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Vegetable Production - Science topic

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I am looking for a hydrological model and a crop model that i can couple to predict crop yield and also to develop an improved irrigation scheduling for dry season vegetable production in a river basin in Ghana for a PhD research work. Please I need suggestions on hydrological and crop models that are available for free on the net. Thank you
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You can use Cropwhat . you can download from FAo.
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I am not economist but agronomist and want to know a scientific measurement for the following aspect -
Hydroponic vegetable production will ensure year-round supply of vegetables in the market since in this farming system, 3 to 4 times crop harvest can be done. What might be the scientific measurement to prove this benefit of hydroponic farming?
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@Rezaul, the availability of product on market car scientifically evaluate by his price. Because on perfect market, the price is one indicator of the demand and the offer. Some times, the quantity of stock can also influence the availability, therefore in assessment of food security, the availability of the intern production and the importation are requires for to get this one.
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I am looking for research on using compost tea as a way to increase beneficial microbial populations aquaculture systems. Or as a compliment to nutrient load in aquaponics.
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I found a reference to using compost tea as a foliar spray that increased production. This was from Dr. Salam's group at Bangladesh Agriculture University.
Effects of molasses and compost tea as foliar spray on water spinach (Ipomoea aquatica) in aquaponics system
  • Liza Akter Bethe, Ma Salam, Umme Kaniz Fatema, Km Shakil Rana
  • Biology
  • 2017 (First Publication: 1 May 2017)
An experiment was conducted to evaluate the effect of foliar spray with molasses and compost tea on water spinach in aquaponics system. Nutrient Film Technique was employed for water spinach culture under three different treatments with molasses (T1), compost tea (T2) and no spray as control (T3). Tilapia fingerlings, fed on a commercial diet, were reared in the aquaponics system. Waste water from the fish tank was re-circulated through the plant grow bed where nitrifying bacteria resided to convert toxic elements into plant available nutrients and supplied clean water to fish tank in return. 180 days trial revealed that T2 yielded the highest production of 5.56 kg water spinach, followed by T1 (4.73 kg) and T3 (4.39 kg). The average productions of water spinach (2.17 kg/m2/month) and tilapia (22.38 ton/ha/month) with an FCR of 2.33 suggest a prospective use of compost tea and molasses as foliar spray to produce organic vegetables. (Less)
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My research interest is on agricultural products processing or manufacturing in West Africa especially fruits and vegetables. These are products that often get spoiled due to lack of markets or poor storage facilities. I wish to dig more and see the available researches on the subject. Thanks.
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Please, read one of the my article based on vegetables and spices contamination in Catering.
It will me useful to your research, Hopefully.
Warm wishes
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Hello all indoor gardening scientists and researchers. I wish to grow vegetatables in indoor 2000 sqft area.
I wish to know how... Name of vegetables, yield, approx investment and profit loss ratio. Which technology is best for... Commercial production?
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Tomato, chilli, capsicum, Broccoli, Mungbean, Cowpea, etc are easy to grow.
For the 1st time the investment will be more and less profit will be there but once it is established the profit wil be increased.
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I have grown different vegetables on the pond dyke where vegetables are grown on fence. But problem is to calculate the area. Fence in on the pond but pit is on the dyke. So what should do here and how can I calculate total productivity?
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You can depend on the appropriate plant distance for your grow vegetable plants, then multiplied plant product by the plant density to calculate the production.
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Why S-Metolachlor is applied only post-transplant on sweet-potato?
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a cultivation prior to vine running (3 to 4 weeks after transplanting) and immediately followed by 0.75 pt Dual Magnum followed by a graminicide (Select, Poast, Fusilade) for grads control. Keep in my your state registrations as sweet potatoes usua require a special label. Also, Dual Magnum (active ingredient = S-metolachlor) is registered for application any time after transplanting until 60 days before harvest. Depending on your state, some states the label states that the maximum labeled rate is 1.3 pints/acre and must be applied in a single application. The best application timing will depend on what weeds are present in each production field. In production fields with nutsedges, Dual Magnum should be applied to a clean production field immediately after transplanting. Remember that S-metolachlor only controls yellow nutsedge, not purple. The standard 0.75 pt/acre recommendation has provided control of yellow sedge equivalent to higher rates. In fields where nutsedge is not present or at very low densities, Dual Magnum applications should be delayed until at least 10 days after transplanting. Why delay this application? Dual Magnum applications made immediately after transplanting and followed by moderate to heavy rainfall can result in modest plant stunting, reduced yields, and misshapen storage roots. Crop tolerance increases every day through at least 14 days after transplanting.
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Farmers assessment of the risk factors in vegetable production and their perception on market performance
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Mr. Peter,
Based on some statements of your subject matter(though it requires methodology)you can take the responses of the targeted stakeholders in bipolar mode or use the 5 point likert scale
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Is there a way to stimulate carotenoid (beta-Carotene) biosynthesis on field ?
Furthermore is there a correlation of the Sweet-potato skin color with any fertilization practices ? (more intense orange skin color)
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Hi!
Are you talking about the Orange Flesh sweet potatoes (OFSP) or normal sweet potatoes? Because OFSP is a genetically improved variety that contain high level of beta-carotene sometimes comparable to carrots.
But talking of a nutrient inducing the biosynthesis of beta-carotene in normal potatoes!! That may be a research topic! Though some mineral elements are Always needed as enzymes cofactors during synthesis, but then the pathway should exist.
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I am asking because that it seems that research on True Potato Seed is decreasing.
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I have a colleague of mine who worked on TPS in the nineties in Egypt. Yes it is easy to transfer and free of virus but it takes too long until you have an economic yield compared to seed tuber methods. So If the country have plenty of lands that can be cultivated for a long season of one crop, it will have a future there otherwise......
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We are open for collaboration in the horizon of 2020 programme.
I am working in the Department of Fruit and Vegetable Product Technology. We have experience with modern techniques of fruit and vegetables preservation: high pressure processing, continuous microwave heating, supercritical carbon dioxide as well as access to these equipment. We are also interesting in pulsed electric fields and high pressure homogenization techniques. If you intends to take to coordinate the grant in Horizon 2020 program as well as you are looking for teams or people to work together we are open to all suggestions. We have a well-equipped technological laboratory with laboratory and pilot plant equipment as well as an accredited physicochemical and microbiological laboratory.
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Let me know the procedure and eligibility.
As a young researcher it will be good opportunity for me.
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In some parts of Africa some land races of watermelon used as vegetable. though i have very little information about it. Another melon (musk melon) often used as vegetable in immature stages. in my area watermelon is not a major crop. only in some river beds it cultivated in spring-summer seasons. so i like to know if there is a possibility to use immature fruits of watermelon as vegetable. please give some idea.
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Trying to think of a substrate material that makes sense in the context of my study - in a field of vegetable production.
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Thanks so much for the advice! This is going to be a pretty small study, as I'm a grad student with other projects going on, unfortunately. It would be exciting to test nutrient availability & water holding capacity in the future. My basic methododlogy is going to be using a control and treatment transect lines, with 5 samples of each across 50 or 100 feet (not sure yet), and I'm looking to monitor decomposition rates, soil moisture, and soil temperature.
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Please help about get the latest book on the vegetable production. With thanks
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you may consult book, VEGETABLE CROPS, by,Dennis R Decoteau, Princeton Hall, Inc.Nj, I think this will be helpful.
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We have a cucumber wilt that is spreading in greenhouses.
I have done some search online and found similar cases in the area (I posted the photos that is similar to the case we have).
Please share your opinion.
Thank you,
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Vegetables (and fruits) are key elements in human alimentation, with benefits on health for example. At the ame time, they are often the results of intensified systems, heavily relying on chemical inputs to maintain soil fertility and to protect crops. Promoting agroecological transitions in such systems is therefore a real concern.
Food systems are one of the tools that public policies or local policies can use to promote these agrocecological transitions in vegetable production.
It is therefore clear that vegetable production and food systems are linked. I would like to clarify all these links, and all their implications, not only in terms of sociological quesitons, but also economic, agronomic, on land-use patterns, on culture and culinary traditions...
My first step is then to get a idea of who is interested by all or part of this topic (I also am doing a litterature survey, of course!).
Thanks for getting in touch, my feeling is that there are not so many forces on such topic, and we can gain by sharing our eforts.
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Dear Marc,
Check out also the work of Peter Rosset (especially the work he has been doing in Cuba).
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I am trying to find out the best preventive measures to reduce the post harvest losses during storage of onion.
I have read research papers related to PHL. If any of you are working on post harvest losses in onion, please help me.
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Post harvest loss results from fungal or bacterial rot at harvest to a couple of months and from weight loss or physiological disorder such as transluscent or water scale in intermediate day type onions. Normally disease rot is mainly affected by unsuitalbe preharvest management such as late or excessive nitrogen application or excessive irrigation, failure to disease management including Botrytis spp. Fusarium spp. or black mold etc.
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Dear all,
I have a question regarding ways to reduce soil phosphorus levels in a soil with excessive soil P levels. There has been vegetable production in the field for quite some years, fertilised with compost and chicken manure (high P sources). The soil P levels range from 200 to 400 ppm (Mehlich III). The calcium saturation is also high. This field is in a cold temperate climate (southern Norway). As P doesn´t leach, the only way is to remove P by crop removal (and no more added P). So my questions are:
  1. Which crop plants will take up and remove most P from the soil? The crops will be exported off the land.
  2. Which methods can be applied to reduce micronutrient (Zn, Fe etc) lockup so the crop plants still thrive?
Thank you very much in advance!
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Yes i agree with you Dr Kulvir, phosphorous toxicity is a rare phenomenon , despite its accumulation in soil as a result of residual effects of continuous application . Under such conditions, there is no other way , except omitting the fertilizer application for few years.
Is there any possibility of phosphorous removal using the process of phyto-remediation..?
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Hello everybody,
I have to quantify the nitrates amount in vegetables and I would like to validate my data with a reference material for nitrate content in vegetables. But I cannot find a supplier. Can anybody suggest me where/how to find it?
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Dear Dr. Pulgar
I think it is depend on government decisions and varied in different countries. please have a look this paper
Best wishes
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Precooling temperature chart for green leafy vegetables.
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Greetings
Can anyone refer me to articles that deals with diallel analysis of postharvest traits (during storage) in any horticultural crop
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I am enclosing here a thesis where few post harvest aspects (such as pulp thickness, pulp weight, total sugars, ascorbic acid, have also been covered.
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We are currently building an aeroponic system for cultivation of various vegetables.
However, we seem to be stuck at the choice of an appropriate type of spray nozzle head. Ideally, the droplet size would be about 50 µm and it should be sprayed in an angle as wide as possible.
I've tried several companies specialized in distribution of these nozzle heads, but none of them seem to have an appropriate one.
Am I being to strict?
Does anybody have a suggestion? Or better yet, could you share which nozzle heads you use?
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Thank you!
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Good evening respected teachers/scholar/researcher, I hope you are fine and doing well, I am Ph. D student in china, working on current project "Sustainable vegetable production in china" in College of Horticulture, Northwest A&F University, China. I analysed soil microbial diversity by Illumina MiSeq platform. i have data in figure form, some of them i couldn't understand How to interpret it well especially "Heat map analysis" ? my capabilities are very limited in soil bio diversity and microbial ecology. So i need assistance belong to bioinformatic or soil microbial ecology experts for my figure illustration? Details about these figures are in attached file. I really thankful if someone help me in this regard.
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The colors suggest a positive or negative relation between the environmental parameters and the abundance of the different classes/genera. 
The top dendrogram shows which environmental parameters have the most similar responses. The side dendrogram shows which classes/genera are behaving most similar.
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Please provide data on the history of the Ziban region and its palm groves ?
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Mohammed:
This link should prove useful:
Best
Syed
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Hydroponic systems currently employ normalized, sterile, water soluble fertilizer solutions which are highly effective for growing high quality crops quickly. However, these mined salts are not sustainable and must be replaced with organic sources. As we know, plants do not utilize organic compounds in the root zones for nutrition, and insects and microorganisms must break these compounds down to usable inorganic plant nutrients. Would it be preferable to create a process by which consistent compost material is harvested of its degradation products for use in hydroponics, or would it be best to employ fertilizers with mixed organic and inorganic nutrients to a system pre-innoculated with beneficial mycorrhizae and rhizobacteria? Research has shown that hydroponic cultivation can impart higher nutritional value to edible crops when compared to organic and conventional cultivation. However, it has also shown that aquaponic cultivation supplemented with inorganic nutrients performs even better on yield. Could this be because soluble nutrients are supplied alongside insoluble ones in a living system? Thank you in advance for your thoughts on the matter.
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Aqueous ammonia (NH3+H2O) is a liquid fertilizer which may be used in customized fertilizers for hydroponics. It is low pressure ammonia solution which contains both gaseous ammonia and ammonium hydroxide. But due to limited safety hazards, handling of this fertilizer is little difficult.
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I conducted a variety trial of tomato. However, due to early frost period, I decided to harvest all mature fruits and cut the plants to determine plant biomass while there was some premature fruits (green fruits) which was also weighted separately from plant biomass. I am wondering if it makes sense to include these premature fruits as yield? The proportion of the remaining fruits was about from 10-20% comparing to the harvested mature fruits.
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Good explanation by our RG colleagues. Usually tomatoes are harvested at turning stage. Immature fruits will not ripen as they have not attained physiological maturity and shall not have any market value 
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Dear all. I'm following a procedure in order to use AOM (Azoxymethane) in a mice colorectal cancer inducing. I've determined I need only 20 microliters from a glass container of 100 microliters of commercial AOM. Can I only use 20 microliters and storage 80 microliters in a sterile glass container? Or maybe the remaining AOM will evaporate and concentrate? What is the best choice in order to preserve the remaining 80 microliters (temperature, diluting, etc.). Thanks in advance. 
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Yes, but you must aliquoted in small amounts (which you will use) and freezing (-20°C)
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Silencing CWIN expression in tomato resulted in increased fruit abortion, and reduced fruit size and seed number per plant (Zanor et al., 2009). An article from a team led by Dr. Yong Ling Ruan in cotton says that silencing of VIN genes led to fiberless seed phenotype, but not the viability and the development of the seed set.
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Seed developments can be put in several stages and there are to many genes participate in seed developments. When you say fruit abortion that means you skip all steps involved in seed development except embryo desiccation which the responsibility of   Lea gens 
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I am particularly interested in the use of Paclobutrazol in South Africa.
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You can use Paclobutrazol in leafy vegetables for increasing green colour and decreasing height. Besides you can use Paclobutrazol in fruit vegetables for dwarfness and increasing yield. 
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Artichocke's irrigation performance need a comparison with theoretical requirements. What kind of data are necessary for this ?
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The inflorescence is too frigile that it may brake, while handling, esp when we attempted hot water treatment.
If we cut the top 1/3rd portion of the flower for emasculation, the flower turns brown and dries up.
Pl let me know the methods available and how to go about standardising the procedure for artificial crossing
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The anther pollen can be very heat and water sensitive. In sorghum under a tropical condition the placing of a plastic bag over the head prevents normal anther development and pollen release. 
Use a non pigmented seed type double recessive as your female line. Use a pigmented purple seed or flower type as the donor male. Change the plastic from your female to a male bag which used paper. Put the paper bag over the female when stigmas are open and receptive and have the seeds when mature. 
Grow out your seeds any nonpigmented are selfs and any purple pigmented are pollinated from your male. 
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Dear Sir/Madam,
I am studying about a small-scale units (processing units) of drying vegetable and fruits. I would like you to inform me if there are any articles about layout of a building for drying vegetables and fruits (e.g. inspect, wash, peel and dry).
I would be grateful if you could reply as soon as possible.
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you should consult the topic considerations of laying out greenhouses, that will help you in getting the idea how to start the things
good luck
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Like number of producers, processors, wholesalers and retailers? Either for meat, fruit, cereals or vegetables. Thanks
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Hi Elias
I note your question was posted over a month ago, but in case it might help others I would mention a Eurostat source Food: From Farm to Fork Statistics.
This is only occasionally updated, last edition is 2011. According to the webpage, "This pocketbook provides the reader with information on how the food chain evolves in Europe; it presents a range of statistical indicators for each step of this chain from the farm to the fork, passing from production on the farm, through food processing, to logistical activities such as importing, transporting and distributing, before reaching the end consumer either through purchases made in retail outlets or through the consumption of food and drink in cafés, bars and restaurants. Its aim is to give a summary of the data currently available within Eurostat s Food: from farm to fork database."
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Hi,
I am looking for regulations on nitrite limits in vegetables. I have found nitrate limits but nothing on nitrite. Does it mean there are not allowed any nitrites in vegetable products?
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Nitrate is required by plant for N requirement for producing protein beneficial for humans, however nitrite are not safe as lead to carcinogenic products as said by Ingo and Petropoulos.
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How a man takes to harvest by hand a hectare of  carrot ? Because I'm doing a study on carrot crop to compare to mechanical harvesting
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Dear Charles thanks for your answer
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I want to know the effective of bio-fertilizers in banana bunches characteristics
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I attach one that i believe matches quite well with your interest. Besides, you can easily find articles about specific bioinoculants such as arbuscular mycorrhizal fungi. Good luck!
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A concept of stress has a bit of controversy when we move from species to vegetation. Environmental stress means that overall vegetation productivity is reduced for whatever cause (more limited resources, presence of toxic elements, reduced or imbalanced water/energy supply). But species behave in a mixed way: while most species respond as expected to the stress and reduce their productivity, some species are so specialized that grow better under such stressful conditions [example – alpine Rhododendrons (Rh. caucasica) – a cold-adapted species from high elevations that cannot be grown in lowlands even under garden experiments]. Does anybody know any similar examples re light? Any examples of shade-specialists who die if the shade is removed?
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Dear Zaza
You might be interested by this paper we published in Plant Ecology where we showed that the removal of the tree canopy of a broad-leaved temperate forest killed one understorey species (Galium odoratum) which is known to characterize these highly shaded forests. Thus, this species can be called a light-intolerant species. In contrast, another species (Deschampsia flexuosa) growed better in the gaps than in the shade and was rather a shade-tolerant species. Attached also another paper in JVS where we showed similar patterns during the 2003 heat-wave for two different conifers, Abies alba and Picea abies, respectively.
Sincerely
RIchard Michalet 
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I'm working with a college group looking for ways to modify the vigor of tomatoe plants using grafting on other Solanaceae rootstock. We would all be grateful to get some research results on this. 
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Quite a few tomato rootstock varieties have been released recently. Many are interspecific hybrids between tomato and other Solanum species.
They are commerically available. A list of about 60 tomato rootstock varieties is available from vegetablegrafting.org.
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In 1 ha of land with sandy soil and a limited water source, how can I design a several range of cereals, vegetables, bushes and fruit trees well adapted to arid climate? the aim is to feed a small population of about 12 families of 5 persons in average. 
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First, you might want to get some insight about Permaculture design : There's plenty of literature on this regard such as Permaculture 1 & 2 from Bill Molison and Holmgrem, which are the original sources of permaculture design principles. 
Secondly, you might also be interested to get closer from permaculturist Geoff Lawton who was financed for a permaculture project in Jordan in an arid environment : http://permaculturenews.org/2013/12/10/desert-food-forest-organic-commercial-production-three-years-update-wadi-rum-consultancy/
That might be a good start. Good luck with your project!
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Hi 
I hope you have a good time.
I wonder if someone could answer me:
How we can decrease the ethylene level in tomato? Can we use of decreasing of the ethylene level in plants?
Thanks a million.
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Your interest is to delay ripening in preharvest or postharvest. If your interest is to delay ripening in postharvest, 1-MCP is an ethylene inhibitor and consequently can delay ripening in tomatoes. You may review the followings references: Postharvest Biology Technology (PBT) 2007 43:23-27, PBT 2009 54:1-8, PBT 2006 42:235-242, Chilean Journal of Agricultural Research 2009 69:134-144, Biotechnology Advances 2006 24:389-409.
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Green sand (K feldspar?) is considered a natural source of potassium (K) and is acceptable to organic farming. However, its K ( about 5 - 6%) is released very slowly. Are there any treatments/amendments that could increase/speed up its K release?
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I think there are some strains of micro organisms can do this action using different doses 
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Legume-cereal cover crop mixes are often promoted because they combine the ability of legumes to add atmospheric nitrogen to the system through biological fixation in root nodules, and the ability of the cereals to scavenge nitrogen that is prone to leaching during the winter. Efficient nitrogen use is especially pertinent in organic systems because the cost per unit of nitrogen in organic fertilizers is relatively high. Cover crops can provide important ecosystem services (soil improvement, nutrient cycling, weed suppression, etc.) and therefore are crucial in sustainable agriculture. An important question to ask is whether or not legume-cereal mixtures are a good fit in tillage-intensive organic vegetable production systems that are common in California? I addressed this question in a presentation at the 2014 American Society of Agronomy conference based on my experience with short-term and long-term research on organic vegetable studies conducted in the major region for high-value vegetable production in California. See YouTube link below.  This research has shown that the performance (i.e., biomass production, ground cover, weed suppression, potential nitrogen fixation) of cover crop mixtures can vary markedly between and within farms based on soil type, land history, cover crop management (i.e., seeding rate, planting method, planting date, mixture composition), and climate (i.e., winter rainfall and temperature).  I'd love to hear what other researchers think about the complexity of integrating these mixtures into vegetable production systems. 
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Dear Eric and others
As already discussed, the optimal choice of cover crop depend on many factors, the growth conditions of the region, the time of year and how long time the cover crop can be allowed to grow, soil diseases and many others, so local experience is needed. None the less, mixtures of e.g. hairy vetch and barley or rye have been shown to be successful in many experiments under very different conditions in many countries.
I think that especially in vegetable rotations, the soil N level is often high, and then cover crops without legumes are often the best, while mixtures with legumes, or even pure stand legumes can be the best choice when soil N supply is low. In a diverse rotation, this would ideally mean that non-legume cover crops should be grown after vegetables to take up the excess soil N, whereas mixtures with legumes could be grown before vegetable crops, to improve the supply N if needed, such as in organic crop rotations.
I always wonder about this discussion of the need for synchronization of N release from cover crops with the N demand of the following crop. When just stated, it seems correct, but what exactly do we mean by synchronization, and why is it really important? We often need an early N release in order to supply the early N demand of the crop, but this is normally not a problem if the C/N ratio of the cover crop is kept low, which can be achieved by the correct choice of cover crop species and management.
Cover crops tend to increase early N supply for the succeeding crop (sometimes too much), but then often to reduce the later supply. This is mainly due to the fact that N availability after cover crops is not only affected by the dynamics of N mineralization from the cover crop residues, but also by the spatial redistribution of N in the soil caused by cover crops. After a cover crop, more N is normally available in the topsoil, but less in the subsoil, as compared to plots where no cover crops were grown, i.e. cover crops concentrate the available N in the uppermost soil layers. While the following crop is young, and have its root growth mainly in the uppermost soil layers, their N supply is enhanced by the increased N availability there, but later during the crop growth this can be reversed. When roots grow deeper, crops grown after a cover crop will find little N there, whereas crops grown where the soil has been left bare, will continue to find N resources in deeper layers as the roots reach these layers.
We have shown the effect of cover crops on the depth distribution of available N in the soil in a number of experiments, and also shown how this interacts with root development of the succeeding crops, I can recommend these papers dealing with this topic, also in vegetable rotations:
Thorup-Kristensen, K., Dresbøll, D.B. and Kristensen, H.L. (2012) Crop yield, root growth, and nutrient dynamics in a conventional and three organic cropping systems with different levels of external inputs and N re-cycling through fertility building crops. European Journal of Agronomy, 37, 66-82
 Thorup-Kristensen K, Salmeron M, Loges R 2009. Winter wheat roots grow twice as deep as spring wheat roots, is this important for N uptake and N leaching loss? Plant and Soil, 322: 101-114
Thorup-Kristensen, K. (2006) Effect of deep and shallow root systems on the dynamics of soil inorganic N during three year crop rotations. Plant and Soil, 288: 233-248
 Thorup-Kristensen, K. (2006) Root growth and nitrogen uptake by carrot, early cabbage, onion and lettuce following a range of green manures. Soil Use and Management, 22, 29-38
Kristian
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We need to provide a good variety of turmeric for planting them in a greenhouse. 
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Indian Institute of Spices Research [ http://www.spices.res.in/index.php?option=com_content&view=article&id=52&Itemid=77 ] possesses world's largest germplasm collection in various spices. Germplasm collection conserved in germplasm conservatory and in vitro gene banks. Number of Turmeric accessions: 899.
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In Fiji we found fertility variance even in small areas. Farmers are spending a lot to cultivate vegetable and we found many patches of poor growth. To give a solution I am looking for some equipment which can  give a rough idea about the soil fertility in the farmers field.  
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As Dr. Ramesh mentioned, there are several soil nutrient testing kits in the world, such as Soil nutrient analyzer TRF-3, which can rapidly monitor the soil fertility status. But such data mainly used for providing indexing information, the precision is not sufficient to publish in the international peer-reviwed journals. I suppose such system can meet your needs. Good luck!
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For a hydroponics research lab. I would ideally have a chart that provided me info on if cucumbers needed more nitrogen than tomatoes, etc. for every relevant vegetable. Hydroponics have proven most successful with small root system vegetables (salad greens, herbs). I want to optimize nutrient intake in each stage of vegetable growth.
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Hydroponic tomato production is a highly standardized commercial operation these days.
Mississippi State has a nice guide to fertility, Written by Rick Snyder who is probably the most experienced US academic working on the issue.
Ohio State also has a nice modeling program to try different nutrient regimes
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I'm working with ADM1 model for dynamic simulation of anaerobic treatment of vegetable wastes. I have uncertainty about mass transfer in this model. Is anyone interested in keeping in touch?
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Could you please give more precision about your problems with mass transfer? Do you mean liquid to gas (kla) parameter?
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Biotechnology has emerged as a modern tool for improvement of crop plants since last 30 years. Even then there is not even a single commercially important variety which is developed by using biotechnological tools eg. somatic hybrids, cybrids, GE variety in India. what are the possible reasons responsible for failure of this technology. Why this work is limited only to laboratory and research papers? Why even after spending big amounts on this technology it is not giving desired results in favour of poor farmers? Is it worthless? Please do share your ideas.
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There are a great many hindrances, biological, political and economic.
One of the biological hindrances is that it is difficult to predict what a particular genetic modification will do. Everything on the market now has a very simple mode of action, and the concept for them was proved in the 1980s. The classic FlavrSavr tomato was intended to maintain firmness to allow shipping riper fruit. In practice, the gene ended up keeping over-mature fruit firmer  but did not make it possible to ship riper fruit. That is a subtle biological difference that's hard to predict, but also one that cause a huge difference in value. I have followed many academic efforts at crop improvement where the transgene didn't do at all what was predicted or hoped for in the initial efficacy tests. In short, it is difficult to do crop improvement by transgenics. Conventional breeding using current genetic methods is generally faster and cheaper.
In the US, the cost of deregulating a transgenic event is currently estimated by those in the know at $3 to 5 million; it also takes many years of the inventors time to do the regulatory support for deregulation. No academic scientist has the resources to deregulate a crop, nor can they spend so many years not publishing or doing research. That reality has made transgenics unattractive in academic vegetable crops. There were some nice successes in the 1990s though. For industry, vegetable seed sales are not high enough to justify such a development cost. Monsanto offers transgenic sweet corn, but they did not transform sweet corn because of the cost, they instead did the difficult work of breeding excellent sweet corn from a transgenic field corn.
In Europe and some Asian countries, the deregulation process is far more difficult than the one in the US.
In developing a transgenic fruit or vegetable, one needs to use technologies that are patented by others. While that is not a big barrier for biological discovery, getting license agreements to commercialize a new variety has proven to be an insurmountable barrier to many.
Those are some of the reasons that I have seen influence the decisions and strategies of breeders and prospective breeders of horticultural crops.
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How to differentiate determinate and semi-determinate varieties of tomato in the field?
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Dear Anoop
The definitions to determinate and indeterminate varieties as already given by few of our colleagues hold good. But I feel the concept of semi-determinate tomato is not clearly brought out in these answers.
At field level, determinate tomatoes are characterized by the bushy growth that does not require a support, in normal cases. The height of the plants vary from 30-65 cm depending on the cultivars. Though many books define this growth habit in terms of number of nodes (6-15) it is again genotype specific.
The semi-determinate tomatoes are typical determinate types except in the length of the branches. Since the number of branches are lesser (compared to determinate) and the length of each branch is more, these varieties require the support of a pole of 1 metre lenth, to avoid trailing in the ground. The plant height comes to almost 1-2 metres. Pruning to maintain the apical dominance will not be effective and lead to reduced yields.
When we say, indeterminate, this refers to the varieties that got the capability to grow up to a height of 5-15 metres depending on the genotype and the type of pruning that we adopt. In general, the indeterminate varieties are pruned to a single stem that will grow to continuously to reach the top of the greenhouse, may be up to 10-15 meters. This stem will be supported from the greenhouse roof with twines. Once the shoot tip reaches the roof, the twine will be released gradually so that base of the plant where the harvest is completed will rest on the ground and continuous growth of shoot tip is ensured (process is called lowering).