Low Soil Moisture Levels Research Articles

Does the urban CO2 dome of Phoenix, Arizona contribute to its heat island?

Phoenix, Arizona has both a strong urban heat island and a large near‐surface atmospheric CO2 “dome” during periods of atmospheric stability. In this investigation, we use a detailed one‐dimensional infrared radiation simulation model to determine the thermal impact of the elevated CO2 levels in the urban environment. We find that the increased CO2 concentrations below the inversion layer contribute only slightly to the observed heat island, which suggests that other factors, such as absorption of solar energy by urban surface materials and lower soil moisture levels, are largely responsible for the observed increase in urban temperatures.

Water status and stomatal behaviour of cowpea, Vigna unguiculata (L.) Walp, plants inoculated with two Glomus species at low soil moisture levels

The effects of arbuscular mycorrhizal (AM) fungi on water status and stomatal behaviour of cowpea, Vigna unguiculata (L.) Walp. cv. B89-504, under water-stressed conditions in the greenhouse were studied. The 3 × 2 experimental design included two levels of mycorrhizal colonisation ( Glomus mosseae, Glomus versiforme) and non-mycorrhizal control treatment and two soil moisture levels (well-watered pots and pots allowed to dry). Relative water content and leaf water potential values were higher in well-watered mycorrhizal and non-mycorrhizal plants than in water-stressed mycorrhizal and non-mycorrhizal plants. AM species had no significant effect on leaf osmotic potential, stomatal conductance and leaf transpiration in both well watered and water-stressed plants. The values of stomatal conductance and leaf transpiration were high during the vegetative stage and low during the flowering stage. These responses which can be related to the age of the plant suggest that mycorrhizal colonisation did not affect stomatal closure of cowpea plants during water stress. The decrease in plant growth and dry matter production in both mycorrhizal and non-mycorrhizal plants shows that drought resistance in cowpea was unaffected by mycorrhiza in the vegetative phase.

Allelopathic activity of Mexican sunflower [Tithonia diversifolia (Hemsl.) A. Gray] in soil under natural field conditions and different moisture conditions

The allelopathic activity of Mexican sunflower [Tithonia diversifolia (Hemsl.) A. Gray] in soil under natural field conditions and the effect of water stress on the growth and allelopathic activity of this plant were investigated. Seed germination, shoot growth and root growth of tested plant species in soil collected from a field where Mexican sunflower had been grown for 5 years were less than those in soil from an area without the plant. Growth of young leaves, mature leaves, senescent leaves, stem and roots of Mexican sunflower was reduced with decrease in soil moisture level. The allelopathic activity of water extracts (per dry weight of starting material) from each part of the plants grown at low soil moisture levels was greater than that of the water extracts from the same part of the plants grown at high soil moisture levels. The allelopathic activity was found in the soil from the pots previously planted with Mexican sunflower to a similar extent (per plant) at different soil moisture levels. These results suggested that, in the field, under water stress conditions, the growth of Mexican sunflower was reduced but the plants contained a greater amount of allelopathic substance(s) per dry weight than in the absence of water stress. It was considered that allelopathic activity of Mexican sunflower in soil was maintained to a similar extent under various soil moisture conditions in natural fields.

Evidence for natural selection in a fern hybrid zone

Morphological characters, chloroplast DNA, and allozymes were used to analyze the distribution of individuals within a hybrid population of the ferns Polystichum munitum and P. imbricans in northwestern California. Microsites within the population were characterized according to soil moisture and light levels reaching the plants. In sites with low soil moisture and high light levels, all of the ferns were genetically and morphologically like P. imbricans. In contrast, ferns with the genetic and morphological identity of P. munitum predominated in moist shady sites. Intermediate sites supported very few P.munitum, a wide variety of hybrid recombinants, and a majority of ferns with P. imbricans characteristics. The pattern of variation within the population is noteworthy because of the close proximity of the habitat extremes and the long-range dispersal of fern spores. We conclude that natural selection along environmental gradients must be a major factor in determining the ecological and genetic associations within the hybrid zone. The results of this study are evaluated in the context of the fern life cycle and compared to the assumptions of models explaining the establishment and maintenance of hybrid zones, which vary in the role attributed to environmentally mediated natural selection.

Effects of Mulches on Soil Properties and Tomato Production I. Soil Temperature, Soil Moisture and Marketable Yield

ABSTRACT The effects of hay, compost, plastic and paper mulches on soil temperature, soil moisture and yield of paste tomato were evaluated on five farms in Virginia. Organic mulches reduced afternoon soil temperature and maintained higher soil moisture levels than other treatments. Black plastic mulch increased soil temperatures by 1–2°C, but sometimes resulted in lower soil moisture levels in early summer, probably by hindering penetration of rainfall. Both undyed kraft paper and black paper mulches reduced afternoon soil temperature slightly. Oiled paper initially increased afternoon soil temperature by 4°C, but this effect diminished over time. Paper mulches decomposed before the end of the season, allowing increased evaporative losses of soil moisture. Mulch treatments apparently affected early tomato yield by influencing soil temperature regime, but affected later yields by modifying soil moisture levels. Early yields were generally highest with black plastic mulch and lowest in organic mulches, with paper mulch intermediate. At sites not affected by late blight, total yields were generally: organic mulch ≥ plastic ≥ paper > unmulched. At sites affected by late blight, later-maturing fruit were lost, so that the delay in ripening in soil-cooling organic mulches resulted in a significant yield reduction compared to black plastic.

Induced resistance of cucumber seedlings caused by some non-pathogenicRhizoctonia (np-R) isolates

Among 153 isolates ofRhizoctonia spp. obtained from 95 soil samples collected from different fields in the USA, 42 (27.5%) isolates were hypovirulent or non-pathogenic on cabbage (tested on tap water agar plus 250 μg/ml chloramphenicol plates). Of these, 14 (33.3% of the np-R) isolates protected >60% of the cabbage seedlings againstR. solani, and the best eight isolates protected 73–95% of the cucumber seedlings. The np-R isolates RU56-8 (AG-P) and RU89-1 [AG-B(o)] induced the highest resistance against hypocotyl challenge inoculation with virulentR. solani (38.3–85.7%), whereas most of the challenged control seedlings (85–100%) collapsed. Similarly, isolates RU56-8 and RU89-1 induced the highest resistance (22.2–87.5%) against hypocotyl challenge inoculation withPythium aphanidermatum, whereas most of the challenged control seedlings collapsed (90–100%). Isolates RU56-8 and RU89-1 significantly reduced the lesion numbers and area/leaf (to 8.9–42.0% of the control) caused by challenge inoculation of the first true leaves withPseudomonas syringae pv.lachrymans. No np-R isolate could be recovered from the upper hypocotyls or from the leaves, indicating that there was no contact between the inducer and the pathogen. Root colonization with some np-R increased seedling tolerance to low soil moisture levels.

The role of oxygen diffusion in passive bioremediation of petroleum contaminated soils

In passive bioremediation of petroleum hydrocarbon contaminated soils, oxygen diffusion is the primary mechanism for supplying the oxygen which is required for microbial hydrocarbon biodegradation processes. It is the objective of this research to theoretically evaluate whether passive bioremediation can be a feasible treatment alternative for petroleum contaminated soils. In this paper we derive equations for the steady-state oxygen concentration profiles which are expected to develop as a result of simultaneous oxygen diffusion and consumption in hydrocarbon contaminated soils. These equations are used to estimate the maximum oxygen penetration distance and the total cleanup time for several environmental scenarios such as surface and subsurface soil contamination as well as contaminated soil piles. It was found that oxygen is expected to penetrate most contaminated soils for up to several meters if hydrocarbon biodegradation rates are similar to those measured during bioventing respiration tests, i.e. approximately 2.5–10 ppm TPH day −1. Both the depth of oxygen penetration and the total passive bioremediation cleanup time were found to be strongly dependent on the magnitude of the diffusion coefficient for oxygen in soil ( D s). As expected, increased oxygen penetration distances and decreased cleanup times are associated with increased D s values. Since the magnitude of D s is inversely related to the soil moisture content, it is imperative to maintain moderately low soil moisture levels in order to maximize the effectiveness of passive bioremediation treatment. Passive bioremediation is expected to be a feasible and cost-effective treatment alternative for TPH contaminated soils in cases where the minimization of cleanup times is not a major remediation objective.

Changes in soil physical properties of four different fields during and after upland reclamation that involved grading

Abstract In four fields reclaimed with grading (Shari: coarse Stratic Regosolic Andosols; Kyowa: fine Brown Andosols; Hokuryu: Acid Brown Forest soils with medium texture; and Toma: Acid Brown Forest soils with Dark Epipedon and medium texture), changes in the physico-chemical and structural properties of soil strata subjected to surface layer handling (hereafter referred to as “surface layer handled soil strata” (SLHS)) were investigated during and after reclamation. 1. SLHS were estimated to be derived mainly from the A and B horizons of each pre-reclaimed forest soil except for the Shari field where buried horizons were also treated in the same way as the surface soil layer.2. During surface layer handling (SLH), SLHS were structurally degraded in all the fields.3. During SLH, the compaction (increase in bulk density and decrease in coarse-size pore volume (CP: from 0 to -6.23 kPa) and easily-available water-holding pore volume (EAW: from -6.23 to -100 kPa)) of SLHS proceeded except for coarse textured soils (Shari).4. In the Kyowa and Toma fields, bulk density of SLHS decreased, CP increased after a single plowing and harrowing, unlike EAW, even when SLH was performed at a low soil moisture level. In both fields, the recovery of EAW was smaller than that of CP during the several years after SLH. Countermeasures for the recovery of EAW should be investigated further.5. In the Hokuryu field where SLHS contained swelling clay and the soil moisture was estimated to have been high when SLH was performed, bulk density, CP, and EAW of the upper SLHS did not recover appreciably during the 8-year period after SLH. Shrinkage with dehydration proceeded in the lower SLHS during this period. Reclamation procedures should thus be conducted when the soil moisture is low.6. The effects of subsoiling conducted after SLH differed with the soil types and soil moisture levels.

Urban vs. Natural Sugar Maple Growth: II. Water Relations

Physiologic measurements of the internal water relations of sugar maple in a natural forest and along an urban street in Michigan were performed as a complement to a companion site characterization study. Investigations were carried out to determine how street trees are affected by the urban habitat, and to confirm through correlation analysis that siterelated water stress adversely influences tree growth and vitality. Significant water relations differences exist between the street site sugar maples and those in natural habitats. Predawn water potential, osmotic potential, and stomatal conductance were significantly lower in the street trees, and were significantly correlated with the low soil moisture levels and high atmospheric demands of the street site. Findings of this study, in conjunction with the site characterization data, can be of value in selecting appropriate remedial treatments for stressed urban trees, as well as to reiterate the need for further screening of drought-tolerant cultivars for urban sites.

Kinetics of Potassium Fixation in Vermiculitic Soils under Different Moisture Regimes

AbstractFixation of K in vermiculitic soil and the residual benefit from fertilizer‐K addition are influenced by soil moisture. The purpose of this study was to determine K fixation rates under simulated field moisture regimes. Fixation rates were measured during three consecutive wetting‐drying cycles and in long‐term aerobic incubations with soil moisture held constant at different matric pressures. In all studies, 12 mmol KCl kg−1 soil was applied before monitoring K fixation. All rates conformed to first‐order kinetics. Each wetting‐drying cycle had a rapid fixation phase lasting 2 d with slower fixation thereafter, and rate constants of fixation decreased in each successive cycle for both phases. Depending on the soil, rate constants of the rapid phase in the first cycle ranged from 0.064 to 0.143 d−1 and were 0.026 to 0.061 d−1 in the second cycle. Slow‐phase rate constants ranged from 0.030 to 0.058 d−1 in the first cycle and 0.005 to 0.021 d−1 in the second cycle. In samples maintained as saturated pastes, the rapid phase was extended to 5 d but the rate constant was smaller in magnitude than when soil was drying. The rapid phase represented an abiotic process that was controlled by K+ diffusion. When soil moisture was held constant in a long‐term aerobic incubation, K fixation rate constants increased at lower soil moisture levels. Rate constants of fixation were 0.00055 d−1 at −0.03 MPa and 0.00114 d−1 at −0.48 MPa, an increase of 107%. The measured fixation rates were sufficient to explain long‐term fixation measured in a related field study.

Determination of the water use of two pairs of soybean isolines differing in stomatal frequency using a heat balance stem flow gauge

Using heat-balance stem flow gauges, we were able to measure directly and continuously the sap flow rates in two pairs of soybean [Glycine max (L.) Merr.] isolines differing in stomatal frequency. Plants with high stomatal frequency transpired significantly more water than the low stomatal frequency plants at high soil moisture levels. Under low soil moisture levels, the water use rate decreased greatly for the high stomatal frequency plants. Plants with low stomatal frequency were able to maintain greater sap flow rates than those with high stomatal frequency. Higher leaf temperatures associated with the low stomatal frequency plants were likely due to lower transpiration rates which reduced evaporative cooling especially under well-watered conditions. Key words:Glycine max (L.) Merr., transpiration, water deficits

Management and Environment Effects on Brassica Forage Quality

AbstractForage Brassica spp. have been shown to produce adequate amounts of herbage during the cooler months of the fall, thus allowing extension of the grazing season in higher latitudes. The objective of this study was to determine if the nutritive quality of initial and regrowth herbage was influenced by planting and harvest date. In 1987, 1988, and 1989, three Brassica spp. (rape [B. oleracea L.], turnip [B. rapa L.] and turnip hybrid [B. rapa L. × B. pekinensis L.]) were planted in late May to early June, late June to early July, and late July to early August and were harvested each year at 64, 76, or 85 DAP. The plants regrew 60, 70, or 80 d and were harvested. Nutritive components measured were CP, NDF, ADF, Ca, Mg, and P. Nutritive levels declined with warmer temperatures and low soil moisture levels particularly during July and August. Neutral‐detergent fiber and ADF levels were higher, while the CP levels were lower in herbage from the earliest planting date compared with the later planting dates, regardless of species and year. The levels of Ca, Mg, and P were influenced by species and planting date. In general, the regrowth herbage had a lower fiber and a higher protein content than the initial herbage. The variation in nutritive quality among the three species was relatively small. Of more importance to the producer is that the quality of brassica herbage is more comparable to a concentrate than a traditional forage because of the relatively low fiber and high protein content.

Soil Moisture, Native Revegetation, and Pinus lambertiana Seedling Survival, Growth, and Mycorrhiza Formation Following Wildfire and Grass Seeding

AbstractGrass seeding is widely used for erosion control, but its consequences for soil and regeneration following fire have been measured only infrequently. This study investigates the effect of grass seeding on the type and extent of plant cover; soil moisture percentage; and moisture stress, survival, growth, and root‐tip and mycorrhiza formation of Pinus lambertiana (sugar pine) seedlings in a clearcut intensely burned by wildfire. One‐year‐old containerized sugar pine seedlings were planted in seeded and nonseeded areas in Spring 1988 and 1989 in the Longwood Fire area of southwest Oregon. In 1988, tree seedlings in grass‐seeded plots experienced intense competition from the grass, reduced root‐tip and mycorrhiza formation, low levels of soil moisture to meet evapotranspirational demand, high levels of mortality, and reduced growth. In 1989, however, the opposite was true: tree seedlings in nonseeded plots experienced competition from invading native annuals and perennials, low levels of soil moisture in summer, and higher levels of mortality. The studies we report here further indicate that, in an area characterized by extended summer drought, annual ryegrass impeded regeneration of sugar pine during the first season following the fire. Native species cover and richness have been significantly reduced in the seeded area and may affect long‐term soil stability, productivity, and conifer restoration. Seeding of annual ryegrass at high rates under these conditions would seem ill advised.

Morning vs afternoon sun patches in experimental forest gaps: consequences of temporal incongruency of resources to birch regeneration.

We investigated whether the timing of high light availability as sun patches within forest gaps, independent of total or peak photosynthetic photon flux (PPF), influences the physiology and growth of four coexisting birch species (Betula alleghaniensis, B. lenta, B. papyrifera, and B. populifolia). Birch seedlings were grown for two years along either the east or west sides of experimental gap structures and at two moisture levels. Seedlings positioned in the west received sun patches earlier in the day than those in the east, and environmental conditions for carbon gain were generally more favorable during the earlier sunpatches in the west; air and leaf temperatures were lower, and relative humidity higher, relative to conditions during sun patches in the cats, simulating patterns observed in natural forest gaps. Seedlings positioned along the west edges of gaps fixed more carbon earlier in the day than those in the east, and in many cases, peak net photosynthetic rates were greater for west positioned seedlings. In year two, leaf-level integrated daily carbon gain was greater for west- than eastpositioned plants, and for the most pioneer species, B. populifolia, differences between west and east seedlings were greatest at lower soil moisture levels. Despite some small effects on leaf gas exchange, the timing of high light availability, and its temporal congruence with other factors critical to carbon gain, had no significant effects on first or second year seedling biomass. The responses of birch seedlings to controlled variations in the timing of high light availability were generally much smaller than birch seedling responses to variations in other components of daily light regimes such as total integrated and peak PPF.

高温時の空気湿度と土壌水分がキュウリの葉緑素蛍光発生に及ぼす影響

Effects of atmospheric humidity and soil moisture content on the relative intensity of chlorophyll fluorescence of cucumber (Cucumis sativus L.) exposed to high air temperatures were assessed as a measure of heat stress or injury.1. After exposure to 25 °C (control) and 42°, 44° and 46°C for two to three hours, the intensity of fluorescence decreased a little at 42° and 44°C but markedly at 46°C. However there was no significant difference in seedling growth among those grown for 12 days at the three high temperature treatments and those at 25°C.2. Chlorophyll fluorescence decreased significantly in plant kept at a humidity of 0.3 kPa of vapor pressure deficit (VPD) and 46°C, compared with those held at the same temperature but at 4.8 kPa VPD. The intensity decreased to 5% of that at 25js_°C immediately after a high humidity and 46°C treatment. It recovered to 55% of the control two days after the treatment was terminated but never attained more than 70% of control even after 5 days at 25°C. The reduction in chlorophyll fluorescence is attributed to the high leaf temperature and humidity which depressed transpiration.3. Chlorophyll fluorescence intensity of seedlings exposed to 46°C and 55% soil moisture content for one to three hours decreased significantly, whereas it decreased just slightly when cucumbers were grown at the same high atmospheric humidity but in soils with 97% moisture content. The leaf temperature of plants grown at the low soil moisture level gradually increased and surpassed that of plants grown at high soil moisture content ; the transpiration rate was apparently higher in moister soil than in drier soil.These results indicate that determinig chlorophyll fluorescence may be a method of detecting heat stress or injury to the photosyntetic apparatus. They support the idea that heat injury may be avoided by maintaining low atmospheric humidity and high soil moisture content which hasten the transpiration and thereby tend to keep the leaf temperahire low.

Translocation of aged cyclodiene insecticide residues from soil into forage crops and pastures at various growth stages under field conditions.

Field trials were conducted to measure translocation of pesticides by summer and winter forage/pasture species from soil containing aged residues of heptachlor and, to a lesser extent, dieldrin. Substantial amounts of heptachlor epoxide, and lesser amounts of gamma-chlordane were translocated to plants from contaminated soil. Residue levels varied with crop species and stage of plant development. In summer crops residues were higher in soybean > cowpeas > lab-lab > Sorghum > millet > sweet saccaline at the grazing and mature stages. Compared to glasshouse studies undertaken previously, residues in crops grown under field conditions were much lower. This apparently reflects the lower soil moisture levels and the reduced rates of translocation. Heptachlor residues in winter crops were highest in Saia oats > Berseem clover > Haifa clover > Cassia oats > Tetila ryegrass > Schooner barley > Shaftal clover > Hunter river lucerne at the grazing stage. There were no detectable levels in barley and oats at the mature stage. No dieldrin residues were translocated into the various crop species.

Soil, water and crop management alternatives in rainfed agriculture in the Sahel: an economic analysis

Most agriculture in the Sahel Region is carried out under rainfed conditions where low and uncertain soil moisture levels limit productivity. Improved soil, water and crop management practices are required to reverse the steady decline in per capita food production and sustain output over the long term. Several technological innovations and related farm management practices are evaluated in a case study of a typical farm in Mali. Through use of a soil–water balance model and a whole-farm economic model an optimal mix of these measures is identified. Compared to a base case where no modern inputs are utilized, the combination of animal traction (oxen team), low levels of NPK fertilizer, tied-ridges, traditional long-season food grain crops and early planting was most effective: food grain output was 35% higher than with the traditional base case; soil erosion was reduced by 72%; and even with residual future soil erosion damage capitalized into current income, net farm income was larger by a factor of almost 45.

Soil, water and crop management alternatives in rainfed agriculture in the Sahel: an economic analysis

ABSTRACTMost agriculture in the Sahel Region is carried out under rainfed conditions where low and uncertain soil moisture levels limit productivity. Improved soil, water and crop management practices are required to reverse the steady decline in per capita food production and sustain output over the long term. Several technological innovations and related farm management practices are evaluated in a case study of a typical farm in Mali. Through use of a soil‐water balance model and a whole‐farm economic model an optimal mix of these measures is identified. Compared to a base case where no modern inputs are utilized, the combination of animal traction (oxen team), low levels of NPK fertilizer, tied‐ridges, traditional long‐season food grain crops and early planting was most effective: food grain output was 35% higher than with the traditional base case; soil erosion was reduced by 72%; and even with residual future soil erosion damage capitalized into current income, net farm income was larger by a factor of almost 45.

Germination of seven perennial arid land species, subjected to soil moisture stress

Seven perennial arid land species were studied for germination at low soil moisture levels. The research was conducted to test the hypothesis that seeds of arid land species could germinate at relatively low soil moisture. This would allow selection of strains that germinate at low soil moisture, improving direct seeding success in ecosystem restoration projects. The method used allowed seeds to be in contact with soil. Soil moisture was kept at constant levels by a polyethylene glycol solution that was separated from the soil by a semi-permeable membrane. Highest germination rates were 86%, 61·5% and 66% for Agropyron cristatum, Bassia prostrata and Sporobulus airoides at –0·2 MPa respectively. Maximum germination rates for Atriplex canescens, Grayia brandegei and Sphaeralcia sp. were at –0·8 MPa and were 22%, 38% and 9·5% respectively. Germination of Sarcobatus vermiculatus was intermediate with the two groups and showed a maximum percentage of 37·5% at –0·4 MPa. In general, germination was lowest at 0·0 MPa or no soil moisture stress except with Sporobulus airoides. All seven species germinated readily at soil moisture stress and some species maintained high germination levels as low as –1·6 MPa. In particular Bassia prostrata and Agropyron cristatum showed little decline in germination with increasing soil moisture stress. Data indicate that arid land species have an adaptation to germinate under some levels of soil moisture stress. Thus, establishment can be successful at low soil moisture levels near the surface of the seed bed if soil moisture at lower levels of the soil is sufficient for growth and development.

Predicting Yield Prospects for the 1989 Kansas Grain Sorghum Crop Based upon Soil Moisture Levels Prior to Planting

Because most of the management decisions for growing a dryland crop are made by the time the crop is planted, unpredictable and variable climates present obstacles to obtaining consistently profitable yields. Years of weather extremes further complicate crop management because of producer lack of practical experience under those conditions. Crop growth models provide a method of evaluating yield prospects and examining alternate management practices over a range of possible weather conditions. The lack of rainfall across much of Kansas from the spring of 1988 to the spring of 1989 led to a serious reduction in soil moisture levels by the 1989 planting season. Doubts were raised about the chances of obtaining crop yields capable of returning a profit. Crop growth models are the only means available to answer questions of this type with an accurate assessment of the probabilities. The SORKAMI grain sorghum growth model was used to evaluate yield probabilities at five locations. Soil moisture levels, either measured or estimated, were used along with climatic data for the past 32 years to simulate sorghum yields. These yields were compared to yields simulated with normal soil moisture levels to demonstrate the likely effects of 1989 soil moisture levels at planting on final grain yields. The model showed significant yield reductions for all locations where soil moisture was below normal. Reductions were greatest in years with below average rainfall and least in years with above average rainfall. Yields simulated with 1989 soil moisture data ranged from 16 to 100 percent below those simulated using normal soil moisture inputs. This study demonstrates that regardless of the historical rainfall pattern experienced, low soil moisture levels at planting, such as those experienced in Kansas in 1989, will significantly lower the yield potential of grain sorghum. Contribution No. 91-141-J. From the Kansas Agric. Exp. Sta., Manhattan 66506. ' SORKAM-software program acronym. This content downloaded from 157.55.39.8 on Wed, 30 Nov 2016 05:02:52 UTC All use subject to http://about.jstor.org/terms VOLUME 94, NUMBERS 1-2 59 100 100 90 32 year avg. 90 32 year avg. 80 ..----1988-89 80 ..... 1988-89 70 E 70 ,60 6050 50 4....... 40 40 30 230Cl 20 ... Garden City 20-Colby 0 I1 0 -I JAN MAR MAY JUL SEP NOV JAN MAR JAN MAR MAY JUL SEP NOV JAN MAR