scholarly journals Collard—Cowpea Intercrop Response to Nitrogen Fertilization, Redroot Pigweed Density, and Collard Harvest Frequency

HortScience ◽  
1997 ◽  
Vol 32 (5) ◽  
pp. 850-853 ◽  
Author(s):  
Francis M. Itulya ◽  
Vasey N. Mwaja ◽  
John B. Masiunas
Keyword(s):  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Cropping System ◽  
Dry Mass ◽  
N Fertilization ◽  
Amaranthus Retroflexus ◽  
Redroot Pigweed ◽  
Harvest Frequency ◽  
N Fertility ◽  
Crop Planting

Field experiments were conducted in 1992 and 1993 to determine the effect of N fertility, cropping system, redroot pigweed (Amaranthus retroflexus L.) density, and harvesting frequency on collard (Brassica oleracea var. acephala D.C) and cowpea [Vigna unguiculata (L.) Walp.] growth. The N fertilization regimes were 0, 80, 160, and 240 kg·ha-1, applied as urea in a split application. Four weeks after crop planting, redroot pigweed was seeded at 0, 300, and 1200 seeds/m2. Between weeks 6 and 12, collard leaves were harvested at 1- to 3-week intervals. Year, N fertility, and cropping system interacted to determine collard leaf number and mass. For example, in 1992, with N at 160 kg·ha-1, collards intercropped had more total leaf mass than those monocropped. Pigweed density had no effect on collard yields, which were greatest from the 3-week harvest frequency. Cropping system and pigweed density interacted to determine cowpea vine length, shoot dry mass, and branching. The high density of pigweed caused a 56% reduction of cowpea dry mass in 1992.

Effect of Corn-Induced Shading and Temperature on Rate of Leaf Appearance in Redroot Pigweed (Amaranthus retroflexus L.)

Weed Science ◽  
1993 ◽  
Vol 41 (4) ◽  
pp. 590-593 ◽  
Author(s):  
Stephane M. Mclachlan ◽  
Clarence J. Swanton ◽  
Stephan F. Weise ◽  
Matthijs Tollenaar
Keyword(s):  
Field Experiments ◽  
Linear Increase ◽  
Amaranthus Retroflexus ◽  
Planting Date ◽  
Weed Interference ◽  
Redroot Pigweed ◽  
Field Temperature ◽  
Effects Of Temperature ◽  
Leaf Appearance ◽  
Rate Of Leaf Appearance

Leaf development and expansion are important factors in determining the outcome of crop-weed interference. The comparative effects of temperature and corn canopy-induced shading on the rate of leaf appearance (RLA) of redroot pigweed were quantified in this study. Growth cabinet results indicated a linear increase in RLA with increased temperature. Weed RLA was predicted utilizing both this function and field temperature data. The ratio of observed to predicted RLA of redroot pigweed grown in field experiments decreased in 1990 and 1991 as shading increased with increased corn density and delayed weed planting date. Results indicated that RLA is substantially affected by canopy-induced shading in addition to temperature.

Interference of Redroot Pigweed (Amaranthus retroflexus) in Corn (Zea mays)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Stephan F. Weise ◽  
Clarence J. Swanton
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Seed Production ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Corn Yield ◽  
Leaf Stage ◽  
Redroot Pigweed ◽  
Emergence Date

Redroot pigweed is a major weed in corn throughout Ontario. Field experiments were conducted at two locations in 1991 and 1992 to determine the influence of selected densities and emergence times of redroot pigweed on corn growth and grain yield. Redroot pigweed densities of 0.5, 1, 2, 4 and 8 plants per m of row were established within 12.5 cm on either side of the corn row. In both years, redroot pigweed seeds were planted concurrently and with corn at the 3- to 5-leaf stage of corn growth. A density of 0.5 redroot pigweed per m of row from the first (earlier) emergence date of pigweed (in most cases, up to the 4-leaf stage of corn) or four redroot pigweed per m of row from the second (later) emergence date of pigweed (in most cases, between the 4- and 7-leaf stage of corn) reduced corn yield by 5%. Redroot pigweed emerging after the 7-leaf stage of corn growth did not reduce yield. Redroot pigweed seed production was dependent upon its density and time of emergence. The time of redroot pigweed emergence, relative to corn, may be more important than its density in assessing the need for postemergence control.

Fertilization effects on the fungal biomass in grasslands

2020 ◽  
Author(s):  
Ana Barreiro ◽  
Aaron Fox ◽  
Andreas Lüscher ◽  
Franco Widmer ◽  
Linda-Maria Dimitrova Mårtersson
Keyword(s):  
Nitrogen Fertilization ◽  
Mycorrhizal Fungi ◽  
Fungal Biomass ◽  
Field Experiments ◽  
Production Systems ◽  
Arbuscular Mycorrhizal ◽  
Fatty Acid Analysis ◽  
N Fertilization ◽  
Lipid Fatty Acid ◽  
Neutral Lipid Fatty Acid

<p>Fertilisation is a common practise in grass production systems performed to increase primary production, a supporting ecosystem service essential for other services. However, different fungal groups, like saprothropic fungi (SF) and the obligate symbionts arbuscular mycorrhizal fungi (AMF), have potential differential response to the fertilizer concentration and composition. Three controlled field experiments were utilised in our study, two medium-term (6 years) in the south of Sweden (SE) and one long-term experiment (46 year) in Switzerland (CH), all sampled in 2018. The Swedish sites included the same two factor treatment, i.e. four different plant mixtures and two (SE-Lanna) or three (SE-Alnarp) nitrogen fertilization levels (0, 60, 120 kg ha<sup>-1</sup> yr<sup>-1</sup>); while the Swiss experiment  included different proportions of N, P and K fertilization under different cutting regimes (CH-Bremgarten). The PLFA and NLFA (phospholipid- and neutral lipid fatty acid) analysis was used to estimate the fungal biomass (SF+AMF). The application of N was associated with a decrease in the AMF biomass, with significant effects with the application of 60 and 120 kg N ha<sup>-1</sup> in SE-Alnarp, and 75 and 150 kg N ha<sup>-1</sup> in CH-Bremgarten. On the other hand, the SF biomass was only negatively affected by the N fertilization in SE-Lanna (60 kg N ha<sup>-1</sup>) under the plant mixture that showed the biggest SF biomass in the unfertilized plot; and by the highest application of N in CH-Bremgarten. Our findings indicate that nitrogen fertilization influences microbial community structure and reduces the abundance of AMF, with these being more sensitive than SF to fertilizer application.</p>

INFLUENCE OF NITROGEN FERTILIZATION AND MECHANICAL STUBBLE REMOVAL ON SEED PRODUCTION OF KENTUCKY BLUEGRASS IN MANITOBA

1989 ◽  
Vol 69 (3) ◽  
pp. 939-943 ◽  
Author(s):  
D. J. THOMPSON ◽  
K. W. CLARK
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
N Fertilization ◽  
Shoot Height ◽  
Straw Yield ◽  
Panicle Weight

Three field experiments were performed to determine the effects of fall nitrogen fertilization and post-harvest mechanical stubble removal (to 2.5 cm) on seed yield in Kentucky bluegrass (Poa pratensis L. ’Nugget’). In all experiments, N fertilization and stubble removal increased seed yield. Increases were greater in a 3-yr-old than in a 5-yr-old stand. Nitrogen fertilization increased panicle density, panicle weight, shoot height and straw yield. Stubble removal increased panicle density, reduced panicle weight, shoot height, and straw yield and increased harvest index.Key words: Nitrogen, stubble removal, seed, Kentucky bluegrass

Investigations on Nigerian root and tuber crops. Influence of nitrogen fertilization on the yield and chemical composition of two cassava cultivars (Manihot esculenta)

1976 ◽  
Vol 86 (2) ◽  
pp. 401-406 ◽  
Author(s):  
G. O. Obigbesan ◽  
A. A. A. Fayemi
Keyword(s):  
Nitrogen Fertilization ◽  
Manihot Esculenta ◽  
Yield Components ◽  
Field Experiments ◽  
N Fertilization ◽  
Yield Performance ◽  
Local Cultivar ◽  
Improved Cultivars ◽  
Starch Yield ◽  
Tuber Crops

SummaryThe results of field experiments on the influence of nitrogen fertilization on the yield components, starch and prussic acid content of two of the cassava cultivars recommended for cultivation in Nigeria are presented. The two cultivars 53101 (local) and 60506 (improved) were harvested at 9, 12 and 15 months. In general, the improved cultivars appeared to respond better to N fertilization, but high rates of N (150 kg N/ha) tended to reduce the yield performance of the two cultivars. The local cultivar produced maximum yields of 31·5, 37·5 and 55·7 fresh tuber t/ha with 60 kg N/ha at 9, 12 and 15 months, respectively, while the improved cultivar gave maximum yields of 31·5 and 48·4 t/ha with 120 kg N/ha at 9 and 12 months, respectively, and 64·1 t/ha with 90 kg N/ha at 15 months. By allowing the crop to grow up to 15 months, the starch yield was more than doubled and about three times the yield obtained at 9 months. The 53101 strain seemed to produce maximum starch yields with 60 kg N/ha while the 60506 type tended to give maximum starch yields with 90 kg N/ha. Influence of N treatments was significant up to 12 months of age but not at 15 months.The HCN content of both cultivars diminished considerably with the age of the plant, dropping at 15 months to about half the level at 9 months. While the HCN concentration of the local cultivar tended to increase with higher N-fertilization, that of the improved cultivar diminished, particularly at 12 months after planting. At 15 months however, the HCN content of both cultivars rose with increasing N. fertilization.

scholarly journals ACÚMULO DE FITOMASSA DO MILHO APÓS O ESPIGAMENTO EM FUNÇÃO DO PARCELAMENTO DA COBERTURA NITROGENADA

2019 ◽  
Vol 18 (1) ◽  
pp. 61-73
Author(s):  
LUIS SANGOI ◽  
FERNANDO PANISON ◽  
MURILO MIGUEL DURLI ◽  
LUCIELI SANTINI LEOLATO ◽  
ANTONIO EDUARDO COELHO ◽  
...  
Keyword(s):  
Zea Mays ◽  
Nitrogen Fertilization ◽  
Grain Filling ◽  
Dry Mass ◽  
N Fertilization ◽  
Growth Stages ◽  
Nitrogen Rate ◽  
South Of Brazil ◽  
Mass Accumulation

RESUMO – O fracionamento da adubação nitrogenada é uma estratégia que pode aumentar o acúmulo de massa nosgrãos do milho. Este trabalho objetivou avaliar os efeitos do parcelamento da cobertura nitrogenada sobre o acúmulode fitomassa nas folhas, colmos e grãos após o espigamento do milho. O experimento foi implantado em Lages-SC.Foram testados dois híbridos (P30F53YH e P1680YH) e seis sistemas de aplicação do nitrogênio: testemunha semN, todo N aplicado em V5, V10 ou VT (pendoamento), ½ N em V5 + ½ N em V10, 1/3 N em V5 + 1/3 N em V10 +1/3 N em VT. A dose de N foi de 300 kg ha-1. Avaliou-se o acúmulo de fitomassa aos 0, 14, 28, 42, 56 e 70 dias apóso espigamento. A massa seca dos grãos dos dois híbridos aumentou linearmente em todos os sistemas testados. Asmaiores taxas de incremento (2,4 a 2,7 g dia-1) foram obtidas com a aplicação integral de N em V5 e as menores (1,5a 1,6 g dia-1) na testemunha. O fracionamento da adubação nitrogenada de cobertura em três estádios fenológicos nãoaumentou a massa dos grãos, em relação à fertilização feita integralmente em V5 ou V10.Palavras-chave: Zea mays, enchimento de grãos, cultivares, fenologia, nitrogênio. MAIZE DRY MASS ACCUMULATION AFTER SILKING AS AFFECTEDBY THE SPLITTING OF NITROGEN SIDE-DRESS FERTILIZATIONABSTRAT- The splitting of nitrogen fertilization is a strategy that can increase kernel dry mass accumulation of maize.This work was carried out aiming to evaluate the effects of splitting nitrogen side-dress fertilization on leaf, stem andgrain dry mass accumulation after maize silking. The experiment was set in Lages, SC, South of Brazil. Two hybrids(P30F53YH and P1680YH) and six nitrogen fertilization systems were tested: control without N, all N side-dressed atV5, V10 or VT (tasseling), ½ N at V5 + ½ N at V10, 1/3 N at V5 + 1/3 N at V10 + 1/3 N at VT. Nitrogen rate was 300kg ha-1. Dry mass accumulation was determined at 0, 14, 28, 42, 56 and 70 days after silking. The kernel dry mass ofboth hybrids increased linearly at all six N fertilization systems. The highest increment rates (2.4 to 2.7 g day-1) wereachieved when all N was side-dressed at V5. The lowest rates (1.5 to 1.6 g day-1) were registered in the control. Thesplitting of nitrogen side-dress fertilization in three growth stages did not increase kernel dry mass, when compared tothe fertilization carried out entirely at V5 or V10.Keywords: Zea mays, grain filling, hybrids, phenology, nitrogen.

scholarly journals Influence of Adjuvants on Efficacy of Imazapic and 2,4-DB

1999 ◽  
Vol 26 (1) ◽  
pp. 1-4 ◽  
Author(s):  
D. L. Jordan
Keyword(s):  
Weed Management ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Major Influence ◽  
Xanthium Strumarium ◽  
Redroot Pigweed ◽  
Eclipta Prostrata ◽  
Pitted Morningglory ◽  
Postemergence Herbicides ◽  
Organosilicone Surfactant

Abstract Adjuvants can have a major influence on efficacy of postemergence herbicides. Imazapic and 2,4-DB are applied postemergence in peanut (Arachis hypogaea L.) to control a variety of weeds. Determining how adjuvants influence efficacy of these herbicides could lead to more efficient weed management. Field experiments were conducted during 1997 and 1998 to determine the influence of nonionic surfactant, crop oil concentrate, organosilicone surfactant, and a blend of organosilicone surfactant and methylated seed oil on efficacy of imazapic and 2,4-DB. No-adjuvant and nontreated controls were also included. Adjuvants did not increase redroot pigweed (Amaranthus retroflexus L.) or common cocklebur (Xanthium strumarium L.) control by imazapic. Only minor differences in control of eclipta (Eclipta prostrata L.), entireleaf morningglory (Ipomoea hederacea var. integriuscula Gray), and pitted morningglory (Ipomoea lacunosa L.) by imazapic were noted among adjuvants. Sicklepod [Senna obtusifolia (L.) Erwin and Barneby] and pitted morningglory control increased when 2,4-DB was applied with adjuvants. Common cocklebur control was improved in one of three experiments when adjuvants were applied with 2,4-DB. Redroot pigweed and entireleaf morningglory control by 2,4-DB was not affected by adjuvants.

Weed Control in Soybeans by Glyphosate Applied in the Recirculating Sprayer

Weed Science ◽  
1977 ◽  
Vol 25 (2) ◽  
pp. 135-141 ◽  
Author(s):  
C.G. McWhorter
Keyword(s):  
Adverse Effect ◽  
Glycine Max ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Sorghum Halepense ◽  
Redroot Pigweed ◽  
Sesbania Exaltata ◽  
Hemp Sesbania ◽  
June July ◽  
Over The Top

Field experiments were conducted to study the feasibility of applying glyphosate [N-(phosphonomethyl)glycine] postemergence for the control of johnsongrass [Sorghum halepense(L.) Pers.], redroot pigweed (Amaranthus retroflexusL.), and hemp sesbania [Sesbania exaltata(Raf.) Cory] in soybeans [Glycine max(L.) Merr.]. Herbicide sprays were directed across the row to weeds growing taller than soybeans in June, July, and August. Herbicide not sprayed on weeds was trapped and reused. Glyphosate at 1.12 and 1.68 kg/ha effectively controlled johnsongrass with little soybean injury and with greatly increased soybean yields. The use of 0.1% surfactant frequently increased the toxicity of glyphosate at 1.12 and 1.68 kg/ha to soybeans, but this adverse effect was overcome by the use of 0.1% anti-drift polymer in sprays. Control of redroot pigweed with glyphosate at 1.12 kg/ha was improved by the use of 0.1% surfactant, but surfactant did not increase control with glyphosate at 1.68 kg/ha. Glyphosate at 1.68 kg/ha, with 0.1% surfactant, was required to provide more than 80% control of hemp sesbania. Glyphosate applied at 1.12 kg/ha in the recirculating sprayer provided equal johnsongrass control, increased soybean yields and caused less soybean injury than when glyphosate at 0.56 kg/ha was applied over-the-top in water or in foam.

scholarly journals Effects of tillage practices and rate of nitrogen fertilization on crop yield and soil carbon and nitrogen

2014 ◽  
Vol 60 (No. 3) ◽  
pp. 100-104 ◽  
Author(s):  
Y. Feng ◽  
T. Ning ◽  
Z. Li ◽  
B. Han ◽  
H. Han ◽  
...  
Keyword(s):  
Soil Carbon ◽  
Crop Yield ◽  
Nitrogen Fertilization ◽  
Field Experiments ◽  
Total Yield ◽  
Cropping System ◽  
Conventional Tillage ◽  
Carbon And Nitrogen ◽  
Tillage Practices ◽  
Soil Carbon And Nitrogen

We conducted field experiments since 2006 to determine the effect of tillage practices and rate of nitrogen fertilization on soil properties and crop yield. Four tillage practices and five N rates were used. The results showed that the year-round total yield of wheat and maize under harrow tillage (HT) and rotary tillage (RT) was not significantly different from that of conventional tillage (CT, moldboard tillage) but was higher than that of no-tillage (NT). Reduced tillage (HT and RT) with straw returned and rate of nitrogen (157.5 kg/ha for wheat and 202.5 kg/ha N for maize) were suitable to increase the yield and adjust the soil carbon and nitrogen situation for the winter wheat-summer maize cropping system.

Control of Five Broadleaf Weeds in Sugarbeets (Beta vulgaris) with Glyphosate

Weed Science ◽  
1982 ◽  
Vol 30 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Edward E. Schweizer ◽  
Larry D. Bridge
Keyword(s):  
Beta Vulgaris ◽  
Field Experiments ◽  
Total Population ◽  
Chenopodium Album ◽  
Amaranthus Retroflexus ◽  
Kochia Scoparia ◽  
Common Lambsquarters ◽  
Redroot Pigweed ◽  
The Common ◽  
Vertical Roller

Field experiments were conducted to study the feasibility of applying glyphosate [N-(phosphonomethyl) glycine] postemergence with a recirculating sprayer and a vertical roller for the control of common lambsquarters (Chenopodium albumL.), common sunflower (Helianthus annuusL.), kochia [Kochia scoparia(L.) Schrad.], redroot pigweed (Amaranthus retroflexusL.), and velvetleaf (Abutilon theophrastiMedic.) in sugarbeets (Beta vulgarisL.). Glyphosate was applied twice each year at 1.7 kg/ha with a recirculating sprayer in 1977 and 1978, or twice as a 20% (v/v) solution with a vertical-roller applicator in 1979. By harvest, 70 to 74% of the total population of treated common sunflower, kochia, and redroot pigweed, 61% of the common lambsquarters, and 30% of the velvetleaf was dead. Root yields in glyphosate-treated plots, when averaged over 3 yr, were increased 5800, 8500, 12 500, and 13400 kg/ha at densities of 6, 12, 18, and 24 broadleaf weeds (equal densities of common lambsquarters, kochia, and redroot pigweed)/30m of row, respectively. Where equal densities of common sunflower and velvetleaf competed with sugarbeets, root yields in glyphosate-treated plots, when averaged over 2 yr, were increased 4400, 11900, 11700, and 10700 kg/ha, respectively, at these same densities.

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