Rows Of Lettuce Research Articles

Can Plants Sense Humans? Using Plants as Biosensors to Detect the Presence of Eurythmic Gestures.

This paper describes the preliminary results of measuring the impact of human body movements on plants. The scope of this project is to investigate if a plant perceives human activity in its vicinity. In particular, we analyze the influence of eurythmic gestures of human actors on lettuce and beans. In an eight-week experiment, we exposed rows of lettuce and beans to weekly eurythmic movements (similar to Qi Gong) of a eurythmist, while at the same time measuring changes in voltage between the roots and leaves of lettuce and beans using the plant spikerbox. We compared this experimental group of vegetables to a control group of vegetables whose voltage differential was also measured while not being exposed to eurythmy. We placed a plant spikerbox connected to lettuce or beans in the vegetable plot while the eurythmist was performing their gestures about 2 m away; a second spikerbox was connected to a control plant 20 m away. Using t-tests, we found a clear difference between the experimental and the control group, which was also verified with a machine learning model. In other words, the vegetables showed a noticeably different pattern in electric potentials in response to eurythmic gestures.

Mad at the World: A Life of John Steinbeck

<i>Mad at the World: A Life of John Steinbeck</i>

Your next salad could be grown by a robot

At first glance, the crops don't look any different from other crops blanketing the Salinas Valley, in California, which is often called America's salad bowl. All you see are rows and rows of lettuce, broccoli, and cauliflower stretching to the horizon. But then the big orange robots roll through.

EFFECT OF ROOSTER TREE GREEN MANURE ON CARROT AND LETTUCE INTERCROPPING SYSTEM

ABSTRACT Intercropping is a cropping system that involves cultivating two or more crops in the same area with different cycles and vegetative architectures. One of the ways to increase productivity and efficiency in this cropping system is through green manuring and by properly considering crop combinations, cultivation timing, and planting configuration of the component crops. Thus, the aim of this study was to evaluate the productive performance of carrot and lettuce intercropping systems under different amounts of rooster tree biomass incorporated into the soil and under different spatial arrangements. The study was conducted at the experimental farm Rafael Fernandes, RN, Brazil, in the period from September 2012 to January 2013, in an experimental design of randomized complete blocks in a 4 x 3 factorial scheme, with twelve treatments and 3 replicates. The treatments consisted of the combination of four rooster tree biomass amounts incorporated into the soil (10, 25, 40 and 55 t ha-1 on a dry basis) with three predetermined spatial arrangements between the component crops (2:2, 3:3 and 4:4), which correspond to the rows of carrot alternating with the rows of lettuce. The agronomic performance of the carrot and lettuce intercropping system was optimized in the amount of approximately 46.36 t ha-1 of rooster tree incorporated into the soil. There was no influence of the spatial arrangements on the agronomic efficiency of the carrot and lettuce intercropping. The use of rooster tree as green manure is agronomically viable in intercropped systems of carrot and lettuce.

Effect of population density of lettuce intercropped with rocket on productivity and land-use efficiency.

The objective of this study was to evaluate the influence of the spacing of lettuce rows on the production of a lettuce-rocket intercropping system over two growing seasons (11 August to 25 September 2011 and 12 January to 24 February 2012) in Jaboticabal, São Paulo, Brazil. We evaluated 11 treatments in each season: lettuce-rocket intercrops with five row spacings for the lettuce (0.20, 0.25, 0.30, 0.35 and 0.40 m) and the rocket planted midway between the lettuce rows, sole crops of lettuce at the same five row spacings and a sole crop of rocket. Fresh and dry masses of the lettuce and rocket and number of lettuce leaves per plant were highest with a lettuce row spacing of 0.40 m, but the productivities of the lettuce and rocket were higher with a lettuce row spacing of 0.20 m. The productivities and fresh and dry weights of the lettuce and rocket and the number of lettuce leaves per plant were highest in the sole crops, but the fresh and dry weights of the rocket were higher with intercropping. The land equivalent ratios were >1.0 in both seasons in all intercrops and were highest for the densest crop (1.41). Intercropping was therefore 41% more efficient than sole cropping for the production of lettuce and rocket.

ECONOMIC FEASIBILITY OF LETTUCE INTERCROPPED WITH ROCKET IN FUNCTION OF SPACING AND GROWING SEASON

ABSTRACT Intercropping is a production system that can reduce the production cost and increase the profitability of vegetable producers, since it permits more efficient land and agricultural inputs use. In order to evaluate the effect of lettuce plant density on the economic feasibility of lettuce-rocket intercropping system over two growing seasons (winter and summer), two experiments were conducted in the field at São Paulo State University “Júlio de Mesquita Filho” (UNESP), Jaboticabal, São Paulo, Brazil. The treatments consisted of five lettuce-rocket intercrops with spacing between lettuce rows of: 0.20; 0.25; 0.30; 0.35 and 0.40 m, five sole crop of lettuce in the same spacing between rows adopted in the intercropping system, and a sole cropping of rocket with spacing between rows of 0.20 m. The statistical design adopted was the complete randomized block with four replicates. During winter, higher profitability was achieved with the highest population density. Highest profitability of the crops in both seasons was obtained in summer.

Consórcio de manjericão (Ocimum basilicum L.) e alface sob dois arranjos de plantas

Ocimum basilicum L. (Lamiaceae) é comercialmente utilizada como aromatizante ou condimento preparado com suas folhas verdes e aromáticas, que podem ser usadas frescas ou secas. O objetivo deste trabalho foi avaliar a produção de biomassa de manjericão sob duas ou três fileiras no canteiro, consorciado ou não com alface. O manjericão e a alface foram alocados no campo em experimento conjunto, sendo constituídos cinco tratamentos da seguinte forma: duas fileiras solteiras de manjericão (M2) espaçadas de 0,50 m; três fileiras solteiras de manjericão espaçadas de 0,33 m (M3); quatro fileiras solteiras de alface espaçadas de 0,25 m (A4); duas fileiras solteiras de manjericão consorciadas com quatro fileiras de alface (M2A4) e três fileiras de manjericão consorciada com quatro fileiras de alface (M3A4). O delineamento utilizado foi em blocos casualizados, com oito repetições. As plantas de alface foram colhidas aos 48 dias após o transplantio e as de manjericão, em duas épocas, aos 96 e 113 dias após o transplantio (DAT). O consórcio não influenciou as áreas foliares nem as produções de folhas ou inflorescências do manjericão nem de cabeças comerciais ou não-comerciais da alface. No entanto, quanto ao arranjo de plantas, na segunda época de colheita, as plantas de manjericão cultivadas sob duas fileiras tiveram maior área foliar (2.076,99 cm² planta-1) e maior massa fresca de folhas (5.012,53 kg ha-1). Considerando-se que os valores da Razão de Área Equivalente - RAE na primeira e segunda colheita do manjericão foram maiores que 1,0, conclui-se que o consórcio manjericão com alface é viável. Recomenda-se o arranjo de três fileiras de manjericão alternadas com quatro fileiras de alface, e colheita aos 96 DAT, por ter tido RAE de 2,01.

Crescimento e produção de alface e marcela em cultivo solteiro e consorciado

The aim of this study was to evaluate the yield and the gross income of lettuce and marcela in single-cultivar and intercropping. The experiment was carried with two rows of marcela grown 0.50 m apart, two rows of marcela 0.35 m apart, three rows of lettuce 0.35 m apart, four rows of lettuce 0.25 m apart, two rows of marcela 0.50 m apart alternated with four rows of lettuce, and two rows of marcela 0.35 m apart alternated with three rows of lettuce. A random block design was used with four replications. Different variables of plants were evaluated in each specie. Intercropping was evaluated by land equivalent ratio (LER) and the validation was by gross income determination. The productions of lettuce and marcela did not differ in relation to culture type. The calculated LERs indicated that both intercroppings were effective. However, regarding gross income, it was evidenced that the option of intercropping was economically viable only for the producers of marcela, whereas for the lettuce producers, the single-cultivar presented better performance.

Produção e renda bruta de rabanete e alface em cultivo solteiro e consorciado

The objective of this paper was to verify yield and gross income of lettuce and radish in monocrop and intercrop systems. Crespa Grand Rapids Nacional lettuce and Crimson Vip radish varieties were studied in monocrop system with three and four rows, as well as the R4A3 and R3A4 intercroppings. Radish cultivated under four rows of plants in plot had significant increase of 1.16 t ha-1 of fresh mass in plants with commercial root in relation to those cultivated under three rows. In monocrop system, the highest values (16.36 cm height, 25.04 cm of diameter and 137,780 plants ha-1) were obtained from four rows and with intercrop, the highest values of height (13.84 cm) and diameter (21.86 cm) were obtained from four rows, and the highest number of commercial plants (133,220 plants ha-1) was obtained from three rows. Land Equivalent Ratio (LER) for R4A3 intercropping was 1.69 and for R3A4, it was 2.05. Considering gross income, R3A4 intercropping is recommended because it induced monetary increases of R$ 24,748.00; R$ 1,224.00 and R$ 39,686.00 in relation to R4A3 intercropping and to monocrop system with four rows of lettuce and radish, respectively.

Produtividade biológica em sistemas consorciados de cenoura e alface avaliada através de indicadores agroeconômicos e métodos multicritério

O experimento foi conduzido de maio a setembro de 2002, na UFERSA, Mossoró-RN, para avaliar consórcios de cenoura e alface, através de critérios agronômicos, econômicos (rendimentos financeiros) e de eficiência produtiva (avaliada segundo modelos de Análise de Envoltória de Dados - DEA). Para agregar a informação de todos os critérios e identificar os melhores tratamentos, foram utilizados os métodos multicritério ordinais de Borda, Condorcet e Copeland. O delineamento experimental foi blocos casualizados, em fatorial 3 (cultivo solteiro e consorciado, em faixas, com três fileiras de cenoura e três de alface (3F) e quatro de cenoura e quatro de alface (4F)) x 4 (cultivares de alface americana: Lucy Brown, Tainá, Laurel e Mesa 659), com quatro repetições. Em cada bloco foi plantada a cenoura solteira. Avaliou-se o índice de uso eficiente da terra (UET), o índice de lucratividade (IL) e a eficiência produtiva DEA. Uma análise de variância univariada foi usada para avaliar estes indicadores, no esquema fatorial 2 x 4 + 1 (dois sistemas consorciados em faixas, quatro cultivares de alface e cenoura solteira). Os UETs dos sistemas consorciados foram significativamente superiores ao UET do cultivo solteiro, com a vantagem dos sistemas consorciados variando de 90 (cenoura + cultivar Tainá 4F) a 133% (cenoura + cultivar Mesa 659 4F). Não se observou diferença significativa no índice de lucratividade entre os cultivos solteiro e consorciado. Na eficiência produtiva DEA foi observada interação significativa entre sistemas de cultivo e cultivares de alface. Os métodos multicritério indicaram Cenoura + Mesa 659 (4F), Cenoura + Laurel (3F) e Cenoura + Mesa 659 (3F) como os melhores sistemas de cultivo. A eficiência produtiva DEA e a ordenação dos métodos multicritério foram mais eficientes na discriminação do desempenho dos sistemas de cultivo consorciados que os indicadores agroeconômicos.

Desempenho agroeconômico do bicultivo de alface em sistema solteiro e consorciado com cenoura

Dois experimentos foram implantados de setembro a dezembro/2002, na ESAM (RN), para avaliar o desempenho agroeconômico do bicultivo de dois grupos de alface em sistema solteiro e consorciado com duas cultivares de cenoura em faixas. O delineamento experimental foi de blocos balanceados em grupos, com quatro repetições. Foram avaliadas as cultivares pertencentes aos grupos crespa (Lucy Brown, Tainá, Laurel e Verônica) e lisa (Babá de Verão, Maravilha das Quatro Estações, Elisa e Carolina). No experimento consorciado foi utilizado o esquema de parcelas sub-divididas, onde os tratamentos designados às parcelas foram as cvs. de cenoura Alvorada e Brasília e os designados às sub-parcelas foram as cvs. de alface do grupo crespa e as do grupo lisa. Na alface foi avaliado o rendimento de folhas e na cenoura o rendimento total, comercial e a classe das raízes. Foram usados índices agroeconômicos para medir a eficiência do sistema consorciado: Índice de Uso Eficiente da Terra, Renda Bruta, Renda Líquida, Vantagem Monetária, Vantagem Monetária Corrigida, Taxa de Retorno e Índice de Lucratividade. Não houve interação significativa entre os fatores cvs. de cenoura e cvs. de alface sobre os rendimentos das culturas. As cvs. de cenoura não influenciaram os rendimentos das culturas. As cvs. de alface não afetaram os rendimentos da cenoura. No bicultivo da alface consorciada com cenoura, recomenda-se o emprego das cvs Lucy Brown e Tainá do grupo crespa ou da 'Babá de Verão' e 'Maravilha das Quatro Estações' do grupo lisa no primeiro plantio. No segundo plantio, apenas a cv. do grupo lisa Maravilha das Quatro Estações se sobressaiu das demais no desempenho produtivo em cultivo consorciado.As cultivares de alface do grupo crespa consorciadas com cenoura se sobressaíram daquelas do grupo lisa no desempenho produtivo. Os consórcios cenoura 'Alvorada' x alface 'Lucy Brown'; e cenoura 'Brasília' x alface 'Maravilha das Quatro Estações', tiveram os melhores indicadores agroeconômicos, com índices de uso eficiente da terra de 2,16 e 2,15, taxas de retorno de 2,05 e 2,33, e índices de lucratividade de 53,92% e 59,83%, respectivamente.

Influence of method of phosphorus application on smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) interference in lettuce

Abstract Field trials were conducted to investigate the influence of P application method on the critical period of smooth pigweed and common purslane interference in lettuce. Studies were carried out in low-P histosols, where supplemental P fertilization is needed for lettuce production. Phosphorus was either broadcast or banded 5 cm beneath the lettuce rows at rates of 250 or 125 kg ha−1, respectively. Seedlings of either smooth pigweed or common purslane were transplanted at a density of 16 plants per 5.4 m2 (6-m row by 0.9 m wide). Weed interference duration was achieved by manual removal 2, 4, 6, or 8 wk after lettuce emergence and subsequently keeping the plot weed free until harvest. A weed-free control within each P regimen was also established. Marketable head number, head fresh yield, and head diameter were measured at harvest. Weed-free lettuce fresh yield was 20% higher with banded P than broadcast applications. In the weed–lettuce mixtures, the P regimen by weed removal interaction affected l...

Desempenho agroeconômico do consórcio cenoura x alface lisa em dois sistemas de cultivo em faixa

O desempenho de quatro cultivares de alface lisa, em cultivo solteiro e consorciado com cenoura, em dois sistemas de cultivo em faixas, foi avaliado em experimento, de outubro a dezembro de 2000, na ESAM em Mossoró. O delineamento experimental utilizado foi de blocos casualizados completos em esquema fatorial 3 x 4 + 1, com quatro repetições. Os tratamentos do fatorial resultaram da combinação dos sistemas de cultivos (solteiro, consorciado em faixas com três fileiras de cenoura alternadas com três fileiras de alface e consorciado em faixas com quatro fileiras de cenoura alternadas com quatro fileiras de alface) com quatro cultivares de alface lisa (Babá de Verão, Karla, Verdinha e Elisabeth), mais um tratamento adicional (cenoura 'Brasília' solteira). Avaliou-se para a cultura da alface: altura e diâmetro de plantas, número de folhas por planta, matéria seca da parte aérea e produtividade; para a cultura da cenoura avaliou-se: altura de plantas, matéria fresca da parte aérea, produtividade total, comercial e classificação de raízes. Alguns indicadores agroeconômicos foram usados para medir a eficiência dos sistemas consorciados. Não houve interação significativa entre sistemas de cultivos e cultivares de alface para nenhuma das características avaliadas. Os sistemas de cultivo afetaram todas as características avaliadas tanto na cultura da alface como na da cenoura, e as cultivares de alfaces testadas influenciaram apenas o número de folhas/planta, com a cultivar 'Karla' registrando maior número. A produtividade média da alface nos sistemas consorciados, embora inferior à do sistema solteiro, representou uma fonte adicional de renda. O consórcio cenoura 'Brasília' x alface cv. 'Verdinha' em faixas com quatro fileiras foi o que apresentou maior viabilidade agroeconômica, com índice de uso da terra em torno de 19% e taxa de retorno ao redor de 3,0.

Influence of common lambsquarters ( Chenopodium album) densities and phosphorus fertilization on lettuce

Field trials were conducted in organic soils to determine the effects of different phosphorus fertilization programs and common lambsquarters ( Chenopodium album L.) densities on ‘South Bay’ lettuce ( Lactuca sativa L.) yield loss. Phosphorus was applied either banded (125 kg P/ha) or broadcast (250 kg P/ha) prior to lettuce planting. Common lambsquarters population densities of 0, 2, 4, 8 or 16 plants/6 m row (5.4 m 2) interfered with lettuce for 10 weeks. Two rectangular hyperbola models characterized the relationship between common lambsquarters density and lettuce yield loss. When phosphorus was applied broadcast, predicted lettuce yield losses were 39%, 50%, 59% and 65% for 2, 4, 8 and 16 common lambsquarters plants/6 m row, respectively. However, when the phosphorus rate was reduced by 50% and was applied in bands beneath lettuce rows, these predicted losses were 23%, 30%, 35%, and 38% for the same common lambsquarters densities. Based on the lettuce yield loss models, if a single common lambsquarters plant interferes with lettuce every 6 m row, then predicted lettuce yield losses could be approximately 27% and 16% for broadcast and banded phosphorus applications, respectively.

Relação entre coeficientes de cultura e graus-dia de desenvolvimento da alface

Este estudo foi conduzido na Fazenda Campbell da Universidade do Arizona , no período de junho de 1994 a fevereiro de 1995, com objetivo de determinar a equação do coeficiente de cultura (Kc) como função de graus-dia de desenvolvimento (GDD) usando a série de senos Fourier, para alface (Lactuca sativa, L.), do tipo folhosa. Foram usadas dez parcelas casualizadas, irrigadas de maneira a manter o potencial matricial da água no solo acima ou igual a -20kPa, que constituiram as repetições na determinação dos valores de evapotranspiração máxima da cultura (ETm). Cada parcela foi constituida por seis canteiros de 1,0 m x 7,3 m, com duas linhas de plantas (cultivar Waldmann's Green) em cada, com população, após desbaste, de 48 plantas por canteiro. A época de desbaste ocorreu com GDD de 228ºC e Kc médio de 0,4 e a colheita com GDD igual a 742ºC e Kc médio de 1,2. Os valores de Kc como função de GDD, em diferentes estádios do ciclo da cultura, permitiram gerar uma equação que pode ser inserida em programa de computador para manejo de irrigação, considerando um GDD final (GDD de ajuste) de 900ºC.

Aster Leafhopper and Aster Yellows Control in Carrot, 1984

Abstract Three insecticides were evaluated to determine their effects on the aster leafhopper and its transmission to aster yellows (mycoplasma-like organism) to carrots. The trial was conducted at the University of Minnesota Agricultural Experiment Station, Rosemount, MN. Each plot had eight 20-ft rows (12-inch centers), and treatments were arranged in a randomized complete block with 4 replicates. Both sides of each plot were bordered by 2 rows of lettuce, Lactuca sativa L., ‘Great Lakes’ which remained unsprayed and served as a source of aster leafhopper and aster yellows. Individual plots were separated from others by 10 ft of bare ground on all sides to minimize interplot movement of the aster leafhopper. Treatments were applied using a CO2 powered backpack sprayer at 40 psi (57.5 gal/acre). Application dates were 18, 24, 31 Jul and 16 Aug. Sweep samples were taken with a 15-inch diam sweep net taking 25 sweeps per plot.

Aster Leafhopper and Aster Yellows Control in Carrot, 1983

Abstract Three insecticides were evaluated to determine their effects on the aster leafhopper and its transmission of aster yellows (mycoplasma-like organism) to carrots. The trial was conducted at the Univ. of Minnesota Agric. Exp. Stn., Rosemount, Minn. Each plot had two 20-ft rows (40-in. centers) of ‘Scarlet Nantes’ (aster yellows resistant) and ‘Nantes Coreless’ (aster yellows susceptible) and treatments were arranged in a randomized complete block with four replicates. Both sides of each plot were bordered by two rows of lettuce, Lactuca sativa L., ‘Great Lakes’ which remained unsprayed and served as a source of aster leafhopper and aster yellows. Individual plots were separated from others by 10 ft of bare ground on all sides to minimize interplot movement of ickpack sprayer at 30 lb/in2 (27.0 the aster leafhopper. Treatments were applied using a CO2 powered backpack sprayer at 30 lb/in2 (27.0 gal/acre) except for Sevin XLR which was applied at 15 lb/inz (11.5 gal/acre). Treatments were applied biweekly from 30 June to 4 Aug. and weekly from 4 Aug. through 25 Aug. Fourteen applications in all were made. Sweep samples were taken with a 15-in. diameter sweep net (25 sweeps per plot). Insect counts were taken from all four rows, but not separated with respect to cultivar.

Banding Activated Carbon to Increase Herbicide Selectivity on Lettuce1

Abstract Activated carbon applied in a 5 cm wide band over seeded rows of lettuce (Lactuca sativa L.) protected the lettuce from the injurious effects of several herbicide combinations. Although activated carbon rates greater than 0.38 g/linear m protected lettuce, a marginally tolerant crop, an increase in the rate of the activated carbon also decreased weed control within the treated band. For conditions in two reported Hawaiian locations, an activated carbon rate of 0.38-0.76g/linear m assured protection from herbicide damage with minimal weed growth in the treated band.

THE USE OF ENDRIN AND OTHER INSECTICIDES AGAINST LETTUCE ROOT APHID, PEMPHIGUS BURSARIUS L

Several insecticides have been used as protectants against lettuce root aphid, including, in 1955, lindane, schradan, aldrin and endrin; the last‐named giving the most promising results. With a dressing of an equal weight of 50% endrin dust added to lettuce seed, 86% reduction in aphid numbers was obtained. In 1957, a seed dressing with endrin also gave a good control, which was superior to that obtained with thimet 44D. However, in 1956 and 1958 endrin seed dressing failed to control the aphid. When a seed dressing with endrin was supplemented by an endrin spray applied to the seedlings a consistently good control resulted.A high level of aphid control was obtained in 1958 with two sprays of diazinon applied along the lettuce rows, the first applied after singling and the other at the early rosette stage. Diazinon or endrin, applied to the soil at 4 lb. actual insecticide/acre and rotavated into the top 3 in. before sowing, also gave high levels of control.No recommendations for the use of endrin on lettuce can be made until levels and persistence of residues are known.