Radiation and nitrogen use at the leaf and canopy level by wheat and oilseed rape during the critical period for grain number definition.

2000 ◽  
Vol 27 (10) ◽  
pp. 899 ◽  
Author(s):  
M. Fernanda Dreccer ◽  
Ad H. C. M. Schapendonk ◽  
Marcel van Oijen ◽  
C. Sander Pot ◽  
Rudy Rabbinge
Keyword(s):  
Vertical Distribution ◽  
Oilseed Rape ◽  
Critical Period ◽  
Plant Density ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Grain Number ◽  
N Supply ◽  
Leaf N Content ◽  
Leaf N

During the critical period for grain number definition, the amount of biomass produced per unit absorbed radiation is more sensitive to nitrogen (N) supply in oilseed rape than in wheat, and reaches a higher value at high N. This response was investigated by combining experimental and modelling work. Oilseed rape and wheat were grown at three levels of N supply, combined with two levels of plant density at high N supply. Canopy photosynthesis and daytime radiation use efficiency (RUEA) were calculated with a model based on observed N-dependent leaf photosynthesis and observed canopy vertical distribution of light and leaf N. In oilseed rape, RUEA was higher than in wheat and, in contrast to wheat, the sensitivity to canopy leaf N content increased from the start to the end of the critical period. These results were partly explained by the higher leaf photosynthesis in oilseed rape vs wheat. In addition, oilseed rape leaves were increasingly shaded by the inflorescence. Thus, RUEA increased because more leaves were operating at non-saturating light levels. In both species, the vertical distribution of leaf N was close to that optimising canopy photosynthesis. The results are discussed in relation to possibilities for improvement of N productivity in these crops.

scholarly journals Pollen Grain Number and Viability Contribute to Variation in Effective Ovule Number Among Oilseed Rape Genotypes

2021 ◽  
Author(s):  
Xiao Guo ◽  
Bao-Luo Ma ◽  
Neil B. McLaughlin ◽  
Yajun gao ◽  
Xiaoming Wu ◽  
...  
Keyword(s):  
Oilseed Rape ◽  
Critical Period ◽  
Pollen Viability ◽  
Pollen Grain ◽  
Abortion Rate ◽  
Utilization Efficiency ◽  
Grain Number ◽  
Ovule Abortion ◽  
Nitrogen Utilization Efficiency ◽  
Ovule Number

Abstract While no significant differences in initial ovule number were found among oilseed rape genotypes, there was a large variation in effective ovule number (EON), which determines the final seeds per silique (SPS), a critical component of yield. In this study, we selected 18 oilseed rape genotypes with contrasting nitrogen utilization efficiency (NUtE) to unravel the main factors responsible for different EON and determine the critical period of EON formation under both a field and a pot experiments from 2016-2018. The high NUtE genotypes displayed significantly higher NUtE by 14.3%, along with greater yield per plant (29.4%) and SPS (21.1%) than the low NUtE genotypes. The greater productivity of the high NUtE genotypes was associated with 44.1% higher pollen grain number, 23.5% greater pollen viability, and 39.3% lower ovule abortion rate, compared to the low NUtE genotypes. In addition, the heart stage was the critical ovule development period for delineating the variability of EON among contrasting NUtE oilseed rape genotypes, when the high NUtE genotypes displayed higher silique net photosynthetic rate, surface area, biomass, and RNA expression levels. Taken together, this study indicated the pollen grain number, pollen viability and ovule abortion rate contributed to the final variation in EON and the heart stage was the critical period of determining the EON differences among contrasting NUtE genotypes. Increasing pollen grain number and pollen viability, and decreasing ovule abortion rate before heart stage should be the prerequisite for breeders to improve yield and NUtE of oilseed rape genotypes.

Scaling leaf photosynthesis to canopy in a mixed deciduous forest. I. model description

1997 ◽  
Vol 62 ◽  
Author(s):  
R. Samson ◽  
S. Follens ◽  
R. Lemeur
Keyword(s):  
Temperature Dependence ◽  
Quercus Robur ◽  
Deciduous Forest ◽  
Growing Season ◽  
Model Description ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Layer Model ◽  
Mixed Deciduous Forest ◽  
Leaf Level

A  multi-layer model (FORUG) was developed, to simulate the canopy  photosynthesis of a mixed deciduous forest during the growing season.  Measured photosynthesis parameters, for beech (Fagus  sylvatica), oak (Quercus  robur) and ash (Fraxinus  excelsior), were used as input to the model. This  information at the leaf level is then scaled up to the level of the canopy,  taking into account the radiation profiles (diffuse and direct PAR) in the  canopy, the vertical LAI distribution, the evolution of the LAI and the  photosynthesis parameters during the growing season, and the temperature  dependence of the latter parameters.

scholarly journals A novel approach for nitrogen diagnosis of wheat canopies digital images by mobile phones based on histogram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xin Qi ◽  
Yanan Zhao ◽  
Yufang Huang ◽  
Yang Wang ◽  
Wei Qin ◽  
...  
Keyword(s):  
Neural Network ◽  
Mobile Phones ◽  
Mean Value ◽  
Wheat Cultivars ◽  
N Content ◽  
Color Parameters ◽  
The Neural Network ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

AbstractThe accurate and nondestructive assessment of leaf nitrogen (N) is very important for N management in winter wheat fields. Mobile phones are now being used as an additional N diagnostic tool. To overcome the drawbacks of traditional digital camera diagnostic methods, a histogram-based method was proposed and compared with the traditional methods. Here, the field N level of six different wheat cultivars was assessed to obtain canopy images, leaf N content, and yield. The stability and accuracy of the index histogram and index mean value of the canopy images in different wheat cultivars were compared based on their correlation with leaf N and yield, following which the best diagnosis and prediction model was selected using the neural network model. The results showed that N application significantly affected the leaf N content and yield of wheat, as well as the hue of the canopy images and plant coverage. Compared with the mean value of the canopy image color parameters, the histogram could reflect both the crop coverage and the overall color information. The histogram thus had a high linear correlation with leaf N content and yield and a relatively stable correlation across different growth stages. Peak b of the histogram changed with the increase in leaf N content during the reviving stage of wheat. The histogram of the canopy image color parameters had a good correlation with leaf N content and yield. Through the neural network training and estimation model, the root mean square error (RMSE) and the mean absolute percentage error (MAPE) of the estimated and measured values of leaf N content and yield were smaller for the index histogram (0.465, 9.65%, and 465.12, 5.5% respectively) than the index mean value of the canopy images (0.526, 12.53% and 593.52, 7.83% respectively), suggesting a good fit for the index histogram image color and robustness in estimating N content and yield. Hence, the use of the histogram model with a smartphone has great potential application in N diagnosis and prediction for wheat and other cereal crops.

scholarly journals Effects of ontogenetic stage and leaf age on leaf functional traits and the relationships between traits in Pinus koraiensis

2021 ◽  
Author(s):  
Meng Ji ◽  
Guangze Jin ◽  
Zhili Liu
Keyword(s):  
Significant Positive Correlation ◽  
Leaf Age ◽  
Leaf Traits ◽  
Ontogenetic Stage ◽  
Pinus Koraiensis ◽  
Mature Trees ◽  
N Content ◽  
Ontogenetic Stages ◽  
Leaf N Content ◽  
Leaf N

AbstractInvestigating the effects of ontogenetic stage and leaf age on leaf traits is important for understanding the utilization and distribution of resources in the process of plant growth. However, few studies have been conducted to show how traits and trait-trait relationships change across a range of ontogenetic stage and leaf age for evergreen coniferous species. We divided 67 Pinus koraiensis Sieb. et Zucc. of various sizes (0.3–100 cm diameter at breast height, DBH) into four ontogenetic stages, i.e., young trees, middle-aged trees, mature trees and over-mature trees, and measured the leaf mass per area (LMA), leaf dry matter content (LDMC), and mass-based leaf nitrogen content (N) and phosphorus content (P) of each leaf age group for each sampled tree. One-way analysis of variance (ANOVA) was used to describe the variation in leaf traits by ontogenetic stage and leaf age. The standardized major axis method was used to explore the effects of ontogenetic stage and leaf age on trait-trait relationships. We found that LMA and LDMC increased significantly and N and P decreased significantly with increases in the ontogenetic stage and leaf age. Most trait-trait relationships were consistent with the leaf economic spectrum (LES) at a global scale. Among them, leaf N content and LDMC showed a significant negative correlation, leaf N and P contents showed a significant positive correlation, and the absolute value of the slopes of the trait-trait relationships showed a gradually increasing trend with an increasing ontogenetic stage. LMA and LDMC showed a significant positive correlation, and the slopes of the trait-trait relationships showed a gradually decreasing trend with leaf age. Additionally, there were no significant relationships between leaf N content and LMA in most groups, which is contrary to the expectation of the LES. Overall, in the early ontogenetic stages and leaf ages, the leaf traits tend to be related to a "low investment-quick returns" resource strategy. In contrast, in the late ontogenetic stages and leaf ages, they tend to be related to a "high investment-slow returns" resource strategy. Our results reflect the optimal allocation of resources in Pinus koraiensis according to its functional needs during tree and leaf ontogeny.

scholarly journals Combining Process Modelling and LAI Observations to Diagnose Winter Wheat Nitrogen Status and Forecast Yield

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 314
Author(s):  
Andrew Revill ◽  
Vasileios Myrgiotis ◽  
Anna Florence ◽  
Stephen Hoad ◽  
Robert Rees ◽  
...  
Keyword(s):  
Field Experiments ◽  
Process Models ◽  
Agricultural Technologies ◽  
N Application ◽  
Area Index ◽  
Complex Process ◽  
C Cycle ◽  
The Mean ◽  
Leaf N Content ◽  
Leaf N

Climate, nitrogen (N) and leaf area index (LAI) are key determinants of crop yield. N additions can enhance yield but must be managed efficiently to reduce pollution. Complex process models estimate N status by simulating soil-crop N interactions, but such models require extensive inputs that are seldom available. Through model-data fusion (MDF), we combine climate and LAI time-series with an intermediate-complexity model to infer leaf N and yield. The DALEC-Crop model was calibrated for wheat leaf N and yields across field experiments covering N applications ranging from 0 to 200 kg N ha−1 in Scotland, UK. Requiring daily meteorological inputs, this model simulates crop C cycle responses to LAI, N and climate. The model, which includes a leaf N-dilution function, was calibrated across N treatments based on LAI observations, and tested at validation plots. We showed that a single parameterization varying only in leaf N could simulate LAI development and yield across all treatments—the mean normalized root-mean-square-error (NRMSE) for yield was 10%. Leaf N was accurately retrieved by the model (NRMSE = 6%). Yield could also be reasonably estimated (NRMSE = 14%) if LAI data are available for assimilation during periods of typical N application (April and May). Our MDF approach generated robust leaf N content estimates and timely yield predictions that could complement existing agricultural technologies. Moreover, EO-derived LAI products at high spatial and temporal resolutions provides a means to apply our approach regionally. Testing yield predictions from this approach over agricultural fields is a critical next step to determine broader utility.

scholarly journals Nitrogen topdressing and application ways of fluazifop-p-butyl + fomesafen in weed control and agronomic performance of common bean

2015 ◽  
Vol 87 (4) ◽  
pp. 2301-2307 ◽  
Author(s):  
MATHEUS G. SILVA ◽  
ORIVALDO ARF ◽  
PAULO E. TEODORO
Keyword(s):  
Common Bean ◽  
Weed Control ◽  
Yield Components ◽  
Dry Matter ◽  
Block Design ◽  
Agronomic Performance ◽  
Randomized Block Design ◽  
Bean Yield ◽  
Leaf N Content ◽  
Leaf N

ABSTRACT The objective of this study was to investigate the effect of interaction between nitrogen topdressing and different application ways (active ingredients) a.i. fluazifop-p-butyl + fomesafen in weed control and agronomic performance of common bean. The experiment was conducted during winter 2003 in Selvíria/MS. The experimental design used was a randomized block design with four replications in a factorial scheme 2x7. The first factor was composed by the absence or presence of nitrogen topdressing, while the second factor consisted of different application ways of fluazifop-p-butyl + fomesafen. The following variables were measured: leaf N content, dry matter of plants, yield components (number of pods plant-1, number of grains plant-1, the average number of grains pod-1 and mass of 100 grains), grain yield, phytotoxicity and weed control percentage. The nitrogen topdressing with 75 kg ha-1provided higher dry matter of plants, higher weed control and higher common bean yield of irrigated winter. In the absence of nitrogen topdressing in the application of urea before or together to fluazifop-p-butyl + fomesafen increased their effectiveness in controlling weeds without interference in the agronomic performance of common bean.

scholarly journals Patterns of tillering and grain production of winter wheat at a wide range of plant densities.

1978 ◽  
Vol 26 (4) ◽  
pp. 383-398 ◽  
Author(s):  
A. Darwinkel
Keyword(s):  
Winter Wheat ◽  
Grain Yield ◽  
Harvest Index ◽  
Plant Density ◽  
Fold Increase ◽  
Grain Production ◽  
Higher Plant ◽  
Grain Number ◽  
Wide Range ◽  
Plant Densities

The effect of plant density on the growth and productivity of the various ear-bearing stems of winter wheat was studied in detail to obtain information on the pattern of grain production of crops grown under field conditions. Strong compensation effects were measured: a 160-fold increase in plant density (5-800 plants/m2) finally resulted in a 3-fold increase in grain yield (282 to 850 g DM/m2). Max. grain yield was achieved at 100 plants/m2, which corresponded to 430 ears/m2 and to about 19 000 grains/m2. At higher plant densities more ears and more grains were produced, but grain yield remained constant. Tillering/plant was largely favoured by low plant densities because these allowed tiller formation to continue for a longer period and a greater proportion of tillers produced ears. However, at higher plant densities more tillers/unit area were formed and, despite a higher mortality, more ears were produced. The productivity of individual ears, from main stems as well as from tillers, decreased with increasing plant density and with later emergence of shoots. In the range from 5 to 800 plants/m2 grain yield/ear decreased from 2.40 to 1.14 g DM. At 800 plants/m2 nearly all ears originated from main stems, but with decreasing plant density tillers contributed increasingly to the number of ears. At 5 plants/m2, there were 23 ears/plant and grain yield/ear ranged from 4.20 (main stem) to 1.86 g DM (late-formed stems). Grain number/ear was reduced at higher densities and on younger stems, because there were fewer fertile spikelets and fewer grains in these spikelets. At the low density of 5 plants/m2, plants developed solitarily and grain yield/ear was determined by the number of grains/ear as well as by grain wt. Above 400 ears/m2, in this experiment reached at 100 plants/m2 and more, grain yield/ear depended solely on grain number, because the wt. of grains of the various stems were similar. The harvest index showed a max. of about 44% at a moderate plant density; at this density nearly max. grain yield was achieved. At low plant densities the harvest index decreased from 45% in main stems to about 36% in late-formed stems. However, no differences in harvest index existed between the various ear-bearing stems if the number of ears exceeded 400/m2. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Effects of high plant populations on the growth and yield of winter oilseed rape (Brassica napus)

1999 ◽  
Vol 132 (2) ◽  
pp. 173-180 ◽  
Author(s):  
J. E. LEACH ◽  
H. J. STEVENSON ◽  
A. J. RAINBOW ◽  
L. A. MULLEN
Keyword(s):  
Brassica Napus ◽  
Oilseed Rape ◽  
Plant Density ◽  
High Density ◽  
Growth And Yield ◽  
Winter Oilseed Rape ◽  
Plant Populations ◽  
Rothamsted Experimental Station ◽  
Plant Densities ◽  
Very High

The effects of plant density on the growth and yield of winter oilseed rape (Brassica napus) were examined in a series of five multifactorial experiments at Rothamsted Experimental Station between 1984 and 1989. Plant densities, manipulated by changing the seed rate and row spacing, or because of overwinter losses, ranged from 13·5 to 372 plants/m2. Normalized yields for the multifactorial plots increased with densities up to 50–60 plants/m2. In very high density plots in 1987/88, yield decreased as density increased >150 plants/m2. Plants grown at high density had fewer pod-bearing branches per plant but produced more branches/m2. Branch dry matter (DM) per plant was decreased by 42%, the number of fertile pods per plant and pod DM/plant by 37%. There was no effect of density on the number or DM of pods/m2. Over 74% of the fertile pods were carried on the terminal and uppermost branches of plants grown at high density in 1987/88 compared with only 34% in plants grown at low density in 1988/89. Seed DM/plant decreased with increase in density but seed size (1000-seed weight) increased. There was no effect of density on seed glucosinolate or oil contents.

Modelling Canopy Production. II. From Single-Leaf Photosynthesis Parameters to Daily Canopy Photosynthesis

1995 ◽  
Vol 22 (4) ◽  
pp. 603 ◽  
Author(s):  
PJ Sands
Keyword(s):  
Simple Algorithm ◽  
Light Response ◽  
Daily Maximum ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Daily Production ◽  
Area Index ◽  
Single Leaf ◽  
Diurnal Temperature Variation ◽  
Analytical Expressions

This paper presents a simple algorithm for calculating daily canopy photosynthesis given parameters of the single-leaf light response, the canopy extinction coefficient, canopy leaf area index, daylength, daily solar irradiance and daily maximum and minimum temperatures. Analytical expressions are derived for total daily production by a canopy of leaves whose light response is either a rectangular hyperbola or a Blackman response. An expression which gives an excellent approximation to canopy photosynthesis for an arbitrary hyperbolic light response is then derived. These expressions assume photosynthetically active radiation (PAR) within the canopy follows Beer's law, light-saturated photosynthetic rate at any point in the canopy is proportional to the ratio of local PAR to full-sun PAR, diurnal variation of PAR is sinusoidal, and parameters of the single-leaf photosynthetic light response do not vary diurnally. It is shown how these expressions can be used to accommodate diurnal temperature variation of photosynthesis in a simple manner. The accuracy of the approximation to the basic integral of leaf photosynthesis over the canopy and over time is illustrated by applying the algorithm to compute the seasonal variation of daily canopy photosynthesis and comparing these data with corresponding values obtained by numerical integration.

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