An accurate method for predicting spatial variability of maize yield from UAV-based plant height estimation: a tool for monitoring agronomic field experiments

Lodging stress seriously affects the yield, quality, and mechanical harvesting of maize, and is a major natural disaster causing maize yield reduction. The aim of this study was to obtain light detection and ranging (LiDAR) data of lodged maize using an unmanned aerial vehicle (UAV) equipped with a RIEGL VUX-1UAV sensor to analyze changes in the vertical structure of maize plants with different degrees of lodging, and thus to use plant height to quantitatively study maize lodging. Based on the UAV-LiDAR data, the height of the maize canopy was retrieved using a canopy height model to determine the height of the lodged maize canopy at different times. The profiles were analyzed to assess changes in maize plant height with different degrees of lodging. The differences in plant height growth of maize with different degrees of lodging were evaluated to determine the plant height recovery ability of maize with different degrees of lodging. Furthermore, the correlation between plant heights measured on the ground and LiDAR-estimated plant heights was used to verify the accuracy of plant height estimation. The results show that UAV-LiDAR data can be used to achieve maize canopy height estimation, with plant height estimation accuracy parameters of R2 = 0.964, RMSE = 0.127, and nRMSE = 7.449%. Thus, it can reflect changes of plant height of lodging maize and the recovery ability of plant height of different lodging types. Plant height can be used to quantitatively evaluate the lodging degree of maize. Studies have shown that the use of UAV-LiDAR data can effectively estimate plant heights and confirm the feasibility of LiDAR data in crop lodging monitoring.

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Comparative Experimental Effects of Intercropping and Cypermethrin on Insect Pest Infestation and Yield of Maize, Cowpea and Okra in Two Cameroonian Agro-Ecological Zones

AgriEngineering ◽

10.3390/agriengineering3020025 ◽

2021 ◽

Vol 3 (2) ◽

pp. 383-393

Author(s):

Patient Farsia Djidjonri ◽

Nukenine Elias Nchiwan ◽

Hartmut Koehler

Keyword(s):

Field Experiments ◽

Insect Pests ◽

Cropping Systems ◽

Insect Pest ◽

Maize Yield ◽

Ecological Zones ◽

Pest Infestation ◽

Final Yield ◽

Cropping Seasons ◽

Agro Ecological Zones

The present study investigates the effect of intercropping (maize-cowpea, maize-okra, maize-okra-cowpea, okra-cowpea) compared to insecticide application on the level of infestation of insect pests and the final yield of maize, cowpea and okra. Field experiments were conducted during the 2016 and 2017 cropping seasons in the Guinean Savannah (Dang-Ngaoundere) and Sudano Sahelian (Gouna-Garoua) agro-ecological zones in Cameroon. Our experimental design was a split plot arrangement in a randomized complete block with four replications. The main factor was assigned to the use of insecticide (Cypermethrin) and sub plots were devoted for cropping systems. We compared the efficiency of intercropping to that of Cypermethrin application on the Yield of maize, cowpea and okra as influenced by insect pest damages. The comparison of monocropped sprayed by Cypermethrin to unsprayed showed that, in Dang, insect pests reduced maize yield by 37% and 24% in 2016 and 2017, respectively, whereas in Gouna, it was lower than 8% during the both years. Reduction in seed yield by insect pests on cowpea in Dang represented 47% and 50% in 2016 and 2017, respectively, whereas in Gouna, it was 55% and 63% in 2016 and 2017, respectively. For okra, insect pests reduced okra fruit yield by 25% and 44% in Dang and 23% and 28% in Gouna, respectively, in 2016 and 2017. Crop yield was lower in intercropping compared to monoculture due to competition of plants in association on different resources. Considering the total yields obtained from each intercropping, intercropping trials resulted generally in higher yields compared to mono-culture (LER > 1) in both sites and years but the respective yields were quite different. On the basis of the results obtained, we recommend maize-cowpea intercropping as a sustainable solution to reduce the infestation level of their pest insects.

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Effect of Fertilization with Urea and Inhibitors on Growth, Yield and CBD Concentration of Hemp (Cannabis sativa L.)

Sustainability ◽

10.3390/su13042157 ◽

2021 ◽

Vol 13 (4) ◽

pp. 2157

Author(s):

Ioanna Kakabouki ◽

Angeliki Kousta ◽

Antigolena Folina ◽

Stella Karydogianni ◽

Charikleia Zisi ◽

...

Keyword(s):

Plant Height ◽

Field Experiments ◽

Cannabis Sativa ◽

Nitrification Inhibitor ◽

Growth Yield ◽

Urease Inhibitor ◽

Significance Level ◽

Yield And Quality ◽

Positive Effect ◽

Urea Fertilization

Field experiments were conducted during 2019 in two different locations in Greece (Athens and Farsala) to evaluate the effect of urea and urea fertilization with inhibitors on the agronomic yield and quality characteristics of two cannabis varieties (Cannabis sativa L.), “Uso31”and “Fedora 17”. The experimental design was split-plot with four different fertilization treatments—control, Urea (U), urea with Urease Inhibitor (UI), and urea with Nitrification Inhibitor (NI) and urease inhibitor (UI). The significance of differences between treatments was estimated by using Tukey’s test with a significance level of p = 0.05. The plant height was significantly affected by the different fertilizations and different varieties as well as by the two locations. The maximum plant height was 197 cm for “Fedora 17”in Farsala. The seed yield was higher forthe urea with inhibitors treatment in both varieties. The Cannabidiol (CBD) content was significantly affected by the fertilization—it was higher in urea with inhibitors in “Uso31”and “Fedora 17” treatments. The lowest CBD content value was 1.29% (control) and the highest was 1.69% (urea NI + UI). In conclusion, in both varieties, it seems that urea with inhibitors has a positive effect on their growth, as well as on the increase in cannabidiol (CBD) content.

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Genetic variability of rye-xenic-hybrid traits

Acta Societatis Botanicorum Poloniae ◽

10.5586/asbp.1996.050 ◽

2014 ◽

Vol 65 (3-4) ◽

pp. 329-333 ◽

Cited By ~ 1

Author(s):

Lechosław Grochowski ◽

Jan Kaczmarek ◽

Władysław Kadłubiec ◽

Henryk Bujak

Keyword(s):

Genetic Diversity ◽

Genetic Variability ◽

Plant Height ◽

Combining Ability ◽

Field Experiments ◽

Correlation Coefficients ◽

Winter Rye ◽

Arithmetic Means ◽

Coefficients Of Variation ◽

Standard Cultivar

In field experiments performed in two localities (Smolice, Wrocław) 18 xenic hybrids of winter rye, two testers and standard cultivar Dańkowskie Złote, were analysed. The objects of detailed evaluations were 11 traits. For six of them arithmetic means (x), standard deviations (S), coefficients of variation (cv), coefficients of genetic diversity (h<sup>2</sup>), correlation coefficients were calculated. Moreover, analyses of variance were carried out and the effects of general (GCA) and specific (SCA) combining ability were estimated. The existence of quantitative xenia in hybrids was confirmed. It was shown that xenic hybrids, in respect to most of the analysed traits, were insignificantly inferior to the testers and the standard cultivar. However, the decrease of plant height has shown to be significant and a tendency to higher yield was observed.

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Solar Radiation Effects on Dry Matter Accumulations and Transfer in Maize

Frontiers in Plant Science ◽

10.3389/fpls.2021.727134 ◽

2021 ◽

Vol 12 ◽

Author(s):

Yunshan Yang ◽

Xiaoxia Guo ◽

Guangzhou Liu ◽

Wanmao Liu ◽

Jun Xue ◽

...

Keyword(s):

Solar Radiation ◽

Radiation Effects ◽

Dry Matter ◽

Field Experiments ◽

Maize Yield ◽

Planting Density ◽

Stay Green ◽

Vegetative Organs ◽

Maize Hybrids ◽

Weak Light

Solar radiation is the energy source for crop growth, as well as for the processes of accumulation, distribution, and transfer of photosynthetic products that determine maize yield. Therefore, learning the effects of different solar radiation amounts on maize growth is especially important. The present study focused on the quantitative relationships between solar radiation amounts and dry matter accumulations and transfers in maize. Over two continuous years (2017 and 2018) of field experiments, maize hybrids XY335 and ZD958 were grown at densities of 4.5 × 104 (D1), 7.5 × 104 (D2), 9 × 104 (D3), 10.5 × 104 (D4), and 12 × 104 (D5) plants/ha at Qitai Farm (89°34′E, 44°12′N), Xinjiang, China. Shading levels were 15% (S1), 30% (S2), and 50% (S3) of natural light and no shading (CK). The results showed that the yields of the commonly planted cultivars XY335 and ZD958 at S1, S2, and S3 (increasing shade treatments) were 7.3, 21.2, and 57.6% and 11.7, 31.0, and 61.8% lower than the control yields, respectively. Also, vegetative organ dry matter translocation (DMT) and its contribution to grain increased as shading levels increased under different densities. The dry matter assimilation amount after silking (AADMAS) increased as solar radiation and planting density increased. When solar radiation was <580.9 and 663.6 MJ/m2, for XY335 and ZD958, respectively, the increase in the AADMAS was primarily related to solar radiation amounts; and when solar radiation was higher than those amounts for those hybrids, an increase in the AADMAS was primarily related to planting density. Photosynthate accumulation is a key determinant of maize yield, and the contributions of the vegetative organs to the grain did not compensate for the reduced yield caused by insufficient light. Between the two cultivars, XY335 showed a better resistance to weak light than ZD958 did. To help guarantee a high maize yield under weak light conditions, it is imperative to select cultivars that have great stay-green and photosynthetic efficiency characteristics.

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Influence of Wild Blueberry Fruit Yield, Plant Height, and Ground Slope on Picking Performance of a Mechanical Harvester: Basis for Automation

Applied Engineering in Agriculture ◽

10.13031/aea.12187 ◽

2017 ◽

Vol 33 (5) ◽

pp. 655-666

Author(s):

Aitazaz Ahsan Farooque ◽

Qamar Uz Zaman ◽

Travis Esau ◽

Young Ki Chang ◽

Arnold Walter Schumann ◽

...

Keyword(s):

Spatial Variability ◽

Real Time ◽

Plant Height ◽

Fruit Yield ◽

Operating Parameters ◽

Profit Margins ◽

Ground Speed ◽

Ground Slope ◽

Head Height ◽

Wild Blueberry

Abstract. Spatial variability in fruit losses in relation to fruit yield, plant height, and ground slope can help to automate the wild blueberry harvester to improve picking performance. Currently, harvester operators adjust harvester’s head height, ground speed, and revolutions per minute (rpm) manually. This is not only laborious but also stressful for operators, as they encounter spatial variability during harvesting. The goal of this work was to identify the automation potential of the harvester to improve harvestable yield and reduce operator’s stress, keeping in view the spatial variability. Two fields were selected and test plots were constructed to examine the performance of the harvester in five zones of plant height, fruit yield, and ground slope. Fruit yield plant height and ground slope were recorded from each plot manually to examine their impact on total fruit loss. Keywords: Automation, Fruit losses, Spatial variability, Wild blueberry, Zonal analysis.Results confirmed significant variability in fruit yield, plant height, and ground slope. Fruit losses were significantly influenced by the spatial variations. Fruit losses increased with an increase in fruit yield and ground slope during mechanical harvesting. The picking performance of the blueberry harvester was significantly lower in short and very tall plants within selected fields. The dependence of fruit losses on fruit yield, plant height, and ground slope emphasize the need for real-time adjustments in machine operating parameters to improve berry recovery. Based on the results, it is concluded that there is a significant advantage of harvester’s automation to increase profit margins for growers with no additional cost. Keywords: Automation, Fruit losses, Spatial variability, Wild blueberry, Zonal analysis.

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Effect of Bensulfuron-Methyl on Cotton (Gossypium hirsutumL.) Growth and Development

Weed Technology ◽

10.1017/s0890037x00040914 ◽

1996 ◽

Vol 10 (4) ◽

pp. 851-855

Author(s):

C. Dale Monks ◽

Michael G. Patterson ◽

Malcolm Pegues

Keyword(s):

Methyl Ester ◽

Plant Growth ◽

Plant Height ◽

Growth Regulator ◽

Plant Growth Regulator ◽

Growth And Development ◽

Field Experiments ◽

Mepiquat Chloride ◽

Boll Rot ◽

Effect On Yield

Field experiments were conducted in Alabama from 1992 through 1994 to evaluate the potential of the methyl ester of bensulfuron applied at sublethal rates as a plant growth regulator for reducing plant height and boll rot in cotton. Bensulfuron at 0.017 and 0.034 g ai/ha or mepiquat chloride at 10 g ai/ha was applied POST alone at the pinhead square or early-bloom stage of cotton growth or sequentially at 0.017 followed by (fb) 0.017 g/ha, 0.034 fb 0.034 g/ha of bensulfuron and 5 fb 5, 10 fb 10, 10 fb 20, or 20 fb 20 g/ha of mepiquat chloride. Mepiquat chloride had no effect on yield in 1992 and 1994 but decreased yield when applied sequentially in 1993. Bensulfuron was generally detrimental to first position fruit retention, and it delayed maturity. Treatments that reduced plant height did not reduce boll rot. Bensulfuron treatments that reduced plant height also reduced yield; therefore, the potential for its use as a growth regulator in cotton appears limited.

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Using QUEFTS model for estimating nutrient requirements of maize in the Northeast China

Plant Soil and Environment ◽

10.17221/417/2017-pse ◽

2017 ◽

Vol 63 (No. 11) ◽

pp. 498-504 ◽

Cited By ~ 5

Author(s):

Jiang Wenting ◽

Liu Xiaohu ◽

Qi Wen ◽

Xu Xiaonan ◽

Zhu Yucui

Keyword(s):

Northeast China ◽

Field Experiments ◽

Nutrient Use Efficiency ◽

Maize Yield ◽

Yield Potential ◽

Nutrient Requirements ◽

Plant Nitrogen ◽

Nutrient Use ◽

Supply Surplus ◽

Use Efficiency

Accurate estimating of the balanced nutrition for maize is necessary for optimizing fertilizer management to prevent nutrient supply surplus or deficiency. Data from 300 field experiments in the Northeast China conducted between 2006 and 2011 were gathered to study the characteristics of maize yield, and using the QUEFTS model to estimate the balanced nutrition at different yield potential. The average grain yield was 10 427 kg/ha, and average internal efficiencies were 54.3, 251.5 and 78.2 kg grain per kg plant nitrogen (N), phosphorus (P) and potassium (K), respectively. With the harvest index values < 0.40 as outliers were excluded, the model simulated a linear-parabolic-plateau curve for the balanced N, P and K uptake when the initial yield target increased to the yield potential levels of 10 000 to 14 000 kg/ha. When the yield target reached approximately 60–70% of the yield potential, 16.7 kg N, 3.8 kg P, and 11.4 kg K were required to produce 1000 kg grain. The corresponding internal efficiencies were 60.0, 265.7 and 88.0 kg grain per kg plant N, P and K, respectively. These results contributed to improving nutrient use efficiency, and to demonstrate that the QUEFTS model could be a promising approach for estimating the balanced nutrition.

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Leaf Removal Affects Maize Morphology and Grain Yield

Agronomy ◽

10.3390/agronomy10020269 ◽

2020 ◽

Vol 10 (2) ◽

pp. 269 ◽

Cited By ~ 1

Author(s):

Guangzhou Liu ◽

Yunshan Yang ◽

Wanmao Liu ◽

Xiaoxia Guo ◽

Jun Xue ◽

...

Keyword(s):

Grain Yield ◽

Leaf Area ◽

Field Experiments ◽

Photosynthetic Capacity ◽

Maize Yield ◽

Light Distribution ◽

Planting Density ◽

Leaf Removal ◽

Area Index ◽

Source Sink

Increasing planting density is an important practice associated with increases in maize yield, but densely planted maize can suffer from poor light conditions. In our two-year field experiments, two morphologically different cultivars, ZD958 (less compact) and DH618 (more compact), were planted at 120,000 plants ha−1 and 135,000 plants ha−1, respectively. We established different leaf area index (LAI) treatments by removing leaves three days after silking: (1) control, no leaves removed (D0); (2) the two uppermost leaves removed (D1); (3) the four uppermost leaves removed (D2); (4) the leaves below the third leaf below the ear removed (D3); (5) the leaves of D1 and D3 removed (D4); (6) the leaves of D2 and D3 removed (D5). Optimal leaf removal improved light distribution, increased photosynthetic capacity and the post-silking source-sink ratio, and thus the grain yield, with an average LAI of 5.9 (5.6 and 6.2 for ZD958 and DH618, respectively) for the highest yields in each year. Therefore, less-compact cultivars should have smaller or fewer topmost leaves or leaves below the ear that quickly senesce post-silking, so as to decrease leaf area and thus improve light distribution and photosynthetic capacity in the canopy under dense planting conditions. However, for more compact cultivars, leaves below the ear should senesce quickly after silking to reduce leaf respiration and improve the photosynthetic capacity of the remaining top residual leaves. In future maize cultivation, compact cultivars with optimal post-silking LAI should be adopted when planting densely.

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The spatial variability of soil water content in a potato field before and after spray irrigation in arid northwestern China

Water Science & Technology Water Supply ◽

10.2166/ws.2020.006 ◽

2020 ◽

Vol 20 (3) ◽

pp. 860-870 ◽

Cited By ~ 1

Author(s):

Tao Li ◽

Jian-feng Zhang ◽

Si-yuan Xiong ◽

Rui-xi Zhang

Keyword(s):

Spatial Variability ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Precision Agriculture ◽

Field Experiments ◽

Soil Layer ◽

Northwestern China ◽

Potato Field ◽

Arid Northwestern China

Abstract Assessing the spatial variability of soil water content is important for precision agriculture. To measure the spatial variability of the soil water content and to determine the optimal number of sampling sites for predicting the mean soil water content at different stages of the irrigation cycle, field experiments were carried out in a potato field in northwestern China. The soil water content was measured in 2016 and 2017 at depths of 0–20 and 20–40 cm at 116 georeferenced locations. The average coefficient of variation of the soil water content was 20.79% before irrigation and was 16.44% after irrigation at a depth of 0–20 cm. The spatial structure of the soil water content at a depth of 20–40 cm was similar throughout the irrigation cycle, but at a depth of 0–20 cm a relatively greater portion of the variation in the soil water content was spatially structured before irrigation than after irrigation. The autocorrelation of soil water contents was influenced by irrigation only in the surface soil layer. To accurately predict mean soil moisture content, 40 and 20 random sampling sites should be chosen with errors of 5% and 10%, respectively.

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