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Take a closer look at the relationship between agriculture and the environment in this new series from PPI/PPIC ... called Enviro-Briefs. These short articles present important facts and observations on the interaction among crop production, nutrients, and the Earth's air, water, and soil resources. Consumers, students, agronomists, farmers, and all who are interested in the environment will find this series informative and easy to read. Click on the topics below for complete articles.
 Crop Plants Take Up (Absorb) Nutrients in Inorganic Form
There is an ongoing debate as to the relative advantages and disadvantages of organic farming compared to conventional farming. At the center of the issue is the use of organic nutrient sources – animal manures, plant residues, and biosolids – versus manufactured (mineral) fertilizer sources. While the resolution of the overall debate involving organic and inorganic remains to be found, crop preference for nutrient sources is a given. Crops take up (absorb) and use inorganic nutrient forms.
 Organic or Inorganic: Which Nutrient Source Is Better for Plants?
A quick answer to the question asked in the title is that neither organic nor inorganic (manufactured or mineral) nutrient sources are better for plants. Both have their places and should be used where appropriate. Each has its advantages and disadvantages. Their relative merits need to be explored further, however.
 Crop Fertilization Improves Soil Quality
Consider all the roles the soil plays in the production of food and fiber for the world’s people. It is the medium in which plants grow and the source of most plant nutrients. Soil water and air bathe plant roots and help keep them and above-ground plant parts healthy and growing. The quality of soil in which plants grow is extremely important in determining yield potential as well as the sustainability of crop production.
 Nutrient Balance: Critical to Crop Production and Environmental Protection
People and crop plants are a lot alike in several ways, one in particular. They both need balanced nutrition for normal growth and good health. Unlike people (who require a variety of foods) crop plants need only 17 nutrients, some obtained from air and water, to grow normally – if those nutrients are supplied in the proper balance. When crops have balanced nutrition, an added bonus is increased environmental protection.
 Nutrient Balance Can Be Achieved Using Both Inorganic and Organic Sources
The impact of modern agriculture on the environment has been the subject of much discussion. Some challenge the sustainability of high yield crop production, particularly from an environmental standpoint. Some claim that any synthetic input—such as commercially produced mineral (inorganic) fertilizers—will eventually damage, if not destroy, the environment. The fact is that nutrient balance, using both inorganic and organic sources, goes hand-in-hand with high yield agriculture and environmental protection.
 Nutrient Use and Beneficial Soil Organisms
Soil organisms are essential to crop production. In addition to their role in soilforming processes, they are important recyclers of soil nutrients. A major benefit is to break down organic materials in crop residues and release the nutrients they contain in the inorganic form so crop plants can use them.
 Crop Fertilization and Heavy Metal Accumulation in Soils
Trace elements and heavy metals occur naturally in all agricultural soils. Several of them are either essential or beneficial to plants as well as animals. However, they can become toxic if accumulated in excessive amounts. Proper fertilization, which results when both agronomic and environmental considerations are included in the development of a nutrient management plan, can prevent or greatly reduce the potential for such toxicities.
 Crop Fertilization and Water Quality
By developing nutrient management plans and fertilizing according to soil tests, farmers help to assure that most of the fertilizer nutrients they apply are taken up by the crop being grown, not left in the soil for possible entry into nature’s water system. Nitrogen (N) and phosphorus (P) are the only nutrients of concern with regards to potential water problems from fertilization. But, when they are used in balance with other essential nutrients such as potassium (K), and within systems utilizing best management practices, there is little danger to either surface water or groundwater.
 Managing Nitrogen to Protect Water
Nitrogen fertilization is essential to crop production. Farmers can’t grow enough food to meet ever increasing world demands without it. The good news is that with proper management of available N fertilizer sources, farmers can achieve their yield goals and sustain water quality at the same time.
 Phosphorus Fertilization and Environmental Protection
There is no question that phosphorus (P) is essential to crop production. Agronomically, it is one of the three primary plant nutrients, along with nitrogen (N) and potassium (K). It is also essential for healthy fish and other aquatic life in our lakes and streams.
 Crop Production and Environmental Protection
Since man first began to cultivate the soil for the purpose of growing food, crop production has had an impact on the environment. It affects both soil and water quality, and those effects have not always been positive.
 Human Health and the Use of Animal Manure in Crop Production
Animal manure (and certain other organic materials) is a good source of essential plant nutrients when properly used. It improves soil fertility and biological and physical properties. However, manure has several disadvantages when compared to commercially produced fertilizers, including low nutrient content and high volume, making it uneconomical to transport far from its production source.
 Aglime…It’s Good for the Environment
Farmers apply aglime to neutralize soil acidity...and for a host of other reasons. Aglime improves the physical, chemical, and biological conditions of soil. It increases crop growth and improves nutrient and water uptake, which helps protect the soil from wind and water erosion. It enhances the effectiveness of some herbicides and improves fertilizer nutrient efficiency.
 Crop Fertilization and Air Quality
Improved fertilizer management can help to eliminate most losses of the global warming gases. High, efficiently produced crop yields can actually contribute to a drop in the production and release of global warming gases, particularly CO2, because of crop fertilization.
 Crop Fertilization Helps Stabilize Carbon in the Soil
The primary role of crop fertilization has been and will continue to be that of increasing crop yield and quality. An additional environmental benefit of fertilization is that it contributes to the stabilization of carbon (C) in the soil.
 Does Fertilizer Harm Soil Microbes?
Microbes in the soil are important to the nourishment of plants. Many of them facilitate the chemical conversions and physical transport needed to make nutrients available. Some also claim that applying soluble forms of plant nutrients harms the biology in the soil and reduces its capacity to make the native soil nutrients available. Let’s look at the evidence. |
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