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Effects of water stress on tomato at different growth stagesNuruddin, Molla Md. January 2001 (has links)
The study sought to identify the effects of deficit irrigation on the yield and quality of tomatoes. A greenhouse experiment was conducted during the summer of 1999 and repeated in winter 2000 using nine treatments. Two threshold soil moisture deficit levels, 65% and 80% depletion of plant available water, were factorially combined with 5 irrigation timing patterns: (i) no water stress (ii) stress throughout season, (iii) stress during flowering and fruit set, (iv) stress during fruit growth and (v) stress during fruit ripening. The treatments were set up in a randomized complete block design with 4 replicates. Crop yields, maximum and minimum equatorial diameter and fruit heights were measured. The quality parameters included: soluble solids, pH and the color index. Water stress throughout the growing season significantly reduced yield and fruit size but increased the level of soluble solids. No water stress throughout the growing season or stress only during the flowering stage provided highest tomato yield.
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Effects of water stress on tomato at different growth stagesNuruddin, Molla Md. January 2001 (has links)
No description available.
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Effects of pruning and nutrition on growth and yield of hydroponic tomatoes (Lycopersicon esculentum Mill)Fulton, Craig Mark 12 1900 (has links)
Thesis (MScAgric)--Stellenbosch University, 2011. / ENGLISH ABSTRACT: The potential importance of soilless production, particularly in tomatoes, in an increasingly
water scarce South Africa prompts a need for research under local conditions. In soilless
production systems the application and availability of nutrients is closely linked to that of
water, necessitating the research of methods to increase water and fertiliser use efficiency in
soilless production systems, while diminishing environmental pollution and maintaining, or
ultimately improving, tomato yield and quality. Poor management of hydroponic fertigation
water results in pollution, and wastes precious water and expensive fertiliser. Pruning is an
important cultural practise for ensuring high productivity of hydroponic tomatoes. Adapting
pruning practises to climatic conditions could be a cheap and effective manner to improve
productivity without increasing inputs. Improving water and fertiliser use efficiency is crucial
to ensuring sustainable production of intensive crops, such as the tomato. Three experiments
were carried out to investigate the effects of pruning and fertilisation on growth and yield and
water and fertiliser use efficiency of hydroponic tomatoes.
In the first experiment the effect of EC (electrical conductivity), irrigation frequency
and growing media on water use, nutrient uptake, yield and quality of greenhouse tomato was
examined. A factorial design with split plots was used. Two EC treatments (1 and 2 mS.cm-1)
in factorial arrangement with 3 irrigation treatments (5x, 10x, 20x) were applied to the main
plots. Plants grown in different growing media (coir, sand, sawdust) represented the split
plots. Plants grown at EC 1 mS.cm-1 were still able to uptake sufficient nutrients to achieve
leaf nutrient contents associated with optimal production. Also, increasing the absolute
nutrient concentration had a small effect on nutrient uptake. The organic media, coir and
sawdust, reduced available N early in the tomato crop life, and tomatoes grown in coir had
reduced Ca uptake compared to plants grown in sand and sawdust. Coir grown plants used
more water compared to sand and sawdust grown plants. Plants grown at EC 1 mS.cm-1 used
less water compared to plants grown at EC 2 mS.cm-1. Tomatoes grown at an EC 1 mS.cm-1
did not differ significantly from higher EC plants in terms of marketable and green fruit yield.
Plants cultivated at the lower EC had significantly lower percentage soluble solids content
(Brix) compared to the higher EC treatment. The second experiment examined the effect of leaf and fruit pruning on fruit size,
total yield and marketable yield of tomatoes. Plants were grown using the high wire system
and pruned to two stems. Three different leaf pruning treatments were applied: no leaf
pruning, pruning every 2nd young leaf after 1m plant height, and pruning every 2nd young leaf
after 2m plant height. Two fruit pruning treatments were also applied: no fruit pruning and trusses pruned to 4 fruits. The experiment used a factorial design. Leaf pruning treatments
had no effect and this was probably due to too late a removal of young leaves. Fruit pruning
resulted in no significant difference between treatments in terms of marketable yield. Plants
with unpruned trusses did have a significantly higher total yield, higher early yield, lower
average marketable fruit weight, and higher yield of unmarketable fruit (particularly small
fruit compared to the pruned treatment). From these results it can be concluded that fruit
pruning isn’t necessary on short tomato crops but this may be different over a longer
cropping cycle.
The third experiment determined the combined effects of different EC and stem
pruning practices on nutrition, growth and early yield of hydroponically grown tomatoes in
coir. A factorial design was used, with two EC treatments (1 and 2 mS.cm-1) in factorial
arrangement with 2 stem pruning treatments (single and double). Stem pruning had little
effect on plant growth but did alter plant development. Plants pruned to two stems produced
significantly more trusses, but did not produce a significantly higher DM or leaf area
compared to single stem plants. Stem pruning’s major effect appears to be influencing fruit
load; this may in the long term result in differences in plant growth and nutrition. EC 1
mS.cm-1 plants produced significantly lower leaf area and organ dry masses but had a
significantly higher marketable yield compared to EC 2 mS.cm-1 plants. Over fertilisation in
young tomatoes can negatively impact on early yield, whereas lower fertiliser application in
early tomato growth improves early yield but limits canopy development which may limit
plant productivity in the long term. These differences in growth are believed to be primarily
related to differences in N and P nutrition. / AFRIKAANSE OPSOMMING: Die potensiële belang van grondlose produksietegnieke, veral by tamaties, in Suid-Afrika wat
toenemend meer water skaars raak, motiveer dat navorsing onder plaaslike toestande gedoen
moet word. By grondlose produksie stelsels word die toediening en die beskikbaarheid van
voedingstowwe nou gekoppel aan dié van water. Navorsing rakende metodes wat water en
kunsmis gebruiks doeltreffendheid sal verhoog en terselfdertyd besoedeling van die
omgewing voorkom asook die opbrengste en kwaliteit van tamaties behou of verbeter is dus
van uiterste belang. Swak bestuur van bemesting in hidroponiese stelsels gee aanleiding tot
water besoedeling en vermorsing van kosbare water en duur kunsmis. Snoei is 'n belangrike
kulturele praktyk om hoë produktiwiteit by hidroponiese tamaties te verseker. Die aanpassing
van snoei praktyke by klimaatstoestande is 'n goedkoop en doeltreffende manier om
produktiwiteit te verbeter sonder om insette te verhoog. Die verbetering van water en
kunsmis gebruiks doeltreffendheid is dus noodsaaklik om te verseker dat intensiewe gewasse,
soos tamaties, volhoubaar geproduseer word. Drie eksperimente is uitgevoer om die effek van
snoei en bemesting op die groei, opbrengs en water en kunsmis gebruiks doeltreffendheid van
hidroponiese tamaties te ondersoek.
In die eerste eksperiment is die effek van die EG, besproeiings frekwensie en
groeimedium op die water gebruik, voedingstofopname, opbrengs en kwaliteit van tamaties
ondersoek. 'n Faktoriaal ontwerp met gesplete plotte is gebruik. Twee EG behandelings (1 en
2 mS.cm-1), 3 besproeiings behandelings (5x, 10x, 20x per dag) en 3 groei media (kokos,
sand, saagsels) is ondersoek. Selfs by ‘n EG van 1 mS.cm-1 was die voedingstof opname van
plante vergelykbaar met waardes wat geassosieer word met blaar ‘n voedingstof inhoud wat
voorgeskryf vir optimale produksie. die verhoging van die absolute voedingstof konsentrasie
het ook 'n klein uitwerking op voedingstofopname gehad. In die organiese media - kokos en
saagsels – het die beskikbare N vroeg in die seisoen verminder, en die tamaties wat in kokos
gegroei het, het ook ‘n verminderde Ca opname getoon in vergelyking met die plante wat in
sand en saagsels gegroei het. Die plate wat in kokos gegroei het, het meer water gebruik in
vergelyking met plante wat in sand en saagsels gegroei het. Plante besproei met ‘n
voedingsoplossing van 1 mS.cm-1 EG het minder water gebruik as die plante wat besproei
met ‘n voedingsolossing by ‘n EG van 2 mS.cm-1. Tamaties wat gekweek word by 'n EG van
1 mS.cm-1 het nie beduidend verskil van hoër EG plante in terme van bemarkbare en groen
vrugte nie. Plante wat gekweek is by die laer EG het ‘n aansienlike laer persentasie oplosbare
vastestof inhoud (Brix) in vergelyking met die hoër EG-behandeling gehad. Die tweede eksperiment het die effek van blaar- en vrug snoei op die vruggrootte,
totale opbrengs en bemarkbare opbrengs van tamaties ondersoek. Plante is vertikaal opgelei
tot by die horisontale draad en na twee stamme gesnoei. Drie verskillende blaar snoei
behandelings is toegepas: geen blaar snoei, snoei elke 2de jong blaar na 1m plant hoogte en
snoei van elke 2de jong blaar na 2m plant hoogte. Twee vrug snoei behandelings is ook
toegepas: geen vrugte gesnoei en trosse gesnoei tot 4 vrugte. ‘n Faktoriale ontwerp is vir
hierdie eksperiment gebruik. Blaar snoei behandelings het geen effek gehad nie, waarskynlik
omdat die jong blare te laat verwyder was. Met die vrug snoei behandelings was daar geen
beduidende verskil tussen die behandelings in terme van bemarkbare opbrengs nie. Plante
waarvan die trosse nie gesnoei was nie het 'n aansienlik hoër totale opbrengs gelewer, asook
‘n hoër vroeë opbrengs maar ‘n laer gemiddelde bemarkbare vrug massa en ‘n hoër
persentasie onbemarkbare vrugte (baie klein vrugte in vergelyking met die gesnoeide
behandeling). Vanuit hierdie resultate kan daar afgelei word dat vrug snoei nie nodig is
tydens ‘n kort groeiperiode vir tamaties nie, alhoewel dit wel ‘n rol mag speel gedurende ‘n
langer groeiperiode.
Met die derde eksperiment is die gekombineerde effek van verskillende EG en stam
snoei praktyke op voeding, groei en vroeë opbrengs van hidroponies verboude tamaties
bepaal. 'n faktoriale ontwerp is gebruik, met twee EG behandelings (1 en 2 mS.cm-1) en 2
stam snoei behandelings (enkel en dubbel). Stam snoei het ‘n geringe uitwerking op die groei
van die plant gehad, maar het wel die ontwikkeling van plante verander. Plante gesnoei na
twee stamme het aansienlik meer trosse gehad, maar nie 'n hoër DM of blaar oppervlak as die
enkele stam plante nie. Stam snoei se grootste effek blyk te wees op die aantal vrugte per
plant en dit kan op die lang termyn lei tot verskille in die groei van plante en hul voeding. EG
1 mS.cm-1 plante het ‘n aansienlik laer blaaroppervlakte en droë massas geproduseer, maar
het 'n aansienlik hoër bemarkbare opbrengs in vergelyking met EG 2 mS.cm-1 plante gelewer.
Oorbemesting kan 'n negatiewe impak op die vroeë opbrengste van tamaties hê, terwyl laer
bemesting in die vroeë stadiums van groei vroeë opbrengs bevoordeel maar blaaroppervlak
ontwikkeling beperk wat dan ook produktiwiteit beperk in die lang termyn. Hierdie verskille
in groei word hoofsaaklik toegeskryf aan verskille in die N-en P-voeding.
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Yield and quality response of hydroponically grown tomatoes (Lycopersicon esculentum Mill.) to nitrogen source and growth mediumLangenhoven, Petrus 12 1900 (has links)
Dissertation (PhD)--Stellenbosch University, 2004. / ENGLISH ABSTRACT: Pine sawdust-shavings (Pinus spp.) is at present a very popular soilless substrate in
South African greenhouses. Growers use fresh pine sawdust-shavings as a substrate,
which is biologically highly unstable. The greenhouse industry is looking at
alternative organic substrates such as coco peat, which already went through a
decomposition process and is more stable. A biological inactive substrate such as sand
was included to compare microorganism activity with organic substrates. The main
objective of this study was to compare the growth, yield and quality of hydroponically
grown tomatoes in response to different growth mediums in combination with
nitrogen source, irrigation frequency, period of substrate use and liming. In general
the drainage water pH declined with an increase in NlLt+-N in the nutrient solution.
Low pH values in the drainage water, especially when coco peat was used, had a
detrimental effect on marketable yield. The drainage water pH of pine sawdustshavings
increased during the growing season when 100 % N03--N was used. Due to
the higher cation exchange capacity of coco peat, the drainage water electrical
conductivity tends to increase more rapidly than with pine sawdust-shavings, during
conditions with high temperatures and when insufficient irrigation volumes per
irrigation cycle is applied. As expected the drainage water N03--N content decreased
as the NlLt+-N content increased in the nutrient solution. Pine sawdust-shavings
recorded a much lower N03--N and NlLt+-N content than sand and coco peat and thus
supports the hypothesis that microbiological activity is higher in pine sawdustshavings,
especially in the second season of substrate use. Coco peat produced the
highest number of marketable fruit and yield per plant, followed by pine sawdustshavings
and sand in the first season of substrate use. The number of marketable fruit
and yield decreased with an increase in NlLt+-N content in the nutrient solution during
production in warmer, summer conditions. Contrary to these fmdings, production in
cooler, winter conditions recorded high yields when only N03--N or 80% N03--N :
20% NRt +-N was applied. The unmarketable yield increased with an increase in
NlLt+-N in the nutrient solution. Visual evaluations showed that blossom-end rot
(BER) was the main contributor to unmarketable yield. Increasing levels ofN03--N as
nitrogen source in the nutrient solution, reduced weight loss and increased the loss of
fruit firmness of tomatoes during storage. Increasing levels of N03 --N also increased
fruit pH and reduced total titratable acidity. Coco peat produced fruit with a higher pH
than pine sawdust-shavings. An increase in irrigation frequency affected fruit firmness
negatively when coco peat was used as substrate. Different irrigation and fertigation
practices are needed for different growth mediums and management needs to be
adapted according to the growing season (winter vs. summer). / AFRIKAANSE OPSOMMING: 'n Mengsel van dennesaagsels en -skaafsels (Pinus spp.) word tans deur Suid-
Afrikaanse kweekbuisprodusente gebruik as grondlose groeimedium. Hierdie
groeimedium word nie vooraf gekomposteer nie en is dus biologies onstabiel. Die
kweekbuisindustrie ondersoek tans die gebruik van alternatiewe, gekomposteerde en
stabiele organiese groeimediums soos kokosveen. 'n Biologies onaktiewe
groeimedium soos sand is ook ingesluit om met organiese groeimediums te kan
vergelyk. Die hoof doelwit van die studie was om plantontwikkeling, opbrengs en
kwaliteit van hidroponies geproduseerde tamaties te evalueer in verskillende
groeimediums en in kombinasie met stikstofbron-verhouding, periode van
groeimedium gebruik, besproeiingsfrekwensie en bekalking. Oor die algemeen het die
pH in die dreinaat gedurende die groeiseisoen toegeneem soos die NH/-N inhoud
verhoog het in die voedingsoplossing. Lae pH waardes in die dreinaat, veral waar
kokosveen gebruik was, het 'n nadelige effek op bemarkbare opbrengs gehad. Die pH
in die dreinaat van dennesaagsels en -skaafsels het gedurende die groeiseisoen
toegeneem met die gebruik van 100% NO)--N in die voedingsoplossing. Die
elektriese geleiding in die dreinaat van kokosveen neem vinniger toe gedurende
toestande waarin hoë temperature en onder besproeiing voorkom, as in dreinaat van
dennesaagsels en -skaafsels. Die NO)--N inhoud in die dreinaat het soos verwag
afgeneem soos die NRt+-N inhoud in die voedingsoplossing toegeneem het. 'n Baie
laer NO)--N en NRt+-N inhoud is by dennesaagsels en -skaafsels aangeteken wat dus
die hipotese ondersteun dat mikrobiologiese aktiwiteit, veral in die tweede seisoen
van gebruik, hoër is in dennesaagsels en -skaafsels as in sand en kokosveen.
Kokosveen het die hoogste aantal bemarkbare vrugte en massa per plant geproduseer,
gevolg deur dennesaagsels en -skaafsels en sand. Die aantal bemarkbare vrugte en
opbrengs het verlaag met 'n verhoging in NRt+-N in die voedingsoplossing gedurende
warm, somer toestande. In teenstelling met vorige resultate is gevind dat 100% NO)--
N of 80% NO)--N : 20% NRt+-N hoë opbrengste gelewer het gedurende koeler,
winter toestande. Die onbemarkbare opbrengs het verhoog met hoër NRt+-N vlakke.
Visuele waarnemings het aangedui dat blom-end verrotting die grootste bydrae tot
onbemarkbare opbrengs gelewer het. 'n Verhoging in NO)--N vlakke het massaverlies
beperk en die verlies in fermheid verhoog gedurende opberging. Hoër NO)--N vlakke
het ook die pH van vrugte verhoog en die totale titreerbare suur verlaag. Kokosveen
het vrugte met 'n hoër pH as dennesaagsels en -skaafsels geproduseer. 'n Toename in
besproeiingsfrekwensie het vrug fermheid negatief beïnvloed wanneer kokosveen as
groeimedium gebruik was. Verskillende besproeiings- en voedingspraktyke word
benodig vir verskillende groeimediums en bestuur van die groeimediums moet
aangepas word by klimaatstoestande gedurende die spesifieke produksieseisoen.
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Effects of water table depths and fertilizer treatments on yield and quality of tomatoesTrenholm, Leif January 1995 (has links)
A field lysimeter experiment was conducted during 1993 and 1994 using 4 water table depths (WTD) (0.3, 0.6, 0.8, and 1.0 m), 13 treatment levels of calcium (0, 1500, and 2500 kg/ha) and potassium (0, 160, and 400 kg/ha), to determine their effects on tomato quality and yield. Plant parameters measured included: yield (fruit/plant), fruit height, maximum and minimum equatorial width, degree of catfacing (scale of 1 to 5), and sunscald (scale of 0 to 2). / Water table treatment was usually highly significant for the parameters measured at harvest. Largest height, equatorial width and yield of tomato fruit occur with 0.6 to 0.8 m WTD. Fertilizer treatments were rarely significant by WTD, but if they were, they tended to be in the 0.3 or 1.0 m WTD. Maintaining a WTD of 0.6 to 0.8 m and fertilizing with 160 kg/ha of K can improve quality and total yield of tomatoes.
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Effects of water table depths and fertilizer treatments on yield and quality of tomatoesTrenholm, Leif January 1995 (has links)
No description available.
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Yield and quality parameters of tomato cultivars as affected by different soilless production systems and beneficial micro-organisms.Maboko, Martin Makgose. January 2013 (has links)
Most tomato cultivars used for commercial food production are imported into South
Africa. Optimal growing conditions for these specific cultivars need to be determined, as
wrong cultivar choices can lead to great financial losses. Lack of information on selecting
well-performing cultivars may lead to lower yield or unacceptable fruit quality. Information
on the performance of tomato cultivars under South African conditions, utilizing plastic
tunnels or shadenet structures under soilless cultivation is still very limited. Soilless
cultivation of vegetables is becoming a preferable over in-soil cultivation due to the
improved yield and quality of produce, efficient water and nutrients usage by the crop;
furthermore, the grower can regulate nutrient solution, electrical conductivity and pH of the
nutrient solution.
To identify the optimal system for growing tomatoes hydroponically, the performance
of four tomato cultivars (‘FA593’, ‘Miramar’, ‘FiveOFive’ and ‘Malory’) under different
growing conditions was evaluated: directly planted in soil under 40% shadenet with drip
irrigation, a closed hydroponic system under 40% shadenet, an open bag system under 40%
shadenet, or an open-bag system in a temperature controlled as well as a non-temperature
controlled tunnel. The study revealed that ‘Miramar’ performed better than the other cultivars
in all production systems, with the exception of soil cultivation where there were no
differences amongst the four cultivars. Fruit cracking was found to be directly correlated with
fruit size, as the large-sized cultivars ‘Malory’ and ‘FA593’ were more susceptible than the
other two cultivars. Plants grown under shadenet were prone to fruit cracking and raincheck
as well as early blight. Higher yields were obtained when plants were produced in the open
bag system under temperature controlled conditions and in the closed system under shadenet.
Growing tomatoes in the non-temperature controlled tunnel resulted in high incidences of
fruit cracking, poor yield and pre-mature fruit ripening probably due to high and fluctuating
temperatures under such conditions. The average marketable yield was 88% and 59% of the
total yield in the temperature controlled and non-temperature controlled tunnels, respectively.
A further experiment was carried out to improve yield and quality of tunnel tomatoes
using beneficial micro-organisms, i.e., arbuscular mycorrhiza fungi (AMF) at different nutrient concentrations. Tomato seedlings were treated with Mycoroot™ containing four
mycorrhiza species (Glomus etunicatum, Paraglomus occultum, Glomus clarum and Glomus
mossea) at transplanting and subsequently transferred to either a temperature controlled or a
non-temperature controlled tunnel under the recommended (100%) or reduced (75 and 50%)
nutrient concentrations. Sawdust was used as a growing medium in this experiment.
Application of AMF neither enhanced plant growth, yield, nor fruit mineral nutrient
concentrations; although fruit Mn and Zn concentrations in the temperature controlled tunnel
increased significantly following AMF application. Plants grown in the non-temperature
controlled tunnel had significantly poorer plant growth, and lower yield and lower fruit
mineral concentrations, compared with fruit from plants in the temperature controlled tunnel.
Tomato plants in the non-temperature controlled tunnel had higher levels of micro-elements
in leaf tissue, compared with those in the temperature controlled tunnel. The highest yields
were obtained from plants fertigated with 75% of the recommended nutrient concentration, as
compared with the 100 and 50% nutrient concentrations.
When coir was subsequently used as the growing medium, Mycoroot™ applied at
seeding and transplanting did not enhance mycorrhizal colonization or fruit quality. Growing
tomatoes under reduced nutrient supply reduced the total soluble solids in the juice of the
fruit, but improved total and marketable yield, as well as the number of marketable fruit. This
effect was more substantial in the temperature controlled than in the non-temperature
controlled tunnel. Fruit firmness and leaf chlorophyll concentrations were significantly
higher in plants grown in the temperature controlled tunnel. Growing tomatoes in sawdust
improved the leaf Mn and Ca concentration over that of tomato plants grown in coir.
Mycorrhizal colonisation did not have a beneficial effect on tomato yield and quality.
The study indicated that cultivar selection was important in obtaining the highest
yield and quality of tomato using the closed hydroponic system under shadenet and the open
bag hydroponic system in the temperature controlled tunnel. Temperature controlled tunnels
with a pad–and-fan cooling system are still an effective way of cooling the tunnel
environment which resulted in high yield and high quality of tomatoes with a higher fruit
mineral content than that obtained under non-temperature controlled conditions where only
natural ventilation is relied on. Results also demonstrated that mycorrhizal colonization in soilless condition has limited beneficial effects in allowing for better nutrient uptake and
thereby for improved yield and quality of tomatoes. Further studies, including different
media, nutrient composition and concentrations, need to be carried out to investigate the
possible causes of AMF failure to improve yield, despite good AMF root colonization. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2013.
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