1,721,055 research outputs found
Caratterizzazione e valorizzazione di due tipici ortaggi pugliesi: carosello e barattiere
No full textSUPPLEMENTO AL NUMERO
Production and nitrate content in lamb’s lettuce grown in floating system
No full textSmall-size leafy vegetables can be profitably cultivated in floating system all year round to obtain ready-to-use vegetables. In the present study two cultivars of lamb's lettuce (Valerianella locusta L. Laterr.) were used: 'Baikal' and 'Valerianella a seme grosso di Olanda', both characterised by long and pale green leaves and suitability for greenhouse growing. The growing set-up consisted of benches containing the nutrient solution and floating boards to support the plants. A density 3 of 1200 plants M was adopted. Approximately 50 days after sowing fresh leaf production was 1900 g M-2, with a dry matter content of 7.5 g 100 g fresh weight (fw)(-1). Nitrate content was nearly 4000 mg kg fw(-1). The replacement of the nutrient solution with rain water three days before harvesting resulted in nitrate reduction in leaves by one third. Moreover, the obtained product had no discarded parts, substrate or pesticide residues. In the management of the nutrient solution the usual pH increase due to NO3--N absorption was recorded and continuous correction with acids was needed. The permanence of the nutrient solution in the tanks or benches for a long time proved to diminish oxygen level in the nutrient solution. This aspect is crucial in the high growth phase when solution enrichment with oxygen is needed by recirculating the solution between the benches and the relevant tanks or by insufflating air in the nutrient solution. The daily water consumption increased with increasing growth. Total water consumption was 51 L m(-3)
GROWTH, YIELD, AND MINERAL CONTENT OF BUTTERHEAD LETTUCE (LACTUCA SATIVA VAR. CAPITATA) GROWN IN NFT
No full textTo improve greenhouse lettuce yield and quality and avoid enviromental pollution it is necessary to optimize plant nutrition. Plants uptake nutrients at different ratios during the growing period. Therefore, total N, K+, Mg2+, and Ca2+ accumulation and NO3-, NH4+, K+, Mg2+, and Ca2+ uptake were evaluated during greenhouse growth of two cultivars of butterhead lettuce (‘Mindoro’ and ‘Tibet’) in a discontinous closed loop NFT sstem. Growth rate and water consumption were also measured.
In the last 20 days of the growing cycle, lettuce plants produced 70% of the shoot dry weight and 60% of the leaf area obtained in the enitre growing period. From 30 DAT to harvest, the shoot dry matter content decreased from 7.0 to 5.1 g·100 g-1 fw in 'Mindoro', and from 7.0 to 6.0 g·100 g-1 fw in 'Tibet'. From 30 to 50 DAT, both cultivars had increasing content of leaf total N up to 4.3 and 4.6 g·100 g-1 dw in 'Mindoro' and 'Tibet', respectively, when RGR was still high. Thereafter, and
up to harvest the total N concentration decreased more markedly in ‘Mindoro’ (14%) than in 'Tibet' (6%) while simultaneous dry biomass production was peaking.
Similar variations with time were found for K+, Ca2+, and Mg2+ leaf contents.
'Mindoro' had higher N use efficiency (NUE) than 'Tibet'. Leaf NO3 content was
moderate (1,622 mg·kg-1 fw) and 80% of total N was in reduced form. During the whole growing cycle, 5.5 L/plant of water was used with a water use efficiency
(WUE) of 12.4 dw g·L-1
Yield and quality of lettuce grown in floating system using different sowing density and plant spatial arrangements
No full text
Yield and quality of greenhouse multi-leaf lettuce cultivars grown in soil and soilless culture under Mediterranean conditions
Full text linkMulti-leaf lettuce has been proposed as a new type of product to be grown in open field or protected cultivation, especially for ready-to-eat salads. Like Batavia, oak leaf or lollo, multi-leaf lettuce
is more attractive in characteristics such as size, colour, texture, but has smaller, more uniform leaves
attached in a single point at the base. In the current research, we evaluated yield and quality of three
multi-leaf lettuce cultivars (Ezra, Ezabel and Eztoril), in both autumn-winter and winter-spring cycles,
by comparing soilless versus soil cultivation, and within soilless by comparing the supply of 50% nitrogen
as ammonium form instead of sole nitrate fertilization. Soilless cultivation improved crop yield by
about 20%, but only with the limiting environmental conditions of the first cycle. Among cultivars, Ezra
always presented taller leaves than the others. Multi-leaf lettuce had good ammonium tolerance, never
showing symptoms of toxicity. Ammonium nitrogen supply caused a slight increase in dry matter content,
but only at the spring harvests. Simultaneously, it was responsible for a lower nitrate content, compared
to nitrate-fed plants (-11 and -30%, respectively in first and second cycle). Generally, the nitrate
content was quite low (2,470 and 1,000 mg kg-1 fresh weight, respectively in the two cycles), considering
that it was a protected cultivation in winter or winter-spring. Under the operating conditions of our
experiment, the influence of soil cultivation on dry matter and nitrate content was variable in relation to
the cultivars. Mixed ammonium nutrition tended to increase the chlorophyll content in soilless-grown
lettuce, only in the autumn-winter cycle, but this did not cause colour changes
Gestione della soluzione nutritiva per ridurre il contenuto dei nitrati nell'indivia (Chicorium endivia L. var. crispum Hegi)
No full text
- …
