Organic materials: sources of nitrogen in the organic production of lettuce

When people walk into the grocery store and proceed to the fresh produce section. Often they are faced with a difficult question. Do I want organic lettuce or mass produced lettuce? Some choose the mass produced lettuce for reasons such as cost and quantity. Others are starting to choose the organic brands for a sense of better well-being. The organic brands tend to be more expensive than the mass produced brands, but they come with the peace of mind that they were grown in a natural environment. The organic farms don’t use pesticides or artificial manures. Since they don’t use artificial manures organic farmers have to find another way to enrich their soil with nutrients like nitrogen. Materials like animal manures, guano, soybean seeds, and forage pea see, are all naturally occurring compounds that contain lots of nitrogen (Maja, 2000). What people don’t know is do they work the same? Which one requires more work?

Scientists from Serbia and Slovenia recently published their findings from a two yearlong study looking at the nitrogen residue left from organic fertilizers compared to inorganic, and the rate at which the nitrogen became usable for the plants or mineralization rate. They did this by testing four different organic manures and compared it to a control. The materials tested consisted of farmyard manures, guano, soy beans, and forage seed. This was done by creating controlled environments within PVC containers. These containers were each treated with a fertilizer and were used to grow lettuce. Scientists Maja MANOJLOVIĆ1, Ranko ČABILOVSKI1, and Martina BAVEC conducted several tests on the lettuce and the soil in the environment in which the lettuce was grown. They paid particular attention to attributes like rate of nitrogen absorption, the rate at which nitrogen becomes useful to plants, and the amount of nitrogen left over once the plants have been harvested for each fertilizer (Maja, 2000). The data collected was then analyzed and conclusions drawn.

What was found during this study was interesting, in the fact that there was a minimal difference between organic fertilizers and artificial fertilizers (Maja, 2000). Though organic fertilizers are much less expensive and more cost effective it would make sense that organic farming would be more popular. Unfortunately organic farming is more expensive because it takes longer and there is a smaller yield. Though organic farming can be made cheaper due to studies like this one, since the study found that although the totally amount of nitrogen found in a fertilizer may differ from fertilizer to fertilizer, they may have the same output of nitrogen. This is because of the different chemical make-up of the different fertilizers. The study found that guano had the least amount of nitrogen content within it, but released the same amount of nitrogen as a manure fertilizer (Maja, 2000). This idea can have a great change on the way farmers choose to fertilize their fields. If a farmer is able to understand the rate at which nitrogen is released from the fertilizer he is using, there is a potential to be able to use smaller amounts of inexpensive organic materials rather than a large amount artificial fertilizer. Allowing farmers to save money on fertilizer and use it somewhere else.

The study also showed that along with artificial fertilizers, organic fertilizers if over used can have a nitrogen residue left in the soil after the plants are harvested. This is due to over fertilization, and can become a problem when the left over nitrogen residue forms into a nitrate. Nitrates often get into the water table and pollute ground water due to the run off from fertilized fields. Forage pea seed was the organic fertilizer that left the most nitrogen residue within the soil (Maja, 2000). It also showed that there was a connection between the climates that the fertilizers were used in drastically affected the rate of the nitrogen mineralization, and the amount of nitrogen residue left in the soil (Maja, 2000). With this being said each type of fertilizer has its positives and negatives.

Organic and artificial fertilizers each provides their own different advantages when put to use. In the study Organic materials: sources of nitrogen in the organic production of lettuce, different types of organic materials were used and tested to determine how much of a difference there was between organic and artificial fertilizers. From what was discussed within the journal one could deduct that the soils are almost the same. Each soil has specific attributes that make them better for certain situations and others do not. This meaning that when the lettuce was grown in the entire different sample there was little to no difference in growth of the plant. With that in mind and the new push for healthier lifestyles, just know the plant will grow virtually the same in organic fertilizers.

Bavec, M. , Cabilovski R. , Manojovic M. (2000). Organic materials: sources of nitrogen in the organic production of lettuce.

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