A Simple Model of the Relationship Between Plant Density, Plant Biomass, and Time

1983 ◽  
Vol 20 (3) ◽  
pp. 905 ◽  
Author(s):  
R. C. Hardwick ◽  
D. J. Andrews
Keyword(s):  
Simple Model ◽  
Plant Density ◽  
Plant Biomass ◽  
The Relationship

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.

scholarly journals Relationships between resource availability and elevation vary between metrics creating gradients of nutritional complexity

Oecologia ◽  
2021 ◽  
Vol 195 (1) ◽  
pp. 213-223
Author(s):  
Mark A. Lee ◽  
Grace Burger ◽  
Emma R. Green ◽  
Pepijn W. Kooij
Keyword(s):  
Species Richness ◽  
Plant Species ◽  
Resource Availability ◽  
Plant Biomass ◽  
Plant Species Richness ◽  
Mineral Contents ◽  
Nutritive Values ◽  
Animal Community ◽  
Nutritional Chemistry ◽  
The Relationship

AbstractPlant and animal community composition changes at higher elevations on mountains. Plant and animal species richness generally declines with elevation, but the shape of the relationship differs between taxa. There are several proposed mechanisms, including the productivity hypotheses; that declines in available plant biomass confers fewer resources to consumers, thus supporting fewer species. We investigated resource availability as we ascended three aspects of Helvellyn mountain, UK, measuring several plant nutritive metrics, plant species richness and biomass. We observed a linear decline in plant species richness as we ascended the mountain but there was a unimodal relationship between plant biomass and elevation. Generally, the highest biomass values at mid-elevations were associated with the lowest nutritive values, except mineral contents which declined with elevation. Intra-specific and inter-specific increases in nutritive values nearer the top and bottom of the mountain indicated that physiological, phenological and compositional mechanisms may have played a role. The shape of the relationship between resource availability and elevation was different depending on the metric. Many consumers actively select or avoid plants based on their nutritive values and the abundances of consumer taxa vary in their relationships with elevation. Consideration of multiple nutritive metrics and of the nutritional requirements of the consumer may provide a greater understanding of changes to plant and animal communities at higher elevations. We propose a novel hypothesis for explaining elevational diversity gradients, which warrants further study; the ‘nutritional complexity hypothesis’, where consumer species coexist due to greater variation in the nutritional chemistry of plants.

scholarly journals Soil Nutrient and Vegetation Diversity Patterns of Alpine Wetlands on the Qinghai-Tibetan Plateau

2021 ◽  
Vol 13 (11) ◽  
pp. 6221
Author(s):  
Muyuan Ma ◽  
Yaojun Zhu ◽  
Yuanyun Wei ◽  
Nana Zhao
Keyword(s):  
Species Diversity ◽  
Tibetan Plateau ◽  
Soil Properties ◽  
Soil Ph ◽  
Plant Biomass ◽  
Principal Component ◽  
Vegetation Diversity ◽  
Vegetation Biomass ◽  
Relative Contribution ◽  
The Relationship

To predict the consequences of environmental change on the biodiversity of alpine wetlands, it is necessary to understand the relationship between soil properties and vegetation biodiversity. In this study, we investigated spatial patterns of aboveground vegetation biomass, cover, species diversity, and their relationships with soil properties in the alpine wetlands of the Gannan Tibetan Autonomous Prefecture of on the Qinghai-Tibetan Plateau, China. Furthermore, the relative contribution of soil properties to vegetation biomass, cover, and species diversity were compared using principal component analysis and multiple regression analysis. Generally, the relationship between plant biomass, coverage, diversity, and soil nutrients was linear or unimodal. Soil pH, bulk density and organic carbon were also significantly correlated to plant diversity. The soil attributes differed in their relative contribution to changes in plant productivity and diversity. pH had the highest contribution to vegetation biomass and species richness, while total nitrogen was the highest contributor to vegetation cover and nitrogen–phosphorus ratio (N:P) was the highest contributor to diversity. Both vegetation productivity and diversity were closely related to soil properties, and soil pH and the N:P ratio play particularly important roles in wetland vegetation biomass, cover, and diversity.

The Tensile Property of the SPF/Cotton Blended Yarn

2011 ◽  
Vol 321 ◽  
pp. 192-195
Author(s):  
Qing Bin Yang ◽  
Xiao Yang
Keyword(s):  
Experimental Data ◽  
Simple Model ◽  
Tensile Property ◽  
Cotton Fibers ◽  
Blended Yarn ◽  
The Difference ◽  
The Relationship

In order to analysis the relationship between the strength and elongation and the blended ratio of SPF/Cotton blended yarn, the strength and elongation of SPF /cotton blended yarn with different blended ratio were measured and compared with the simple model. The results indicated that For the SPF/cotton blended yarn, the difference between the experimental data and the model value is remarkable because of the high cohesion of the cotton fibers.

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.

scholarly journals Determination of leaf area coefficient in sunflower.

1977 ◽  
Vol 25 (4) ◽  
pp. 238-242
Author(s):  
A.S.R. Pereira
Keyword(s):  
Leaf Area ◽  
Yield Components ◽  
Plant Density ◽  
Photosynthetic Capacity ◽  
Leaf Position ◽  
Area Estimation ◽  
End Use ◽  
The Relationship

For studies on the relationship between photosynthetic capacity and yield components in sunflower a method for estimating leaf area was required. To this end use of the leaf area coefficient (LAC), i.e. the quotient area/(length X max. width), was evaluated. It was found that LAC may be a function of leaf position and plant density, depending on the cv. concerned. For the Russian cv. Armavirec, LAC was independent of leaf position and plant density. For the Rumanian hybrid HS 18, LAC was dependent on leaf position but not plant density. For the French hybrid INRA 4701, LAC depended on both leaf position and plant density, but even in this case, it was concluded that LAC can be a useful aid in leaf area estimation. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals ESTIMATION OF EFFICIENCY OF CONSTRUCTION OF AGRO-PHYTOCENOSES AND FERTILIZER OF THE OIL RADISH ON THE BASIS OF THE MODULAR-VITALITY METHOD

2019 ◽  
pp. 54-78
Author(s):  
Yaroslav Tsytsiura
Keyword(s):  
Plant Density ◽  
Morphological Characters ◽  
Climatic Conditions ◽  
Morphological Integration ◽  
Plant Oil ◽  
Long Term Study ◽  
Relationship Of ◽  
The Relationship ◽  
Fertilizer Rates

The article presents the results of a long-term study of the features of the phytocenology of agrophytocenoses of oil radish using different methods for assessing their condition and studying the tactics of the plant vitality strategy. A comprehensive assessment was made of the effect of changes in row spacing, seeding rates and fertilizer rates on the formation of various plant morphotypes, the variability of morphological characters and the general characteristics of plant viability. Three idiotypes of the plant oil radish were identified in a vertical study of agrophytocenosis, on the basis of which a detailed analysis of the variability of each group and a statistical assessment of the reliability of its existence were carried out. The features of the morphological integration of each tier are analyzed and its impact on the formation of the overall field productivity is evaluated. Based on the modular and vitality grouping, the effectiveness and feasibility of combining various options for plant density and fertilizer in the range of 30-90 kg of active substance per 1 ha were evaluated. Conclusions are drawn about the desired model of agrophytocenosis of oil radish based on the characteristics of its vital tactics and the goals of its growing. Grouping was carried out according to a variety of morphological traits of plants in the population and the possibilities of applying the basic patterns of phytocenology in their application to radish oilseed plants were evaluated. Through the use of regression analysis, the influence of climatic conditions on the formation of various morphological types of plants and the nature of the relationship of plants of oil radish in cenoses of various densities against the background of various fertilizer options has been evaluated. The main promising areas for further research on the peculiarities of creating highly productive and highly adaptable agrophytocenoses of oil radish have been outlined.

THE RELATIONSHIP BETWEEN FINAL YIELD AND PHOTOSYNTHESIS AT FLOWERING IN INDIVIDUAL MAIZE PLANTS

1979 ◽  
Vol 59 (3) ◽  
pp. 585-601 ◽  
Author(s):  
G. O. EDMEADES ◽  
T. B. DAYNARD
Keyword(s):  
Grain Yield ◽  
Shoot Growth ◽  
Plant Density ◽  
Meteorological Data ◽  
Dry Weight ◽  
Plant Variation ◽  
Final Yield ◽  
Black Layer ◽  
Maize Plants ◽  
The Relationship

In an attempt to explain plant-to-plant variation in dry weight of maize (Zea mays L.), a computer program was developed to predict daily assimilation per plant and its distribution throughout the shoot at flowering. Inputs to the model were meteorological data, photosynthetic rate-irradiance curves, measurements of intraplant assimilate distribution at flowering, and the positions of individual leaves of plants grown in the field at three densities (50 000, 100 000 and 150 000 plants/ha). Dry weights were recorded on these same plants following black layer formation. Predicted effects of plant density on shoot growth compared favorably with available data. The correlation coefficient between predicted assimilation 1 day after anthesis and grain yield on the same plants, with treatment effects removed, was 0.67 (N = 360). The coefficient of variation of predicted assimilate flux per plant increased significantly with increasing density, and the fluxes were generally normally distributed. Results supported the concept of a threshold assimilation rate per plant below which grain would not normally form, and this appears to be the cause of the bimodal frequency distribution of grain yield per plant observed at high densities.

scholarly journals The relationship between plant density and survival to water stress in seedlings of a legume tree

2019 ◽  
Vol 33 (3) ◽  
pp. 602-606
Author(s):  
Eliane Akiko Honda ◽  
Natashi Aparecida Lima Pilon ◽  
Giselda Durigan
Keyword(s):  
Water Stress ◽  
Plant Density ◽  
Legume Tree ◽  
The Relationship
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