Hail Damage Research Articles

Yield Loss Due to Simulated Hail Damage on Corn: A Comparison of Actual and Predicted Values1

AbstractThree simulated hail damage experiments were conducted to compare realized grain yields with those predicted by current hail adjustment procedures. Treatments included reductions in plant density and defoliation. Population density reduction was studied for 3 yr. An initial population of 6.4 plants m−2 was reduced to 5.9, 4.9, 4.0, and 3.0 plants m−2 at the 6‐, 9‐, 12‐, and 15‐leaf stages. Leaf stage did not affect grain yield, but yield decreased −2, 2, 6, and 19%, respectively, with each reduction in population. Yield losses due to population density reduction were less than those predicted by hail insurance procedures, especially for losses after the 10‐leaf stage. One‐hundred percent defoliation at the 4‐, 5‐ and 6‐leaf stages did not significantly reduce grain yield. One‐hundred percent defoliation from the sixth through the ninth leaf stages showed a linear decrease (regression coef. = −1.15) in grain yield with later leaf stage. The effects of early season complete defoliation varied with year. These results generally agree with the hail loss charts for very early season, 100% defoliation. Defoliation of 0, 33, 66, and 100% at the 6‐, 12‐, tassel, and blister stages was performed over four environments. Grain yield was reduced with increasing severity of defoliation, and with growth stages near the tassel stage. Five treatments produced a greater yield reduction than predicted by the hail adjustment procedures, while one treatment showed less yield reduction than predicted. Later treatments tended to show greater yield loss than predicted.

Hail in Southwestern France. I: Hailfall Characteristics and Hailstrom Environment

Abstract In the context of an experiment of hail prevention in the Aquitaine region, 12 869 reports of damaging hail have been compiled during 29 years in an area of 88 980 km2. These observations, together with crop insurance data, have led to a unique hail climatology. The data presented in this paper concern the geographical distribution of hail damage, the yearly, 5-day and hourly frequencies of hailfall, and the distributions of hailstone size and of hailfall duration. Most of these data are well explained by the fact that hail in the surveyed area is the result of almost any rather severe thunderstorm: large hail, however, is produced by a few isolated long-lived hailstorms traveling downwind of the central part of the Pyrenees with the strong upper level winds. Study of the mean characteristics of 30 of the most severe storms which have damaged the Aquitaine in the last three decades leads to the following description: a typical long-traveling hailstorm moves at 15 m s−1 for 1.5 h, dropping a hail ...

The Relationships of Nitrate Concentrations in Young Corn Stalks to Soil Nitrogen Availability and Grain Yields1

AbstractThe importance of N in crop production makes accurate estimation of the available N in the soil desirable, especially with increasing costs of N fertilizers and concern for environmental hazards associated with excessive fertilization. Although several soil N availability indices have been developed, none of those tested has had wide success in Pennsylvania. A 2‐yr study was conducted in central Pennsylvania to determine if nitrate (NO−3) analysis of young corn plants (Zea maysL.) was significantly related to soil N availability. The NO−3contents of basal stalks were determined weekly for several weeks after emergence in two N fertilizer response experiments in 1982 and 1983. The soil in sites in 1982 and 1983 were Murrill silt loam, a Typic Hapludult, and Hagerstown silt loam, a Typic Hapludalf, respectively. Stalk NO−3−N increased with increasing N fertilizer rates. The effect of plant age on stalk NO−3concentration varied between the 2 yr, probably due to hail damage or available water differences. Differences in stalk NO−3among N fertilizer treatments increased with time in both years. The optimum time for sampling appeared to be approximately 30 days after emergence (DAE). Correlations of stalk NO−3at this time with relative grain yield and N uptake were significant (r>0.94) both years. Based on regression lines, at approximately 30 DAE, the critical concentration of stalk NO−3−N (for 95% of the plateau yield) was about 11 g NO−3kg−1in 1982, and 16 g NO−3−‐N kg−1in 1983. Combined data from both years had a significant but lower correlation (r=0.754) between stalk NO−3and relative grain yield, with an apparent critical concentration of 15.7 g NO−3−N kg−1. The potential for predicting soil N availability from NO−3tissue testing appears possible if the environmental factors that affect tissue NO−3accumulation can be identified and quantified.

Hail damage in Australian pine plantations II. Aerial photographic techniques for mapping the damage

Summary A brief discussion is presented of five aspects which must be considered when planning an aerial photographic mission to map mechanical hail damage of pine plantations per se or the subsequent dieback due to infection by Diplodea pinea. These are the timing of photography, the film, scale and format to be used and the likely costs. A number of recommendations are made which will enable forest managers to prescribe a suitable aerial survey of any particular damage event.

Hail damage in Australian pine plantations I. Nature and extent of damage

Summary From data gathered on twenty hailstorms which severely damaged pine plantations in various parts of Australia during the past decade, and from a review of the literature, an analysis is presented of the nature and effects of hail damage on Pinus radiata and Pinus elliottii. Meterorological data from Australia indicate that plantations in this country are likely to experience about two physically damaging hailstorms per 35-year rotation, and scars left by the impact of hailstones tend to confirm this. Hailstones knocked needle fascicles and thin shoots off the trees and thus caused up to 70% defoliation. They also killed 1–4 cm wide patches of bark and cambium where the bark was thin, i.e. on limbs, and the top 6–12 m of the stem. More serious damage resulted when these physical injuries were followed by shoot dieback associated with infection by Diplodia pinea. Except for vigorous young (<6 yr) plants, all classes of trees were susceptible to the dieback, largely irrespective of dominance, vigour, site quality, stand density and drought stress. Many trees died, but most recovered in about 2 to 4 years. Those that had lost several metres of their leader developed badly deformed stems. During 1971–80, dieback necessitated the salvage of about 100 000 m−1 of stem wood per year, i.e. about 3.6% of the total harvests.

Differential Recovery Among Cotton Genotypes Following Early‐Season Defoliation1

An objective of many cotton (Gossypium hirsutum L.) breeding programs is the development of faster fruiting or earlier maturing cultivars. Such cultivars may allow producers to avoid production problems associated with early planting or late harvest as well as aid in disrupting the parallel buildup of certain pests with increased fruit load. Three cotton genotypes exhibiting different genetic maturities were evaluated over a 3‐year period to determine degree and speed of recovery from earlyseason defoliation, simulating stress due to hail damage. Arkugo 4, a fast‐fruiting strain; ‘DES 56’, a moderately early‐maturing, mid‐South cultivar; and ‘Deltapine 61’ (DPL 61), a full‐season, mid‐South cultivar were defoliated immediately above the first true‐leaf node when at the V5 and R2 stages of growth. A nondefoliated control of each genotype was included. When compared as a percent of nondefoliated controls (to remove the confounding effects of yield potential), the faster fruiting Arkugo 4 was not significantly lower yielding than its control when defoliated at the V5 stage in 1980 and 1981. Defoliation of DES 56 and DPL 61 at stage V5 caused a significant decrease in yield each year. Defoliation of all genotypes in all years at the R2 stage, except for Arkugo 4 in 1982, reduced or further reduced yield below that of defoliation at the V5 stage. Arkugo 4 also recovered more rapidly than DES 56 or DPL 61 following defoliation at both growth stages in 1980 and 1981, but not in 1982. These data indicate that yield‐competitive, fast‐fruiting cultivars have the potential to recover from early‐season stress more rapidly and to a greater degree than moderately early‐season or full‐season, mid‐South cultivars.

Upper-Level Structure of Oklahoma Tornadic Storms on 2 May 1979. I: Radar and Satellite Observations

Abstract This paper discusses the observational characteristics of the upper level structure of severe tornadic storms in Oklahoma on 2 May 1979 during SESAME. The data analyzed consist of limited-scan GOES-East and West visible, infrared (11 μm), and stereo satellite data, dual-Doppler radar observations, and special storm scale soundings. The time-histories of stereo cloud top height, minimum equivalent blackbody temperature (TBB) and radar reflectivity are followed for three severe storms over a several hour period; two of the storms are tornadic. Cloud top IR growth rates and vertical velocities of the storms are computed and found to have maxima which fall into Adler and Fenn's severe storm classification. For one of the storms there is an interesting coupling between cloud top parameters and low-level radar echoes; the other tornadic storm showed no unique relationship. Hail damage began shortly after tropopause penetration by thee storms. Two major IR cold areas associated with the leading downwind...

Effects of simulated hail damage on yield and quality of flue-cured tobacco

Tobacco crops were artificially damaged to simulate effects of hail in two series of experiments run over three years. In the first series, four treatments ranging from no damage to complete loss of leaves plus the apex were imposed when 5,10 or 15 leaves had unfolded. The performance of crops replanted or ratooned at the same stages was also measured. In the second series, the effects of lamina loss or midrib damage, or both in crops at early flowering were investigated. The first series showed that yield and quality were drastically reduced by severe damage at the 15 leaf stage. Yields where all the leaves were lost were only 940 kg/ha compared with controls yielding 2400 kg/ha. Replanted crops also yielded poorly at this stage (91 0 kg/ha) but ratooned crops produced satisfactory yields (1840 kg/ha) of good quality leaf. However, ratooning led to significant delays in harvest. In the second series, yields decreased from 2370 and 2030 to 161 0 kg/ha with loss of one-third and two-thirds of the lamina tissue, respectively. Damage to midribs caused additional losses of up to 400 kg/ha. However, only the most severe loss of lamina tissue depressed leaf quality.

Recoverability of Cotton Following Simulated Hail Damage1

AbstractMany areas of the so‐called cotton belt frequently receive hail sufficient to cause measurable damage to cotton (Gossypium hirsutum L.). The indeterminant growth habit of cotton allows for varying degrees of recoverability from hail damage depending upon the stage of growth of the plants when damaged and the severity of damage.Research was initiated in 1977 to evaluate the recoverability of cotton from simulated hail damage. These tests were conducted at three locations in Arkansas representing several silt loam soils with one site being severely infested with verticillium wilt [Verticillium albo‐atrum (Reinke and Berth)].Upon developing the 4th, 7th, and 10th true leaves, plants were hand cut to immediately above the cotyledonary node (CC type damage) or immediately above the second true leaf node (C2). At the Marianna location only, plants with 10, 12, and 14 true leaves also were damaged (C5 and C7) to assess recoverability of plants just prior to flowering, approximately at flowering, and just after flowering. The field design was a randomized complete block with four replications of plots 12 to 15 m in length.The degree of recoverability decreased as the severity of damage increased or as the same damage was applied to older plants. Plants infested with Verticillium wilt did not recover from simulated hail damage as well as plants at the other two locations indicating an accumulative effect of yield limiting stresses. Stepwise regression analysis indicated that 79% of the variability in seedcotton yields following the early season treatments could be accounted for by the number of nodes removed and the stage of plant development at the time of injury. Recoverability of plants damaged when near flowering could not be predicted by the number of nodes removed and/or stage of growth. Quality characteristics of the fiber were affected little.

Weather modification: hail suppression in Spain

Hail damage to agricultural and horticultural crops alone costs the equivalent of millions of dollars annually in Spain, as it does in many other hail-prone countries. The use of radar and computer technology facilitates hailstorm studies and enables the probability of hail formation to be predicted from mathematical cloud models. Modern aircraft give a much better chance of success to cloud-seeding techniques formerly dependent on rockets and ground-based generators.

THE EFFECT OF HAIL DAMAGE ON BARLEY

After a severe hailstorm at Fort Ellis, Montana, an experienced hail insurance adjuster estimated 90–100% damage in replicated yield plots of barley (Hordeum vulgare L.). After harvest, grain yield losses for all 66 entries in the nursery were found to range from 26 to 84%. A group of 11 cultivars selected for further study averaged 55% less than normal yield with a range of 29–82%. Yield and heading date were significantly (P &lt; 0.05) correlated for all cultivars (r = 0.39*, n = 42), within six-rowed cultivars (r = 0.79*, n = 7), and for the 11 selected cultivars (r = 0.62*, n = 11). Although there was no significant correlation between yield and heading date within two-rowed cultivars, a group of two-rowed early isogenics was significantly reduced in grain yield compared to their late counterparts. The number of days between heading and time of hail damage was a better indicator of final yield loss than number of culms remaining (the criterion used for hail-adjuster estimates of damage). Regrowth is more likely to occur in barley if the hail damage is near or before heading time rather than 5–15 days after heading. Therefore, the positive correlation in this test between late heading date and yield is because the later entries had just headed out when the hail came, while the low yielding entries headed 10–15 days before the hailstorm.

ADJUSTMENTS TO NATURAL HAZARDS: FACTORS AFFECTING THE ADOPTION OF CROP-HAIL INSURANCE∗

As crop losses from hail continue to rise, farmers increasingly rely on crop-hail insurance to mitigate the effects of hail damage. This paper examines a series of socio-economic and psycho-dynamic factors that affect the adoption decision in a relatively homogeneous agricultural region in central Illinois. The very high rates of insurance adoption found in the area indicate that adoption is based on the perceived existence of a hazard, satisfaction with insurance and its availability at acceptable costs, and the perceived lack of alternative adjustments.

The Changing Societal Consequences of Risks from Natural Hazards

In recent years, the federal government has pro vided substantial relief to victims of natural disasters. A pri mary reason for this assistance is that many of the individuals suffering damage have not protected themselves with insur ance. Standard coverage, normally required as a condition for a mortgage, offers protection against fire, wind, and hail damage; flood and earthquake policies can be purchased sep arately, and most residents of hazard-prone areas have not voluntarily bought this coverage. Recent empirical evidence on individuals' decision processes with respect to protection against events which have a relatively small chance of oc curring but can result in severe losses is summarized. Unless individuals have been made graphically aware of the conse quences of disasters, typically through past experience, they are unlikely to even consider purchasing insurance protec tion. Once their interest is stimulated they use informal net works such as friends and neighbors to guide them in their actions. Tradeoffs between using voluntary means of promot ing insurance or some other form of required coverage are discussed. Policy decisions have to reflect both the decision processes of individuals as well as value judgments on the appropriate role of the private and public sectors in natural disasters.

Long term effects of hail damage on radiata pine

Summary On 20 October, 1940, some 510 ha of 4 to 13 years-old Pinus radiata in the Ovens Plantation, near Myrtleford, Victoria, were damaged by a severe hail storm. When clearfelling began 20 years later it was found that the logs from the hail-damaged trees had defects. Severe degrade of the timber was found in trees with open and occluded scars on the limbs and trunk or with death of the original tree top. Hail imprints on the bark often indicated the presence of separation of wood between growth rings. Other forms of degrade were cankers on the tree trunk, faulty knots, and accumulations of resin which caused staining when softened during seasoning. Sawn timber recovery from damaged logs was about 50% of that normally obtained from undamaged logs, and new defects sometimes appeared after milling.

Some Growth Effects of Hail Damage and Drought inP. patulaPlantations

SUMMARY Internodal stem analysis of Pinus patula growing in the Usutu Forest, Swaziland, revealed past abnormalities in grwoth due to hail damage and low rainfall. Hail caused breakage of leaders and, where severe, the resulting loss in tree height could lead to serious errors in measuring site growth potential if the damage was not known to have occurred. Low rainfall on two occasions in the 1960s, but especially 1963/1964 and 1964/1965, appears to have caused a five per cent drop in total forest productivity.

Early Defoliation Affects Corn Grain Yields1

Field experiments designed to simulate hail damage at various developmental stages revealed an unexpected and potentially important grain yield response from corn (Zea mays L.). Of particular interest were yields following defoliation at the 5‐leaf stage. Two hybrids representing different maturity classes were defoliated. One hybrid was full‐season for southern Minnesota. The other was approximately 80%, of full‐season. Yields of the full‐season hybrid were decreased by 80% (3‐year average, 1973 to 1975). Average yields of the short‐season hybrid were increased by 48% (same 3‐year period). Eleven additional early hybrids at one Southern Minnesota location were defoliated at the 5‐leaf stage in 1975. Yield responses ranged from a 37%, increase to a 14% decrease. Trials conducted in 1976, involving several locations and hybrids, resulted in yield changes varying from a 32% reduction to a 53% increase — suggesting interactions among genotype, environment, and defoliation timing. We propose a physiological explanation for observed yield responses. It appears that early growth alteration or inhibition of leaf function could result in yield enhancement. Effective growth regulation might consist of altering source‐sink relations at the time of reproductive initiation.

Sugarbeet Yield and Seasonal Growth Characteristics as Affected by Hail Damage and Nitrogen Level

Sugarbeets (Beta vulgaris L.) grown in the western United States are subject to hailstorms that reduce yield and profits to the grower. A better understanding of growth characteristics before and after hail damage will enable growers to make correct decisions regarding soil and plant treatments to hasten recovery from hail damage and maximize sucrose yields.

On Relationships between Hailfall Characteristics and Crop Damage

The purpose of this paper is to show relationships among several hailfall parameters and degree of crop damage to those concerned about hail hazards in Japan. There are a few papers discussing this subject in Japan, but in those were used hail data obtained by interviews and questionaries from people living within and around hail damage areas. Such data are generally very inaccurate and not infrequently unbelievable values are reported as truly occurred. Even now physically unsound theories using unrealistic scales have been adopted even in an authorized handbook as a guide to hailfall characteristics vs. crop injury relationships. On account of establishment of hail observation network by the National Research Center for Disaster Prevention (NRCDP), and later increase of number of stations operated by local governments, it has become possible to obtain more accurate data in a portion of northwestern Kanto district where damaging hailstorm hit relatively frequently. However, the instruments used there are so called hail pads, the simplest kind hail-recorder.The parameters examined in this paper are the maximum hailstone diameter dmax, number of hailstones N (for all sizes) and N* (for d>6.4mm) per unit area, amount of hail per unit area M, impact energy per unit area EI, and percent crop damage D. We deduced hailstone diameters from dent diameters on aluminum foils. Discrete values are obtained. The value 6.4mm which happened to be equal to 0.25 inches is one of such a value. The percent crop damage is determined just after the hailstorm, and the values are quite rough. Although there were various kinds of crops in the area under consideration, the values of D refer to wheats which were just before harvest. The case studied here occurred on 9 June 1975. On this day damaging hail occurred at many places scattered over the wide area in northern and eastern Honshu, the main island of Japan. Gunma prefecture experienced the most extensive damaging hail ever known. About a dozen of hailclouds were identified by the NRCDP's radar situated at Fujioka in the southern part of this prefecture. Detailed study of the hailstorm were made by the authors (Omoto, Yagi, and Seino, 1976). The damaging hail discussed in this paper was brought by one of a quasi-supercell type convective system. It formed near the southwestern edge of bandshaped multicellular intense convective system, but unlike to other previously formed cells this one moved more or less independent of the main echo. The storm accompanied extraordinary intense rain (20-30mm in 5 minutes or less) as well as severe hail and strong gusts. There appears to be a quasi-periodic change in the intensity of the storm as revealed by the distributions of various hailfall parameters (Fig. 8). However, no corresponding change was identified from the radar data.Following statements are made as the summary of this preliminary study. (1) Degrees of crop injuries are relatively well correlated with following hailfall parameters: a) impact energy per unit area EI, b) the amount of hail per unit area M, c) the number of hailstones equal or larger than 6.4mm. (2) Total number of hailstones per unit area N, and maximum hailstone diameter dmax are less correlated with crop injuries compared with those given above. (3) Damage intensity is roughly proportional to Log EI and N* for 30≤D≤95% (note: Fig. 10 showing this relationship is more or less illustrative and not given for practical use). (4) Hailstones smaller than 6.4mm in diameter give weak or no damage to crops unless the amount is extraordinarily great. (5) Duration of hailfall in the area was very short, i.e., even in severely damaged area it was less than 5 minutes.(6) Hailfall amounts converted to rainwater were relatively small. Even in an area with severe

An Analysis of a Possible Crop Response to Hail Suppression Seeding: The Nelspruit Hail Suppression Project

A commercial hail suppression program has been in operation at Nelspruit, South Africa (25°S, 31°E) since December 1971. The seeding technique employed has been the “on-top” method, which consists of dropping silver iodide pyrotechnics into the tops of cloud turrets growing on the flanks of mature storms. Daily crop insurance records of hail damage to tobacco are compared for seeded and nonseeded days. The control (unseeded) days consist of historical data and of days during the operational period when storms in the area were definitely not seeded, usually for operational reasons. A “hail severity ratio”, defined as the ratio of the crop lost to the total crop planted in the areas hit by hail, is derived from the hail-damage assessments and appears to be the parameter most sensitive to the claimed treatment effect. A comparison of seeded days during the initial phases of the program, when propeller aircraft were used, with more recent days when one or two jets were used for the seeding, indicates significantly lower severity ratios for jet-seed days. The analysis of the seed versus the control days for three separate regions in the operational area show, on the average, statistically significant reductions in hail severity on the days on which jets were used for seeding. As a ratio, the severity parameter can be altered by changes in the numerator (total crop damage) and/or the denominator (total crop planted) in the areas hit by hail. An analysis of total damages and areas hit by hail indicates that the numerator appears to be affected most strongly by the treatment, and that there is no indication that the seeding is causing an increase in the area hit by hail. It is unfortunate that the data were not collected within the framework of a randomization scheme planned before the initiation of the seeding; the statistics, however, do possess an internal consistency that lends support to the validity of the conclusions.

Comments on “The Hailpad Calibration for Italian Hail Damage Documentation”

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