The relationship between crop yield (or mean plant weight) of lettuce and plant density, length of growing period, and initial plant weight

1976 ◽  
Vol 86 (1) ◽  
pp. 83-91 ◽  
Author(s):  
M. A. Scaife ◽  
D. Jones
Keyword(s):  
Time Course ◽  
Plant Density ◽  
Unit Area ◽  
Subterranean Clover ◽  
Plant Weight ◽  
Relative Growth ◽  
Growing Period ◽  
Lettuce Growth ◽  
Log Linear ◽  
The Relationship

SUMMARYLettuce obeys the Shinozaki–Kira relationship in which the reciprocal of plant weight is linearly related to plant density. The intercept (a) represents the reciprocal of the weight of an isolated plant and the slope (b) represents the reciprocal of yield/unit area at high densities (the ‘ceiling yield’). This work examines the time course of (a) and (b) in an ‘ideal environment’ in which water and nutrients are non-limiting, and the light/temperature regime is constant.Two pot experiments are described: the first showed that the growth of isolated lettuces follows a logistic expression, which can therefore be substituted for a–1 in the Shinozaki-Kira equation. It was then hypothesized that b–1, the ‘ceiling yield’ would be constant over time. This was confirmed by the second experiment, giving the equationw–1t = w–10 e1–kt × w–1max × bd,in which wt is mean plant weight at time t, w0 and wmax are the initial and final weights of isolated plants, k is the early relative growth rate of such plants, b–1 is the constant ceiling yield, and d is the plant density.Two examples of the use of the equation are given: one shows how it predicts the interaction between seed size and plant density within a species (subterranean clover): the other illustrates how it can be used to explain why lettuce growth appears to be log-linear against time whereas cereal growth is more nearly just linear.

Effect of plant density on the winter production of annual clovers grown in monocultures

2002 ◽  
Vol 42 (2) ◽  
pp. 135 ◽  
Author(s):  
P. M. Evans ◽  
S. Walton ◽  
P. A. Riffkin ◽  
G. A. Kearney
Keyword(s):  
Plant Density ◽  
Unit Area ◽  
Subterranean Clover ◽  
Dry Weight ◽  
Equal Weight ◽  
Harvest Time ◽  
Higher Plant ◽  
Plant Weight ◽  
Plant Densities ◽  
Western Victoria

The small-seeded annual clovers, balansa and Persian, are often assumed to be poor winter producers. Their small seed size, of about 1 mg or less, and poor regeneration, possibly due to inappropriate grazing management in many instances, contributes to this perception. To test the hypothesis that early growth of these clovers is determined by the weight of germinating seed, as it is in subterranean clover, an experiment with 2 cultivars of subterranean clover, Leura and Trikkala, 2 cultivars of balansa clover, Paradana and Bolta, and 1 of Persian clover, Nitro Plus, was established in the field at Hamilton, western Victoria, at 6 sowing densities. The winter production at 2 additional sites, Lake Bolac and Streatham, in their third and second and third seasons, respectively, was also examined. Plant density varied from 30 to 37000 plants/m2 across sites and species. With equal weight of germinating seed per unit area at sowing, balansa and Persian clovers produced more herbage in winter than did the 2 subterranean clover cultivars Leura and Trikkala (P<0.05). Even though there was high correlation between seed weight and seedling weight across all species shortly after emergence (r2 = 0.99), by harvest time no differences in plant weight existed between any treatments growing at the same plant density. From this we conclude the following: (i) for the same weight of germinable seed per unit area, balansa and Persian clovers produced more dry weight per hectare than subterranean clover, because they had higher plant densities; (ii) there were no differences in dry matter production per hectare between species growing at similar plant densities by harvest time at the end of winter; (iii) it appeared that in winter the small-seeded species exhibited a higher relative growth rate than the 2 subterranean clovers.

The influence of maturity grading on total yield and seed production in strains of Trifolium subterraneun L. grown as single plants and in swards

1959 ◽  
Vol 10 (3) ◽  
pp. 305 ◽  
Author(s):  
RC Rossiter
Keyword(s):  
Soil Moisture ◽  
Seed Production ◽  
Plant Density ◽  
Total Yield ◽  
Subterranean Clover ◽  
Reverse Situation ◽  
Production Pattern ◽  
Seed Yields ◽  
The Relationship ◽  
Early Strain

A large number of strains of subterranean clover was grown as single plants and in swards in a series of 1-year experiments. The relationship between the interval from seeding to flowering ("maturity grading") and the production pattern varied according to plant density. In the case of single plants, both total yields and seed yields increased linearly with increasing maturity grading. With swards, on the other hand, total yields showed scarcely any relation to increasing maturity grading – there was a slight decline, in fact – while seed production fell rapidly. Hence the early strain Dwalganup gave the lowest seed yields as single plants, but the highest seed yields in swards, whereas the reverse situation held for the late strains Wenigup and Tallarook. The main factor responsible for the differences in these production patterns was considered to be available soil moisture supply. It was shown that in the few cases where soil moisture was severely limiting in spring for single plants, yields levelled off (and seed yields even declined) at higher maturity gradings. Three points are discussed at some length: the influence of environment on the seed yield of strains grown as single plants, the effect of plant density on the ratio seed weight/total weight, and production in relation to maturity grading in swards.

The effect of seed size on seedling growth in subterranean clover (Trifolium subterraneum L.)

1972 ◽  
Vol 23 (4) ◽  
pp. 595 ◽  
Author(s):  
GB Taylor
Keyword(s):  
Light Intensity ◽  
Seed Size ◽  
Seedling Growth ◽  
Subterranean Clover ◽  
High Light Intensity ◽  
High Light ◽  
Plant Weight ◽  
Trifoliate Leaf ◽  
Relative Growth ◽  
Leaf Stage

The effect of seed size on seedling growth in a single population of Daliak subterranean clover was studied by growing individually weighed seeds to the third trifoliate leaf stage in three controlled environments. The environments were: 18°C at high light intensity (27,000 lux), 12° at high light intensity, and 18° at low light intensity (5400 lux). Plant weight at emergence exceeded the weight of embryo in the original seed, owing in part to the utilization of endosperm. At emergence the ratio of plant weight to seed weight increased with increasing seed size. Nevertheless, in all environments the smaller seeds ultimately produced relatively larger plants owing to a higher relative growth rate, particularly during the cotyledon and unifoliate leaf stage of growth. Higher relative growth rates in seedlings from smaller seeds were associated with higher leaf area ratios resulting from the production of relatively larger cotyledon and individual leaf areas in all environments. More rapid leaf expansion in seedlings from larger seeds progressively offset this advantage.

Effect of sowing date and plant density on yield and yield components in the faba bean

1997 ◽  
Vol 48 (8) ◽  
pp. 1161 ◽  
Author(s):  
T. Adisarwanto ◽  
R. Knight
Keyword(s):  
Faba Bean ◽  
Yield Components ◽  
Harvest Index ◽  
Plant Density ◽  
Unit Area ◽  
Sowing Date ◽  
Low Density ◽  
Plant Weight ◽  
Pod Development ◽  
Number Of Seeds

Faba bean cv. Fiord was sown at 3-week intervals between 24 April and 26 June at 6 densities varying from 20 to 56 plants/m2. Days to emergence, flowering, pod set, and maturity were determined. At harvest, the biomass, yield, pod number, seeds per pod, and weight per seed were evaluated per unit area and the distribution of the yield components was evaluated for each node of the main stem. Later sowing had little effect on the number of days to the appearance of the first pod but it progressively reduced the duration of the pod development period from 98 to 60 days. The biomass at maturity of the plants sown on 24 April was constant across all densities, at about 13·5 t/ha. Yield, however, decreased linearly with density from 6·7 to 5·2 t/ha. Harvest index, therefore, also fell with density. With later sowing, biomass and yield increased with density. The increase in yield was not as great; so again harvest index fell with density. Later sowing resulted in much lower yields and even at the highest density only reached 5·2 t/ha. Variation in yield was largely determined by variation in the number of pods per unit area. Seeds per pod was constant across the treatments but weight per seed decreased if sowing was delayed beyond 10 June. With later sowing, the number of pod-bearing nodes on the main stems declined from 27 to 15. Early-sown plants at high density had fewer pods per node at the lower nodes and more pods per node at the higher nodes than plants at low density. This interaction was not evident at the second sowing and the number of pods at each node was unaffected by density. For the sowings in June, all nodes of the low density plants bore more pods The number of seeds per pod was smaller at the lowest and highest nodes, but as there were so few pods at these nodes, this did not affect the mean number of seeds per pod when evaluated for all pods on a plant. Weight per seed was more uniform for the nodes of the early-sown plants than for those of the plants sown later, in which there was a marked decrease in weight per seed at the upper nodes

Methods of analysing yield from trials in which the produce is graded according to diameter

1981 ◽  
Vol 97 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Elizabeth A. Chapman
Keyword(s):  
Plant Density ◽  
Large Range ◽  
Unit Area ◽  
Total Yield ◽  
Mathematical Equation ◽  
Degree Polynomial ◽  
Variety Trials ◽  
Plant Densities ◽  
The Relationship ◽  
Common Equation

SUMMARYA study was made of the relationship between yields in particular size grades of carrots and onions and the number of plants per unit area with a view to providing adjustments to yields for differences in plant densities. It is concluded that the relationship for individual small grades cannot be fitted consistently by a single mathematical equation but that estimates of yields in small grades are best obtained by fitting a common equation to the accumulated yield at the limits of the grade and obtaining the yield by difference. Eleven previously published equations which have been shown to fit the relationship between total yield and plant density for a number of crops are compared with one newly developed for graded produce. It was found that the latter,where y = yield/ha, ρ = number of plants/m2 and A, B and C are constants, generally leads to the best fits when a large range of densities is present, but it is argued that, for adjustment of yields for small differences in densities such as are obtained in variety trials, a simpler equation such as a second degree polynomial is equally effective.

Radiation Damage, Contrast and Statistics in High Resolution Biological Electron Microscopy

1970 ◽  
Vol 28 ◽  
pp. 260-261
Author(s):  
Robert M. Glaeser
Keyword(s):  
High Resolution ◽  
Particle Flux ◽  
Unit Area ◽  
Signal To Noise ◽  
Resolution Image ◽  
High Resolution Image ◽  
Pass Through ◽  
Counting Statistics ◽  
The Relationship ◽  
Picture Element

It is well known that a large flux of electrons must pass through a specimen in order to obtain a high resolution image while a smaller particle flux is satisfactory for a low resolution image. The minimum particle flux that is required depends upon the contrast in the image and the signal-to-noise (S/N) ratio at which the data are considered acceptable. For a given S/N associated with statistical fluxtuations, the relationship between contrast and “counting statistics” is s131_eqn1, where C = contrast; r2 is the area of a picture element corresponding to the resolution, r; N is the number of electrons incident per unit area of the specimen; f is the fraction of electrons that contribute to formation of the image, relative to the total number of electrons incident upon the object.

IMPROVEMENT OF SPRING DURUM WHEAT SELECTION METHODOLOGIES UNDER CLIMATE CHANGE CONDITIONS

1970 ◽  
pp. 33-36
Author(s):  
А. I. Grabovets ◽  
V. P. Kadushkina ◽  
S. А. Kovalenko
Keyword(s):  
Grain Yield ◽  
Durum Wheat ◽  
Correlation Coefficient ◽  
Harvest Index ◽  
Unit Area ◽  
Correlation Coefficients ◽  
Chemical Mutagenesis ◽  
Main Method ◽  
The Relationship ◽  
Selection Of

With the growing aridity of the climate on the Don, it became necessary to improve the methodology for conducting the  breeding of spring durum wheat. The main method of obtaining the source material remains intraspecific step hybridization. Crossings were performed between genetically distant forms, differing in origin and required traits and properties. The use of chemical mutagenesis was a productive way to change the heredity of genotypes in terms of drought tolerance. When breeding for productivity, both in dry years of research and in favorable years, the most objective markers were identified — the size of the aerial mass, the mass of grain per plant, spike, and harvest index. The magnitude of the correlation coefficients between the yield per unit area and the elements of its structure is established. It was most closely associated with them in dry years, while in wet years it decreased. Power the correlation of the characteristics of the pair - the grain yield per square meter - the aboveground biomass averaged r = 0.73, and in dry years it was higher (0.91) than in favorable ones (0.61 - 0.70) , between the harvest and the harvest index - r = 0.81 (on average). In dry years, the correlation coefficient increased to 0.92. Research data confirms the greatest importance of the mass of grain from one ear and the plant in the formation of grain yield per unit area in both dry and wet years. In dry years, the correlation coefficient between yield and grain mass per plant was on average r = 0.80; in favorable years, r = 0.69. The relationship between yield and grain mass from the ear was greater — r = 0.84 and r = 0.82, respectively. Consequently, the breeding significance of the aboveground mass and the productivity of the ear, as a criterion for the selection of the crop, especially increases in the dry years. They were basic in the selection.

Nitrogen Demand of Cut Chrysanthemums in Relation to Shoot Height and Planting Date

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 523c-523
Author(s):  
Siegfried Zerche
Keyword(s):  
Dry Matter ◽  
Plant Density ◽  
Plant Biomass ◽  
N Uptake ◽  
Planting Date ◽  
Dry Matter Accumulation ◽  
Planting Dates ◽  
Shoot Height ◽  
Climate Conditions ◽  
Growing Period

Refined nutrient delivery systems are important for environmentally friendly production of cut flowers in both soil and hydroponic culture. They have to be closely orientated at the actual nutrient demand. To solve current problems, express analysis and nutrient uptake models have been developed in horticulture. However, the necessity of relatively laborious analysis or estimation of model input parameters have prevented their commercial use up to now. For this reason, we studied relationships between easily determinable parameters of plant biomass structure as shoot height, plant density and dry matter production as well as amount of nitrogen removal of hydroponically grown year-round cut chrysanthemums. In four experiments (planting dates 5.11.91; 25.3.92; 4.1.93; 1.7.93) with cultivar `Puma white' and a fixed plant density of 64 m2, shoots were harvested every 14 days from planting until flowering, with dry matter, internal N concentration and shoot height being measured. For each planting date, N uptake (y) was closely (r2 = 0.94; 0.93; 0.84; 0.93, respectively) related to shoot height (x) at the time of cutting and could be characterized by the equation y = a * × b. In the soilless cultivation system, dry matter concentrations of N remained constant over the whole growing period, indicating non-limiting nitrogen supply. In agreement with constant internal N concentrations, N uptake was linearly related (r2 = 0.94 to 0.99) to dry matter accumulation. It is concluded that shoot height is a useful parameter to include in a simple model of N uptake. However, in consideration of fluctuating greenhouse climate conditions needs more sophisticated approaches including processes such as water uptake and photosynthetically active radiation.

scholarly journals Optimizing Grain Yield and Water Use Efficiency Based on the Relationship between Leaf Area Index and Evapotranspiration

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 313
Author(s):  
Guoqiang Zhang ◽  
Bo Ming ◽  
Dongping Shen ◽  
Ruizhi Xie ◽  
Peng Hou ◽  
...  
Keyword(s):  
Grain Yield ◽  
Water Use Efficiency ◽  
Leaf Area Index ◽  
Water Use ◽  
Plant Density ◽  
Maize Yield ◽  
Area Index ◽  
Irrigation Level ◽  
Use Efficiency ◽  
The Relationship

Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.

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