scholarly journals Crop Management in Controlled Environment Agriculture (CEA) Systems Using Predictive Mathematical Models

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3110 ◽  
Author(s):  
Chiara Amitrano ◽  
Giovanni Battista Chirico ◽  
Stefania De Pascale ◽  
Youssef Rouphael ◽  
Veronica De Micco

Proximal sensors in controlled environment agriculture (CEA) are used to monitor plant growth, yield, and water consumption with non-destructive technologies. Rapid and continuous monitoring of environmental and crop parameters may be used to develop mathematical models to predict crop response to microclimatic changes. Here, we applied the energy cascade model (MEC) on green- and red-leaf butterhead lettuce (Lactuca sativa L. var. capitata). We tooled up the model to describe the changing leaf functional efficiency during the growing period. We validated the model on an independent dataset with two different vapor pressure deficit (VPD) levels, corresponding to nominal (low VPD) and off-nominal (high VPD) conditions. Under low VPD, the modified model accurately predicted the transpiration rate (RMSE = 0.10 Lm−2), edible biomass (RMSE = 6.87 g m−2), net-photosynthesis (rBIAS = 34%), and stomatal conductance (rBIAS = 39%). Under high VPD, the model overestimated photosynthesis and stomatal conductance (rBIAS = 76–68%). This inconsistency is likely due to the empirical nature of the original model, which was designed for nominal conditions. Here, applications of the modified model are discussed, and possible improvements are suggested based on plant morpho-physiological changes occurring in sub-optimal scenarios.

1993 ◽  
Vol 23 (12) ◽  
pp. 2459-2466 ◽  
Author(s):  
George J. Harper ◽  
Edith L. Camm

Nursery grown seedlings of Piceaglauca (Moench) Voss were stored frozen in the dark from approximately 10–31 weeks, thawed and grown for 28 days in a growth chamber at three soil temperatures (3, 7, and 11 °C). During the growing period gas exchange measurements were made every three days. Seedling net photosynthesis (pn) and stomatal conductance (gs) showed significant interactions between soil temperature and storage duration treatments. Soil temperature did not affect seedling gs or pn, though the degree and extent of storage duration effects were dependent on soil temperature. Recovery of gs occurred over a 4–7 day period from low levels after planting. Seedlings stored longer than 22 weeks showed lower rates of pn, than those stored for shorter durations. The lower pn in long-stored seedlings did not result from stomatal limitations to carbon fixation, as gs increased in seedlings stored >22 weeks.


1986 ◽  
Vol 16 (4) ◽  
pp. 841-846 ◽  
Author(s):  
S. R. Pezeshki ◽  
J. L. Chambers

The effects of water stress on stomatal conductance and net photosynthesis of cherrybark oak (Quercusfalcata var. pagodaefolia Ell.) and sweet gum (Liquidamberstyraciflua L.) seedlings were studied under controlled environment conditions during the 1983 growing season. Drought stress induced stomatal closure and significant declines in net photosynthesis for both species. Stomatal conductance declined by as much as 43% in cherrybark oak and 82% in sweet gum compared with predrought levels. Net photosynthetic rates also declined 85% from predrought levels in sweet gum and fell below zero in cherrybark oak. The remarkable decline in net photosynthesis in cherrybark oak while stomata remained partially open suggests that in addition to a stomatal effect, nonstomatal factors were involved in the reduction of net photosynthesis. In sweet gum, however, stomatal limitation of net photosynthesis seems to be the dominant factor. The greater relative decline in mean leaf conductance in sweet gum suggests a greater reaction to drought by this species through effective and rapid stomatal closure resulting in avoidance of leaf desiccation. Stomata of cherrybark oak, on the other hand, were less sensitive to low leaf water potentials; therefore, stomatal closure occurred at significantly lower (more negative) leaf water potentials when compared with sweet gum.


1996 ◽  
Vol 126 (2) ◽  
pp. 183-190 ◽  
Author(s):  
M. V. K. Sivakumar ◽  
B. R. Ntare ◽  
J. M. Roberts

SUMMARYThe response of four cowpea (Vigna unguiculata(L.) Walp.) cultivars to the warm, semi-arid tropical environment at the ICRISAT Sahelian Center at Sadore, Niger was studied during 1985 and 1986 interms of leaf area index (LAI), dry matter (DM) accumulation, net photosynthesis, stomatal conductance, total water use and yield. Among the three improved cultivars, IT82D–716 is early and erect, cv. IT83S–947 is early and spreading and cv. TVX4659–03E is a medium-duration, highyielding, dual-purpose type. The local cv. Sadore Local is a long-duration, photosensitive, spreading type used mainly for fodder. In both years, Sadore Local recorded the highest LAI. IT82D–716 and IT83S–947 produced < 1·3 t/ha of DM in both years, whereas TVX 4659–03E produced > 2 t/ha of DM and proved superior to Sadore Local in partitioning DM into pods. The four cultivars did not differ significantly either in stomatal conductance or in net phytosynthetic rates. Observed maximum photosynthetic rates of c. 20 μmol/m2/s lie at the bottom of the range 21–38 μmol/m2/s reported for 31 cowpea genotypes in an earlier study. Photosynthetic rates increased with increasing photon flux density. TVX4659–03E had an advantage in total seed plus fodder yields while the local cultivar gave significantly greater fodder yields in both years. Seed and fodder yields, as well as water-use efficiency, confirmed the advantages offered by the dual-purpose cultivar TVX4659–03E. Future breeding efforts in the Sahel should focus on dual-purpose (grain/fodder) cowpea types.


1985 ◽  
Vol 15 (2) ◽  
pp. 371-375 ◽  
Author(s):  
S. R. Pezeshki ◽  
J. L. Chambers

Effects of short-term flooding on stomatal conductance, net photosynthesis, and water status of sweet gum (Liquidambarstyraciflua L.) seedlings were studied under controlled environment conditions. Flooding for 9 days induced partial stomatal closure, resulting in significant declines in transpiration and net photosynthesis. The response to flooding was rapid with an average daily stomatal conductance declining from a preflood level of 0.43 cm•s−1 to 0.26 cm•s−1 by 24 h after flooding began (40% reduction). The average preflooding daily net photosynthesis was reduced from 13.7 to 10.2 mg CO2•dm−2•h−1 (25% reduction) during the same period and the average daily stomatal conductance and net photosynthesis for the 9th day of flooding were reduced by 70 and 77%, respectively, compared with preflood levels. The leaf xylem pressure potential measurements, however, indicated that water deficits did not develop as a result of flooding. Partial stomatal reopening 3 days after termination of flooding was noted with an average daily stomatal conductance approaching 63% of the preflood levels and an average daily net photosynthesis reaching 46% of its preflood levels. Maintenance of positive net photosynthesis throughout flooding, and partial stomatal and photosynthetic recovery following drainage may account for the tolerance of sweet gum seedlings to short-term flooding.


Water ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 252
Author(s):  
Muhammad Shahinur Alam ◽  
David William Lamb ◽  
Nigel W. M. Warwick

Estimating transpiration as an individual component of canopy evapotranspiration using a theoretical approach is extremely useful as it eliminates the complexity involved in partitioning evapotranspiration. A model to predict transpiration based on radiation intercepted at various levels of canopy leaf area index (LAI) was developed in a controlled environment using a pasture species, tall fescue (Festuca arundinacea var. Demeter). The canopy was assumed to be a composite of two indistinct layers defined as sunlit and shaded; the proportion of which was calculated by utilizing a weighted model (W model). The radiation energy utilized by each layer was calculated from the PAR at the top of the canopy and the fraction of absorbed photosynthetically active radiation (fAPAR) corresponding to the LAI of the sunlit and shaded layers. A relationship between LAI and fAPAR was also established for this specific canopy to aid the calculation of energy interception. Canopy conductance was estimated from scaling up of stomatal conductance measured at the individual leaf level. Other environmental factors that drive transpiration were monitored accordingly for each individual layer. The Penman–Monteith and Jarvis evapotranspiration models were used as the basis to construct a modified transpiration model suitable for controlled environment conditions. Specially, constructed self-watering tubs were used to measure actual transpiration to validate the model output. The model provided good agreement of measured transpiration (actual transpiration = 0.96 × calculated transpiration, R2 = 0.98; p < 0.001) with the predicted values. This was particularly so at lower LAIs. Probable reasons for the discrepancy at higher LAI are explained. Both the predicted and experimental transpiration varied from 0.21 to 0.56 mm h−1 for the range of available LAIs. The physical proportion of the shaded layer exceeded that of the sunlit layer near LAI of 3.0, however, the contribution of the sunlit layer to the total transpiration remains higher throughout the entire growing season.


2009 ◽  
Vol 36 (7) ◽  
pp. 645 ◽  
Author(s):  
Dennis H. Greer ◽  
Sylvie M. Sicard

Assessing the impacts of environmental stresses on plant growth and productivity requires an understanding of the growth processes and the carbon economy that underpins this growth. Potted grapevines of the Vitis vinifera L. cv. Semillon were grown in a controlled environment and canopy growth; leaf, bunch and stem extension and net photosynthesis were routinely measured from budbreak to harvest. Allometric relationships enabled dry matter to be determined and, with net photosynthesis, used to determine the shoot carbon economy. Stems, leaves and bunches all followed a sigmoid growth pattern with leaves and stems allocated similar amounts of biomass and carbon while bunches had twice as much. Rates of carbon sequestered as biomass exceeded rates of carbon acquisition through net photosynthesis for over 25 days after budbreak. Despite the high demand for biomass in bunch growth, rates of carbon sequestration actually declined and overall, the vines maintained a positive carbon balance throughout the period of bunch growth. The Semillon shoots relied on carbon reserves to commence growth then produced a 53% carbon surplus after leaf (9%), stem (10%) and bunch (28%) growth demands were satisfied. This suggests these vines also allocated carbon to reserves to sustain the next season’s growth.


2004 ◽  
Vol 129 (1) ◽  
pp. 106-111 ◽  
Author(s):  
S. Kumudini

Cranberry [Vaccinium macrocarpon (Ait.)] yield has been associated with photosynthate supply. However, the impact of temperature and radiation on photosynthesis of the cranberry plant is not well understood. The objective of this experiment was to characterize the photosynthetic response to radiation and temperature in order to develop a model for estimation of cranberry photosynthetic rates. Two cranberry cultivars, `Stevens' and `Ben Lear', were tested for photosynthetic response at air temperatures ranging from 15 to 35 °C and radiation intensities from 200 to 1200 μmol·m-2·s-1. Depending on temperature, maximum photosynthesis (Pmax) was ≈10 or 12 μmol CO2/m2/s (net photosynthesis) and the saturating radiation level was estimated to be 600 to 800 μmol·m-2·s-1. Cranberry quantum yield was estimated as 0.03 mol CO2/mol photon. Both models; Blackman and the nonrectangular hyperbola with a Θ (angle of curvature) of 0.99 were a good fit for measured photosynthetic rates under controlled environment conditions. The disparity between modeled predicted values, and observed values in the field around midday, indicates a reduction in potential photosynthetic rates in a diurnal cycle that is consistent with the phenomenon of midday depression.


2020 ◽  
Vol 11 ◽  
pp. E3113
Author(s):  
José Sebastião de Melo Filho ◽  
Toshik Iarley da Silva ◽  
Anderson Carlos de Melo Gonçalves ◽  
Leonardo Vieira de Sousa ◽  
Mario Leno Martins Véras ◽  
...  

Although not considered an essential element, silicon can be used to increase crop productivity, especially under stress conditions. In this sense, the objective was to evaluate the gas exchange of beet plants irrigated with saline water depending on the application of silicon. The experiment was conducted in a randomized block design, in a 5 x 5 factorial, referring to five levels of electrical conductivity of irrigation water (ECw): (0.5; 1.3; 3.25; 5.2 and 6.0 dS m-1) and five doses of silicon (0.00; 2.64; 9.08; 15.52 and 18.16 mL L-1), with six beet plants as an experimental unit. The effect of treatments on beet culture was evaluated at 30 and 60 days after irrigation with saline water from measurements of internal carbon concentration, stomatal conductance, net photosynthesis rate, instantaneous water use efficiency and instantaneous carboxylation efficiency using the LCpro+Sistem infrared gas analyzer (IRGA). Irrigation with saline water reduced the gas exchange of beet plants at 60 days after irrigation, but at 30 days after irrigation, the use of saline water increased stomatal conductance, transpiration rate and internal carbon concentration. The application of silicon decreased stomatal conductance, internal carbon concentration and efficiency in the use of water, but increased the rate of net photosynthesis, the rate of transpiration and instantaneous efficiency of carboxylation at 30 and 60 days after irrigation.


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