Showing papers on "Growing season published in 1969"
TL;DR: Biomass of mature desert winter annual populations was measured during three growing seasons, which included the possible extremes in length, in 68 Mojave and Great Basin Desert communities, and Precipitation was measured concurrently.
Abstract: Biomass of mature desert winter annual populations was measured during three growing seasons, which included the possible extremes in length, in 68 Mojave and Great Basin Desert communities. Precipitation was measured concurrently. Biomass was highly variable from site to site, and season to season. Its site variability was related primarily to local edaphic variables and was usually not correlated with the shrub dominants of the site; seasonal variations were related, directly or indirectly, to the rainfall regimes. Values ranged from 0 to 616 kg/ha on sites with undisturbed soils, and seasonally were 2 to 5 times higher on burned sites than on comparable unburned sites in the same area. Maximum site value was 753 kg/ha, obtained on a burned site where most of the weight was due to high density of Bromus rubens L., an introduced grass species. Although in two of the three years averaged site values were similar, the biomass was overall the greatest in the 38 Mojave Desert communities, least in the 10 Great Basin Desert communities, and intermediate (if large contributions of Bromus on about half the sites are excluded) in the 20 communities considered transitional between the two desert regions. Pe3IoMe
78 citations
TL;DR: In this article, the authors measured phenological development, herbage production, basal area, and density of annual and perennial grasses and of the half-shrub burroweed (Aplopappus tenuisectus (Greene) Blake), over a 4-year period.
Abstract: Measurements of phenological development, herbage production, basal area, and density of annual and perennial grasses and of the half—shrub burroweed (Aplopappus tenuisectus (Greene) Blake), over a 4—year period show that production of each class of plant was affected to some extent by each of the others, except that annual grasses had no effect on burroweed crown area. Production of Arizona cottontop (Trichachne californica (Benth.) Chase), the dominant perennial grass, was restricted about 25% on plots with annual grass or burroweed competition and 46% by both together. Annual grass production averaged 18% lower with burroweed competition and 44—54% lower with perennial grass competition. Burroweed crown area increased 220% on plots with no perennial grass, but only 111% on plots with perennial grass competition. Presence of burrowed reduced perennial grass yield only moderately, because the root systems of burroweed and grass do not overlap greatly, and their main growth periods are at different seasons. High evaporation rates during the summer growing season masked most differences in moisture extraction between species. During the winter—spring growing period, on the other hand, burroweed depleted the available soil water rapidly, while water loss on perennial grass plots was little more than from bare soil.
68 citations
TL;DR: The larvae for this second invasion may have come from the most recently formed cysts, which may have been stimulated to hatch either by root exudates or by substances from other soil organisms.
Abstract: SUMMARY
Changes in the numbers of all stages of Heterodera rostochiensis in plants and soil were studied in a potato crop growing on infected land. Hatching and invasion occurred early in the season, when plants were very young and temperatures were below those considered necessary for hatching and invasion in Long Island, U.S.A. More larvae hatched from cysts nearer than away from potato roots. Males were abundant during June and July, when fertilization probably occurs. Many new cysts appeared during late June and early July. In May/June, there were many larvae in the roots of young plants but later there were few; a slight increase during August probably indicated a small second generation. The larvae for this second invasion may have come from the most recently formed cysts, which may have been stimulated to hatch either by root exudates or by substances from other soil organisms.
30 citations
TL;DR: The density of herbivores was higher on winter cress plantsgrowing in previously cultivated plots than it was on nearby plants growing in an old hayfield, and large populations of flea beetles overwintered near B. vulgaris plants at the immediate edge of cultivated fields.
Abstract: Because of its phenology and habitat distribution, Barbarea vulgaris R. Br. is the principal host for several members of the crucifer fauna at the beginning and close of the growing season in New York. The invertebrates found on B. vulgaris during the spring are listed. The density of herbivores was higher on winter cress plants growing in previously cultivated plots than it was on nearby plants growing in an old hayfield. Large populations of flea beetles (Chrysomelidae) overwintered near B. vulgaris plants at the immediate edge of cultivated fields. The relationships of the results to other studies on the crucifer fauna and to the control of flea beetles are considered briefly.
28 citations
TL;DR: Yellow birch seedlings grew more in height and leaf area, but those in full sun accumulated more dry weight, and Shade seedlings were more efficient photosynthetically near the end of the growing season than unshaded seedlings.
Abstract: Yellow birch seedlings were grown under heavy (86%) shade, moderate (72%) shade, and full sun. Shaded seedlings grew more in height and leaf area, but those in full sun accumulated more dry weight. Shaded seedlings were also more efficient photosynthetically near the end of the growing season than unshaded seedlings. Percentage dry weight was greater in leaves and stems of shaded seedlings and greater in roots of unshaded seedlings.
24 citations
TL;DR: In this paper, a simulation model was programmed in the computer to execute the water budgeting of corn for a silt loam soil, and the magnitude and frequency of the need for supplemental irrigation was determined on the basis of the growing seasons of 1938-1967.
23 citations
TL;DR: The alpine Erythronium grandiflorum of the Rocky Mountains and E. umbilicatum of the North Carolina deciduous forest both experience very short growing seasons which are similar in many respects as discussed by the authors.
Abstract: The alpine Erythronium grandiflorum of the Rocky Mountains and E. umbilicatum of the North Carolina deciduous forest both experience very short growing seasons which are similar in many respects. The temperature regimes of the deciduous forest floor in the early spring and of the alpine snowbank border in midsummer were found to be similar, although the average temperature in the West was higher with fewer diurnal fluctuations. However, solar radiation was considerably higher in the West. Soils were strikingly similar in both textural and chemical properties. Both species grew during the periods of highest insolation in their respective environments. However, both species were able to grow at very low temperatures. The general phenological responses were found to be well correlated with air temperature near the ground. The temperature control of growth initiation and the total degree-hours required for development were similar for both species. Neither species exhibited measurable water stress during its growing season.
22 citations
TL;DR: Field experiments were carried out in south-eastern New South Wales to establish the relationships between three plant tests for phosphorus and for sulphur, and the yield responses of subterranean clover pastures to applied phosphorus and sulphur.
Abstract: Field experiments were carried out in south-eastern New South Wales to establish the relationships between three plant tests for phosphorus and for sulphur, and the yield responses of subterranean clover pastures to applied phosphorus and sulphur. Subterranean clover plants (CV. Mt. Barker), sampled early in the growing season of 1963 and on five occasions at approximately monthly intervals in 1964, were analysed for total and soluble phosphorus and for total and reducible sulphur. The third plant test involved a comparison of the leaf area responses measured seven days after transfer to appropriate nutrient solutions of clover plants sampled in the field plots at the beginning of each growing season. Correlation coefficients (R) varying from 0.546 to 0.908 were obtained for the curvilinear regression of relative yields on total phosphorus contents of the clover, but only under conditions of an adequate sulphur supply. The correlation coefficients for soluble phosphorus were generally lower and differed greatly between samplings. The correlation coefficients for the curvilinear regressions of yield responses on the total or reducible sulphur content of clover, under conditions of ample phosphorus supply, were never less than 0.606 at the end of the season, and for some of the earlier samplings were as high as 0.947. The correlation coefficients (r) between leaf area responses and yield responses to phosphorus were 0.576 and 0.716, and those for sulphur 0.710 and 0.692 in 1963 and 1964 respectively. In contrast to those based on leaf analysis, the relationships between leaf area responses and yield response for each one of the elements were not affected by the level of supply of the other element.
21 citations
TL;DR: Glycolic acid oxidase activity at 25 C in leaf homogenates of ecotypic populations of Typha latifolia varied according to native climate of the population and current growing conditions.
Abstract: A B S T R A C T Glycolic acid oxidase activity at 25 C in leaf homogenates of ecotypic populations of Typha latifolia varied according to native climate of the population and current growing conditions. Activity of plants grown under warm/short day conditions was positively correlated with maximum summer temperature at the site of population origin. Activity of plants grown under cool/ long day conditions was negatively correlated with length of growing season at the site of origin. Populations from sites characterized by a long growing season are much less susceptible to environmental regulation of enzymic level than populations originating in short growing season sites. Enzyme activity is not a secondary reflection of differentiation at the level of chlorophyll or cofactor concentration. Enzymic differences between ecotypic populations reflect differences in control systems at the level of protein synthesis and genetic structure. SINCE the discovery of ecotypes by Turesson (1922), there has been substantial progress toward description of the morphological and phenological variation in plant species occupying
19 citations
TL;DR: In this article, the actual and potential evapotranspiration from the potato crop during the growing season was calculated using standard meteorologie data, and the water-use by the crop for different periods was also derived from the water balance.
Abstract: Data from sprinkler irrigation experiments with potatoes were used to calculate the actual and potential evapotranspiration from the crop during the growing season, using standard meteorologie data. During the experiments the moisture extraction from the effective root zone was determined by soil sampling. The water-use by the crop for the different periods was also derived from the water balance and both values were in good agreement in periods without extreme conditions of precipitation, this showing that the derived relations between crop height and surface roughness, between soil cover, light intensity, crop characteristics, soil characteristics and diffusion resistance, and between maturation and internal plant resistance were reasonably established. F.s.-A.G.G.H. (Abstract retrieved from CAB Abstracts by CABI’s permission)
15 citations
TL;DR: In this paper, the major nutrients by maize were determined throughout the growing season, and the uptake of labelled phosphorus showed two distinct peaks associated with root development, indicating that one fifth of the applied phosphorus was recovered by the plants.
Abstract: Uptake of the major nutrients by maize was determined throughout the growing season. Little phosphorus was accumulated, as reflected in its distribution within the plants, but uptake of labelled phosphorus showed two distinct peaks associated with root development. One fifth of the applied phosphorus was recovered by the plants.
RESP-5946
TL;DR: It was shown that nitrogen uptake early in the season was an important factor determining the total amount of nitrogen taken up by the plant, and that differences in leaf growth, rather than net assimilation rate, led to the varietal differences.
Abstract: In an experiment to investigate growth in relation to nitrogen concentration and nitrogen uptake, Proctor was compared with four other varieties of barley at two levels of irrigation and two levels of nitrogen fertilizer by means of weekly samples throughout the growing season. The varieties were Deba Abed, a new variety recommended for high fertility conditions where feeding quality grain is required, and three exotic varieties, chosen for their high concentration of nitrogen in the grain.Irrigation stimulated tillering, although certain varieties responded more strongly than others; irrigation also led to a higher specific growth rate. Certain of the exotic varieties had high growth rates early in the season but growth fell off earlier due to earlier ear emergence. Maximum leaf area index was greater in the irrigated treatment at the high nitrogen fertilizer level. The adapted varieties had higher maximum leaf area indices than the exotic varieties, although some of the exotics had higher rates of leaf area growth early in the season; there were also differences in the way in which the varieties responded to irrigation. Irrigation and variety both affected the rate at which the percentage nitrogen in the shoot fell with time.Analysis of these data indicates that nitrogen uptake early in the season was an important factor determining the total amount of nitrogen taken up by the plant. It was also shown that the relative rate of decline of the specific growth rate and the specific rate of nitrogen uptake differed between varieties. Analysis of the specific growth rate indicated that differences in leaf growth, rather than net assimilation rate, led to the varietal differences. The differential response to irrigation is discussed with reference to drought resistance.
TL;DR: Under irrigation all cultivars tended to exceed the yield of their counterpart without irrigation, particularly evident in Blanca del Pais, Rascana, and Viequera, with average yields increased by 37%.
Abstract: Yields of 12 local and introduced tanier cultivars, genus Xanthosoma , were compared under irrigated and nonirrigated conditions at the Gurabo Substation. Probably due to a wet and rather short growing season, irrigation did not increase yields significantly. However, under irrigation all cultivars tended to exceed the yield of their counterpart without irrigation. This was particularly evident in Blanca del Pais, Rascana, and Viequera, with average yields increased by 37%.
TL;DR: In another study, the authors showed that although one or other of the insecticides reduced the different pests to very low levels, yield increases were not obtained, and suggested that these formulations are slightly phytotoxic to Uganda cottons.
Abstract: Earlier studies of crop loss following insect attack on cotton in the elephant-grass zone of Uganda were followed up for two more seasons (1965–67), using large plots and routine spray schedules with different insecticides. The spray schedules were four or six fortnightly applications of insecticide, beginning at week 8 from emergence in the 1965–66 season, and four fortnightly or eight weekly sprays in the 1966–67 season. The insecticides used were DDT, endrin and dicrotophos in the first season and DDT, endrin and endosulfan in the second.Estimates of Taylorilygus vosseleri (Popp.), Heliothis armigera (Hb.), Earias biplaga Wlk., Cryptophlebia leucotreta (Meyr.), Pectinophora gossypiella (Saund.), Dysdercus spp., Aphis gossypii Glov., Tetranychus sp. and Eotetranychus sp. showed that, although one or other of the insecticides reduced the different pests to very low levels, yield increases were not obtained. In the 1966–67 trial, when the more important pests were present in very low numbers, DDT and endosulfan significantly reduced yields of clean seed cotton and it is suggested that these formulations are slightly phytotoxic to Uganda cottons.The relationship between the shedding of fruiting bodies and the harvesting of the crop showed that sprays applied after week 14 did not affect the total crop in any way. Increased soil fertility caused the plants to form more fruiting bodies and, although many of these were shed, a higher proportion were retained with or without protection from pest damage.It is concluded that the pest damage is too light to affect yields of early-sown cotton where varieties of indefinite growth habit can compensate for early loss of fruiting bodies in the extended growing season. Routine spraying gives no benefit and, in some seasons, can be harmful.
TL;DR: Based on the logistic theory on the plant growth, the analysis was made on the mechanism of soil moisture on the growth of upland rice plant in this paper, where seeds were sown on June 10, 1968 in the plastic Wagner pots (1/2000 a) and after 24 days the soil moisture was regulated to about 10 different levels.
Abstract: Based on the logistic theory on the plant growth, the analysis was made on the mechanism of soil moisture on the growth of upland rice plant. Seeds were sown on June 10, 1968 in the plastic Wagner pots (1/2000 a) and after 24 days the soil moisture was regulated to about 10 different levels. Treatments were continued till the harvest time in glass house, of which air temperature were exceedingly high (about 2-8°C higher than those of outdoor) throughout growing season. Average weight of dry matter of upland rice plant on the 37th, 70th and 119th day from sowing were used for the present analysis.The results were summarized as follows;(1) The effect of soil moisture on the plant growth were the optimum factor in the logistic theory (Fig. 3 and 4).(2) According to the logistic theory, the effect of available soil moisture saticefied the following optimum factor equation, 1/w=Af+A′/f+Bwhere, w is the total dry weight per plant at a certain time (t) and f is the amount of a factor supplied (soil moisture), A, A′ and B are the functions of time as defined by Eq. (2).In this experiment, the fitness of the equation with the experimental results was satisfactory (Fig. 5).(3) Soil moisture must be expressed by the available moisture (% in dry base) which was subtracted by the moisture of the initial wilting point for 37 and 70th day, and of the permanent wilting point for 119th.(4) The optimum soil moisture changed from lower to higher with plant growth.(5) Soil moisture affected mainly the growth of top parts of plant throughout whole growing season, and in the leaf area at middle stage.
TL;DR: In this article, the effects of broadcast application of mineral phosphate at rates from 0-400 units P2O5per acre and top-dressing treatments with nitrogen and potassium at rates up to 30 units N and 180 units K2O per acre on the growth and nutrient uptake of newly planted Sitka spruce on deep oligotrophic peat in western Northern Ireland were described.
Abstract: The effects are described of broadcast application of mineral phosphate at rates from 0–400 units† P2O5per acre and top-dressing treatments with nitrogen and potassium at rates up to 30 units N and 180 units K2O per acre on the growth and nutrient uptake of newly planted Sitka spruce on deep oligotrophic peat in western Northern Ireland. Rate of tree growth and P uptake increased progressively over four years with increasing phosphate application. Applied K appreciably increased rate of growth, length of growing season and K uptake, but tree response decreased in the fifth season after application. Nitrogen application has had little effect except in the year of planting.
Levels of N and K in Sitka foliage at the end of the first growing season were very much higher than in subsequent years.
01 Jan 1969
TL;DR: After five growing seasons on a southwest Missouri outplanting site, trees from a West Virginia eastern redcedar source had better survival, form, vigor, and height growth than trees from eight other sources tested as mentioned in this paper.
Abstract: After five growing seasons on a southwest Missouri outplanting site, trees from a West Virginia eastern redcedar source had better survival, form, vigor, and height growth than trees from eight other sources tested. The local Missouri source, handicapped at planting by an unfavorable top:root ration, is now growing vigorously.