Seasonal Changes In Rainfall Research Articles

Seasonal changes of macroinvertebrate communities in a Western Cape river, South Africa, receiving nonpoint‐source insecticide pollution

A field study was conducted at three different sites along the Lourens River (South Africa) to assess aquatic macroinvertebrate abundances and community structures in relation to seasonal changes in rainfall and particle-associated organophosphorous (OP) insecticide contamination. Redundancy analysis indicated OP insecticide contamination (azinphos-methyl and chlorpyrifos) as the only significant variable determining the community composition. Principal response curves indicated that the invertebrate community dynamics of the Lourens River at the most-contaminated site, Lourens River 3 (38 +/- 23.0 microg total OP/ kg suspended particles), differed significantly from the less-contaminated site, Lourens River 2 (8.0 +/- 4.9 microg total OP/kg in suspended particles) during the dry season (October-December; pesticide application period), whereas no difference was found during the wet season (July-September). Ephemeroptera abundances increased significantly (p = 0.0021) at the control site, Lourens River 1, from the wet to dry season, whereas abundances significantly decreased (p = 0.0011) at Lourens River 3. Two-by-three factorial analysis of variance demonstrated a significant interaction of site and season for the three most abundant mayfly taxa, Baetis sp., Demoreptus sp., and Castanophlebia sp., confirming a possible OP effect. Lourens River 3, however, differed significantly from the other two sites in flow, ortho-phosphate, and algae growth, which may partly explain the lower abundance of sensitive species. Apart from the OP contamination, only flow velocities showed significant differences between the wet and dry season at some sites. In conclusion, the present study suggests that particle-associated OPs affected community structure in the Lourens River at levels greater than 30 microg total OP/kg, whereas levels less then 10 microg total OP/kg yielded no significant effects.

Impacts of climate change on the fate and behaviour of pesticides in surface and groundwater—a UK perspective

Over the last two decades significant effort has been dedicated to understanding the fate and transport of pesticides in surface water and groundwater and to use this understanding in the development of environmental policy and regulation. However, there have been few studies that have investigated the relationships between pesticides and climate change, and where this work has been undertaken it has principally been in relation to the impacts of climate change on agricultural production rather than in the context of environmental protection. This study addresses that gap by reviewing how climate change may impact the fate and transport of pesticides in surface and groundwaters as a pre-cursor to quantitative studies. In order to structure the review, we have adopted a source–pathway–receptor approach where climate sensitivities of pesticide source terms, environmental pathways and receptors are reviewed. The main climate drivers for changing pesticide fate and behaviour are thought to be changes in rainfall seasonality and intensity and increased temperatures, but the effect of climate change on pesticide fate and transport is likely to be very variable and difficult to predict. In the long-term, indirect impacts, such as land-use change driven by changes in climate, may have a more significant effect on pesticides in surface and groundwaters than the direct impacts of climate change on pesticide fate and transport. The review focuses on climate change scenarios and case studies from the UK; however, the general conclusions can be applied more widely.

A ca. 800-Year Lithologic Record of Drought from Sub-annually Laminated Lake Sediment, East Java

Lithostratigraphic analyses of a sub-annually laminated core from Ranu Lamongan, a maar lake on the island of Java, document considerable changes in the lake’s chemistry and water balance over the past ca. 800 calendar years. Composition of the dark (clastics) and light (diatoms and/or calcium carbonate minerals) couplets suggests that these laminations form in response to seasonal changes in rainfall and water-column overturn in the lake. Calcium carbonate is not continuous in the core, and when it occurs it varies, sometimes abruptly, in carbonate phase and elemental composition (low Mg-calcite Mg-calcite, and aragonite). A significant correlation between Mg/Ca changes and δ18O variations in authigenic calcium carbonate suggest the basin is highly sensitive to hydrologic variation. Lithologic data suggest calcium carbonate precipitates and thus records hydrologic conditions during the dry season – a season in which rainfall anomalies are highly correlated with the phase of ENSO. Our carbonate-based record of Mg/Ca shows variability in evaporative concentration on a quasi-seasonal frequency for the past ca. 800 years. Our record shows two multi-decadal periods of drought – ca. 1275–1325 and ca. 1450–1650 CE – the latter of which was especially strong and/or prolonged. Our record also shows a possible change in drought frequency at around 1650 CE, in which periods of calcium carbonate precipitation and Mg/Ca change shifted from multi-decadal to interannual variability. Given the strong correlations between modern-day drought in East Java and ENSO variability, our drought record may indicate a regime shift in the behavior of the ENSO system about 350 years ago. Finally, comparisons between our record and others suggest that variation in ENSO on centennial and sub-centennial scales is not strongly associated with changes in the global mean climate state.

Unexpected changes in resistivity monitoring for earthquakes of the Longmen Shan in Sichuan, China, with a fixed Schlumberger sounding array

An electrical resistivity monitoring experiment using a fixed Schlumberger sounding array was conducted at Pixian in Sichuan Province, China, from January 1984 to June 1989, for the purposes of better understanding some geoelectrical phenomena and detecting earthquake-associated changes. Ancillary data of well water fluctuations and rainfall changes, along with seismicity pattern, fault map, atmospheric humidity, and temperature, have been collected. A very peculiar resistivity behavior was observed: the direction of the change in apparent resistivity for large electrode expanders was opposite to that of the resistivity change for the overburden. The geoelectrical structure beneath the monitoring array could be inferred from resistivity sounding data and available geological information. A method of data analysis applying singular value decomposition to the first-order sensitivity matrix yields the estimated change in true resistivity for the constituent medium in the sense of generalized least-squares. The sensitivity analysis shows that for the Pixian station, the abnormal annual variations in resistivity monitoring with large electrode spacings are related to the multilayered resistivity section with conductive substratum and are caused by the resistivity changes of overlying layer because the sensitivity coefficient for the topmost layer for such a section is negative. The resistivity changes of the overlying layer could be attributed mainly to seasonal rainfall changes. During the experiment, no significant resistivity changes are correlated with the earthquakes of M L 5.4 or less in the Longmen Shan and adjacent regions. However, a detailed interpretation of the observed phenomenon is helpful to improve our understanding of possible resistivity precursors to earthquakes.

Meteorological and land use controls on past and present hydro‐geomorphic processes in the pre‐alpine environment: an integrated lake–catchment study at the Petit Lac d'Annecy, France

AbstractA wide range of environmental records is integrated in order to reconstruct the mechanisms of flooding and sediment transport within the 170 km2 Petit Lac catchment, Annecy, France, over time scales of 10−1 to 102 years. These records include sequential lake sediment trap samples and cores, floodplain stratigraphies, dated landform assemblages, hydro‐meteorological records, and documented histories of river channel and land‐use change. Mineral magnetic measurements are used as the basis for classifying catchment sediment sources and tracing sediment movements through time. Records of magnetic susceptibility for monthly sediment trap samples (1998–99) track seasonal discharge, peaking in winter and spring. Magnetic records in lake sediment cores are compared against and tuned to precipitation records to provide dated proxy records for past discharge spanning sub‐annual to decadal time scales back to 1826. Calculated sediment accumulation rates in lake sediment cores are used as proxies for time‐averaged catchment sediment load. Analysis of the results reveals that climate and land‐use controls on the hydrological and sediment system are complex and vary according to the time scale of observation. In general, cycles of agricultural expansion and deforestation appear to have been the major cause of shifts in the sediment system through the late Holocene. Deforestation in the 18th century may have caused a number of high‐magnitude flood and erosion events. As the time scale of observation becomes shorter, changes in climate and hydro‐meteorological conditions become progressively more important. Since the mid‐19th century, smoothed records of discharge roughly follow annual precipitation; this is in contrast to sediment load, which follows the trend of declining land‐use pressures. Episodic erosion events during this recent period seem to be linked to geomorphic evidence for slope instability in the montane and sub‐alpine zones, triggered by intense summer rainfall. At the annual scale, changes in seasonal rainfall become paramount in determining sediment movement to downstream locations. The study demonstrates that the connections between forcings and responses span a four‐dimensional array of temporal and spatial scales, with strong evidence for dominantly nonlinear forcing–response mechanisms. Copyright © 2003 John Wiley & Sons, Ltd.

Long-term Dynamics of Phytophagous Lady Beetle Populations under Different Climate Conditions in Sumatra and Java, Indonesia.

Since 1990 we have studied population dynamics of the phytophagous lady beetles, Epilachna vigintioctopunctata, E. enneasticta and Epilachna sp. 3 (aff. emarginata), (Coleoptera: Epilachninae) in Padang, Sukarami (West Sumatra), Bogor (West Java) and Purwodadi (East Java), Indonesia. These sites have distinctly different climate conditions, e.g. Padang has a typical tropical rainforest climate without a clear alternation of wet and dry seasons, while Purwodadi has a strong dry season of 6-7 months. We have conducted censuses at 3-7 day intervals, including mark-recapture of beetles and construction of life tables for up to 9 consecutive years in order to clarify the seasonal change in abundance and mortality of the populations. In most populations the adult number changed greatly with the formation of high peaks from time to time at intervals of 6-12 months. Their increase or decrease was gradual, progressing over 3-5 months. Even under conditions with sufficient amount of rainfall in Padang, Sukarami and Bogor, oviposition intensity, number of the following immature stages and, as a result, adult emergence frequently showed discrete peaks at a fixed interval. These “generation cycles” were especially clear during the phase of population increase. There was no simple relationship between the seasonal change in rainfall and that of the beetle populations. We also discussed the impacts of the strong droughts in 1994 and 1997-1998 caused by El Nino, and the degree of synchronization in the trends of the populations among the adjacent study sites.

Seasonal polyphenism in Bicyclus (Lepidoptera: Satyridae) butterflies: different climates need different cues

A comparison is made between northern and southern hemisphere populations of Bicyclus butterflies in Africa regarding their responses in wing pattern polyphenism to seasonal change in rainfall and temperature. In southern habitats where temperature and rainfall are often positively correlated, a high temperature during the larval period induces conspicuous wet season forms whereas a fall in temperature elicits cryptic dry season forms. In northern habitats, however, where temperature and rainfall usually are negatively correlated, a rise in temperature should not induce a wet season form because such a rise is correlated with the onset of the dry season. Here, wing pattern plasticity, as measured using museum material, was regressed on mean monthly values for rainfall and temperature. Rainfall appeared to be a frequent determinant of wing pattern plasticity whereas temperature was much less often a significant independent variate. We conclude that the wing pattern may only respond to seasonal change in temperature if rainfall and temperature are positively correlated; in other situations rainfall remains the only significant determinant for wing pattern plasticity.

Seasonal polyphenism inBicyclus(Lepidoptera: Satyridae) butterflies: different climates need different cues

A comparison is made between northern and southern hemisphere populations ofBicyclusbutterflies in Africa regarding their responses in wing pattern polyphenism to seasonal change in rainfall and temperature. In southern habitats where temperature and rainfall are often positively correlated, a high temperature during the larval period induces conspicuous wet season forms whereas a fall in temperature elicits cryptic dry season forms. In northern habitats, however, where temperature and rainfall usually are negatively correlated, a rise in temperature should not induce a wet season form because such a rise is correlated with the onset of the dry season. Here, wing pattern plasticity, as measured using museum material, was regressed on mean monthly values for rainfall and temperature. Rainfall appeared to be a frequent determinant of wing pattern plasticity whereas temperature was much less often a significant independent variate. We conclude that the wing pattern may only respond to seasonal change in temperature if rainfall and temperature are positively correlated; in other situations rainfall remains the only significant determinant for wing pattern plasticity.

Response of the Shortgrass Steppe to Changes in Rainfall Seasonality

Studies in temperate grassland ecosystems have shown that differences in composition of C3 and C4 plant functional types can have important influences on ecosystem pools and processes. We used a plant community dynamics model (STEPPE) linked to a biogeochemical cycling model (CENTURY) to determine how ecosystem properties in shortgrass steppe are influenced by plant functional type composition. Because of phenological differences between C3 and C4 plants, we additionally simulated the effects of precipitation seasonality on plant communities and examined how C3 and C4 composition interacts with precipitation to affect ecosystems. The model output suggests that differences in C3 and C4 composition can lead to differences in soil organic carbon (C) and nitrogen (N) within 1000 simulation years. Soil organic C and N (g C and N m− 2 to 0.2-m depth) were least in a 100% C4 community compared with a 100% C3 community and a mixed C3–C4 community. A change in the time of maximum precipitation from summer to spring in a simulated shortgrass steppe slightly favored C3 plants over C4 plants. The proportion of total net primary production accounted for by C3 plants increased from 21% to 25% after 200 years, when 90 mm of precipitation was switched from summer to spring. Soil organic matter (SOM) was relatively stable in the C4-dominated communities with respect to changes in precipitation seasonality, whereasSOM in the C3 community was sensitive to precipitation seasonality changes. These results suggest an important interaction between plant community composition and precipitation seasonality on SOM, with phenology playing a key role.

A consideration of rainfall, runoff and losses at Plynlimon in the context of long term hydrological variability in the UK and maritime Western Europe

Abstract. Important questions concerning the resilience of current water management strategies have been raised by the recent volatility of climatic conditions across large parts of western Europe. The last decade, overall, has been exceptionally warm and there have been very large spatial and temporal variations in rainfall, river flows and aquifer recharge rates. Examination of historical rainfall and runoff records for parts of maritime western Europe confirms that there is no close modern parallel to the conditions experienced recently. Some-but far from complete-consistency with a number of favoured climate change scenarios may be recognised. Analyses of recent trends in lengthy rainfall and runoff series for the UK demonstrate significant regional differences and provide conflicting signals especially in relation to trends in catchment losses. Difficulties in reconciling the results from different areas may reflect both real hydroclimatological differences between catchments and variations in the precision of hydrometric time series-uncertainties in the assessment of areal precipitation in upland areas in particular. The dense monitoring networks at Plynlimon together with a rigorous data quality control programme underpins the value of the hydrometric datasets as important benchmarks against which to assess the significance of the very unusual patterns of rainfall and runoff which have characterised the recent past. This paper places the rainfall, runoff and losses data for Plynlimon in the perspective provided by a number of long hydrometric records for maritime western Europe. The representativeness of the Plynlimon base period is considered with particular reference to both the historical stability which typifies the great majority of European hydrometric time series and the recent extension in the recorded range of accumulated rainfall and runoff totals which has been identified in some regions (e.g. western Scotland and Norway). Particular attention is directed to changes in seasonal rainfall and runoff patterns and the recent increases in evaporative demands. Some of the implications for the overall water balance and for water resource management are considered.

Holocene palaeoecology of the northern Flinders Ranges, South Australia, based on stick-nest rat (Leporillus spp.) middens: a preliminary overview

Eight stick-nest rat (Leporillus spp.) middens from three locations in the northern Flinders Ranges, South Australia provide a discontinuous palaeoecological record spanning the Holocene. Evidence from radiocarbon dates, pollen, plant macrofossils and animal macrofossils is presented. Both pollen and plant macrofossils show that in the early to mid-Holocene (c. 8.8-5.3 ka), woodlands with grassy understoreys were more widespread than present. This accords with other studies suggesting wetter conditions at this time. Samples dating of the Pleistocene-Holocene transition (10.9-9 ka) are dominated by halophytes. It is not yet clear whether this is due to the continuation of Pleistocene aridity, changes in rainfall seasonality, or local influences on vegetation.

CAM induction in Clusia minor L. during the transition from wet to dry season in Trinidad: the role of organic acid speciation and decarboxylation

ABSTRACTThe interrelationships between the induction of CAM and the turnover of malate and citrate in the dicotyledenous tree Clusia minor were compared with seasonal changes in rainfall, leaf water status, PFD and photoinhibitory responses during the transition from wet to dry season in Trinidad. Over a period of 8 weeks, as rainfall declined from a maximum observed around week 3, leaf xylem tensions measured at dusk and dawn reflected the concurrent reduction in day‐time carbon gain and an increase in the diel turnover of malate (exposed leaves) and citrate (shaded leaves). Clear seasonal trends were observed in the turnover of malate and citrate during the transition from wet to dry season. In contrast to the declining back‐ground concentrations of citrate during the wet‐dry season transition, malate accumulation was markedly enhanced and the ratio of malalc:citrate accumulated overnight increased as the dry season advanced. Photo‐inhibitory responses, assessed by chlorophyll fluorescence, indicated that photochemistry was largely determined by the diurnal course of PFD incident on leaves, regardless of the magnitude of internal CO2 release from malate and citrate decarboxylation. In the long term, photochemical efficiency in both shaded and exposed leaves appeared to decline as the dry season progressed. Although there was a clear linear relationship between integrated PFD and overnight accumulation of malate, no such correlation was found for citrate. However, citrate breakdown during the day showed a much closer correlation with PFD as compared to malate, with levels of citrate measured at dusk declining in response to higher daily light intensities. Moreover, enhanced citrate decarboxylation during the day was strongly correlated with increased CAM and overnight accumulation of both malate and citrate.

Rainfall changes and rainfall erosivity increase in the Algarve (Portugal)

There is evidence that, between hydrological years 1931/2 and 1990/ 1, rainfall changed in the Algarve. There was an annual rainfall increase (+9%) and a 7% increase in rainfall during the rainy period (October to February). Both trends were statistically confirmed by parametric and nonparametric procedures. Rainfall erosivity and land degradation are related to rainfall regime. The Algarve's rainfall erosivity increase (+17%) was more pronounced than annual and seasonal rainfall changes.

Assessment of C budget for grasslands and drylands of the world

Intergovernmental Panel on Climate Change (IPCC) estimates indicate that potential changes in seasonal rainfall and temperature patterns in central North America and the African Sahel will have a greater impact on biological response (such as plant production and biogeochemical cycling) and feedback to climate than changes in the overall amount of annual rainfall. Simulation of grassland and dryland ecosystem responses to climate and CO2 changes demonstrates the sensitivity of plant productivity and soil C storage to projected changes in precipitation, temperature and atmospheric CO2. Using three different land cover projections, changes in C levels in the grassland and dryland regions from 1800 to 1990 were estimated to be -13.2, -25.5 and -14.7 Pg, i.e., a net source of C due to land cover removal resulting from cropland conversion. Projections into the future based on a double-CO2 climate including climate-driven shifts in biome areas by the year 2040 resulted in a net sink of +5.6, +27.4 and +26.8 Pg, respectively, based upon sustainable grassland management. The increase in C storage resulted mainly from an increase in area for the warm grassland sub-biome, together with increased soil organic matter. Preliminary modeling estimates of soil C losses due to 50 yr of regressive land management in these grassland and dryland ecoregions result in a 11 Pg loss relative to current conditions, and a potential loss of 37 Pg during a 50 yr period relative to sustainable land-use practices, an average source of 0.7 Pg C yr-1. Estimates of the cost of a 20 yr rehabilitation program are 5 to 8 x 109 US$ yr-1, for a C sequestering cost of approximately 10 US$ per tC.

Seasonal and Annual Variation of Insect Abundance in the Nairobi National Park, Kenya

A Malaise trap erected at the interface of grassland and forest in the Nairobi National Park was used to monitor insect abundance during a five-year period. Annual rainfall patterns during the study were extremely variable and included periods of major drought. Increases in insect density that followed the rains were largely due to an increase in the number of individuals per species, but the number of species also increased as much as threefold. The timing of peak seasonal abundance of phytophagous insects (grasshoppers and leafhoppers) and parasitic Hymenoptera was variable from year to year, thus suggesting dependence on environmental variables such as rainfall or host density. By contrast, several insect groups less dependent upon plants showed distinct seasonal meaks of abundance that were quite consistent each year. One annual peak of abundance was observed among Chrysopidae, Psocidae, Tabanidae, and Sarcophagidae. Two peaks were recorded for Asilidae and Satyridae. SEASONALITY IS A CONSPICUOUS FEATURE in the life history of many organisms in temperate zones, but information for tropical organisms remains sketchy. In the tropics, temperature changes are slight, and seasonal changes in rainfall exert the most dramatic effect on the environment. Rainfall patterns, however, can vary greatly from year to year, and for some organisms low rainfall is not likely to present as severe an obstacle as winter in a temperate zone. Thus, for some tropical species development appears to be aseasonal (e.g., Owen and Chanter 1972, Ehrlich and Gilbert 1973, Leuthold and Leuthold 1975) or to continue over a prolonged period (MacArthur 1972). Yet, many other tropical species are highly seasonal, perhaps as a response to close packing of competitors (MacArthur 1972) and to the selection of seasons that are best suited for active development. Distinct seasonal cycles have been observed in tropical plants (Janzen 1967, Burger 1974), fish (Kirschbaum 1975), birds (Snow and Snow 1964), rodents (Field 1975), some large mammals (Leuthold and Leuthold 1975), and several groups of insects from the Neotropics (Fairchild 1942, Galindo et al. 1956, Ricklefs' 1975) and Africa (Owen and Chanter 1970, Owen 1972, Duviard and Pollet 1973, Bigger 1976, Leston 1977). This-report examines the temporal distribution of insects sampled with a Malaise trap in the Nairobi National Park, Kenya, during a five-year period from August 1972 to July 1977. Marked seasonality was observed among several insect taxa, and the overall abundance of insects fluctuated greatly, especially in response to several periods of severe drought. METHODS STUDY AREA.-The trap was erected in grassland 2 m from a forest edge (fig. 1) in the western portion of Nairobi National Park (1?21'S, elevation 1800 m) within 2 km of the Langata gate. According to the Holdridge classification system (Holdridge et at. 1971) the forest would be considered a tropical premontane dry forest. It is dominated by Brachylaena hutchinsii and Croton megalocarpus while the grassland, which is derived from forest, is characterized by Themeda triandra: and Pennisetum clandestinum (Verdcourt 1962, Lind and Morrison 1974). Characteristically, the region has two rainy seasons (fi. 2): the long rains from mid-March to the end of May bring about 450 mm of rainfall and the short rains from mid-October to mid-December yield around 250 mm. Precipitation at other times brings the annual total to 900 mm (50-year average). Mean monthly temperature (fig. 2) ranges from 17?C during July and August to 20?C in March. Monthly rainfall data used in figure 3 were based on records of the East African Meteorological Department for Wilson Airport, a station located 4 km from the study

Definition of rainfall regions of south-eastern Australia by numerical classification methods

The aim of the study is to define homogeneous rainfall regions in order to improve methods for meso-scale extrapolation of isohyets. Two multivariate approaches are used, agglomerative classification and a modification of principal coordinates analysis. The median, mean, upper and lower quartiles and deciles for each month for a 30-year period were used as the attributes for 109 rainfall stations. Several data standardizations and classification methods are examined. Classification results were robust with respect to changes of method. Standardization based on proportions was preferred to that based on standard deviates. Fourteen groups of rainfall stations are recognized arranged in four regions. Use of mean data for groups clearly shows the spatial pattern of seasonal changes in rainfall. Differences in the relationship of rainfall to altitude are shown to be marked between geographically adjacent groups of rainfall stations.

The relationship between total seasonal rainfall and yield of maize in the Kenya highlands

A study of the climate within the maize-growing areas of the West Rift area of the Kenya Highlands showed that rainfall is the major meteorological variable.A further investigation showed that average yields of maize in subdistricts within the region are markedly affected by changes in seasonal rainfall and are apparently unaffected by large changes in acreage planted from year to year over a period of eleven years.

Influence of High, Medium, and Low Soil Moisture on Growth and Alkaloid Content of Cinchona ledgeriana

Soil moisture in Cinchona growing regions may fluctuate greatly with seasonal changes in rainfall; prolonged droughts are experienced almost annually. On the other hand, during the peak of the rainy season the same soils may remain at or near saturation for extended periods. For example, at the Toro Negro National Forest in Puerto Rico, where Cinchona is being grown experimentally, the 23-year-average rainfall for two-week periods from January 1 to March 25 was 2.04 inches with frequent periods of drought. In the current year only 0.21 inch fell during January. From August 13 to November 18 rainfall averaged 5.69 inches for two-week periods. The average total annual rainfall for 23 years was 96.37 inches (4). The above extremes in soil moisture may be expected to exert marked influence on the growth and composition of Cinchona. Heinicke, Boynton and Reuther (3) demonstrated that a flooded (poorly aerated) soil produced symptoms in the apple typical of boron deficiency when the soil was not deficient in that element. It was also indicated that lack of oxygen in the soil interfered with the absorption of nitrogen and potassium. Wager (?) showed that avocado plants were more susceptible to disease if grown in a flooded soil than if watered normally. During the first year from seed, Cinchona plants are primarily herbaceous. It is during this tender stage that soil moisture is most likely to be a critical factor affecting growth. Since the plants are grown in palm-leafcovered nurseries during this stage it is fairly easy to correct a deficiency of soil water by irrigation, but more difficult to prevent an excess during the rainy season. Cinchona nursery plantings have been observed which were apparently healthy during three-fourths ?f the year, but with the advent of heavy daily rains during the peak of the rainy season the plants developed symptoms typical of nutrient deficiencies and many succumbed to fungus attack. The experiment reported here was designed to study the effect of low, medium, and high levels of soil moisture on growth and alkaloid content of young Cinchona ledgeriana seedlings under controlled conditions.