scholarly journals A response analysis of wheat and barley to nitrogen in Finland

1993 ◽  
Vol 2 (6) ◽  
pp. 465-479
Author(s):  
John Sumelius
Keyword(s):  
Functional Form ◽  
Yield Response ◽  
Response Analysis ◽  
Square Root ◽  
Nitrogen Application ◽  
Producer Price ◽  
Root Functions ◽  
Price Increases ◽  
Profit Maximizing ◽  
Better Than

A nonlinear Mitscherlich function was found to be superior to quadratic and square root functions in estimating yield response to nitrogen based on a Finnish sample of barley. Nonnested hypothesis testing (J-test) indicated the Mitscherlich functional form to fit the data better than the quadratic form based on this sample. In the analysis of the crop response for spring wheat the Mitscherlich functional form could not be proved superior by a J-test. The inferred profit maximizing nitrogen fertilization levels based on the Mitscherlich functional form exceeded the quadratic polynomial forms and were lower than the inferred levels using square root specifications. Implementing 100% nitrogen price increases or 50% producer price reductions lowered the profit maximizing nitrogen application doses by 20-24%, according to the Mitscherlich specification.

scholarly journals Image Retrieval Using the Intensity Variation Descriptor

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Zhao Wei ◽  
Guang-Hai Liu
Keyword(s):  
Image Retrieval ◽  
Information Extraction ◽  
Lateral Inhibition ◽  
Intensity Variation ◽  
Spatial Layout ◽  
Inhibition Mechanism ◽  
Square Root ◽  
Optimal Direction ◽  
Selective Mechanism ◽  
Better Than

Variations between image pixel characteristics contain a wealth of information. Extraction of such cues can be used to describe image content. In this paper, we propose a novel descriptor, called the intensity variation descriptor (IVD), to represent variations in colour, edges, and intensity and apply it to image retrieval. The highlights of the proposed method are as follows. (1) The IVD combines the advantages of the HSV and RGB colour spaces. (2) It can simulate the lateral inhibition mechanism and orientation-selective mechanism to determine an optimal direction and spatial layout. (3) An extended weighted L1 distance metric is proposed to calculate the similarity of images. It does not require complex operations such as square or square root and leads to good performance. Comparative experiments on two Corel datasets containing 15,000 images show that the proposed method performs better than the SoC-GMM, CPV-THF, and STH methods and provides good matching of texture, colour, and shape.

scholarly journals Barley Yield Response to Nitrogen Application under Different Weather Conditions

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ryo Tanaka ◽  
Hiroshi Nakano
Keyword(s):  
Weather Conditions ◽  
Yield Response ◽  
Nitrogen Application

Selecting cotton yield response function to estimate profit-maximizing potassium fertilization rates for cotton production in Tennessee

2017 ◽  
Vol 40 (11) ◽  
pp. 1547-1556
Author(s):  
Xavier Harmon ◽  
Christopher N. Boyer ◽  
C. Owen Gwathmey ◽  
James A. Larson ◽  
Roland K. Roberts
Keyword(s):  
Response Function ◽  
Yield Response ◽  
Cotton Yield ◽  
Cotton Production ◽  
Fertilization Rates ◽  
Potassium Fertilization ◽  
Profit Maximizing

Response of Inga rice to application of nitrogen fertilizer at varying growth stages

1984 ◽  
Vol 24 (125) ◽  
pp. 250 ◽  
Author(s):  
PE Bacon ◽  
DP Heenan
Keyword(s):  
Grain Yield ◽  
Nitrogen Fertilizer ◽  
Vegetative Growth ◽  
Yield Response ◽  
Growth Stages ◽  
Nitrogen Application ◽  
Nitrogen Use

The growth, nitrogen use and yield of rice cv. lnga were examined in three experiments in 1978, 1979 and 1980. In each experiment, one rate of nitrogen was applied at six different times between permanent flood and three weeks after panicle initiation. Application of 50 kg N/ha in 1978 and 70 kg N/ha in 1980 at permanent flood increased yield. A higher rate (100 kg N/ha) at permanent flood in 1979 greatly increased vegetative growth but had little effect on grain yield. The grain yield response to 100 kg N/ha in 1979 significantly increased when application was delayed until panicle initiation. Nitrogen topdressing up to 14 d after panicle initiation resulted in an increased percentage of filled florets per panicle and heavier grains compared with application 14-21 d before panicle initiation. Delaying nitrogen application till 2 1 d after panicle initiation resulted in lower numbers of florets per panicle and consequently reduced yield.

Dry matter yield response of pasture grass to application of Nemafos (thionazin).

1972 ◽  
Vol 20 (2) ◽  
pp. 81-96
Author(s):  
G.C. Ennik
Keyword(s):  
Dry Matter ◽  
Field Trials ◽  
Yield Response ◽  
Favourable Effect ◽  
Direct Stimulation ◽  
Pasture Grass ◽  
Yield Responses ◽  
Better Than ◽  
Main Factor ◽  
Stimulation Of

Results of several field trials on the response of permanent grass swards and of sown swards with and without clover to application of thionazin (as Nemafos) at about 8 ml/m2 before each cut are described. Where N was the main factor limiting growth, plots with Nemafos grew better than the controls because of an increase in available soil N. At high levels of N, growth was improved because of direct stimulation of regrowth after cutting. Nemafos had a favourable effect, which lasted longer with successive cuts, on the development and vigour of tillers. The yield responses were unrelated to control of nematodes. [See also HbA 39, 422]. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Feedforward Neural Network Estimation of a Crop Yield Response Function

1994 ◽  
Vol 26 (1) ◽  
pp. 252-263 ◽  
Author(s):  
Wayne H. Joerding ◽  
Ying Li ◽  
Douglas L. Young
Keyword(s):  
Response Function ◽  
Functional Form ◽  
A Priori ◽  
Feedforward Neural Network ◽  
Yield Response ◽  
Fertilizer Response ◽  
Feedforward Networks ◽  
Reasonable Estimate ◽  
Network Estimation ◽  
Polynomial Expansions

AbstractFeedforward networks have powerful approximation capabilities without the “explosion of parameters” problem faced by Fourier and polynomial expansions. This paper first introduces feedforward networks and describes their approximation capabilities, then we address several practical issues faced by applications of feedforward networks. First, we demonstrate networks can provide a reasonable estimate of a Bermudagrass hay fertilizer response function with the relatively sparse data often available from experiments. Second, we demonstrate that the estimated network with a practical number of hidden units provides reasonable flexibility. Third, we show how one can constrain feedforward networks to satisfy a priori information without losing their flexible functional form characteristic.

The effects of frequency of defoliation on the yield response of a perennial ryegrass sward to a wide range of nitrogen application rates

1978 ◽  
Vol 90 (3) ◽  
pp. 447-457 ◽  
Author(s):  
D. Reid
Keyword(s):  
Perennial Ryegrass ◽  
Dry Matter ◽  
Total Yield ◽  
Response Surfaces ◽  
Yield Response ◽  
Dry Matter Yield ◽  
Nitrogen Application ◽  
Nitrogen Rate ◽  
Wide Range ◽  
Cutting Frequency

SummaryIn a 3-year experiment on a sward of S. 23 perennial ryegrass 21 rates of nitrogen fertilizer ranging from 0 to 897 kg/ha were applied annually on plots cut three, five or ten times per year. The cutting dates within each frequency were decided on the basis of herbage growth stage. Four-parameter exponential curves fitted to the herbage yield data show that the pattern of response to nitrogen application in the five cuts per year treatment was markedly similar to that reported for a previous experiment (Reid, 1970). Alterations in the cutting frequency affected the pattern of dry-matter yield response to nitrogen, but not that of crude-protein yield response. The combined effects of cutting frequency and nitrogen rate are illustrated by response surfaces fitted to the dry-matter yield results using an extension of the equation for the curves fitted to the individual frequency results. These surfaces show that as the number of cuts per year was increased the total yield and the response to nitrogen decreased, but the response was maintained to an increasingly high nitrogen rate. The practical implications of the results are discussed in relation to intensive grazing managements for dairy cows.

scholarly journals Effect of cinmethylin against Alopecurus myosuroides Huds. in winter cereals

2021 ◽  
Vol 67 (No. 1) ◽  
pp. 46-54
Author(s):  
Miriam Messelhäuser ◽  
Marcus Saile ◽  
Bernd Sievernich ◽  
Roland Gerhards
Keyword(s):  
Field Experiments ◽  
The Other ◽  
Yield Response ◽  
Control Efficacy ◽  
Winter Triticale ◽  
Alopecurus Myosuroides ◽  
Winter Cereals ◽  
Herbicide Treatments ◽  
Better Than ◽  
Late Sowing

Cinmethylin is a potential new pre-emergence herbicide in Europe inhibiting the fatty acid thioesterases in the plastid against Alopecurus myosuroides and other grass-weeds in winter cereals and oil-seed rape. Five field experiments were conducted in Southwestern Germany from 2018 until 2020 to assess the control efficacy of cinmethylin and other common pre-emergence herbicides alone and combined with post-emergence herbicides against A. myosuroides and yield response of winter wheat and winter triticale. In four experiments, the effect of early and late sowing of winter cereals was included as the second factor in the experiment to investigate if late sowing can reduce A. myosuroides density weed control efficacy. All fields were heavily infested with A. myosuroides with average<br /> densities of 110–730 plants/m<sup>2</sup>. Late sowing reduced densities in three out of four experiments. Herbicides controlled 42–100% of the A. myosuroides plants. However, none of the treatments was consistently better than the other treatments over all experiments. In three out of 5 experiments, grain yields were significantly increased by the herbicide treatments. The results demonstrate that cinmethylin increases the options for controlling A. myosuroides in winter cereals. However, it needs to be combined with other control tactics.  

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