Interception Of Solar Radiation Research Articles

Effect of canopy structure on the diurnal interception of direct solar radiation and photosynthesis in a tree stand.

Effect of canopy structure on the diurnal interception of direct solar radiation and photosynthesis in a tree stand.

Annual variation of the growth and its relation with meteorological factors in potato plants. I. The aspect of annual variation in shoot fresh weight during the growth and its relations with solar radiation, temperature and precipitation.

Considering annual variation of the potato shoot growth and its relation with the meteorological factors, fresh weight of shoot (shoot weight) in three main cultivars was weighed at four to six times during the growing season (June to September) through ten years (1972-1981) at the Hokkaido National Agricultural Experiment Station. 1. Annual variation of shoot weight in each variety increased after sprouting to late July, then decreased slightly on August, when the early variety (Danshakuimo) reached the harvesting stage. Thereafter, in two late varieties (Norin No. 1 and Benimaru). it turned to increase again and showed the maximum value on late September (Fig. 1). Comparing it among the varieties, Danshakuimo showed the larger value than the other two varieties since middle July (Fig. 1). Shoot weight, however, showed significant positive relations among the varieties at most of the sampling date. It indicated that, when shoot weight was larger in one variety, it tended to be larger in the other two varieties (Table 2). 2. Annual variation of the date of sprouting influenced little on shoot weight of July 1 (just before the first flowering stage), which depended mostly on the growth rate of shoot weight (shoot GR) from sprouting to July 1 (Tables 1, 3). Shoot GR from July 1 to 15 showed large effect on shoot weight from middle July to late August. Annual variation of shoot weight on late September was, however, mainly affected by the rate of shoot senescence since late August (Fig. 2, Table 3). 3. Shoot GR from sprouting to July 1 was larger when maximum and minimum temperature was higher. The simple correlation coefficients of shoot GR with these factors were, however, realtively low. It seemed also to be effected by solar radiation and precipitation (Figs. 3, 4). In addition, shoot GR from July 1 to 15 showed remarkable relation with maximum temperature in three varieties, i.e. it was smaller when maximum temperature was within 22°-23°C and precipitation was less than 0.5 mm/day (Fig. 5). 4. The relations of solar radiation with shoot GR on July and with shoot weight on August, and of solar radiation with shoot weight of September were significantly negative. The results indicated that potato plants increased the shoot growth and retarded the shoot senescence when solar radiation was limited, which would result in minimizing the decrease of solar radiation interception by the shoot (Figs. 5, 6, 7).

The Effects of Population Density, Row Spacing and Intercropping on the Interception and Utilization of Solar Radiation by Sorghum bicolor and Vigna unguiculata in Semi-Arid Conditions in Botswana

The Effects of Population Density, Row Spacing and Intercropping on the Interception and Utilization of Solar Radiation by Sorghum bicolor and Vigna unguiculata in Semi-Arid Conditions in Botswana

Water and nitrogen limitations in soybean grain production I. Model development

A simple, phenomenological model was developed to describe the carbon, nitrogen, and water budgets of a soybean (Glycine max (L.) Merr) crop from emergence to maturity. Daily meteorological data input to the model were minimum temperature, maximum temperature, solar radiation, and precipitation. Leaves were grown to give a linear function of mean daily temperature. From the calculated leaf area index the daily intercepted solar radiation by the crop was determined. Daily carbon accumulation was calculated as a linear function of intercepted radiation. The daily nitrogen accumulation rate was calculated as a linear function of vegetative biomass. Leaf growth, carbon accumulation and symbiotic-nitrogen fixation rates were all made sensitive to the amount of soil water. Experimental data were collected to develop the empirical relationships between these three physiological processes and the amount of transpirable soil water. These data showed nitrogen fixation rates to be more sensitive to soil dehydration than either leaf growth or leaf gas exchange. Preliminary tests showed that model predictions compared favorably with field observations. An analysis of the model's behavior showed that crop yield was most sensitive to those variables influencing the interception of solar radiation and its conversion to biomass.

Plant water relations in lychee: Effects of solar radiation interception on leaf conductance and leaf water potential

The effect of radiation interception on leaf conductance and leaf water potential in six-years old lychee trees ( Litchi chinensis Sonn. cv. Bengal) was investigated during the dry season in subtropical Queensland, Australia. A high degree of exposure of leaves to direct radiation raised leaf-air water vapour concentration gradient (Δ w) and resulted in lower leaf conductance and leaf water potential. Interior leaves of the south side of trees were less sensitive to atmospheric and radiation effects and are the best indicator of drought stress in lychee. Completely random or stratified sampling is necessary to estimate a true mean value for calculation of canopy transpiration or photosynthesis.

Photosynthetic efficiency of Amaranthus hybridus grown in the field

The relationship between the interception of solar radiation and dry matter production was studied in a crop of Amaranthus hybridus. The results show that photosynthetic efficiency of this crop was 2.8% but this rose to 10.9% with the addition of NPK 15:15:15 compound fertilizer. The mean reflection coefficient was 0.28 ± 0.06 while the extinction coefficient ranged form 1.01 to 0.19. The extinction coefficient showed a rapid decrease with time and leaf area index.

A simple model to describe variation between years in the early growth of sugar beet

Abstract A simple model of early dry matter increase of sugar beet based on a two-stage expansion of the leaf canopy and its interception of solar radiation is described. The model takes account of differences in temperature and irradiance, and is shown to explain differences in dry matter increase between years in crops grown at one location in England. The differences were as great as 1.0 t ha−1 (from 0.07 to 1.02 t ha−1) even just 60 days after sowing. It is suggested that such differences can be important when considering crop demand for nitrogen.

Solar radiation interception by leafless, semi‐leafless and leafed peas (Pisum sativum) under contrasting field conditions

SUMMARYFoliage composition, photosynthetic area index (PAI) and radiation interception were measured for crop canopies of leafless (var. Filby), semi‐leafless (var. BS3) and leafed (var. Birte) peas (Pisum sativum). Tendrils and petioles contributed more than 60% of total leaf area for leafless peas but less than 30% for semileafless and leafed pea canopies.PAI was related to radiation interception by calculating attenuation coefficients which indicated that leafless peas intercepted more radiation per unit PAI than either semi‐leafless or leafed peas. Data interpretation, however, was complicated because of difficulties in estimating the tendril and petiole surface area contribution to PAI.Radiation interception was related to dry matter accumulation by calculating photosynthetic efficiencies. Leafless and semi‐leafless peas converted intercepted radiation into dry matter as efficiently as leafed peas.Under conditions of moisture stress, leafed and leafless peas both intercepted radiation more effectively but converted it into dry matter with reduced photosynthetic efficiency.

Drought and changes in leaf orientation for two California chaparral shrubs: Ceanothus megacarpus and Ceanothus crassifolius.

Predawn xylem pressure potentials were measured on two California chaparral shrubs, Ceanothus megacarpus and Ceanothus crassifolius, throughout the winter and spring growing season and into the summer drought. On the days xylem pressure potentials were measured, leaf orientation measurements were made on a population of marked leaves from the same shrubs. Predawn xylem pressure potentials decreased from -0.1 MPa in both species to -7.8 and -6.6 MPa in C. megacarpus and C. crassifolius, respectively, between May and August, 1981. Leaf inclinations became more vertical during this period with the greatest change observed in C. crassifolius. This change in leaf inclination was reversible, and, in the late winter and early spring, one year old leaves became more horizontal. Leaf azimuths were random and did not change seasonally. Simulations of solar radiation interception indicated that the increase in leaf inclination associated with summer drought reduced the absorption of solar radiation in August by 6% for C. megacarpus and 20% for C. crassifolius. Standard leaf energy budget calculations suggest that steep leaf inclinations would result in slightly lower leaf temperatures and transpiration rates under summer conditions.

Photosynthesis and Dry Matter Production in C3 and C4 Pasture Plants, With Special Emphasis on Tropical C3 Legumes and C4 Grasses

The nature of C3 and C4 pasture plants is described, and the potential biomass productivity is discussed. Then differences in net annual production and crop growth rates of C3 and C4 pasture plants are analysed in terms of the interception of solar radiation and the efficiency of its conversion to dry matter. Finally, the components of photosynthetic production of tropical C4 grasses and tropical C3 legumes are compared with their growth rates and dry matter yields in the subtropics. The higher crop growth rates of tropical C4 grasses compared with C3 pasture plants, whether they are of temperate or tropical origin, seem to be due mainly to higher leaf net photosynthetic rates and to the absence of photorespiration associated with possession of the C4 pathway. However, light utilization efficiencies are probably also higher in C4 grasses. In addition to these two characteristics, the longer growing season of C4 grasses in the warm conditions of the tropics contributes to their higher net annual production of dry matter. There is a close association between possession of the C4 pathway, higher rates of photosynthesis and growth, and higher dry matter yields when tropical C4 pasture grasses are compared with tropical C3 legumes in a subtropical climate.

Portable monitor for solar radiation that accumulates irradiance histograms for 32 leaf-mounted sensors

A novel and inexpensive instrument to monitor solar radiation interception at up to 32 locations simultaneously is described. It employs small-area, lightweight sensors that are leaf-mountable and have very good spectral and angular responses. A portable computer readily controls fast data acquisition and in-field processing to histograms, which are the most general irradiance measures to relate to nonlinear plant responses such as photosynthesis. Two field tests verified the instrument's reliability and operational convenience, and also directly compared radiation interception at space-fixed locations vs. nearby leaves. A number of new physiological and canopy-model tests that the instrument makes possible are described. The monitor is constructed from standard electronic components and may be readily modified for many expanded capabilities.

Radiation Inteception and the Growth of Soybeans Exposed to Ozone in Open- Top Field Chambers

SUMMARY (1) Soybeans (Glycine max (L.) Merr. 'Davis') were grown in the field in North Carolina, in open-top chambers which were ventilated with either charcoal-filtered air, or non-filtered air, or non-filtered air to which about 0.02, 0.04 or 0.06 ppm ozone (03) was added for 7 h day-' (10.00-17.00 h EDT). (2) Interception of total solar radiation by the canopy in each treatment was measured with tube solarimeters, integrating the signals electronically on a daily basis. (3) From regular harvests throughout the season, components of above-ground biomass and leaf area index (LAI) were determined., Non-destructive assessments of seed development were also made. (4) During vegetative growth (the first 9 weeks from emergence) the relation between dry matter and radiation intercepted from emergence was linear for all treatments. The slopes of the linear regressions consistently decreased as 03 concentration increased; in the highest 03 exposure the slope was about 30% less than that in filtered air. (5) As 03 concentration increased, the maximum radiation interception attained during the season decreased, and earlier senescence gave a shorter persistence of leaf cover. The seasonal mean value of the fraction of radiation intercepted decreased from 0.68 in filtered air to 0.65 in the highest 03 treatment. (6) Rates of seed growth were not significantly influenced by 03 but the duration of seed growth decreased with increased 03. Exposure to 03 reduced pod number per plant and mean seed weight, but the number of seeds per pod decreased only at the highest 03 concentration. (7) Seed yields in the highest 03 treatment were about 50% lower than in filtered air. Analysis of environmental and biological factors limiting seed yield showed that over the whole season the smaller light interception and shorter duration of growth (emergence to cessation of seed growth) each accounted for less than 7% of the yield loss. More important factors restricting yield were the action of 03 in lowering efficiencies of dry matter production early in the season and in altering seed and pod development. (8) The analysis showed that detailed studies of the interactions in the field between air

Crop Productivity and Photoassimilate Partitioning

The photosynthetic basis for increasing the yield of major field crops is examined in terms of improving the interception of seasonal solar radiation by crop foliage, the efficiency of conversion of intercepted light to photosynthetic assimilates, and the partitioning of photoassimilates to organs of economic interest. It is concluded that, in practice, genetic and chemical manipulation of light interception over the season and of partitioning offer the most potential for achieving further increases in yield. During the history of improvement of genetic yield potential of crops, increase in the partitioning of photoassimilates to harvested organs has been of primary importance.

Interception of Summer and Winter Insolation by Five Shade Tree Species

Abstract Five species of ornamental trees were examined with an Eppley pyranometer for interception of total solar radiation between 380 nm and 1100 nm. Measurements were made at the northern dripline and expressed as percentage of shade. Trees were selected for varying forms, branch, and canopy densities. Mean percentage of shade for the fully foliaged and leafless canopies, respectively, were Pyrus calleryana ‘Chanticleer’ 75% and 43%, Acer rubrum ‘Red Sunset’ 69% and 25%, Zelkova serrata ‘Village Green’ 61% and 24%, Gymnocladus dioicus 60% and 15%, Gleditsia triacanthos inermis ‘Moraine’ 56% and 21%. No statistically significant (PSO.05) correlation was observed among solar radiation intercepted and photosynthetically active radiation (PAR) intercepted, pathlength, silhouette area, and canopy volume. Growth habit did not affect shading capacities significantly.

AXIAL ROTATION OF ERYTHRINA HERBACEA LEAFLETS

The leaflets of Erythrina herbacea, a leguminous plant native to subtropical North America, undergo daily movements. During the night, leaflets are oriented with their tips pointing downwards and show no rotation around the midrib of each leaflet. In the morning, leaflets rise, passing through a horizontal orientation and, somewhat before noon, reach a maximum average midrib elevation of approximately sixty degrees above the horizontal plane. Simultaneously, each leaflet rotates about the midrib by an average angle of forty to fifty degrees. These leaflet movements result in an initial increase in the relative leaflet surface area presented to the sun during the morning, a decrease in interception of direct solar radiation around noon, followed by a second maximum in light interception in early afternoon.

The influence of axial rotation upon interception of solar radiation by plant leaves

Axial rotation of a plant leaf about the midrib is an important factor which permits effective maximization or minimization of the interception of direct solar radiation. Through use of matrix rotations of coordinate systems, the cosine of the angle of incidence, a measure of the fraction of solar radiation intercepted by the leaf, is described as a function of angles which specify the relative orientation of the leaf to the sun. All of these angles can be measured directly except for the axial rotation angle, which may be calculated from more easily measured quantities. Computer modeling and theoretical calculations demonstrate that relatively large amounts of average axial rotation permit a plant to reduce the cosine of angle of incidence of each flat leaf to zero, resulting in no interception of direct solar radiation, while smaller amounts of average axial rotation allow a plant to intercept as much as 80% of direct radiation, even if leaves are distributed uniformly over 360° of azimuth.

On the relationship between interception of direct solar radiation by cactus bodies and plant leaves

The interception of direct solar radiation by cactus bodies is calculated by computation of the average of the cosine of the angle of incidence over the surface of two models: a cylindrical model with a horizontal top and a prolate or oblate ellipsoidal model. An expression is obtained for the fraction of maximum possible solar radiation intercepted by a particular surface element for fixed values of the zenith angle of the sun. This expression is averaged by numerical integration over the surface of the cactus body to yield the average cosine of angle of incidence. The resulting relationships between cosine of angle of incidence and solar zenith angle show significant differences with respect to similar relationships for flat leaves. However, if a correction is applied for attenuation of direct solar radiation by the atmosphere, differences are greatly reduced.

Compétition pour le rayonnement solaire en début de succession secondaire dans une érablière à bouleau jaune et hêtre

We demonstrate that sugar maple (Acersaccharum Marsh.), yellow birch (Betulaalleghaniensis Britton), and beech (Fagusgrandifolia Ehrh.) compete for solar radiation against other woody species (noncommercial) and herbaceous species, following clear-cutting. The experiment was carried out at the Duchesnay Forest Station (Quebec, Canada) in a sugar maple – yellow birch – beech community and consisted of one control and two treatments: (1) elimination of noncommercial woody species and (2) elimination of noncommercial woody species and herbaceous species. The graph of solar radiation interception versus cover indicates that crown overlapping does not contribute significantly to any increase in solar radiation interception. Surface soil temperature is strongly linked to the decrease in solar radiation due to its interception by plants.

Spectral Estimates of Solar Radiation Intercepted by Corn Canopies1

AbstractAs the need for timely information on worldwide crop production intensifies the role of remote sensing is becoming more prominent. If agronomic variables related to yield could be reliably estimated from multispectral satellite data, then crop growth and yield models could be implemented for large areas. The objective of this experiment was to develop methods for combining spectral and meteorological data in crop yield models that are capable of providing accurate estimates of crop condition and yields. Initial tests of this concept using data acquired in field experiments at the Purdue Agronomy Farm, West Lafayette, Ind., are presented. Reflectance factor data were acquired with a Landsat band radiometer throughout two growing seasons for corn (Zea mays L.) canopies differing in planting dates, populations, and soil types (Typic Argiaquoll and Udollic Ochraqualf). Agronomic data collected to coincide with the spectral data included leaf area index (LAI), biomass, development stage, and final grain yields. The spectral variable greenness was associated with 76% of the variation in LAI over all treatments. Single observations of LAI or greenness were found to have limited value in predicting corn yields. The proportions of solar radiation intercepted (SRI) by these canopies were estimated using either measured LAI or greenness. Both estimates, when accumulated over the growing season, accounted for approximately 65% of the variation in yields. The Energy Crop Growth (ECG) variable was used to evaluate the daily effects of solar radiation, temperature, and moisture stress on corn yields. Coefficients of determination for grain yields were 0.67 for the ECG model using measured LAI to estimate SRI, and 0.68 for the ECG model using greenness to estimate SRI. We conclude that this concept of estimating intercepted solar radiation using spectral data represents a viable approach for merging spectral and meteorological data in crop yield models. The concept appears to be extendable to large areas by using Landsat MSS data along with daily meteorological data and could form the basis for a future crop production forecasting system.

Solar radiation interception, dry matter production and yield in pigeonpea (Cajanus cajan (L.) Millspaugh)

Abstract Data from a dry season field trial with short growth habit pigeonpea cultivars in Trinidad, West Indies, indicate a linear relationship between the maximum amount of dry matter accumulated by the crop and the amount of solar radiation intercepted by the foliage during growth. Analysis of these data shows that both the seasonal interception of solar radiation and the efficiency of its conversion to dry matter were reduced in plots which did not receive supplemental irrigation. Such plots also partitioned a smaller proportion of their total dry matter into grain. The potential of short growth habit pigeonpeas as a crop for both marginal cultivated areas and relatively sophisticated production systems is discussed.