Radiation Interception Efficiency Research Articles

Effects of Minimum and Maximum Limits of Solar Radiation and Its Temporal and Geographic Interactions

In order to achieve high yields, the use of radiation by agricultural crops must be improved in order to maximize and extend the duration of foliar interception of solar radiation. Appropriately, studies aimed at the understanding and behavior of radiation in plants are extremely relevant. Accordingly, the objective of this study was to approach information about the concepts, radiation availability temporal, geographical, photosynthesis efficiency as a function of leaf arrangement and radiation interception efficiency × leaf area index (LAI). Studies aimed at a significant comprehension of radiation in crops demonstrate that the plant growth and development depend on the intensity and duration of solar radiation. More surveys are required on the subject for a better development of the culture, aiming to guarantee that the plants have better conditions to express their potential.

Genetic and environmental dissection of biomass accumulation in multi-genotype maize canopies.

Multi-genotype canopies are frequent in phenotyping experiments and are of increasing interest in agriculture. Radiation interception efficiency (RIE) and radiation use efficiency (RUE) have low heritabilities in such canopies. We propose a revised Monteith equation that identifies environmental and genetic components of RIE and RUE. An environmental term, a component of RIE, characterizes the effect of the presence or absence of neighbours on light interception. The ability of a given plant to compete with its neighbours is then identified, which accounts for the genetic variability of RIE of plants having similar leaf areas. This method was used in three experiments in a phenotyping platform with 765 plants of 255 maize hybrids. As expected, the heritability of the environmental term was near zero, whereas that of the competitiveness term increased with phenological stage, resulting in the identification of quantitative trait loci. In the same way, RUE was dissected as an effect of intercepted light and a genetic term. This approach was used for predicting the behaviour of individual genotypes in virtual multi-genotype canopies. A large effect of competitiveness was observed in multi-genotype but not in single-genotype canopies, resulting in a bias for genotype comparisons in breeding fields.

Simulating plant water stress dynamics in a wide range of bi-specific agrosystems in a region using the BISWAT model

Abstract The ability to simulate soil and crop processes in many bi-specific systems (vineyards, orchards, silvo-arable agroforestry, strip-intercropping of arable crops…) is one of the major challenge for crop modelling in order to contribute to the design of agro-ecological cropping systems. A typical question is how soil, climate and management would influence the soil water deficit experienced by a plant grown alone or intercropped with a cover crop, with another crop or a tree, in order to improve the resilience of a cropping system to climate change and limit the use of chemical input. This study introduces BISWAT – Bispecific Intercrop System WATer Stress dynamic model - a new water balance model designed to simulate the dynamic of Soil Water deficit Experienced (SWEP) by two Plants when grown together or separated. BISWAT has been built to simulate a large range of agrosystems (annual and perennial crops, mono- or bi-specific) cultivated in various conditions. The model is primarily based on three modelling concepts: i) a 2D generic pattern for the system’s spatial representation, ii) the use of the Radiation Interception Efficiency (RIE) to drive potential plant transpiration and soil evaporation, iii) the use of the Total Transpirable Soil Water (TTSW) concept coupled with a simple root dynamics representation. These concepts are not new but they allowed us to define a model able to simulate many crops and trees (including vineyards) using a limited number of inputs and without an explicit need for parameter calibration. The model was evaluated on five reference agrosystems (mono-specific salads, mono-specific vineyards, bi-specific vineyards, mono-specific peach orchards and bi-specific peach orchards). The RMSE of the SWEP variable ranged from 0.049 to 0.123. A combined sensitivity and uncertainty analysis performed on typical farmer’s fields situations stressed the particular importance of model inputs related to the TTSW of the soil-crop system. We conclude that the genericity of the BISWAT model, its method of parameterization and its performance open the perspective to use the model in a wide range of conditions where the dynamic of water stress between two species grown together is a key variable to be accessed with limited data for parameterization and a large number of fields to simulate.

Reconstructing three-dimensional oil palm architecture from allometric relationships

The development of new breeding strategies to find more sustainable and productive systems is a major challenge to cope with ceaseless increasing demands for palm oil. Optimizing plant architecture to increase radiation interception efficiency could be an option for enhancing potential crop production. Most oil palms grown in the world are Deli dura x AVROS pisifera crosses displaying large phenotypic variations due to genetic segregation. The objective of this study was to analyse and model oil palm architecture taking into account genetic variability. Data were collected in Sumatra, Indonesia, on 5 progenies (total of 60 palms), to describe the aerial architecture from the leaflet to crown scales. Allometric relationships (using linear and non-linear functions) were applied to model these traits according to ontogenetic gradients and leaf position within the canopy. Results pointed out contrasting architectural traits among genotypes, especially for the leaf insertion angle, leaf length and leaflet shape. Mean values of the simulated architectural traits were compared with field measurements to evaluate the quality of the modelling approach. The allometric relationships, parameterized for different genotypes, were then implemented in the AMAPstudio software to generate 3D mock-ups to estimate integrative traits (such as crown dimensions) that were not directly modelled in the allometric-based model. Forthcoming works will be dedicated to the analysis of the impact of the different architectural characteristics on plant light interception using sensitivity analysis methods in order to identify some key architectural traits that could be considered in breeding programs.

Physiological Processes Leading to Similar Yield in Contrasting Soybean Maturity Groups

Core Ideas Different soybean maturity groups with similar yields are farmed in many temperate regions. Reproductive biology and biomass accumulation during seed set was similar for MGs III and IV. Groups differed in radiation interception, N uptake, and the length of the seed set period. Yield limiting traits tailored for earlier and later soybean were identified. Soybean [Glycine max (L.) Merr.] maturity groups (MGs) exhibit large variation in time to maturity, and are adapted to different latitudes. There is a range of MGs that have similar yield potential at most production regions, especially at temperate and tropical environments. We tested whether similar yields in contrasting MGs are achieved through different physiological processes. Our objectives were: (i) to characterize biomass accumulation, reproductive partitioning and seed set efficiency, and (ii) to analyze the role of N and radiation in biomass accumulation during the seed set period in contrasting MGs. Three MG III and V cultivars were tested in two growing environments. No significant yield or seed number differences were detected despite MG V had 20 d longer growth cycle. MG III had a longer seed set period (R1–R5), received more incident radiation during that period, and captured more N compared to the MG V. However, these cultivars had lower nitrogen use efficiency (NUE) (g biomass per g N uptake) and less radiation interception efficiency compared to MG V. These contrasting physiological processes determined similar biomass accumulation during R1 to R5. No differences between MGs were observed in biomass partitioning to reproductive structures and seed set efficiency during this period. Results showed contrasting MGs have different strategies for reaching similar yield, evidencing physiological processes that could be specifically tailored by breeders for either MG III (radiation interception efficiency, NUE) or MG V (duration of R1–R5 period, N uptake rate) cultivars for further yield increases.

GROWTH, PHYSIOLOGY AND YIELD OF FORMOSA 'PAPAYA' CULTIVATED UNDER DIFFERENT DOSES OF COATED AND CONVENTIONAL UREA

ABSTRACT Mineral fertilizer management is one of the most important agronomic techniques applied in papaya cultivation, which generally extracts large amounts of nutrients from soil, especially nitrogen. This study aimed to assess the phytotechnical and physiological attributes and yield of "Formosa‟ papaya hybrid Caliman 01 as a function of different doses of coated and conventional urea in the region of Bom Jesus - PI, Brazil. The treatments were arranged in a factorial scheme (2 × 4) and distributed in a randomized block design with four replications, corresponding to 2 nitrogen sources (coated urea, 43% of N; and conventional urea, 45% of N) and 4 doses nitrogen (350, 440, 530 and 620 g per plant). The N doses used corresponded to 80, 100, 120 and 140% of the nitrogen fertilization. It was used six plants per plot with two row borders, totaling 192 plants cultivated in the field. It was assessed the intercepted photosynthetically active radiation (int.PAR), radiation interception efficiency (PAREff.), leaf area index (LAI), plant height, stem diameter and yield. The coated urea promotes a higher growth and yield of "Formosa‟ papaya compared to the conventional urea. The application of 1.0 g of coated N promotes the production of 2.87 g of fruit per hectare while the application of 1.0 g of conventional N produces only 1.89 g of fruit per hectare, showing that the source of polymerized N increases the use efficiency of N applied to soil.

A soil-plant model applied to phytoremediation of metals

ABSTRACTThis study reports a phytoremediation pot experiment using an open-source program. Unsaturated water flow was described by the Richards' equation and solute transport by the advection-dispersion equation. Sink terms in the governing flow and transport equations accounted for root water and solute uptake, respectively. Experimental data were related to application of Vetiver grass to soil contaminated by metal ions. Sensitivity analysis revealed that due to the specific experimental set-up (bottom flux not allowed), hydraulic model parameters did not influence root water (and contaminant) uptake. In contrast, the results were highly correlated with plant solar radiation interception efficiency (leaf area index). The amounts of metals accumulated in the plant tissue were compared to numerical values of cumulative uptake. Pb2+ and Zn2+ uptake was satisfactorily described using a passive model. However, for Ni2+ and Cd2+, a specific calibration of the active uptake model was necessary. Calibrated MM parameters for Ni2+, Cd2+, and Pb2+ were compared to values in the literature, generally suggesting lower rates and saturation advance. A parameter (saturation ratio) was introduced to assess the efficiency of contaminant uptake. Numerical analysis, applying actual field conditions, showed the limitation of the active model for being independent of the transpiration rate.

Productivity and radiation use efficiency of lettuces grown in the partial shade of photovoltaic panels

Combining photovoltaic panels (PVPs) and crops on the same land unit were recently proposed as an alternative to the conversion of cropland into photovoltaic plants. This could alleviate the increasing competition for land between food and energy production. In such agrivoltaic systems, an upper layer of PVPs partially shades crops at ground level. The aim of this work was to (i) assess the effect on crop yield of two PVPs densities, resulting in two shade levels equal to 50% and 70% of the incoming radiation and (ii) identify morphological and physiological determinants of the plant response to shade. Experiments were conducted on four varieties of lettuces (two crisphead lettuces and two cutting lettuces), during two seasons. In all cases, the relative lettuce yield at harvest was equal or higher than the available relative radiation. Lettuce yield was maintained through an improved Radiation Interception Efficiency (RIE) in the shade, while Radiation Conversion Efficiency (RCE) did not change significantly. Enhanced RIE was explained by (i) an increase in the total leaf area per plant, despite a decrease in the number of leaves and (ii) a different distribution of leaf area among the pool of leaves, the maximal size of leaves increasing in the shade. Our result provides a framework for the selection of adapted varieties according to their morphological traits and physiological responses to PVP shade, in order to optimize agrivoltaic systems.

Altered physiological function, not structure, drives increased radiation-use efficiency of soybean grown at elevated CO2

Previous studies of elevated carbon dioxide concentration ([CO(2)]) on crop canopies have found that radiation-use efficiency is increased more than radiation-interception efficiency. It is assumed that increased radiation-use efficiency is due to changes in leaf-level physiology; however, canopy structure can affect radiation-use efficiency if leaves are displayed in a manner that optimizes their physiological capacity, even though the canopy intercepts the same amount of light. In order to determine the contributions of physiology and canopy structure to radiation-use and radiation-interception efficiency, this study relates leaf-level physiology and leaf display to photosynthetic rate of the outer canopy. We used a new imaging approach that delivers three-dimensional maps of the outer canopy during the growing season. The 3D data were used to model leaf orientation and mean photosynthetic electron transport of the outer canopy to show that leaf orientation changes did not contribute to increased radiation-use; i.e. leaves of the outer canopy showed similar diurnal leaf movements and leaf orientation in both treatments. Elevated [CO(2)] resulted in an increased maximum electron transport rate (ETR(max)) of light reactions of photosynthesis. Modeling of canopy light interception showed that stimulated leaf-level electron transport at elevated [CO(2)], and not alterations in leaf orientation, was associated with stimulated radiation-use efficiency and biomass production in elevated [CO(2)]. This study provides proof of concept of methodology to quantify structure-function relationships in combination, allowing a quantitative estimate of the contribution of both effects to canopy energy conversion under elevated [CO(2)].

Improvement and validation of a pea crop growth model to simulate the growth of cultivars infected with Ascochyta blight (Mycosphaerella pinodes)

A model simulating the growth of a pea crop infected with Ascochyta blight was improved and validated using 6 spring pea cultivars, all equally susceptible to Ascochyta blight, but differing in architectural features (stem height, branching ability, standing ability). This model takes into account the spatial distribution of the disease, including the contribution of each layer of the canopy to the radiation interception efficiency (RIE) and the radiation use efficiency (RUE) of the crop. The decreasing contribution of each layer due to the disease was estimated by the relationship between the photosynthesis of a layer and its disease score. The effect of disease on photosynthesis was assessed in controlled conditions as a means of evaluating the effect of disease on each cultivar. All cultivars were affected equally. In field conditions, cultivars with different canopy architectures displayed differences in the profile of disease on leaves. Cultivar Aladin reached higher disease levels at the top of the plant. Epidemics affected crop growth, and the cultivars tested differed in the magnitude of the decrease in growth. Observed and simulated data were compared. The disease-coupled crop growth model gave satisfactory predictions of crop growth for the six cultivars tested.

A simple model of pea (Pisum sativum) growth affected by Mycosphaerella pinodes

The effect of epidemics of Mycosphaerella pinodes on crop growth, radiation interception efficiency (RIE) and radiation use efficiency (RUE) was studied in field conditions and the growth of diseased crop was modelled. Natural epidemics were simulated in field plots by dispersion on the ground of barley grains colonized by the fungus. Growth and leaf area index (LAI) were measured in healthy and diseased plots during the growth season. Epidemics affected crop growth mainly by decreasing RUE, with a slight decrease in RIE. This was probably due to the strong effect of M. pinodes on leaf photosynthesis and the lateness of Mycosphaerella blight epidemics on spring pea, which became serious when the canopy was already formed, thus decreasing RIE only by accelerating the senescence of leaves. The data were used to evaluate the performance of a crop growth model for diseased pea crops. The model comprised the decrease in photosynthesis rate in the leaves, the vertical gradient of disease intensity and the differences in photosynthetic function of the various layers of the canopy. This model, validated over 2 years in the field, accurately simulated the crop growth in diseased plots. Thus the decrease in RUE may be accounted for solely by photosynthesis losses in diseased leaves. This simple model may be used for disease management, defining damage thresholds for chemical application and criteria for tolerant variety selection.