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

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.

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.

scholarly journals Water stress coefficient determined by orbital remote sensing techniques

2020 ◽  
Vol 24 (12) ◽  
pp. 847-853
Author(s):  
Élvis da S. Alves ◽  
Roberto Filgueiras ◽  
Lineu N. Rodrigues ◽  
Fernando F. da Cunha ◽  
Catariny C. Aleman
Keyword(s):  
Remote Sensing ◽  
Water Stress ◽  
Irrigation Management ◽  
Simple Algorithm ◽  
Landsat 8 ◽  
Stress Coefficient ◽  
Use Efficiency ◽  
Remote Sensing Techniques ◽  
Water Stress Coefficient ◽  
The Relationship

ABSTRACT In regions where the irrigated area is increasing and water availability is reduced, such as the West of the Bahia state, Brazil, the use of techniques that contribute to improving water use efficiency is paramount. One of the ways to improve irrigation is by improving the calculation of actual evapotranspiration (ETa), which among other factors is influenced by soil drying, so it is important to understand this relationship, which is usually accounted for in irrigation management models through the water stress coefficient (Ks). This study aimed to estimate the water stress coefficient (Ks) through information obtained via remote sensing, combined with field data. For this, a study was carried out in the municipality of São Desidério, an area located in western Bahia, using images of the Landsat-8 satellite. Ks was calculated by the relationship between crop evapotranspiration and ETa, calculated by the Simple Algorithm for Evapotranspiration Retrieving (SAFER). The Ks estimated by remote sensing showed, for the development and medium stages, average errors on the order of 5.50%. In the final stage of maize development, the errors obtained were of 23.2%.

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.

Stress protein content of mature Brassica seeds and their germination performance

1998 ◽  
Vol 8 (3) ◽  
pp. 347-355 ◽  
Author(s):  
Mary Bettey ◽  
W. E. Finch-Savage
Keyword(s):  
Molecular Weight ◽  
Water Stress ◽  
Seed Development ◽  
Positive Relationship ◽  
Stress Proteins ◽  
Stress Protein ◽  
Low Molecular Weight ◽  
Optimal Conditions ◽  
Seed Vigour ◽  
The Relationship

AbstractPlants respond to sub-optimal conditions by the synthesis of specific ‘stress’ proteins, and these are thought to play a role in stress tolerance. Some of these proteins accumulate during late seed development, arguably to protect against damage during post-maturation drying and subsequent imbibition, prior to germination. Seed vigour is also determined during this late stage of seed development. High vigour seeds are those that can withstand the desiccation required for storage and successfully germinate under sub-optimal conditions to establish healthy seedlings. If stress proteins are involved in tolerating stress conditions, then they are likely to be important determinants of seed vigour. In this work the relationship between seed vigour (measured by seed germination performance following rapid aging, or under water stress) in Brassica oleracea var. capitata and the content of two classes of stress protein (dehydrins and a low molecular weight heat shock protein HSP17.6) at maturity was examined. Dehydrins did not show a positive relationship with seed performance. However, the protein HSP17.6 showed a positive correlation with seed performance, and a treatment that reduced the amount of this protein in the seed also caused a reduction in subsequent seed performance.

Fuel characteristics and fire behaviour in mature Mediterranean gorse shrublands

2004 ◽  
Vol 13 (1) ◽  
pp. 79 ◽  
Author(s):  
Martín De Luis ◽  
Manuel J. Baeza ◽  
José Raventós ◽  
José C. González-Hidalgo
Keyword(s):  
Forest Fires ◽  
Plant Density ◽  
Structural Characteristics ◽  
Fire Severity ◽  
Fire Behaviour ◽  
Fuel Distribution ◽  
Degree Of Dominance ◽  
Mediterranean Regions ◽  
The Relationship

Since the early 1990s, Mediterranean gorse shrublands have expanded significantly in the Mediterranean regions of Spain mainly as a result of the increase in the frequency and extension of forest fires. Mediterranean gorse (Ulex parviflorus), which has been described as a degradation stage of forest communities after fire, has also been described as a fire-prone community. Thus, its presence increases the risk that new fires might occur. In spite of this evidence, there is little information on both the composition and structural characteristics of these communities or the relationship that might exist between these vegetation characteristics and fire behaviour. In this paper we present the results of a characterization of the vegetative structure (plant density, specific composition, biomass fractions, and horizontal and vertical fuel distribution) in Mediterranean gorse. We also analyse fire behaviour using indicators obtained at different scales. Our results show mature Mediterranean gorse shrublands to be communities with high biomass values (3000–4000 g m−2) and high horizontal and vertical vegetation continuity, in which the proportion of fine dead fuel fractions with low moisture content is around 50% of the total phytomass present. Ulex parviflorus is the dominant species and its degree of dominance is a key element in the behaviour of fire. Both the fire-line intensity values and the fire severity values observed can be considered high with respect to those observed in other Mediterranean communities, thus confirming Mediterranean gorse as a high-risk community.

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.

Estimating the economic optimal target density of hybrid canola based on data from a western Canadian meta-analysis

2020 ◽  
Author(s):  
Murray D. Hartman ◽  
Scott R. Jeffrey
Keyword(s):  
Plant Density ◽  
Meta Analysis ◽  
Yield Response ◽  
Western Canada ◽  
Seeding Rate ◽  
Optimal Density ◽  
Herbicide Resistant ◽  
Plant Densities ◽  
Optimal Target ◽  
The Relationship

Canola production in western Canada has expanded such that in many regions canola area rivals the area seeded to wheat. This change can be mainly attributed to adoption of herbicide resistant hybrid varieties, and resulting higher relative profitability. Producers responded to higher seed prices by reducing seeding rates, leading to plant densities that were often lower than industry recommendations. The study objectives were to examine canola yield response to plant density and assess economically optimal density levels relative to industry recommendations and grower practices. A meta-analysis approach was applied to yield response and plant density data with herbicide resistant hybrid canola from multiple studies. Three alternative marginal yield-density functions were estimated and used to calculate economically optimal plant density. Sensitivity of results to key parameters was assessed. Resulting optimal density levels under recent average prices, seed size and emergence were 62-73 plants m-2, consistent with industry recommendations for western Canada. Recent field surveys report lower densities than this range, suggesting that producers are seeding at less than optimal rates. However, there is significant uncertainty associated with canola production, and interaction of seeding rate with other factors. These would impact on optimal plant density, although much of the uncertainty remains until well after seeding. The empirical results represent a foundation for development of more detailed models, highlight the significance of the relationship between plant density and economically optimal yield, and suggest the need to develop decision making tools to support producers in making canola planting decisions.

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