A Model of the Effect of Interspecies Competition for Light on Dry-Matter Production

1984 ◽  
Vol 11 (4) ◽  
pp. 277 ◽  
Author(s):  
GM Rimmington
Keyword(s):  
Dry Matter ◽  
Incident Light ◽  
Light Energy ◽  
Dry Matter Production ◽  
Interspecies Competition ◽  
Area Index ◽  
Unit Leaf ◽  
Matter Production ◽  
Absorption Of Light ◽  
Competition For Light

A model of the effect of interspecies competition for light on the daily dry-matter production of competing species is developed. It describes the absorption of light by the component species, accounting for their different optical properties. Absorption equations are formulated from the principle of conservation of light energy within a unit-leaf-area-index of canopy, and the integral of absorbed light energy is then used to calculate the rate of dry-matter production of each component species. This model proved useful for the analysis of data from experiments in which New Zealand white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) were grown in mixtures. Application of the model enabled the proportion of incident light energy absorbed by each component to be estimated and unambiguous differentiation between the amount of light energy absorbed and the efficiency of use of the absorbed light energy.

A Test of a Model for Light Interception by Mixtures

1985 ◽  
Vol 12 (6) ◽  
pp. 681 ◽  
Author(s):  
GM Rimmington
Keyword(s):  
Optical Properties ◽  
Dry Matter ◽  
Light Interception ◽  
Light Energy ◽  
Dry Matter Production ◽  
Additional Test ◽  
Matter Production ◽  
Competition For Light

Predicted and observed data for the amount of light energy intercepted by mixtures of clover and ryegrass are compared, in an additional test of a model which relates competition for light to crop dry matter production. The closeness of predicted and observed values for light interception implies that the optical properties of the component species do not change significantly when they are grown in mixtures. If this is true, then it should be possible to predict the growth of mixtures using information about their optical properties when they are grown in monocultures.

A comparison of barley cultivars with different leaf inclinations

1972 ◽  
Vol 23 (6) ◽  
pp. 945 ◽  
Author(s):  
JF Angus ◽  
R Jones ◽  
JH Wilson
Keyword(s):  
Dry Matter ◽  
Canopy Structure ◽  
The Other ◽  
Dry Matter Production ◽  
Visible Radiation ◽  
Area Index ◽  
Assimilation Chamber ◽  
Barley Cultivars ◽  
Matter Production ◽  
Erect Leaf

Under conditions of adequate moisture an erect-leaf barley cultivar, Lenta, responded to an increase in density (resulting from doubling of the sowing rate) with increases in dry matter production and in grain yield, whereas the cultivar Research, which has long lax leaves, responded with decreases in dry matter production and yield. In a study of canopy structure and its effects on light interception and utilization, it was found that in Research, with a leaf area index (LAI) of 6.1, the leaves were concentrated near the canopy surface and a relatively small proportion of the above-crop light penetrated through this layer. The net crop photosynthesis of this canopy (measured in a field assimilation chamber) was 3.8 g CO2/m2.hr when visible radiation was 313 W/m2. With Lenta (LAI 7.0) on the other hand, leaves were concentrated in the middle layers of the canopy and the light was more evenly distributed throughout the canopy. The net crop photosynthesis with the same radiation as for Research was 4.3 g CO2/m2.hr. The relative rates of photosynthesis at various levels in the canopies were determined by introducing 14CO2 into the assimilation chambers enclosing the cultivars and observing where the 14C was fixed. With Research most of it was localized near the canopy surface while with Lenta most of it was near the centre of the canopy. Of the 14CO2 taken up, 7 % was fixed in the leaf sheaths of Research and 12% in those of Lenta.

The growth and performance of cotton in a desert environment: II. Dry matter production

1969 ◽  
Vol 73 (1) ◽  
pp. 75-86 ◽  
Author(s):  
A. B. Hearn
Keyword(s):  
Growth Rate ◽  
Dry Matter ◽  
Initial Period ◽  
Dry Weight ◽  
Dry Matter Production ◽  
Area Index ◽  
Vegetative Phase ◽  
Matter Production ◽  
Sink Size ◽  
And Performance

SUMMARYVariety, water and spacing were treatments in two experiments with cotton in 1963 and 1964 in which fruiting points, flowers and bolls were counted and the dry weights and leaf areas of plants were measured at intervals during the season.Until leaf-area index, L, started to decrease, the equation described how dry weight, W, changed. The equation gave smoothed estimates of crop growth rate, C, which were consistent with estimates of photosynthesis made with de Wit's (1965) model. The relationship between G and L conformed to , derived from Beer's Law, rather than C = aL — bL2 derived from the linear regression of E on L. When L > 3 the crop appeared to use most of the available light, so that C approached a maximum. Treatments initially affected dry-matter production through the numbers and types of branches and nodes, which in turn affected the sinks available and thus the proportion of dry matter reinvested in new leaf. This initial period, when growth was simple to describe in conventional terms, was denned as the vegetative phase of growth.The start of the reproductive phase of growth overlapped the vegetative phase. The change from one to the other was completed when the rate of dry weight increase of the bolls, CB, equalled C. This indicated that the sink formed by the bolls had increased sufficiently in size to use all the assimilates available for growth. Sink size increased as the crop flowered and was estimated from the product of the number of bolls and the growth rate of a single boll.When CB equalled C, bolls were shed which prevented the size of the sink to increase beyond the ability of the plant to supply it with assimilates. This agrees with Mason's nutritional theory of boll shedding. Because of the crop's morphology and because age decreased the photosynthesis of the crop, the size of the sink inevitably increased out of phase with the supply of assimilates. The extent to which this was so determined when CB equalled C. It is postulated that environment, genotype and agronomic practice affect yield according to whether they increase or decrease the extent to which the sink size and the supply of assimilates are out of phase.

Effects of Allelopathic Chemicals on Growth and Physiological Responses of Soybean (Glycine max)

Weed Science ◽  
1981 ◽  
Vol 29 (1) ◽  
pp. 53-59 ◽  
Author(s):  
D. T. Patterson
Keyword(s):  
Glycine Max ◽  
Chlorogenic Acid ◽  
Leaf Area ◽  
Chlorophyll Content ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Sulfosalicylic Acid ◽  
Leaf Production ◽  
Unit Leaf ◽  
Matter Production

The effects of caffeic acid, chlorogenic acid,t-cinnamic acid,p-coumaric acid, ferulic acid, gallic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, vanillic acid, and vanillin on growth, photosynthesis, water relations, and chlorophyll content of 3-week-old soybeans [Glycine max(L.) Merr. ‘Tracy’] grown in aerated nutrient solution were determined. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids significantly reduced dry matter production, leaf expansion, height, leaf production, net assimilation rate (rate of dry matter production per unit leaf area), and leaf area duration (total leaf area present during treatment interval). Chlorogenic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, and vanillin at 10−3M did not inhibit growth. None of the 10 compounds at 10−4M inhibited growth. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids severely reduced net photosynthetic rate and stomatal conductance of single, fully expanded leaves. These same compounds also caused marked reductions in leaf chlorophyll content, with net losses of chlorophyll occurring over an 86-h period after treatment.

Nitrogen-limited light use efficiency in wheat crop simulators: comparing three model approaches

2015 ◽  
Vol 154 (6) ◽  
pp. 1090-1101 ◽  
Author(s):  
A. M. RATJEN ◽  
H. KAGE
Keyword(s):  
Dry Matter ◽  
Dry Matter Production ◽  
Wheat Crop ◽  
Light Use Efficiency ◽  
Data Set ◽  
Area Index ◽  
N Concentration ◽  
Matter Production ◽  
Use Efficiency ◽  
Critical N Concentration

SUMMARYThree different explanatory indicators for reduced light use efficiency (LUE) under limited nitrogen (N) supply were evaluated. The indicators can be used to adapt dry matter production of crop simulators to N-limited growth conditions. The first indicator, nitrogen factor (NFAC), originates from the CERES-Wheat model and calculates the critical N concentration of the shoot as a function of phenological development. The second indicator, N nutrition index (NNI), calculates a critical N concentration as a function of shoot dry matter. The third indicator, specific leaf nitrogen (SLN) index (SLNI), has been newly developed. It compares the actual SLN with the maximum SLN (SLNmax). The latter is calculated as a function of the green area index (GAI). The comparison was based on growth curves and fitted to empirical data, and was carried out independently from a dynamic crop model. The data set included four growing seasons (2004–2006, 2012) in Northern Germany and seven modern bread wheat cultivars with varying N fertilization levels (0–320 kg N/ha). The influence of N shortage on LUE was evaluated from the beginning of stem elongation until flowering. With the exception of 2005, the highest productivity was observed for the highest N level. A moderate N shortage primarily reduced GAI and therefore light interception, while LUE remained stable under moderate N shortage. The relative LUE (rLUE) of a specific day was defined as the ratio of actual to maximal LUE. None of the indicators was proportional to rLUE, but the relationships were described well by quadratic plateau curves. The correlation between simulated and measured rLUE was significant for all explanatory indicators, but different in terms of mean absolute error and coefficient of determination (R2). The performance of SLNI and NNI was similar, but the goodness of prediction was much lower for NFAC. Compared with NNI and NFAC, SLNI corresponded to leaf N and was therefore sensitive to N translocation from leaves to growing grains during the reproductive stage. For this reason, SLNI may have the potential to improve simulation of dry matter production in wheat crop simulators.

scholarly journals Effect of nitrogen and phosphorus on growth and seed yield of French bean

2016 ◽  
Vol 41 (4) ◽  
pp. 759-772
Author(s):  
SS Kakon ◽  
MSU Bhuiya ◽  
SMA Hossain ◽  
Q Naher ◽  
Md DH Bhuiyan
Keyword(s):  
Seed Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Agricultural Research ◽  
Block Design ◽  
French Bean ◽  
Dry Matter Production ◽  
Nitrogen And Phosphorus ◽  
Area Index ◽  
Matter Production

Field experiments were conducted during rabi (winter) seasons of 2010-11 and 2011-12 at the Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur to study the effects of nitrogen and phosphorus on growth, dry matter production and yield of French bean. A randomized complete block design was followed with 10 combinations of N (0,50, 100, 150 and 200) and P (0,22, 33, 44 and 55) kg ha-1 along with a blanket dose of control. All the treatments showed the maximum leaf area index (LAI) at 65 days after sowing (DAS). All the treatments showed the maximum total dry matter production, crop growth rate and net assimilation rate at harvest and at 55-65 DAS, respectively in both the years. LAI, dry matter production, CGR, NAR and seed yield significantly increased with the increase in nitrogen and phosphorus level upto 150 kg N and 44 P kg ha-1 , respectively. Similar trend was followed in maximum number of pods (9.45) and seed yield (1563.33 kg ha-1). The treatment comprises with 150 kg N and 44 P Kg ha-1 gave the highest seed yield which was 51.40 and 54.30 % higher than control plots.Bangladesh J. Agril. Res. 41(4): 759-772, December 2016

The growth of swards of subterranean clover with particular reference to leaf area

1958 ◽  
Vol 9 (1) ◽  
pp. 53 ◽  
Author(s):  
JL Davidson ◽  
CM Donald
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Substantial Reduction ◽  
Ground Surface ◽  
Subterranean Clover ◽  
Climatic Conditions ◽  
Dry Matter Production ◽  
Leaf Production ◽  
Area Index ◽  
Matter Production

An experiment was conducted to study the growth of subterranean clover (Trifolium subterraneum L.) sown at different densities; the control swards were not defoliated while others were subjected to a single defoliation at various dates. During the final month the rate of dry matter production (tops only) increased to a maximum when the leaf area index (the ratio of the area of the leaves to the area of the ground surface — L.A.I.) was about 4-5, falling by about 30 per cent. as the L.A.I. increased to 8.7. The rate of leaf production was greatest at about L.A.I. 4-5, falling to zero at L.A.I. 8.7. Climatic conditions during the growing season influenced the relationship of L.A.I. to growth; as conditions became more favorable the values of the optimum LA.1. for growth and of the ceiling L.,4.1. progressively rose. Irrespective of the density, all swards tended towards a common ceiling L.A.I. and yield by the end of the season. The effect of defoliation depended on the L.A.I. at which defoliation occurred, on the value to which the L.A.I. was reduced, and on current climatic conditions. If swards near the ceiling L.A.I. were defoliated, total dry matter production was slightly increased and there was a great increase in leaf production. On the other hand, defoliation of swards from about the optimum L.A.I. to very low L.A.I. values led to a substantial reduction in both dry matter and leaf production. It is suggested that all these effects depend on the light relationships within the sward and their influence on the balance of photosynthesis and respiration. Pasture at the optimum L.A.I. will give greater production than swards of lower or higher L.A.I.; defoliation can give greatly increased leaf production, unless L.A.I. is reduced to very low values.

Precision drilling combining peas (Pisum sativum L.) of contrasting leaf types at varying densities

1987 ◽  
Vol 108 (2) ◽  
pp. 425-430 ◽  
Author(s):  
M. C. Heath ◽  
P. D. Hebblethwaite
Keyword(s):  
Dry Matter ◽  
Plant Density ◽  
Spatial Arrangement ◽  
Plant Distribution ◽  
Dry Matter Production ◽  
Yield Response ◽  
Area Index ◽  
Radiation Interception ◽  
Matter Production ◽  
Leaf Phenotype

SummaryField experiments were conducted in 1983–4 to investigate the effect of precision drilling and plant density on establishment, growth, radiation interception and yield of combining peas of varying leaf phenotype (Varieties ‘Birte’, leafed; ‘Filby’, leafless; and ‘BS3’, semi-leafless). Precision drilling established a more uniform plant distribution than øyjord drilling; visual differences observed soon after emergence were not observed at flowering. Precision drilling resulted in more radiation interception early in the season for semi-leafless but not leafed peas; dry-matter production and photosynthetic area index (PAI) were not increased. Yield data indicated that precision drilling produced similar yields to øyjord drilling at similar densities. Increasing plant density increased radiation interception, dry-matter production and PAI during vegetative growth; density treatment effects were less marked post-flowering. Pea leaf phenotypes differed in their yield response to increasing density. Radiation interception was related to dry-matter production and PAI to obtain an estimate of photosynthetic efficiency (ε) and the attenuation coefficient (k), respectively, ε and k were constant irrespective of spatial arrangement, leaf phenotype and plant density. The relative importance of spatial arrangement and plant density in increasing radiation interception and PAI and influence on yield is discussed; other potential agronomic advantages of precision drilling are described.

Analysis of the regrowth of a tropical grass/legume sward subjected to different frequencies and intensities of defoliation

1980 ◽  
Vol 31 (4) ◽  
pp. 673 ◽  
Author(s):  
MM Ludlow ◽  
DA Charles-Edwards
Keyword(s):  
Leaf Area ◽  
Dry Matter ◽  
Dry Weight ◽  
Light Interception ◽  
Photosynthetic Characteristics ◽  
Dry Matter Production ◽  
Canopy Photosynthesis ◽  
Area Index ◽  
Matter Production ◽  
Cutting Height

Dry weight, leaf area, light interception and canopy photosynthesis were measured during 3- or 5-week regrowth periods of Setaria anceps/Desmodium intortum swards cut to 7.5 or 15 cm. Dry matter production during the experiment and over the growing season increased with cutting height and with interval between defoliations, but the proportion of grass to legume was unaffected. These effects of defoliation on dry matter production were similar to those estimated for integrated canopy photosynthesis from measured light interception and calculated leaf photosynthetic characteristics. Height and frequency of defoliation had no effect on canopy extinction coefficient for light, nor on the leaf photosynthetic characteristics, except for the first 1-2 weeks after defoliation when leaf photosynthetic rates appeared to be depressed. The main effects of height and frequency of defoliation on dry matter production were through their effects on leaf area index and light interception.

scholarly journals EVALUATION OF EARLY POST-EMERGENCE HERBICIDE APPLICATION ON WEED CONTROL, CROP GROWTH AND NUTRIENT UPTAKE IN TRANSPLANTED RICE (ORYZA SATIVA)

2020 ◽  
Vol 21 (supplement 1) ◽  
Author(s):  
T. Srinithan ◽  
K. Arivukkarasu Arivukkarasu ◽  
P. Sivasakthivelan ◽  
R. Rex Immanuel
Keyword(s):  
Leaf Area Index ◽  
Nutrient Uptake ◽  
Leaf Area ◽  
Plant Height ◽  
Weed Control ◽  
Dry Matter ◽  
Dry Matter Production ◽  
Area Index ◽  
Transplanted Rice ◽  
Matter Production

A field experiment was conducted during Kuruvai season at the Experimental Farm, Department of Agronomy, Annamalai University to evaluate the performance of early post emergence application of herbicides on weed control in transplanted rice. The experiment was carried out in a Randomized Block Design with eight treatments and three replications. All the imposed treatments significantly influenced the weed parameters and crop parameters in rice. The experimental results revealed that, hand weeding twice at 20 and 40 DAT recorded the lowest total weed count (13.74), highest weed control efficiency (WCE) (92.79 per cent), highest plant height (85.76 cm), higher leaf area index (4.28), higher crop dry matter production (7689 kg ha-1 )and highest nutrient uptake by rice crop (134.79, 33.17, 99.41 kg of N, P2O5 , K2O ha-1, respectively) which was statistically on par with application of penoxsulam + cyhalofop butyl@135 g ha-1 (premix)(15 DAT) that recorded the total weed count (16.74), weed control efficiency (91.21 per cent), plant height (85.03cm), leaf area index (4.19), dry matter production (7567 kg ha-1), crop nutrient uptake (132.37 , 32.48, 97.25 kg of N, P2O5 , K2O ha-1, respectively). Highest total weed count, with lowest plant height, leaf area index, crop dry matter production and crop nutrient uptake were recorded with unweeded control.

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