reducing the number attacking and also rendered trees unfavorable for brood development.

The Squash Beetle in Arizona, Occurrence and Probable Manner of Introduction

During 1921 the squash beetle ( Epilachna borealis Fab.) appeared in the vicinity of Douglas, Ariz. It slowly extended its range during the period 1921 to 1924 until it covered about 65 square miles. During 1925 the insect was not found within the previously infested area, and it is believed that a deficiency in precipitation, combined with an increase in the mean temperature, may have been responsible for the disappearance of the pest. The beetle differs from the Eastern form in being somewhat smaller in size and in the absence of marking on the prothorax. The dots on the elytra are also smaller.

Three Years of Paradichlorobenzene Experiments in the South

Paradichlorobenzene treatment of peach trees for control of the peach borer, Aegeria exitiosa Say, has become an annual practice in the program of orchard management in Georgia. Five hundred thousand pounds of the material were used in the Southeast during the 1923 season. The results of experiments indicate that under normal conditions the large doses exposed for short periods are not as effective as the smaller doses exposed for four to six weeks. No tree injury resulted from the use of the various doses around three, four and five year old peach trees in Georgia during 1921 and 1922 when normal weather conditions prevailed. However, during the 1923 season a precipitation deficiency occurred accompanied by abnormally high temperatures. These unusual weather conditions caused rapid action from the gas, and as a result some rather severe injury has shown up on three year old trees from the use of the ¾ and one ounce dose. During each of the three years no injury has resulted from the use of the ¾ ounce dose around four and five year old trees for twenty eight days. One and two year old trees have shown, each year, more or less injury from the use of the ½ and ¾ ounce dose. To date no injury has been revealed from allowing the mounds to remain around the trees over winter. Late October and November applications of paradichlorobenzene gave a control of around seventy-five per cent. December applications were worthless. Applications made around April 1st in Georgia gave about seventy pet cent control. Laboratory experiments show that the gas is liberated at about the same rate in both sandy loam and clay soils. Tests in the laboratory have repeatedly shown that the higher the moisture content of the soil and the lower the temperature, the slower is the action of the gason the borer.