Articles
Optimizing nitrogen availability for organic greenhouse cultures: a study on various organic fertilizers and growing media
Article number
1428_4
Pages
27 – 34
Language
English
Abstract
In organic greenhouse farming, nitrogen (N) management is critical for optimal crop yield, and nutrient imbalances are a major threat affecting the sustainability of fruit-vegetable crops having a very high N demand.
In order to better synchronize the nutrient availability of organic greenhouse crops with their nutrient needs, this study investigated the influence of various organic fertilizers and growing media (GM) on N mineralization rates and microbial activity in controlled microcosms and commercial greenhouse conditions.
The in vitro incubation experiment was conducted over 56 days to compare the mineralization rate of 10 organic fertilizers, including animal and plant-based types, on two new peat-based GM (one with wood fiber) and a 5-year-old GM from Cultures Gen V Inc. (Quebec, Canada). For most fertilizers, the greatest percentage of mineralized N was observed after 14 or 28 days of incubation and ranged from 30 to 80% to the total N. Fertilizers like poultry pellets and blood meal exhibited high N mineralization rates, while alfalfa meal, feather meal, and soy hydrolysate exhibited low mineralization rates.
Microbial activity varied significantly among GM types, with peat-and-wood fiber-based GM showing the highest activity at certain stages.
The commercial greenhouse experiment measured the impact of the same three GM types and six organic fertilizers on the growth of sweet pepper and cucumber crops.
While GM type did not affect cucumber productivity, sweet peppers in the 5-year-old GM showed a 27% decrease in yield compared to new peat-based and peat-and-wood fiber-based GM for the first crop, while no significant difference was observed for the second crop.
On the other hand, fertilization strategies based on plant or animal-derived fertilizers, including the control (animal source), showed no significant differences in growth and productivity in greenhouse commercial trials.
This study, characterizing the mineralization rates of various organic fertilizers in two new GM compared with a 5-year-old GM, showed that substituting a portion of animal-based fertilizers with plant-based sources and reusing the same GM during several years is an interesting approach to enhance the sustainability of organic soilless cultivation.
In order to better synchronize the nutrient availability of organic greenhouse crops with their nutrient needs, this study investigated the influence of various organic fertilizers and growing media (GM) on N mineralization rates and microbial activity in controlled microcosms and commercial greenhouse conditions.
The in vitro incubation experiment was conducted over 56 days to compare the mineralization rate of 10 organic fertilizers, including animal and plant-based types, on two new peat-based GM (one with wood fiber) and a 5-year-old GM from Cultures Gen V Inc. (Quebec, Canada). For most fertilizers, the greatest percentage of mineralized N was observed after 14 or 28 days of incubation and ranged from 30 to 80% to the total N. Fertilizers like poultry pellets and blood meal exhibited high N mineralization rates, while alfalfa meal, feather meal, and soy hydrolysate exhibited low mineralization rates.
Microbial activity varied significantly among GM types, with peat-and-wood fiber-based GM showing the highest activity at certain stages.
The commercial greenhouse experiment measured the impact of the same three GM types and six organic fertilizers on the growth of sweet pepper and cucumber crops.
While GM type did not affect cucumber productivity, sweet peppers in the 5-year-old GM showed a 27% decrease in yield compared to new peat-based and peat-and-wood fiber-based GM for the first crop, while no significant difference was observed for the second crop.
On the other hand, fertilization strategies based on plant or animal-derived fertilizers, including the control (animal source), showed no significant differences in growth and productivity in greenhouse commercial trials.
This study, characterizing the mineralization rates of various organic fertilizers in two new GM compared with a 5-year-old GM, showed that substituting a portion of animal-based fertilizers with plant-based sources and reusing the same GM during several years is an interesting approach to enhance the sustainability of organic soilless cultivation.
Authors
P. Vézina, T.T.A. Nguyen, A. Barrada, A. Brégard, J. Dessureault-Rompré, M. Dorais
Keywords
nitrogen mineralization, growing media, organic fertilizers, crop productivity
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