Does anybody know the mechanism in play when we force plants (usually mangoes) to flower, by using either Potassium Nitrate or Ammonium Nitrate. They also use smoke pots here to smoke the orchard. Graham
I tried some research for you. I found this: In the Philippines, various methods are employed to promote flowering: smudging (smoking), exposing the roots, pruning, girdling, withholding nitrogen and irrigation, and even applying salt. In the West Indies, there is a common folk practice of slashing the trunk with a machete to make the tree bloom and bear in "off" years. My guess is that stress rather than any direct chemical induction is the key factor. I’m not sure why this is. I hope that someone else here could shed further light for you and I would be curious to know what other plant react to stress in this way.
Mangoes are very touchy plants. This year in northern Australia we've had the most miserable season in ages. Weather is a big influence on how well fruit holds and too much rain or not enough at the right time can cause a bad season. In general I have found that a good heavy fruiting season generally is followed by a lighter crop the following year. Stress will cause flowering but does not guarantee fruit. There used be an old saying if your mangoe isn't flowering drive some nails into the trunk this is just another form of stress on the plant encouraging it to reproduce, but again doesn't guarantee a good crop. Generally a potassium based fertiliser as buds begin to form and again when in fruit will help. It basically comes down to environment and conditions.
Go easy on any stress treatments - they may make it flower more this year, but it may well be at the cost of less flower in future years, and quite possibly an earlier death of the tree through decay or disease entry into the wounds.
Howdy Takbok1, Mango is native to the Monsoon areas from India to Vietnam. It likes a hot dry period to build up a good carbohydrate reserves for floral initiation before bursting into flower at the onset of the rainy season. Reseaches in India found that a good C/N (Carbohydrate/Nitrogen) ratio is required for floral initiation. To a certain extent, the rootstock used can affect the C/N ratio in the canopy. All the practices you mentioned have been tried with varying degrees but inconsistant success. There are mangoes that are native to the more tropical regions, nearer the Equator. These are not so fussy and will bloom more reliably. I know I'm not answering your question but hope the above give you something to ponder. Peace Thean
Hi Takbok1, I'm no expert, but due to severely/ever decreasing amounts of rainfall in the state of Queensland, Australia (maybe southern hemisphere???), for the last couple of summers seasons, I've seen reduced/very ordinary/smaller crops of Mangoes off our tree. I tend to agree with other posts that big crop results are sometimes reflected by smaller quantities the following year, based on ground mositure levels.. soil conditions (eg. PH and nutrient deficiencies influence crop sizes, for sure, in my experience. Try commercially available "fruit-inducing" type-specific of fertilizer around the root zone). Best of luck. Cheers, Jirrus. (P.S What's your soil like and what type? Stressing the tree out out may jeapordise the overall longevity of the tree!)
Does anybody know the mechanism in play when we force plants (usually mangoes) to flower, by using either Potassium Nitrate or Ammonium Nitrate. Potassium nitrate and Ammonium nitrate are used in this case to force, stimulate, new growth. With newest early season growth in Citrus under most conditions we will get flower initiation to coincide along with the advent of the new growth. Later in the growing season some plants, including Citrus, will generate new growth first and then set flowers soon after for us. Jim
Hello all Re: The Flowering of mangoes using Ammonium Nitrate. (Or any Nitrate) spray. Thanks for all the input. Thean, Thanks that C/N ratio. It set me to thinking. Well I have found literature which says that when a Nitrate is sprayed on the leaves they form it into an ammonia, which in turn causes a Pre-cursor Hormone (amino Acid) called Methionine which in turn produces Ethylene. Ethylene gas as we know (C H4 I think) is the fruit initiation and ripening ( and other things) hormone. The smoke pots have the hydrocarbon gas (C H4) in them because they are burning wood (a hydro carbon) so it has traces of Ethylene. Ethylenr is also one of the Stress hormones in plants and hence flowering. However plants can not cope with stress any better than we can so it is not a good way to get them to flower, as Michael F pointed out. Graham
