Showing papers on "Growing season published in 1982"
TL;DR: Two different sites in central Iowa were planted with hybrid poplars and subsequently sampled over a growing season for spores of endogonaceous fungi to study the effects of plowing on the spread of these fungi.
Abstract: Two different sites in central Iowa were planted with hybrid poplars and subsequently sampled over a growing season for spores of endogonaceous fungi. At one of the sites, the effects of plowing an...
293 citations
TL;DR: During the growing season, MyriophyZZum appears to be principally important as a physical support for an active microbial community rather than as a P source to its epiphyton and surrounding waters.
Abstract: Ahstrnct The contribution of nine species of macrophytes to the phosphorus nutrition of their epiphytes and the rates of P &ease by Myriophyllum spicntunz L. were measured in situ on fully labeled (“‘I?) plants. The cpiphytcs derived only 3.4-9.0% of their P from the supporting macrophyte, indicating that previously suggested macrophyte-epiphytc nutrient interactions are of relatively minor importance. Although high diurnal P release rates (X = 3.24 pg*g-’ * h-‘) were observed for the Myriophyllum-epiphyte complex, Myriophyllum accounted for only 9.9% (0.32 pg*g-’ ah ‘) of the total I? released: The Myriophyllum-deriveclyZZum-derived P was, however, released in a highly available soh~blc form (minimum estimate: 60.3%). During the growing season, MyriophyZZum thus appears to be principally important as a physical support for an active microbial community rather than as a P source to its epiphyton and surrounding waters.
145 citations
TL;DR: A generalized British Isles oak response function shows that high rainfall, particularly in the growing season, and high temperatures in early summer favour growth in the following season perhaps due to loss of food reserves.
Abstract: SUMMARY (1) At thirteen sites in the British Isles between ten and twenty oak trees (185 in all) were sampled for dendroclimatological study. The growth ring widths were measured and, after standardization, a mean ring width index was derived for each year for each site. (2) The resulting site-index time-series were tested for climate relationships by the response function method which relates tree growth to variations in monthly temperature and precipitation. (3) Marked similarities in response functions throughout the British Isles enabled a generalized British Isles oak response function to be constructed. This shows that high rainfall, particularly in the growing season, and high temperatures in early summer favour growth. High temperatures in the previous winter, however, are detrimental to growth in the following season perhaps due to loss of food reserves.
105 citations
TL;DR: The calculated photosynthesis yield for a hypothetical optimum season of clear days with fully illuminated leaves and optimum temperature as well as for a typical season with the actual light and temperature conditions in the canopy shows that the length of the growing season is probably less important for the success of this prominent alpine plant than the sum of hours with high radiation.
Abstract: The temperature and light responses of CO2 uptake (Fn) in the sedge Carex curvula were investigated in situ by IRGA technic in the Austrian Central Alps at an altitude of 2,310 m. Fn in Carex leaves reaches a maximum of 15.6 mg CO2 dm-2 h-1 at a leaf temperature of 22.5°C and a quantum flux density larger than 1.0 mmol photons m-2 s-1 (400–700 nm). A model based on a polynomal regression analysis of the Fn responses and informations about the microclimate and the canopy structure was used to simulate Fn for individual days and for a whole season. It turned out that the major rate limiting factor is the availability of light in the canopy: The calculated photosynthetic yield for a hypothetical optimum season of clear days with fully illuminated leaves and optimum temperature as well as for a typical season with the actual light and temperature conditions in the canopy, shows that insufficient illumination of the leaves accounts for almost 40% reduction of the possible CO2 uptake while suboptimal temperatures cause only a loss of 8%. Half of the light deficit is caused by mutual shading of the leaves. The minor importance of temperature for the annual CO2 uptake results from the fact that temperature adaptation of Fn in this sedge allows optimal utilization of short periods with high light intensity and hence high photosynthetic yield. The weaker the quantum supply the more becomes temperature limiting. This indicates that the length of the growing season is probably less important for the success of this prominent alpine plant than the sum of hours with high radiation.
74 citations
TL;DR: It is suggested that the quality of tree leaves along with the direct climatic factors is the central factor determining the seasonal species richness pattern of the larvae.
Abstract: The species numbers, seasonal pattern of species richness, and degree of food specialization of Finnish macrolepidopterous larvae on different plant growth forms was analyzed. There is a significant positive correlation between the commonness of the plant and the number of associated lepidopterous species within all plant growth forms. The number of species on trees and shrubs is higher than on forbs and grasses. On dwarf shrubs the lepidopterous species richness is quite evenly distributed throughout the growing season, but on forbs there is a tendency towards the late summer. On trees the species richness pattern varies greatly. On the trees with a short shoot-growth period the larval species pattern is skewed towards the early summer while on the trees with longer shoot-growth period the majority of macrolepidopterous larvae occur in mid or late summer. It is suggested that the quality of tree leaves along with the direct climatic factors is the central factor determining the seasonal species richness pattern of the larvae. The proportion of specialized feeders is highest in those macrolepidopterous groups where the diet mainly consists of herbs. The proportion of lepidopterous species overwintering as larvae is higher on forbs than on trees and shrubs.
65 citations
TL;DR: Calculations of plant production and the interpretation of P/B ratios were complicated by the changing area of the plant population, which affected the calculation of nutrient uptake and a pattern of N03-N loss from the stream water was demonstrated.
Abstract: SUMMARY (1) Quadrat biomass and plant growth measured by shoot extension, together with gross areal changes, were examined on a watercress population in a New Zealand stream. The maximum relative production rate (relative growth rate corrected for losses between sampling intervals) of 0.0569 g g-1 day -1 occurred in mid-summer. Leaf tissue and root tissue both increased early in the growing season, but in late summer and winter, plants had a high proportion (60%) of stem. (2) Calculations of plant production and the interpretation of P/B ratios were complicated by the changing area of the plant population. This also affected the calculation of nutrient uptake. (3) Field measurements of nitrogen uptake by the plant showed that in mid-summer 1.140 g N m-2 day -' was accumulated by watercress. A pattern of N03-N loss from the stream water was demonstrated and this loss could all be accounted for by watercress uptake which exceeded (to a greater or lesser extent depending on the effect of changing area) the loss from the stream. The nitrogen rich soils of the cress beds could provide the deficit.
58 citations
TL;DR: Prior inoculation of seedlings did not significantly increase survival or height growth, but biomass increment during the first growing season was substantially reduced.
Abstract: Mycorrhizal and nonmycorrhizal container-grown Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) seedlings were outplanted on dry, burned-over sites in eastern Washington. Prior inoculation of seedlings did not significantly increase survival or height growth, but biomass increment during the first growing season was substantially reduced. New roots of all seedlings became colonized by native mycorrhizal fungi within 5 months after planting.
49 citations
TL;DR: Pin cherry ( Prunus pensylvania L.), an intolerant short-lived tree, was on the average the tallest species from the second to the sixth year of regrowth, and showed relatively greater annual height increment than beech or sugar maple.
49 citations
TL;DR: Maximum CGR's were higher than those reported for cassava at lower latitudes but, because of the restricted growing season, annual biomass yields from early planting times were similar and of the order of 30 t ha-1 year-1.
47 citations
TL;DR: An agrometeorological crop phenology model for spring wheat that incorporates the photothermal concept suggested in the Robertson crop calendar model is presented and modified to incorporate a crop moisture stress index as an additional model parameter as mentioned in this paper.
41 citations
TL;DR: Soil salinity concentration was the factor most highly correlated with plant growth, survival and ionic content of organs of S. europaea on an inland saline marsh.
Abstract: The relationship between the distribution and growth of Salicornia europaea and soil conditions was studied on an inland saline marsh. Data were collected concerning plant growth, ion content, and water potential of S. europaea throughout the growing season to determine how these responses were related to soil-ionic content, electrical conductivity, and water potential. Soil salinity concentration was the factor most highly correlated with plant growth, survival and ionic content of organs of S. europaea.
TL;DR: In most arable soils the nitrate availability depends mainly on the quantity of nitrate present in the rooting zone at the beginning of the growing season as mentioned in this paper, and the release of non-exehangeable NH4 from clay minerals may in addition control the nitrogen availability during a season.
Abstract: In most arable soils the nitrate availability depends mainly on the quantity of nitrate present in the rooting zone at the beginning of the growing season. Easily mineralizable organic N and the release of non-exehangeable NH4 from clay minerals may in addition control the nitrogen availability during a season.
TL;DR: It is concluded that forest topsoils in areas being surface mined for coal in southern Appalachia can provide diverse plant communities capable of quick, effective cover on reclaimed mine areas.
Abstract: (1) In microplots, forest topsoils from mixed deciduous stands in the Cumberland Mountains of eastern Tennessee were spread over surface minesoils from the same region and supplemented with nitrogen and phosphorus. (2) First-year plant communities originating from seed banks in these topsoils contained about 1-9 x 106 shoots ha-' representing 134 taxa. At the end of the first growing season, oven-dry shoot and root weight was about 8.4 t ha-'. Nutrient analysis suggested that most of the added nutrients were retained in biomass. Roots were extensively colonized with endomycorrhizae. (3) We conclude that forest topsoils in areas being surface mined for coal in southern Appalachia can provide diverse plant communities capable of quick, effective cover on reclaimed mine areas. Results warrant testing of these topsoils on mined sites.
TL;DR: A field study was conducted during the 1980 growing season to determine the effects of soil moisture gradient on sorghum water relationships, growth, and yield of four hybrids: Sorghum bicolor L. as mentioned in this paper.
Abstract: A field study was conducted during the 1980 growing season to determine the effects of soil moisture gradient on sorghum water relationships, growth, and yield of four hybrids: Sorghum bicolor L. ’G-623 GBR,’ ’RS 626,’ ’RS 671’ and ’A 28+’. June to September was warmer than normal (2.3–4.8 °C), with precipitation of only 16.2 cm during the cropping season. Sprinklers provided a continuously decreasing moisture gradient away from the water source. Plant height, dry matter, and leaf area index (LAI) decreased as watering level decreased. Higher leaf diffusive resistance and lower water potentials were associated with decreasing plant height and decreasing LAI. Canopy temperature (Tc) of the water-stressed sorghum was generally 3.2–3.7 °C warmer than canopy temperatures of well-watered plants. Canopy temperature also correlated well with water use by all hybrids. The average canopy minus air temperature was positive for all hybrids receiving less than 25 cm of irrigation and precipitation during the growing ...
TL;DR: The pattern of insect pest succession on the crop over the season is discussed and it is suggested that for small farm holders in Southern Nigeria, who are unlikely to apply insecticides, planting in June is advisable.
Abstract: The trends in flowering, podding and seed yield of four cowpea varieties planted at different times of the growing season in 1975 and 1976, were studied along with the associated pest activity. Flowering, podding and seed yield were found to decrease over the season from April to September irrespective of whether the crop was protected against insect pests or not. However, there seemed to be two peak periods of pest activity—April to July and October to December—when severe damage to the crop occurred in unprotected plots. Planting in June or July usually led to an escape from several major pests even though the cool night temperatures and incidence of overcasts at that period seem to preclude optimal reproductive performance of the crop. The pattern of insect pest succession on the crop over the season is discussed and it is suggested that for small farm holders in Southern Nigeria, who are unlikely to apply insecticides, planting in June is advisable.
TL;DR: It appeared that non-irrigated J. nigra was able to equilibrate with deeper wet areas in the soft profile and thus avoid the lower predawn P levels experienced by Q. alba and A. saccharum, and appeared responsive to high levels of atmospheric evaporative demand.
TL;DR: In this article, monthly changes in the biomass of Ranunculus, Berula and Callitriche were recorded on two 50m sites on the River Lambourn at Bagnor between March 1971 and October 1973.
Abstract: SUMMARY. Monthly changes in the biomass of Ranunculus, Berula and Callitriche were recorded on two 50-m sites on the River Lambourn at Bagnor between March 1971 and October 1973. On the unshaded site. Ranunculus was the dominant macrophyte and characteristically its biomass changed from 20–40 g dry wt m-2 in March to around 400 g dry wt m-2 at the end of the growing season. On the shaded site, where Berula was the dominant macrophyte. the biomass of Ranunculus was lower than on the unshaded site. There was no significant difference between the mean biomasses of Berula on these two sites but Callitriche had a signifieantly higher biomass on the shaded site. Estimates of the total biomass of macrophyte on each site were calculated and the biomass of macrophyte removed during cutting operations each summer was also assessed.
TL;DR: Eriophorum vaginatum was the most abundant species because it had the highest seedling emergence rates, particularly early in the growing season; produced more tillers per seedlings; and had a higher growth rate per seedling than C. bigelowii.
Abstract: The dynamics of seedling establishment, and growth of native cotton grass-tussock tundra species were studied during the natural revegetation of small bare areas excavated in tussock tundra. The seedlings of Eriophorum vaginatum spp. spissum and Carex bigelowii, two sedge species, established most successfully. Few seedlings of nonsedge species emerged with the small disturbances. Most seedling emergence occurred early in the first growing season following the excavation of the bare areas. The density of emerged seedlings was higher in bare areas excavated in the autumn preceding the observations, rather than in bare areas excavated at the start of the first season of observation. After two growing seasons, survival of seedlings was not affected by the time the seedling emerged within the growing season. Eriophorum vaginatum was the most abundant species because it: (1) had the highest seedling emergence rates, particularly early in the growing season; (2) produced more tillers per seedlings; and (3) had a higher growth rate per seedling than C. bigelowii.
TL;DR: In the lower Atchafalaya Basin, water tupelo (Nyssa aquatica L) trees were cut in May and November at three stump heights to study coppice regeneration as discussed by the authors.
Abstract: In the lower Atchafalaya Basin, water tupelo (Nyssa aquatica L) trees were cut in May and November at three stump heights to study coppice regeneration Sprouting was extremely good after one growing season, and live sprouts grew well through the third andfourth seasons However, some stumps began to deteriorate and sprouts die after the second growing season After six years, only 9 percent of the stumps cut in May and 18 percent of those cut in November had live sprouts Water tupelo is found in cypress-tupelo swamps from southern Virginia to northern Florida; in southeastern Texas; and in the Mississippi Valley northward to Illinois, western Kentucky, and Ten nessee It normally grows in dense stands with or without cypress (Taxodium distichum (L) Rich) and other tupelos, and typically has a long, clean, strongly buttressed bole Trees are either cut near the top of the butt swell or felled and bucked to leave the basal wood The butt swell may be from as little as one foot above ground line to as much as 8 to 10 feet, depending on flooding depth in the swamp Water tupelo wood is valued for a number of products because of its white color, lack of odor or taste, good staining qualities, and nail-holding charac teristics The wood is exceptionally clear and used for veneer, box lumber, and furniture stock The butt-swell portion has been shown to be suitable for pulpwood with the possibility of use in grease proof papers and corregating medium (Laundrie and McKnight 1969) Vast acreages of water tupelo are at or near merchantable size When these stands are cut, we need to know if we can rely on the coppice method of regeneration to produce the next stand, and, if so, what effects stump height and season of cutting have on this regeneration METHODS
TL;DR: This study was conducted to evaluate vegetation responses of seeded coal mined lands to 2 years of summer irrigation to indicate positive effects of temporary irrigation in terms of initial vegetation establishment, productivity, and species composition.
Abstract: Responses of reseeded vegetation in the first two growing seasons (1978 and 1979) to irrigation on topsoiled sodic mine spoils are presented. In terms of above-ground productMy and stand composition, irrigation significantly promoted growth of seeded perennial grasses and legumes in total. This stimulation was most pronounced in 1979 for the cool-season grasses, slender wheatgrass, smooth bromegrass and western wheatgrass and the invading cool-season legume yellow sweetclover. Other cool-season grasses and warm-season grasses were stimuiated by inifini irrigation, but were either unaffected or retarded (due to competitive relationships) by continued irrigation. Productivity of invading annual weeds was significantly curtailed by irrigation by 1979. Although differences in composition occurred, total stand productivity was similar for irrigated and nonirrigated plots in 1978, a year of above-average precipitation. In 1979, a drier year, total stand productivity was nearly three times higher under irrigation than nonirrigation. In the first year of study (1978), a higher measured index of stand structural diversity occurred under irrigation. This relationship became reversed in 1979, with higher structural diversity in nonirrigated plots. Root biomass was significantly higher in nonirrigated than in irrigated plots. This difference between irrigation and nonirrigation was most pronounced in the applied topsoil zone. Root distribution was skewed towards shallowest soil depths under irrigation to a far greater extent than under nonirrigation. Impacts of coal surface mining in the western United States will increase during the coming decades, and much mined land will be reclaimed for rangeland use. Moisture availability is often a major factor affecting revegetation of mined land in this region (May 1975). In arid areas irrigation may be the only means to establish vegetation rapidly (Aldon 1978). Success with both sprinkler and drip irrigation systems on mined land has been reported in the Southwest (Bengson 1977; Aldon et al. 1976; DeRemer and Bach Authors are associate research plant ecologist and research assistants in reclamation, respectively, Reclamation Research Unit, Montana Agricultural Experiment Station, Montana State University, Bozeman 59717. This report involves a study through the Montana Agricultural Experimeat S ation cooperatively funded by the Science and Education Administration, U.S. Department of Agriculture, and the Decker Coal Company, Decker. Montana. Manuscript received March 3, 1980. 1977; Gould et al. 1978). Although the semiarid Northern Great Plains coal province receives more precipitation than the Southwest, large seasonal and yearly fluctuations suggest a great utility of irrigation there as well. Mined land research in North Dakota (Ries et al. 1977, Ries et al. 1978) has indicated positive effects of temporary irrigation in terms of initial vegetation establishment, productivity, and species composition. Ries and Day (1978) and Ries et al. (1976)distinguished between sustained irrigation and irrigation for establishment only, the latter being recommended for establishment of nonirrigated pasture. The objective of temporary irrigation is initially to establish vegetation which will survive when irrigation terminated. Sustained irrigation of mined lands was recommended only for sustained production of a given agricultural crop, or if necessary for leaching of excess soil salts. Irrigation may also be beneficial in extending the seeding season and in promoting growth of warm-season species which in the past have proven difficult to establish. One major concern in using temporary irrigation is vegetation response after irrigation cessation. This study was conducted to evaluate vegetation responses of seeded coal mined lands to 2 years of summer irrigation. Sustained irrigation was employed rather than initial irrigation due to necessary requisites for concurrent evaluation of four sodic subsoil amendments (DePuit et al. 1979). This report will summarize vegetation data relative to irrigation only. Objectives of this phase of the project included: I) Evaluation of effects of supplemental irrigation on vegetation establishment, structure, composition, diversity and productivity during the first two irrigated growing seasons. 2) Definition of effects of irrigation on root biomass and
TL;DR: In this article, the response of a grain corn crop to changes in a variety of important environmental and decision-making inputs: air temperature, solar radiation, relative humidity, irrigation frequency, and amount of irrigation water applied was demonstrated.
Abstract: WATER, a parametric crop water use model, employs climatic data to calculate water consumption for a variety of crops, using a modification of the Penman equation which included specific crop and growth stage effects. The objective of this paper was to demonstrate the response of WATER, for a grain corn crop, to changes in a variety of important environmental and decision-making inputs: air temperature, solar radiation, relative humidity, irrigation frequency, and amount of irrigation water applied. Five temperature, five solar radiation, and six relative humidity regimes were examined for an entire growing season. Also, five different water application schemes and four irrigation frequencies were included in this experiment. Additionally, the effect of different soil types, wind regimes, and groundwater depths on crop water requirements were investigated. These analyses were performed using four annual climatic scenario combinations. Among the results, evapotranspiration (ET) increased on the average by about 2.5%/1°C increase in air temperature. One percent change in solar radiation resulted in a 1.5% change in ET, while a similar change in relative humidity caused a 0.4% response in ET. Contrasting soil types, in addition to affecting irrigation frequency, were capable of changing the responding ET by over 10%.
Journal Article•
TL;DR: Levels of atmospheric Ambrosia (ragweed) pollen in the urban environment of Tulsa, Oklahoma, were determined using a Rotorod sampler to suggest it may be possible to predict pollen season levels based upon early summer weather patterns.
Abstract: Levels of atmospheric Ambrosia (ragweed) pollen in the urban environment of Tulsa, Oklahoma, were determined using a Rotorod sampler. The data, representing the distinctly different growing seasons of 1980 and 1981, suggest it may be possible to predict pollen season levels based upon early summer weather patterns.
TL;DR: In this paper, a soil-water model was developed and tested to study the poten-tial effects of basin tillage on soil moisture levels at two locations in Minnesota and south central Texas.
Abstract: A soil-water model was developed and tested. The model provides satisfactory predictions of soil-water content at various depths for corn at a location in south-west Minnesota. The model was used to study the poten-tial effects of basin tillage on soil moisture levels at two locations, one in Minnesota and another in south central Texas. Results of these projections indicated that basin tillage increases soil moisture and decreases crop stress significantly as compared to conventional tillage by in-creasing infiltration of excess precipitation during the growing season, the off-season or both.
TL;DR: In subtropical latitudes temperate crops can be grown during the cool months but the growing season is restricted by the termination and beginning of hot weather, postponing sowing date in south Florida from October to November to January resulted in 150, 130 and 110-d growing seasons respectively.
Abstract: In subtropical latitudes temperate crops can be grown during the cool months but the growing season is restricted by the termination and beginning of hot weather. Postponing sowing date in south Florida from October to November to January resulted in 150, 130 and 110-d growing seasons respectively. Dry matter (DM) yields of turnip, swede, rape and kale were lowered by each later sowing date and shorter growing season, and crude protein (CP) concentration was the same as for, or was increased by late sowing. In vitro organic matter digestibility (IVOMD) of turnip, swede and rape leaves was not affected by sowing date, but roots of turnip and swede from the earlier sowings and longer growing seasons were more digestible. Yield of the four species depended on harvest management as well as date of sowing and length of growing season. Total yield of turnip and swede were unaffected by harvest management but multiple cutting resulted in greater leaf yields and smaller root yields, whereas stockpiling resulted in smaller leaf yields and larger root yields. Kale produced more DM when harvested once at the end of the winter growing season but rape produced the greatest DM yield when sown in October and harvested
TL;DR: The ability of Dicoria to successfully growth through the hot, dry summers of the California deserts may be related to its ability to acquire the available water in locally mesic habitats.
Abstract: The gas exchange characteristics of two C3 desert annuals with contrasting phenologies, Geraea canescens T. & G. (winter-active) and Dicoria canescens T. & G. (summer-active), both Asteraceae, were determined for plants grown under a moderate (25°/15° C, day/night temperature) and a high (40°/27° C) growth temperature regime. Both species had high photosynthetic capacities; maximum net photosynthetic rates were 38 and 48 μmol CO2 m-2 s-1 for Geraea and Dicoria, respectively, and were not influenced by growth temperature regime. However, the temperature optima of net photosynthesis shifted from 26° C for Geraea and from 28° C for Dicoria when grown under the moderate temperature regime to 31° C for both species when grown under the high temperature regime. Although the shifts in temperature optima were smaller than those observed for many desert perennials, both species showed substantial increases in photosynthetic rates at high temperatures when grown at 40°/27° C. In general, the gas exchange characteristics of Geraea and Dicoria were very similar to each other and to those reported for other C3 desert annuals. Geraea and Dicoria experienced different seasonal patterns of change in several environmental variables. For Geraea, maximum daily air temperature (T a) increased from 24° to 41° C over its growing season while Dicoria experienced maximum T a at midseason (45° C). At points during their respective growing seasons when midday T a ranged between 35° and 40° C, leaf temperatures (T 1) of both species were below T a and, therefore, were closer to the photosynthetic temperature optima measured in the laboratory. Leaf conductances to water vapor (g 1) and water potentials (ψ) were high at these times, but later in their growing seasons Dicoria maintained high g 1 and ψ while Geraea showed large decreases in these quantities. The ability of Dicoria to successfully growth through the hot, dry summers of the California deserts may be related to its ability to acquire the available water in locally mesic habitats.
TL;DR: Savannas cover about 300 million hectares of South America and their natural fertility is very low with high acidity, so biological nitrogen-fixation as a possible source of nitrogen to replace that removed in crops is important.
Abstract: Savannas cover about 300 million hectares of South America. The soils are mainly oxisols and ultisols and their natural fertility is very low with high acidity. The natural vegetation varies in density and in the amount of biomass produced annually, which can be equal to that produced by forests in the region. Among the nitrogen-fixing micro-organisms, the only ones well-studied are Rhizobium bacteria. In managing the biomass in these areas, it is important to consider biological nitrogen-fixation as a possible source of nitrogen to replace that removed in crops. Nitrification and denitrification in these soils are intense but not well studied. The rainfall distribution during the growing season seems to have a considerable influence of the nitrogen supply to the soils. A considerable loss of nitrogen occurs in this environment when vast areas are burned annually.
TL;DR: Foliar fertilizer applied at various rates at different time intervals did not increase yields at either location during the four year study of Florunner peanuts.
Abstract: This study was conducted to determine the effects of foliar-applied fertilizer on yield, quality, chemical composition, and vegetative characteristics of Florunner peanuts. Field experiments wre conducted over a four year period, 1976–1979, on two Coastal Plain soils. Foliar fertilizer containing, N, P, K, and S was applied at varying rates and intervals during the growing season. Plants were sampled at three stages of growth to study vegetative characteristics and chemical composition. Yield and quality factors were taken at harvest. Foliar fertilizer applied at various rates at different time intervals did not increase yields at either location during the four year study. A slight increase in %SMK was noted in 1976 at one site for the highest rate applied late in the growing season. The two highest rates (168 and 224 kg/ha) caused severe burn damage to the foliage in 1977 and 1978, and consequently only the low rate (112 kg/ha) was used in 1979. In 1978, pod number was reduced with the highest ...
TL;DR: Photosynthetic production by macrophytes was extremely high early in the growing season; but later declined and heterotrophic processes became predominant; and benthos production was initially low but became the primary source of photosynthesis later in the season.
Abstract: Changes in relative contribution to total stream photosynthetic and respiratory rates by various community components of an open channel stream were estimated. Rates of photosynthetic production of plankton, benthos and macrophytes (with associated epiphytes) were followed through the growing season and compared with total estimates from a diurnal oxygen technique. Photosynthetic production by macrophytes was extremely high early in the growing season; but later declined and heterotrophic processes became predominant. In contrast, benthos production was initially low but became the primary source of photosynthesis later in the season. Plankton contributed little to stream photosynthesis and respiration.
Journal Article•
TL;DR: In this paper, the authors found that the sunflower9s capacity for producing a crop in situations where water stress restricts corn production is because of a drought stress escape mechanism rather than because of lower water requirements.
Abstract: Soil water measurements (by the neutron method)during the growing season indicated that water use by sunflowers (Helianthus annus L.) compares with water use by corn (Zea mays La). These results suggest that the sunflower9s capacity for producing a crop in situations where water stress restricts corn production is because of a drought stress escape mechanism rather than because of lower water requirements.