Net Carbon Exchange Rates of Field-Grown Crops in Relation to Irradiance and Dry Weight Accumulation

1977 ◽  
Vol 4 (4) ◽  
pp. 555 ◽  
Author(s):  
PJM Sale
Keyword(s):  
Exchange Rates ◽  
Leaf Area ◽  
Growth Rates ◽  
Co2 Flux ◽  
Large Field ◽  
Co2 Uptake ◽  
Carbon Exchange ◽  
Area Index ◽  
Stages Of Growth ◽  
Net Carbon Exchange

A range of summer and winter vegetable crops has been grown under favourable conditions, and the relation between net carbon exchange and irradiance determined at several stages of growth, using large field assimilation chambers and semi-closed gas analysis systems. For all crops, leaf area index was an important determinant of net carbon exchange rate during early stages of growth, and rates increased markedly from day to day during the period of rapid vegetative development. Except for cauliflower and cucumber, for which leaf area ceased to be so important as the crops developed, maximum rates of CO2 uptake were achieved at maximum leaf areas, and were in excess of 90 mg CO2 dm-2 (ground area) h-1 for sweet corn, about 64 for rockmelon, 50 for broad bean, cauliflower and cabbage, and 45 mg dm-2 h-1 for cucumber. For both rockmelon and cucumber, net carbon exchange rates in the morning were often greater than those at the same irradiances in the afternoon, which suggests partial stomatal closure at about midday. In all crops, variations in temperature of up to 10°C either side of the ambient temperature, imposed at any time during the day, generally had little effect on negative CO2 flux (uptake), but positive CO2 flux at night was strongly influenced by temperature. In cucurbits uptake was reduced at temperatures above 35°C, but rapidly recovered when the temperature was again lowered. High growth rates were achieved by all crops for most months of the year, and the efficiency of utilization of incident energy was also high compared with other reported values. However, growth rates were not related to the maximum rates of CO2 uptake in the day, for net carbon exchange over each 24 h depended also on factors such as the ratio between day- and nightlength and night temperatures.

Productivity of Vegetable Crops in a Region of High Solar Input. IV. Field Chamber Measurements on French Beans (Phaseolus vulgaris L.) And Cabbages (Brassica oleracea L.)

1975 ◽  
Vol 2 (4) ◽  
pp. 461 ◽  
Author(s):  
PJM Sale
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Rates ◽  
Dark Respiration ◽  
Gas Analysis ◽  
Large Field ◽  
Co2 Uptake ◽  
Vegetable Crops ◽  
Area Index ◽  
French Beans

Net CO2 uptakes have been measured for crop canopies of French beans and cabbages, sown at two plant densities, using a large field assimilation chamber and a semi-closed gas-analysis system. For both species, the maximum rates of uptake were a little less than 40 mg CO2 dm-2 (ground area) h-1, and light saturation of the canopy occurred at 600-650 W m-2 (French beans) or about 800 W m-2 (cabbages). Net CO2 uptake decreased with leaf area index at values below about 5, but was relatively insensitive to temperature over the range used. Once this leaf area index was reached, the relationship between net uptake and solar radiation remained fairly constant throughout the growth period. For both species, dark respiration rates were markedly dependent on temperature, and also were lower at night than during the day when measured at the same temperature. For both French beans and cabbages, growth analyses showed the maximum growth rates to be 18-19 g dry weight m-2 (ground area) day-1. The mean growth rate from emergence to harvest for an overwintered cabbage crop was 5.5 g m-2 day-1. It is suggested that the main advantage of the region in terms of plant productivity lies in the long frost-free growing season and the ability of frost-tolerant crops to maintain fairly high growth rates throughout a mild and comparatively sunny winter.

scholarly journals Comparisons of Herbicide Treated and Cultivated Herbicide-Resistant Corn

2010 ◽  
Vol 2010 ◽  
pp. 1-7 ◽  
Author(s):  
H. Arnold Bruns ◽  
Hamed K. Abbas
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Rates ◽  
Negative Impact ◽  
Growth Yield ◽  
Yield Component ◽  
Dry Matter Accumulation ◽  
Negative Effects ◽  
Area Index ◽  
Relative Growth Rates

Four glyphosate resistant corn (Zea maysL.) hybrids, a glufosinate-ammonium resistant hybrid, and a conventional atrazine resistant hybrid gown at Stoneville, MS in 2005, 2006, and 2007 with furrow irrigation were treated with their respective herbicides and their growth, yield, and mycotoxin incidence were compared with untreated cultivated plots. Leaf area index (LAI) and dry matter accumulation (DMA) were collected on a weekly basis beginning at growth stage V3 and terminating at anthesis. Crop growth rates (CRGs) and relative growth rates (RGRs) were calculated. Plots were later harvested, yield and yield component data collected, and kernel samples analyzed for aflatoxin and fumonisin. Leaf area index, DMA, CRG, and RGR were not different among the herbicide treated plots and from those that were cultivated. Curves for LAI and DMA were similar to those previously reported. Aflatoxin and fumonisin were relatively low in all plots. Herbicide application or the lack thereof had no negative impact on the incidence of kernel contamination by these two mycotoxins. Herbicides, especially glyphosate on resistant hybrids, have no negative effects on corn yields or kernel quality in corn produced in a humid subtropical environment.

scholarly journals Seasonal Net Carbon Exchange in Rotation Crops in the Temperate Climate of Central Lithuania

2019 ◽  
Vol 11 (7) ◽  
pp. 1966 ◽  
Author(s):  
Ligita Baležentienė ◽  
Ovidijus Mikša ◽  
Tomas Baležentis ◽  
Dalia Streimikiene
Keyword(s):  
Climate Change ◽  
Exchange Rate ◽  
Soil Respiration ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Co2 Emissions ◽  
Vegetation Period ◽  
Temperate Climate ◽  
Carbon Exchange ◽  
Area Index

Intelligent agricultural solutions require data on the environmental impacts of agriculture. In order for operationalize decision-making for sustainable agriculture, one needs to establish the corresponding datasets and protocols. Increasing anthropogenic CO2 emissions into the atmosphere force the choice of growing crops aimed at mitigating climate change. For this reason, investigations of seasonal carbon exchange were carried out in 2013–2016 at the Training Farm of the Vytautas Magnus University (former Aleksandras Stulginskis University), Lithuania. This paper compares the carbon exchange rate for different crops, viz., maize, ley, winter wheat, spring rapeseed and barley under conventional farming. This study focuses on the carbon exchange rate. We measure the emitted and absorbed CO2 fluxes by applying the closed chamber method. The biomass measurement and leaf area index (LAI) calculations at different plant growth stages are used to evaluate carbon exchange in different agroecosystems. The differences in photosynthetically assimilated CO2 rates were significantly impacted by the leaf area index (p = 0.04) during the plant vegetation period. The significantly (p = 0.02–0.05) strong correlation (r = 0.6–0.7) exists between soil respiration and LAI. Soil respiration composed only 21% of the agroecosystem carbon exchange. Plant respiration ranged between 0.034 and 3.613 µmol m−2 s−1 during the vegetation period composed of a negligible ratio (mean 16%) of carbon exchange. Generally, respiration emissions were obviously recovered by the gross primary production (GPP) of crops. Therefore, the ecosystems were acting as an atmospheric CO2 sink. Barley accumulated the lowest mean GPP 12.77 µmol m−2 s−1. The highest mean GPP was determined for ley (14.28 µmol m−2 s−1) and maize (15.68 µmol m−2 s−1) due to the biggest LAI and particular bio-characteristics. Due to the highest NEP, the ley (12.66 µmol m−2 s−1) and maize (12.76 µmol m−2 s−1) agroecosystems sank the highest C from the atmosphere and, thus, they might be considered the most sustainable items between crops. Consequently, the appropriate choice of crops and their area in crop rotations may reduce CO2 emissions and their impact on the environment and climate change.

Effects of defoliation management on the productivity of an irrigated Persian clover sward

1994 ◽  
Vol 34 (2) ◽  
pp. 205 ◽  
Author(s):  
CR Stockdale
Keyword(s):  
Leaf Area ◽  
Growth Rates ◽  
Ground Level ◽  
Maximum Growth ◽  
Fungal Disease ◽  
Area Index ◽  
Herbage Yield ◽  
Defoliation Treatment ◽  
Negative Effect ◽  
Persian Clover

A field experiment investigated the effects of frequency and height of defoliation on the productivity of an irrigated Persian clover (Trifolium resupinatum) sward. Combinations of 4 intervals of harvest (3, 6, 9, 12 weeks) and 2 heights of defoliation (to ground level or 5 cm above ground level) were used in a randomised block experiment, with 2 additional treatments of 4 and 18 weeks between harvests defoliated to ground level. Total herbage accumulation ranged from 8.46 to 13.90 t DM/ha and varied according to defoliation management. Except for the very short defoliation intervals, harvesting to 5 cm was less productive than harvesting to ground level. The effects of leaf area index, herbage yield, and infection with leaf fungal disease on growth rates were assessed. Leaf area had a positive effect, and fungal disease a negative effect, on herbage growth rates, while maximum growth rates in autumn-winter were achieved when herbage yield reached about 2.0 t DM/ha. Dead matter accumulation increased with the interval between harvests, and weeds invaded the plots at both the shortest and longest defoliation intervals. The quality of seed produced (seed weight) was not influenced by defoliation treatment (0.1112 g/100 seeds, on average). Defoliation interval was positively related to number of inflorescences and quantity of seed set, but height of defoliation did not significantly affect these variables. It was concluded that the optimum interval of harvest was 6-9 weeks. Height of defoliation had only minor effects, due to the small difference in residual dry matter between the treatments.

Growth Pattern, Carbon Dioxide Exchange and Dry Weight Distribution in Wheat Growing Under Differing Photosynthetic Environments

1977 ◽  
Vol 4 (1) ◽  
pp. 99 ◽  
Author(s):  
RM Gifford
Keyword(s):  
Leaf Area ◽  
Negative Feedback ◽  
Growth Response ◽  
Co2 Enrichment ◽  
Net Photosynthesis ◽  
Carbon Dioxide Exchange ◽  
Co2 Uptake ◽  
Growth Responses ◽  
Reciprocal Effect ◽  
Area Index

Wheat (cv. WW15) was grown as a crop stand in different CO2 concentrations (ambient, ambient plus 200 � 20 vpm CO2, ambient minus 150 � 20 vpm CO2) from germination to maturity in naturally lit growth cabinets under winter or summer light conditions, at 21°C by day and 16°C at night. Ambient CO2 concentration during the daylight hours averaged 280-300 vpm. CO2 level had little effect on phenology of the mainshoot; most of the growth response was through tillering. From data on flag leaves in the winter light experiment, there was no indication of any positive or negative feedback on growth acting through maximum leaf net photosynthesis rate. Leaf area index was increased by CO2 at low light and the related self-shading acted as a negative feedback partially countering the effect due to an enhanced rate of CO2 uptake per unit leaf area. Dark respiratory CO2 loss represented a greater proportion of CO2 uptake in the light for the CO2-depleted crop than for the control crop. But the reciprocal effect was not evident for the enriched crop. Contrary to classical ideas on growth responses to variation of colimiting factors, the growth response to CO2 enrichment was relatively greater under the low radiation than the high radiation regime. The grain was the tissue most flexible in its responsiveness to changes in assimilation under the conditions of the summer experiment. For this crop, for which the grain yield of the control was very high (0.97 kgm-2), response of yield to CO2 enrichment corresponded to 0.25% per vpm.

Studies of grain production in Sorghum bicolor (L. Moench). V.* Effect of planting density on growth and yield

1975 ◽  
Vol 26 (1) ◽  
pp. 31 ◽  
Author(s):  
KS Fischer ◽  
GL Wilson
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Leaf Area ◽  
Growth Rates ◽  
Dry Matter ◽  
Leaf Growth ◽  
Crop Growth ◽  
Area Index ◽  
Crop Growth Rate ◽  
Net Assimilation

Growth analysis was applied to grain sorghum (cv. RS610) grown at low, medium and high population densities, i.e. 14,352, 143,520 and 645,836 plants ha-1 respectively. The medium densities had two arrangements of plants, square (S) and rectangular (R). Crop growth rates, inflorescence growth rates, leaf area indices, net assimilation rates and leaf growth rates were calculated from growth functions of plant dry matter and leaf area over time. Differences in crop growth rate between populations in the early stages were attributed to leaf area development—specifically to the initial leaf area (dependent on seedling number) and not to differences in leaf growth rates. Peak crop growth rates were 15.0, 27.5, 26.0 and 45.8 g m-2 day-1 for the low, medium (S), medium (R) and high populations respectively.The large difference between the growth rates of the medium (S) and the high populations was not explained by differences in the amount of radiation intercepted. Although leaf area indices were 4.6 and 10.2 respectively for the two populations, both canopies intercepted almost all of the noon radiation. Light extinction coefficients were 0.45 and 0.29 respectively. The relationship between net assimilation rate and leaf area index was such that for comparable leaf area indices above 2, plants at higher densities showed greater improvement in yield per unit increment in leaf area index. A maximum grain yield of 14,250 kg ha-1 was obtained at the high population density as a result of higher dry matter production, but a similar harvest index to that of the crops grown at the other densities. Inflorescence growth rate (g m-2 day-l) slightly exceeded crop growth rate in the latter part of grain filling, which indicated that there was some retranslocation to the grain of previously assimilated material. The maximum grain yield represents an efficiency of utilization of short-wave solar radiation during crop life of 2.5 x 10-6g cal-1. *Part IV, Aust. J. Agric. Res., 26: 25 (1975).

Temperature affects dry matter production and net carbon exchange rate of lower-ploidy Fragaria species and species hybrids

2010 ◽  
Vol 90 (6) ◽  
pp. 885-892 ◽  
Author(s):  
R.M. Harbut ◽  
J.A. Sullivan ◽  
J.T.A. Proctor
Keyword(s):  
High Temperature ◽  
Exchange Rates ◽  
Dry Matter ◽  
Dry Weight ◽  
Temperature Treatment ◽  
Dry Matter Production ◽  
Carbon Exchange ◽  
Matter Production ◽  
Net Carbon Exchange ◽  
Fragaria Species

Wild species can contribute to a breeding program through their wide adaptability to a range of habitats. In interspecific crosses it is not known how these species may interact in the hybrids. The dry matter production and net carbon exchange rates (NCER) of four lower-ploidy Fragaria species, four species hybrids (synthetic octoploids, SOs) and two cultivars (Allstar and Jewel) were compared under three day/night temperature regimes, low (15°C/10°C), medium (23°C/18°C) and high (30°C/25°C) in growth cabinets. Light intensity was maintained at 425 µmol m-2 s-1 and day length at 14 h. The wild Fragaria species had the highest NCERs across all temperature regimes. High temperatures had a depressing effect on plant dry weight for most genotypes. However, F. nubicola and SO 8245 produced 15 and 33%, respectively, higher plant dry weight at the high temperature compared with the low temperature treatment. Net carbon exchange rates for most species and synthetic octoploids were not significantly affected by high temperature. However, SO 8212 did not survive the high temperature treatment. The lower ploidy Fragaria species can be used to create synthetic octoploids that can maintain net carbon exchange rates and produce plant dry weights that are comparable with those of Fragaria cultivars. The ecological background of the species did not have a negative impact on the plant dry weight and NCER of the synthetic octoploids. Some of the SOs may be sources for improvement of Fragaria cultivars for dry matter production at higher temperatures.

The seasonal growth characteristics of irrigated cotton in a dry monsoonal environment

1965 ◽  
Vol 16 (3) ◽  
pp. 347 ◽  
Author(s):  
WR Stern
Keyword(s):  
Leaf Area Index ◽  
Leaf Area ◽  
Growth Rates ◽  
Dry Matter ◽  
Seasonal Effect ◽  
Cotton Yield ◽  
Seasonal Growth ◽  
Seed Cotton ◽  
Area Index ◽  
Seed Cotton Yield

Cotton plantings were made at the Kimberley Research Station (128° 36´ E., 15° 42´ S.) from September to July to give overlapping growth curves extending from September 1961 to December 1962. Crop growth was examined in relation to radiation and temperature. Beginning at the third week from sowing, each planting was sampled 12 times at intervals of 15 days. At each sampling, dry matter, leaf area index, number and dry weight of bolls, and seed cotton yield were determined. The development of total dry matter and leaf area index showed a strong seasonal trend. The number of bolls produced was less in the late plantings, and the seed cotton yield was correspondingly lower. The highest seed cotton yields and the highest ratios of seed cotton to total dry matter (30%) were obtained with January–February plantings. The growth rates between 50 and 100 days were used to analyse seasonality; the highest seasonal growth rate was 164 mg dm-2 day-1 in December–January and the lowest value was zero in early September. By using fitted harmonics, a multiple correlation was established between maximum and minimum temperatures and growth rates 30 days later. Potential rates of net photosynthesis of tops were calculated from observed radiation data with the use of the de Wit model and with allowance for light wastage, root growth, and respiration. There was good agreement between observed and potential growth rates from December to April. Midday stomatal apertures declined from November to May, and this appeared to be a seasonal effect. An annual pattern for the diffusive resistance of carbon dioxide through the leaf surface into the substomatal cavities is calculated. Radiation did not appear to be the primary limiting factor, and the seasonal growth pattern was interpreted in terms of the composite effect of maximum and minimum temperatures on extension growth, stomatal opening, and the presence or absence of suitable sinks for carbohydrates. Growth rates are evaluated against rates observed elsewhere, and means of exploiting the Kimberley environment are discussed.

scholarly journals Urban Forest Growth and Gap Dynamics Detected by Yearly Repeated Airborne Light Detection and Ranging (LiDAR): A Case Study of Cheonan, South Korea

2019 ◽  
Vol 11 (13) ◽  
pp. 1551 ◽  
Author(s):  
Heejoon Choi ◽  
Youngkeun Song ◽  
Youngwoon Jang
Keyword(s):  
Change Detection ◽  
Leaf Area ◽  
Growth Rates ◽  
Urban Forest ◽  
Urban Forests ◽  
Forest Growth ◽  
Airborne Lidar ◽  
Light Detection And Ranging ◽  
Light Detection ◽  
Area Index

Understanding forest dynamics is important for assessing the health of urban forests, which experience various disturbances, both natural (e.g., treefall events) and artificial (e.g., making space for agricultural fields). Therefore, quantifying three-dimensional changes in canopies is a helpful way to manage and understand urban forests better. Multitemporal airborne light detection and ranging (LiDAR) datasets enable us to quantify the vertical and lateral growth of trees across a landscape scale. The goal of this study is to assess the annual changes in the 3-D structures of canopies and forest gaps in an urban forest using annual airborne LiDAR datasets for 2012–2015. The canopies were classified as high canopies and low canopies by a 5 m height threshold. Then, we generated pixel- and plot-level canopy height models and conducted change detection annually. The vertical growth rates and leaf area index showed consistent values year by year in both canopies, while the spatial distributions of the canopy and leaf area profile (e.g., leaf area density) showed inconsistent changes each year in both canopies. In total, high canopies expanded their foliage from 12 m height, while forest gap edge canopies (including low canopies) expanded their canopies from 5 m height. Annual change detection with LiDAR datasets might inform about both steady growth rates and different characteristics in the changes of vertical canopy structures for both high and low canopies in urban forests.

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