Related Papers
Acta Horticulturae
NITROGEN FERTILIZATION OF NEW CULTIVARS OF LETTUCE
2006 •
Maria Gonnella, Pietro Santamaria
HortScience
Management of Nitrogen and Irrigation in Lettuce Transplant Production affects Transplant Root and Shoot Development and Subsequent Crop Yields
2005 •
George Hochmuth
Lettuce (Lactuca sativa L.) `South Bay' transplant growth and development were evaluated at 0, 30, 60, 90, and 120 mg·L–1 N fertigated at frequencies of every 1, 2, 3, or 4 days in a floatation production system to produce plants with optimum roots and shoots which easily pull from trays. Greenhouse experiments (four) were conducted to evaluate root and shoot weight, percent transplant pulling success, and leaf N content, 28 days after sowing (DAS). Field trials, using transplants produced in Greenhouse experiments 2 and 4, were conducted to evaluated subsequent yield, head quality characteristics, and leaf N content. Generally, as N concentrations increased, dry shoot weight and leaf N concentration increased, and root:shoot ratios decreased linearly or quadratically. Lettuce transplants grown in a floatation irrigation system fertigated every second to third day with 60 to 90 mg·L–1 N resulted in transplants with optimum root systems to achieve the highest pulling success rate...
Effect of Different Levels of Nitrogen Fertilizer and Cultivars on Growth, Yield and Yield Components of Romaine Lettuce (Lactuca sativa L
Global Science Books
In order to determine the effect of nitrogen fertilizer rates and cultivars on growth and critical yield of lettuce, an experiment was conducted at Shahid Chamran University of Ahwaz, Iran during 2005-2006. This study was arranged in a spilt plot experiment based on a randomized complete block design, in three replications. The treatments included four nitrogen rates (0, 60, 120, and 180 kg N ha-1) as the main plot and two lettuce cultivars ('Pich Ahwazi' and 'Pich Varamini') as the sub-plot. Sampling was done in 86, 100, 114, 126, 142, and 156 days after sowing. The criteria measured were plant length, fresh and dry weights of leaves, leaf area, number of leaves, crop growth rate (CGR), leaf area index (LAI) and yield. Results indicated that different levels of nitrogen fertilizer on all growth characteristics were significant at P<0.01. Nitrogen fertilizer caused head formation to accelerate and delayed the bolting date of lettuce. Cultivar had a significant effect on growth characteristics, on fresh and dry weights of leaves and on leaf number but not on plant length and leaf area. The highest yield was obtained with 120 kg ha-1 treatment by 'Pich Ahwazi'. Also, it took 'Pich Varamini' longer to form a head and to flower than 'Pich Ahwazi'.
IOSR Journal of Agriculture and Veterinary Science
Growth and Yield of Lettuce (Lactuca Sativa L.) Influenced As Nitrogen Fertilizer and Plant Spacing
Jasim Uddain
Acta horticulturae
Lettuce (Lactuca sativa L.) growth and quality responses to applied nitrogen under hydroponic conditions
Dario Stefanelli
Folia Horticulturae
Effect of differentiated nitrogen fertilisation on the yield and quality of leaf lettuce
2011 •
Piotr Chohura
Two field experiments with leaf lettuce were conducted in 2006-2008. The first factor tested was the diversified contents of mineral nitrogen in the soil, amounting to 50, 100 and 150 mg N dm-3 before lettuce cultivation. The second factor tested four nitrogen fertilisers differing in chemical composition and in nitrogen form introduced into the soil: ammonium nitrate 34% N - (NH4NO3), calcium nitrate 15.5% N - (Ca(NO3)2 × H2O + NH4NO3), ammonium sulfate 20.0% N - ((NH4)2SO4), and ENTEC 26% N - (NH4NO3 + (NH4)2SO4 + 0.8% DNPP). Two cultivars of leaf lettuce were used: green leaf ‘Casabella’ (Lollo Bionda type) and red leaf ‘Klausia’ (Lollo Rosa type). The best source of nitrogen for ‘Casabella’ cultivar lettuce was ENTEC 26 fertiliser and calcium nitrate, which resulted in significantly higher yields as compared to ammonium sulfate, yet did not differ from the yields comprising plants fertilised with ammonium nitrate. In the case of the ‘Klausia’ cultivar, ENTEC 26 fertiliser and am...
New Phytologist
What are the effects of nitrogen deficiency on growth components of lettuce?
2000 •
Abraham Escobar-Gutierrez
Journal of Applied Horticulture
A comparison of three mathematical models of response to applied nitrogen using lettuce
Journal of Applied Horticulture, Sadeghi Pour
Modern fertilization recommendation must optimize crop yield and quality and minimize chances of negative environmental effects due to over fertilization. Data from fertilizer studies can be fi tted to several mathematical models to determine optimum fertilizer rates, but resulting recommendations can vary depending on the model chosen. In this research, lettuce (Lactuca sativa L.) was used as a case study vegetable crop to compare models for estimating fertilizer N requirements. Field studies were conducted to measure yield response to applied N. The area was located at 25 ° 21΄ E longitude and 51˚38΄ N latitude in the North of Varamin city, (Tehran province, Iran) in the alluvial plain of Varamin. Soil family was fi ne, mixed, active, thermic, typic haplocambids based on Soil Taxonomic system (USDA, 1999). Plants were grown in Central Research Station of Varamin and received fi ve rates of N (0, 150, 200, 250 and 300 kg ha-1) as a urea in split applications. Data for plant fresh mass and N uptake were recorded. Logistic, linear-plateau and quadratic models were compared for the fi eld data. The logistic model described the data for cultivar quite well, with correlation coeffi cients of 0.90 and above. Coeffi cients for the linear-plateau model were derived from the logistic model. All three models for lettuce production were compared graphically and analytically. The model coeffi cients were used to make improved estimates of fertilizer recommendations for fi eld production of lettuce.
… Symposium on Protected …
Nitrogen fertilization regime and lettuce romaine types influence seedling growth, root architecture and transplant quality
2004 •
Silvana Nicola
Agronomic, physiological and quality response of romaine and red oak-leaf lettuce to nitrogen input
Francesco Di Gioia, Maria Gonnella, Santamaria Pietro
Protecting the environment by improving the crop-system nitrogen (N) use efficiency (NUE) while maximising yield and quality is a primary challenge for modern agriculture, and understanding the processes that govern N fluxes in the plant-soil system is essential to improve NUE. An on-farm study was conducted over two fall-winter seasons to evaluate the NUE, agronomical and physiological response of romaine (var. longifolia, cv Manavert) and red oak-leaf (var. crispa, cv Aruba) lettuce (Lactuca sativa L.) to different N-rates (0, 60, 120, 180 kg ha –1 of N). Nitrogen rate influenced all tested parameters, including plant fresh and dry weight, N accumulation, leaf NO3 – and dry matter content, NUE indices, N nutrition index (NNI), soil residual N and the estimated N losses at the end of the crop season. Fresh yield, dry weight and N-accumulation response to N rate were influenced by lettuce genotype. Manavert had higher N recovery, NUE, and lower leaf NO3 – concentration than Aruba. Analysing the NNI overtime, 120 kg ha –1 of N assured an optimal N status in both Manavert and Aruba, while N deficiency and excess were observed at lower and higher N-rates, respectively. An empirical relationship was observed between NNI and leaf NO3 – concentration , suggesting that leaf NO3 – concentration may be used to predict NNI and thus the crop N status. The relationship between NNI and leaf NO3 – concentration may be used to define optimal leaf NO3 – concentration ranges for the rapid and site-specific assessment of the crop N status, and the dynamic adjustment of N-fertil-isation, contributing to improve crop NUE, minimise N-losses, and optimise yield and quality of lettuce crops.
