The ever - increase cost of fertilizer inputs is just one cause why growers of farming and horticultural crops in both outdoor and controlled glasshouse growing environs have get hold it necessary to take a closer face at their software pace and drill . Across Canada , the horticultural sector and particularly greenhouse agriculturalist have come under additional examination as the possible beginning of contamination when unacceptable levels of pollutant have been feel in nearby stream and ponds . Just as critical , therefore , has been the pauperism to run into increasingly stringent regulations set by environmental agencies to check the quality of irrigation run - off water .
As a result , researchers are now see to answer the seemingly elementary question of “ how low can you go , ” as part of the resolution to both dilemma which currently confront the floriculture greenhouse agriculturist .
A research project currently afoot by the University of Guelph ’s Dr. Barry Shelp , “ optimise nutritious legal transfer in glasshouse - grown potted chrysanthemum : Sub - irrigation and trickle irrigation system ” tests the hypothesis that nutrient consumption can be vastly ameliorate by strategically fake the timing of nutrient manner of speaking to the flora . This project is part of the “ Accelerating Green Plant Innovation for Environmental and Economic Benefit ” Cluster and is fund by the Canadian Ornamental Horticultural Alliance ( COHA - ACHO ) , private sector companies , and the Government of Canada under the Canadian Agricultural Partnership ’s AgriScience Program , a Union , provincial , territorial initiative Dr. Shelp ’s current project is specifically focused on testing the improved delivery of micro - nutrients to both drip irrigate and sub - irrigated chrysanthemum .
Commercial trials with different N ( go forth ) and NPK ( correct ) rates .
The current labor is a sequel of his previous research task under the Growing Forward 2 ( 2013 – 2018 ) Cluster program which demonstrated the successful reduction of macronutrient use . In that task , Dr. Shelp was capable to verify that the supply of atomic number 7 , phosphorous , sulfur and potassium could be reduced by as much as 75 to 87.5 % equate to current industry criterion , without any adverse impacts to craw yield or quality .
The overall premise of his current enquiry , says Dr. Shelp , to test the limits of lowering fertilizer inputs seems very simple . However , far more complex is the understanding of plant physiology and using a plant ’s implicit in content and attributes to inform the decision - making processes about fertilizer app which has form the foundation garment of his hypothesis .
“ For many yr , and even as a spot - doc , I set about to understand and wonder at flora characteristic associated with nutritious acquisition and redistribution in the works . I came to realize that a industrial plant ’s source of nutrition changes as the plant grows and develop and if raise to be reliable , that premise could greatly influence commercial fertilization exercise . Although that was many twelvemonth ago , I am grateful for the context that are finally giving me the opportunity to test my theory . ”
Articulating his hypothesis in mere terms , Dr. Shelp explain that untested plant absorb nutrient through the root system , but that changes as the plant matures . plant then start to use antecedently acquired and stash away nutrients and use them for fruit and prime exploitation . By strategically lowering the nutrition rates , industrial plant can be induced to better take in nutrients early in the growth oscillation and to redistribute their salt away resources later in the outgrowth cycles/second to append the generative parts of the industrial plant .
Rather than continuously supplying a plant with nutrient , Dr. Shelp ’s theory calls for an intermission to fertilizer lotion at a time in a flora ’s maturation cycle when it has sufficient stored nutrient in the leaves to maintain procreative development . Typically , the metre is well at the oncoming of flowering , when the plant transitions from vegetative to generative growth , is most effective at mobilise nutrients , and the ingestion of nutrients through the root organization starts to pass up . Remarkably , this routine can be combined with a reduction in nutrient supply to the young plant , and as long as it not excessive , the efficiency of alimentary uptake by the roots is amend so that the plant acquires and stores the same amount of nutrients as with a much high alimentary supplying .
Research trials with different Fe ( left ) and Zn ( right ) rates .
Dr. Shelp recognizes the challenge connect with agriculturist acceptation of new engineering and growing practices . “ Once growers have a rule that make for for them , it is understandable that change nonplus a huge risk . ” He is all the same confident that it is only a affair of sentence before agriculturist slowly implement the unexampled and reduced fertilisation guidelines based on his research results .
It is a very simple matter to measure the preservation that can be realized through less plant food use . It is more unmanageable to measure the saving that can be achieved through reduce costs associated with cleanse spent irrigation water , and specially the run - off that go on with drip irrigation . “ It ’s difficult to put a value on being capable to meet the strict regulations set by environmental way , but growers instinctively recognize the benefit are significant . ”
Conducted at both the University of Guelph ’s observational greenhouse labs and a Niagara - ground commercial greenhouse grower , Dr. Shelp ’s research focalize on chrysanthemum , using four commonly grown varieties , as they are the largest dollar volume nursery floriculture crop develop in Canada . Crops were measured for take and overall plant tone and nutrient leaf analysis by the University ’s Laboratory Services division was used to provide information on the grade of micronutrient . To date , Dr. Shelp has sour with sub - irrigation system because if managed properly , the composition of the excess nutrient solution is fundamentally unaltered , so it can be recycle and reuse . However , he intends to also test his modified pitch strategy with drip mould irrigation because of its importance in the industry . If the nutritive supply can be reduced , then it should be possible to deoxidize the overirrigation that is required to prevent common salt accumulation in the growing spiritualist , thereby preserve both nutrients and water .
After enquiry validating his possibility on the slenderize use of macronutrients ( nitrogen , phosphorous , K , calcium , magnesium and sulfur ) , Dr. Shelp set out to study the impacts of reducing the use of micronutrient . In disjoined trials , the project looked at zinc , bull , iron , manganese , boron and atomic number 42 . Depending on the formulation of the relative commercial-grade formulas being analyse , results showed that pitch of these nutrient can be reduced by 85 - 95 % over the harvest cycle without sacrifice works and bloom quality .
The significance of the research solution , say Dr. Shelp , degree to several logical “ next - step ” applications , include out-of-door yield of cosmetic floriculture crop and possibly controlled surround production of comestible crops .
For supporting graphics & more info , please visit thewebsiteof COHA .
