Hydroponic cultivation or soil cultivation?
Introduction
Hydroponics seeks to grow plants without soil. But is this any better? In this post, we are going to take a deep dive into the peer-reviewed literature comparing soil crops with hydroponic ones. We are going to look at papers that compare yields, quality, cost, and environmental impact. This will help us determine which growing method is better and under which circumstances. In this comparison, “hydroponics” encompasses any crop grown without soil, including those grown in soilless media.
How to compare
It can be hard to compare soilless and soil culture due to the many ways in which both can be done. Soil crops can be grown with or without fertilization, with or without irrigation restrictions, organically or with synthetic fertilizers, in a greenhouse or the field, etc. Different soils can also have widely different qualities and properties. Similarly, hydroponic crops use a wide variety of different systems and nutrient solutions. For this reason, I will focus my analysis on publications that try to directly compare products grown under both methods by the same researchers.
I will also look into literature reviews that try to describe the global picture. These articles can be important, as they can help us evaluate the impact of soil and soilless culture on a much larger scale. These can help us see the impact of all the different methods used and how tilting the scale one way might affect the big picture.
Quality
Many different studies have compared the quality of vegetables and fruits grown in hydroponic and soil cultures. The table below, shows you some of these studies and my assessment of the “winner” in each one, given their conclusions. I also analyzed these reviews on the matter (12, 13) that looked at the publications on the subject.
Different studies comparing soil and hydroponic crops
The above results show us that, while hydroponics can produce better or equal results compared with soil, it is by no means guaranteed to do so. If the conditions of the hydroponic system are not adequately controlled or the soil is of much higher quality, the hydroponic system might perform worse.
Neither soil nor hydroponic systems are a guarantee of better or worse quality. It is false to assert that soil crops – even those grown organically, as in some of the above studies – can always provide better results compared to a hydroponic crop. Nutrient density, freshness, taste, and quality can be just as good or even better in a hydroponic system.
However, because of the larger control that the grower exerts in a hydroponic system, it is probably easier, on average, for an inexperienced grower to deliver better results in soil. This is because soil culture is more forgiving, and takes care of more aspects that a grower would have to directly control in a hydroponic system, such as root zone chemical conditions.
Returns
In the table below, we have examined the efficiency and a series of other factors such as the ability to sell pumpkin in substrates including coco peat, peat moss, pumice and perlite separately.
None of the articles I reviewed on this subject were superior to crop crops. All articles showed an increase in yield in terms of yield per plant or area under hydroponic cultivation. However, it was difficult to find articles that directly compared soil-free and soil-free growing methods in terms of yield. This is probably because it is generally thought that hydroponic crops always produce more per hectare, so few of them bother to study this difference directly.
The extent of the performance difference is also interesting. Although the article on “hydroponic efficiency” mentions differences as large as twice the magnitude, studies show that the differences are always less than one magnitude and in most cases less than twice the magnitude of the increase. This means that although hydroponic crops are more productive in each region, it is unreasonable to expect a 10-fold increase in yield when moving from soil to soilless cultivation.
Depending on the product, an increase of only 20 to 30 percent may be reasonable. It is also important to understand that higher efficiencies are associated with more complex hydroponic settings. For this reason, the highest reported return on investment may only be available through much larger investments.
environmental effects
The environmental impact of hydroponic products largely depends on how they react with nutrient solutions. Open hydroponic systems consume significantly more water and fertilizer than closed systems. In closed systems, the type of system and the efforts made to treat and reuse the nutrient solutions play a key role in determining the environmental impact. With this in mind, an open hydroponic system is highly adverse in terms of environmental impact. However, if you are treating runoff, this is desirable in a soil system that uses synthetic fertilizers.
Note that the environmental impact of hydroponic systems is greatly enhanced by the use of artificial lighting. If so, the soil-based approach will always be less effective, unless renewables are used to generate energy.
In the case of soil, the environmental effects can vary greatly depending on the growing methods used. Organic growth methods have a significantly lower impact compared to traditional soil agriculture, mainly due to lower energy consumption and to prevent contamination of soil and aquifers with large amounts of nitrate and phosphate.
When considering environmental impacts, it is also important to consider performance in each area. While a closed hydroponic crop may have a greater environmental impact per hectare of land used than an organic soil crop, if it produces 3 times as much crop, the environmental impact of each gram of fruit or vegetable produced may be much less. Be.
Although I have not been able to find any direct studies comparing the environmental effects of soil and hydroponic methods, it is reasonable to think that a closed hydroponic system should have less environmental impact per gram of crop, as long as the yield in each area is significant. Compared to the higher organic soil approach.
However, an approach that uses low energy inputs, uses water very efficiently, and has a high planting density may be the ideal growth system in terms of environmental impact. If you are interested in this topic, I suggest you read my blog post about aquaponics. Closed hydroponic systems that use treated wastewater instead of freshly prepared hydroponic nutrients may also be very inefficient and highly efficient systems.
Cost
Money is important in agriculture because it is the main driver in determining the growth system. Hydroponic products have a higher start-up cost compared to soil. This is because minimum hydroponic regulation is significantly more complex than minimum soil regulation. However, even when greenhouses are involved, setting up hydroponics will often have higher start-up costs.
Although start-up costs are higher, the life cycle costs of hydroponic start-ups can be lower due to higher yield, fertilizer and water use efficiency. This is especially true when growing high-yield crops such as lettuce. In this study, they compared the yield, cost, and water efficiency of different hydroponic and protected soil assemblies. Hydroponic NFT startups were much more efficient in water consumption and much more economically feasible.
Hydroponic crops also have access to areas that are not traditionally suitable for soil farming. For example, hydroponic products can be planted on rooftops and in some cases generate significantly more money than solar panels. In this case, hydroponic crops fill a niche that has no equivalent comparable to soil, because the area is never used by soil farming.
Result
The best soil cultivator is better than the worst hydroponic grower. The best hydroponic breeder is better than the best soil breeder. The most important thing when you decide to grow in a certain way, is to try to do it in a way that leads to higher quality, maximum efficiency, reduced environmental impact and, if possible, low cost.
Soil agriculture has its place. It is cheaper to start, requires less material, can be done on a much larger scale, and if done correctly can produce lasting and quality results. Hydroponic cultivation offers higher yields in each region, fewer potential environmental impacts and lower life cycle costs. However, it is more expensive and requires more knowledge and care to provide comparable results.
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