Comparison of empirical models depicting density of Amaranthus retroflexus L. and relative leaf area as predictors of yield loss in maize (Zea mays L.)

Weed Research ◽  
2006 ◽  
Vol 35 (4) ◽  
pp. 207-214 ◽  
Author(s):  
S. Z̆. KNEZ̆EVIĆ ◽  
S. F. WEISE ◽  
C. J. SWANTON
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Yield Loss ◽  
Zea Mays L ◽  
Amaranthus Retroflexus ◽  
Empirical Models

MEASUREMENT OF EVAPORATION FROM SOIL BENEATH CROP CANOPIES

1983 ◽  
Vol 63 (1) ◽  
pp. 137-141 ◽  
Author(s):  
G. K. WALKER
Keyword(s):  
Zea Mays ◽  
Key Words ◽  
Leaf Area ◽  
Energy Supply ◽  
Zea Mays L ◽  
Growing Season ◽  
Soil Core ◽  
Crop Cover ◽  
Intact Soil Core ◽  
Intact Soil

Evaporation rates beneath maize canopies were measured using an intact soil core technique. Early in the growing season evaporation rates were periodically high (4.0 mm∙day−1) following rain, but declined rapidly. At full crop cover, when energy supply normally limits evaporation, significant differences in evaporation were detected between canopies with leaf area indices of 3.0 and 4.0. Key words: Evaporation measurement, energy supply, Zea mays L., leaf area, soil evaporimeter, lysimeter

Effects of Routine Handling on Maize Growth

1977 ◽  
Vol 4 (6) ◽  
pp. 857 ◽  
Author(s):  
MF Beardsell
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Zea Mays L ◽  
Dry Weight ◽  
Controlled Environment ◽  
Short Term ◽  
Total Leaf Area ◽  
Reduced Height ◽  
Plant Characteristics ◽  
Routine Handling

Maize (Zea mays L. cv. XL45) plants were grown from seed in controlled-environment rooms. Twice-daily weighings of the plants and containers for 7 days reduced height, and removing plants from the rooms for two 20-min periods daily for 7 days gave significant reductions in stem and leaf dry weights and total leaf area. Transpiration rates were not affected by either of these treatments. Short-term removal from the rooms (up to 10 min daily) produced no significant reductions in plant characteristics. Measuring leaf lengths daily for 10 days resulted in significant reductions in stem dry weight and plant height. It is suggested that control plants should always be subjected to the same degree of handling as treated plants.

scholarly journals Effect of reduced herbicide rates on weed control, environmental impact and profitability of corn

2009 ◽  
Vol 89 (5) ◽  
pp. 969-975
Author(s):  
Nader Soltani ◽  
Richard J Vyn ◽  
Laura L Van Eerd ◽  
Christy Shropshire ◽  
Peter H Sikkema
Keyword(s):  
Zea Mays ◽  
Environmental Impact ◽  
Zea Mays L ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Ambrosia Artemisiifolia ◽  
Corn Yield ◽  
Profit Margins ◽  
Profitability Analysis ◽  
Biomass Reduction

A study was conducted over a 3-yr period (2003, 2004, and 2005) to evaluate the effect of reduced herbicide rates - 20, 40, 60, 80, and 100% of the manufacturer’s recommended rate (MRR) - on weed biomass reduction, environmental impact (EI), yield, and profitability of corn (Zea mays L.) in Ontario. The herbicide rate required to provide 95% biomass reduction of velvetleaf (Abutilon theophrasti Medic.), redroot pigweed (Amaranthus retroflexus L.), common ragweed (Ambrosia artemisiifolia L.), common lambsquarters (Chenopodium album L.), and annual grasses was 92, 30, 41, 28, and 83% of the MRR for isoxaflutole plus atrazine, >200, 119, 23, 23, and 117% of the MRR for dimethenamid plus dicamba/atrazine, 141, 72, 46, 45, and >200% of the MRR for glufosinate plus atrazine, and 81, 29, 18, 24, and 88% of the MRR for nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr, respectively. The herbicide rate required to provide 95% of weed-free corn yield was 61, 22, 130, and 11% of the MRR for isoxaflutole plus atrazine, dimethenamid plus dicamba/atrazine, glufosinate plus atrazine, and nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr, respectively. Nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr had the lowest EI. The results of profitability analysis suggested that the MRR rates do not tend to maximize profit margins. In most cases, there were no significant differences in profit margins for treatments with 40, 60, 80, and 100% of the MRR. Key words: Atrazine, dicamba, diflufenzopyr, dimethenamid, glufosinate, nicosulfuron, rimsulfuron, Zea mays L.

RESPOSTAS MORFOAGRONÔMICAS DE MILHO SUBMETIDO A DESFOLHA ARTIFICIAL

2017 ◽  
Vol 16 (3) ◽  
pp. 460
Author(s):  
EMERSON TROGELLO ◽  
LUAN FERREIRA BORGES ◽  
FÁBIO ARAÚJO DE OLIVEIRA ◽  
QUÉZIA SANCHES MUTAGUTI ◽  
INGRID GOMIDES BARROS ◽  
...  
Keyword(s):  
Zea Mays ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Analysis Of Variance ◽  
Zea Mays L ◽  
Grain Weight ◽  
Area Index ◽  
Plant Removal ◽  
And Control ◽  
Different Levels

RESUMO - O objetivo deste estudo foi avaliar as características morfoagronômicas do híbrido simples de milho em função da aplicação de diferentes intensidades de desfolha artificial, realizadas no estádio R1 de desenvolvimento. O experimento foi conduzido na área experimental do Instituto Federal Goiano,em Morrinhos-GO, na safra 2015/2016. Foi aplicado o delineamento de blocos completamente casualizados, com oito tratamentos e quatro repetições, sendo eles: remoção de uma folha acima e uma abaixo da espiga; remoção de duas folhas acima e abaixo da espiga; remoção de três folhas acima e abaixo da espiga; remoção de todas as folhas da planta; remoção de todas as folhas acima da espiga; remoção de todas as folhas abaixo da espiga; remoção da folha da espiga; e testemunha sem desfolha. Os caracteres avaliados foram: estande de plantas, número de plantas acamadas, prolificidade, densidade de colmo, comprimento e diâmetro de espiga, comprimento de grão, massa de mil grãos, massa de grãos espiga-1 e produtividade. Os dados foram submetidos à análise de variância pelo teste F a 5% de probabilidade, observando que todas as variáveis avaliadas foram influenciadas quanto aos efeitos dos tratamentos empregados. O enchimento dos grãos esteve intimamente relacionado à fotossíntese. Sem as folhas, esta fase ficou plenamente comprometida.Palavras-chave: Zea mays, fotoassimilados, translocação, índice de área foliar, rendimento. MORPHOAGRONOMIC CHARACTERISTICS OF MAIZE AS A FUNCTION OF DIFFERENT LEVELS OF ARTIFICIAL DEFOLIATION  ABSTRACT - The objective of this study was to evaluate of morphoagronomic characteristics of simple hybrids of maize, depending on the application of different intensities of artificial defoliation, carried out in R1, when the style-stigma were fertilized. The experiment was conducted in an experimental area of the Instituto Federal Goiano, Campus Morrinhos, State of Goiás, Brazil, during the agricultural year 2015/2016. We applied the design of completely randomized block with eight treatments, in four replications: removal of a leaf above and one below the ear; removal of two leaves above and below the ear; removal of three leaves above and below the ear; removal of all leaves of the plant; removal of all leaves above the ear; removal of all leaves below the ear; removal of the leaf of the ear; and control without defoliation. The traits evaluated were stand of plants, number of plant lodging, prolificacy, density, length and diameter of the cob, length of a grain, weight of a thousand grains, grain mass cob-1 and productivity. The data obtained were subjected to analysis of variance by F test at 5% probability, noting that all variables were influenced as to the effects of the treatments used. The filling of grains is closely related to photosynthesis. Without the leaves, this phase was fully damaged.Keywords: Zea mays L., photoassimilates, translocation, leaf area index, yield.

Phytotoxical effect of Lepidium draba L. extracts on the germination and growth of monocot (Zea mays L.) and dicot (Amaranthus retroflexus L.) seeds

2013 ◽  
Vol 31 (3) ◽  
pp. 247-254 ◽  
Author(s):  
Yusuf Kaya ◽  
Ozkan Aksakal ◽  
Serap Sunar ◽  
Filiz Aygun Erturk ◽  
Sedat Bozari ◽  
...  
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Amaranthus Retroflexus ◽  
Lepidium Draba ◽  
Germination And Growth

scholarly journals Application of the Richards function to the description of leaf area growth in maize (Zea mays L.)

2014 ◽  
Vol 63 (1) ◽  
pp. 5-7 ◽  
Author(s):  
Andrzej Grzegorczyk
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Nonlinear Regression ◽  
Growth Process ◽  
Zea Mays L ◽  
Logistic Function ◽  
Area Growth ◽  
Richards Function ◽  
Constant Coefficients ◽  
Leaf Area Growth

The leaf area growth in maize was approximated basing on the Richards function in the form of: y=A[l+b exp(-kt)]<sup>1/(1-m)</sup> . The constant coefficients of the Richards function were found by means of the Marquardt's method. The initial values of parameters were given basing on results of the preliminary approximation of the growth process by means of logistic function y = A[l+b exp(-kt)]<sup>-1</sup>. The procedure of nonlinear regression was found to be useful (curvilinear determination coefficient R<sup>2</sup> = 0.995). The Richards curve precisely describes the course of changes of the leaf area in maize since sprouting to a tassel flowering phase.

scholarly journals Aplikasi Biochar dan Kompos Terhadap Peningkatan Hasil Tanaman Jagung (Zea Mays L.)

GEMA AGRO ◽  
2018 ◽  
Vol 23 (1) ◽  
pp. 24 ◽  
Author(s):  
Petrus Kaliang Lelu ◽  
Yohanes Parlindungan Situmeang ◽  
Made Suarta
Keyword(s):  
Zea Mays ◽  
Leaf Area ◽  
Harvest Index ◽  
Zea Mays L ◽  
Block Design ◽  
Growth And Yield ◽  
Randomized Block Design ◽  
Compost Treatment

This study aims to determine the effect of biochar dosage and compost fertilizer and its interaction on the growth and yield of corn crops. This experiment used a randomized block design (RBD) with a factorial pattern consisting of 2 factors. The first factor was the dose of biochar (B) consisting of 4 levels, namely: 0 ton ha-1 (B0), 5 ton ha-1 (B1), 10 ton ha-1 (B2), 15 ton ha-1 (B3). The second factor is the dosage of compost fertilizer (K) consisting of 2 levels: 0 ton ha-1 (K0), and 20 ton ha-1 (K1). The results showed that the interaction between the treatment of biochar dose and compost fertilizer had no significant effect on all observed variables. Biochar and compost treatment have significant effect to most observed variables, except on leaf area and harvest index have no significant effect. Treatment of biochar with a dose of 10 ton ha-1 gave the highest dry kiln seedlings weight of 7.83 tons increased by 35.60% compared to the lowest dose without biochar of 5.77 tons. Treatment of compost doses of 20 ton ha-1 gave the highest dry seed oven per hectare weight of 7.42 tons increased by 16.60% when compared with the lowest yield on treatment without compost dose as much as 6.37 tons.

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