Science and Technology of Organic Farming

Allen V. Barker

• Editorial: CRC Press
• Año: 2021
• ISBN:
  9781000352245
• Edición: 2
• Categoría: Biowissenschaften
• Categoría: Biologie

Organic farming is not only a philosophy; it is also a well-researched science. The second edition of The Science and Technology of Organic Farming presents the scientific basis of organic farming and the methods of application needed to achieve adequate yields through plant nutrition and protection.

Organic farming is a scientifically derived method of improving soil fertility to increase agricultural yields with limited chemical inputs. As such, it can meet public demand for reduced chemical inputs in agriculture and play a key role in meeting the needs of a growing world population. The new edition of this highly regarded book gives clear and comprehensive details on how soil fertility can be maintained and how plants can be nourished in organic agriculture.

• Chapters on soil fertility and plant nutrition explain the chemistry of the plant, the soil, and the soil solution and outline the importance of plant macronutrients and micronutrients.
• The book offers practical information on using of green manures, composts and lime to maintain soil fertility; introduces methods of tillage of land; provides organic methods of controlling weeds, insects, and diseases; and suggests how food produce can be stored without refrigeration.
• The text provides information on how to assess and govern the nutritional status of crops and the fertility and condition of soil and presents guidelines, recommendations, and procedures for determining the best fertility recommendations for individual situations.
• This edition includes an entirely new chapter on hydroponics that explains organic approaches to hydroponic crop production.

With a full bibliography of references, this text is a practical guide for anyone interested in organic farming, from farmers and agricultural advisers to teachers, soil scientists, plant scientist, entomologists and students of other biological and environmental sciences.

1	Definitions and Philosophies of Organic Farming

History and Background

The term “organic farming” was introduced into common usage around 1940, following farming movements that had begun in the 1920s and 1930s promoting the concept of management of a farm as a living unit or whole system. During the period of the 1920s and 1930s, Albert Howard in the United Kingdom based on his work in India laid out the social and practical groundwork for the organic gardening movement. Rudolph Steiner, through his lectures and teaching beginning in 1924, laid the foundation for biodynamic agriculture, which created the first organic-like certification and labeling system. However, biodynamic agriculture differs from organic agriculture in that the biodynamic system has spiritual, mystical, and astrological guidelines that are not part of conventional organic farming. Lord Northbourne (Walter James, 1896–1992), an agronomist in England, in reference to farming, introduced the term “organic” to the World in 1940 in his book Look to the Land. J.I. Rodale, introduced the organic movement to the United States about 75 years ago with publications that advocated for health through farming organically. During the 1940s, the Rodale Institute (United States), the Soil Association (United Kingdom), and Soil and Health (New Zealand) were founded as associations devoted to the study and promotion of organic farming. Similar organizations arose in Germany and Japan at about the same time or just following the establishment of the institutions in the United States, the United Kingdom, and New Zealand.

At the time of the early development of the organic movements, however, use of chemical fertilizers and pesticides was very modest compared to current practices; hence, the development of organic farming not only was related to the materials used for soil fertility and crop protection but also had a base of managing a farm as a system with integration of soils, crops, animals, and society. This concept of a systematic approach is fundamental in organic farming today and is expressed with opposition to the production of genetically engineered crops and irradiation of foods, among other practices. The association of organic agriculture with environmental sustainability arose in the 1960s and 1970s and brought about changes in the politics and social elements of organic farming. The involvement of governmental agencies in organic farming increased markedly during the 1980s and afterward.

Until recently with the applications of legal restraints to organic farming, no universally accepted definition or identification of organic farming and gardening was developed. The difficulty of defining organic agriculture arose from multiple conceptions of the basic nature of the term “organic” among biologists, chemists, and practitioners. In some cases, terms such as “naturally grown”, “wild”, “biologically grown”, and “ecologically grown” were used to characterize organic production. Interpretation and application of these terms are often as difficult as defining organic farming. Some people say that organic farming is agriculture that is based on the use of crop rotations, cover crops, composts, and nonchemical means of pest control and that excludes the use of manufactured fertilizers or pesticides. That concept is limited in scope and does not cover the diverse practices and restrictions of organic farming. Some people say that organic farming can occur only in soil or cropland.

In the early years, about 1940 to 1970, of organic farming, the practice was essentially local operations with much contact between consumers and farmers or retailers. With the expansion of organic production and markets in the 1970s, this association became more remote, and consumers, growers, and marketers needed means of proving that produce was organic. These needs led to the formation of certifying agencies that would vouch that the produce was grown organically and permit labeling of produce as being organically grown. By the 1980s, several private and state-run certifying agencies were operating in the United States. These agencies had variable standards for certification and charged variable fees for services. Some agencies did not recognize certifications by other agencies. Many regions of the country did not have locally accessible certifying agencies. These differences created problems of lack of certification, lack of uniform standards, unreasonable fees, and even fraud. To address these problems, the organic community sought federal legislation to enact national standards for certification of organic farming. This action led to the Organic Foods Production Act of 1990 and the establishment of the National Organic Program (NOP) of the United States Department of Agriculture. The NOP sets regulations for certification. The NOP regulations are implemented through certifying agencies that are accredited by the NOP. Accreditation ensures that the certifying agencies understand and use the regulations of the NOP and conduct business properly. Certification applies to crops and crop products and to livestock, poultry, and products of their production. The certification practices referred throughout this book are those established by the NOP for the United States. Several hundred governmental and nongovernmental organizations in the World offer certification systems. Governmental organizations have increased in prominence and importance as the volume and value of organic production has increased.

The regulations of the NOP establish transition periods for movement from conventional farming into organic agriculture. A transition period is generally 3 years following the ending of applications of nonorganic practices. Some agencies may aid growers in selection of crops to grow during the transition period. In practice, growers may certify part of a farm and leave the rest in conventional agriculture. In that case, buffer zones between the organic farm and the conventional farm operations must exist. Regulations specify what physical distance or barriers are needed to separate the organic areas from conventional areas. Produce from mixed systems must be segregated at harvest. The regulations of the NOP also establish materials that are permitted, restricted, or prohibited for use in organic agriculture. Permitted materials can be used regularly in organic farming. Items that are restricted can be used only within the limitations set by the NOP standards. For example, farm manures need to be composted or an amount of time between application of the manure to cropland and harvest of produce must lapse to meet the organic standard. Prohibited materials cannot be used in organic production. Prohibited materials may be naturally occurring or manufactured. Consequently, definitions of organic agriculture by the NOP include listings of allowable practices in fertilization of crops, control of pests, and use of adjuvants (materials that affect the activity of other agents but that have little effect when supplied alone). Restriction of activities to those allowed in the listings and following specified practices of crop and soil management may permit a grower or the grower’s produce to be certified as organic.

Organic certification is a legal process for producers of food and other agricultural products to be able to sell products as organic. Certification also can include seed suppliers, food processors, retailers, and restaurants. The organic brand provides consumers with verified choices in the marketplace. Certification is mainly by private organizations or agents that work with development and review of allowable practices for growers who want to market their produce as organic according to USDA standards. Most USDA-accredited agents are authorized to certify farms and businesses anywhere in the world. However, many countries have their own certification standards. Farmers, ranchers, and processors may choose to work with any USDA-accredited certifying agent.

Types of certification vary. Certification can be for products that are labeled as “100% organic”, “organic”, “made with organic ingredients”, or “products with less than 70% organic ingredients”. The grower or handler and certifier agree on a production or handling system that is appropriate for each classification. The certifier provides growers with definitions, guidelines, practices, and lists of materials that may be used in organic farming. A NOP of allowed and prohibited substances that can be used in organic farming is followed. This list includes natural and synthetic substances that are allowed or not allowed.

Growers that have sales of less than US$5,000, currently, do not to be certified by agencies to market produce as organically grown, but the production standards of organic farming should be followed. Certification is not covered in this book, and people interested in the details should consult the entries on certification and the NOP that are presented in the Bibliography.

Organic Materials Review Institute (OMRI) Products List

The OMRI Products List is a list of products that the Organic Materials Review Institute (OMRI, Eugene, Oregon) has determined are allowed for use in organic agriculture, including production, processing, and handling of farm-grown commodities. The products are reviewed for compliance with the policies of the USDA NOP, and if they pass the review, the products are included on the OMRI Products List. Products on the list can carry the OMRI-listed seal, ensuring that the product listed meet NOP standards. The OMRI review program is private, and participation by providers is voluntary and has a fee. Hence, a product may not be on the list and yet may meet NOP standards. Growers should consult the NOP list or their certifying agency for compliance of items not on OMRI Products List.

Other Concepts and Background

Many people are not interested in certification for commercial organic agriculture and may want to develop their own working definitions. An understanding of “organic” as this term is defined by different scientists is helpful in definition of organic agriculture. To biologists, organic means existing in or derived from a living organism. This definition is not unambiguous, for arguments may be made about the levels of existence in an organism, about contamination, and about modifications that may occur after the death of an organism. In chemistry, organic refers to the study of carbon-containing compounds with exception of some compounds, such as carbonates, which are considered to be inorganic compounds. Combination of these two definitions into one may indicate that organic farmers and gardeners can work with carbon-containing materials obtained from organisms. Working with this combined definition, one could be a successful organic grower but would not be using the materials that would be permitted if the definitions were applied singularly. Limestone, largely calcium carbonate, is derived from living organisms and is an inorganic, carbon-containing compound. Diatomaceous earth for insect control is mostly silica, is strictly inorganic in chemistry, but is derived from unicellular algae, which are organisms. Rocks and minerals, such as granite dust and greensand, are considered to be organic fertilizers by some people, and these materials were never living and are essentially void of carbon.

Organic farming has been defined as crop or animal husbandry with natural materials, whether these materials are from living or nonliving matter. The weakness of this definition in certification or in practice is in the use of the words “natural materials”. Not all natural materials are considered organic materials by the National Organic Program. Potassium chloride is a naturally occurring fertilizer, but because of its high concentration of nutrients and high solubility, it does not qualify unrestricted as being organic on the lists of certifying organizations. On the other hand, potassium sulfate and potassium magnesium sulfate (langbeinite) are considered organic materials. Mined potassium chloride might be considered organic, however. Water-extracted potassium chloride might not be organic. Cottonseed meal is suspected of contamination with insecticides used in cotton growing and is restricted in use in organic farming. One might ask then if cottonseed meal should be considered organic if it is from genetically engineered cotton to which insecticide application is limited by crop improvement. Use of sewage sludge is prohibited because of the fear of contamination of land by heavy metals transmitted by the sewage sludge. However, application of sewage sludge is regulated heavily, and metal-contaminated sludge is not permitted to be applied to farmland.

Naturally occurring is a restrictive term and does not permit the use of manufactured materials, even though they may be identical to the materials produced in nature. For example, urea from the fertilizer plant is chemically equivalent to urea that is in urine. The latter source would be considered organic, whereas the former would not. Because of the potency of potassium chloride and fertilizer urea, these materials are not “organic” even though they are naturally occurring or identical to naturally occurring material. Some growers may recognize that the discrimination against these materials is due to the lack of understanding of how to use them. Growers who are educated on their use may feel that they can use potassium chloride and fertilizer urea and justify for their own interests that they are organic growers, but they cannot be certified as organic growers by the USDA.

Yet, strict definitions mandate that organic fertilizers be naturally occurring. A corollary to this definition is that the fertilizers be of low solubility or low in nutrients or have both properties. Potassium chloride does not meet the stipulations of the corollary. Rock phosphate is naturally occurring and has a high phosphorus concentration but has low solubility and is therefore organic.

Physical treatment of materials normally is permitted. Rock phosphate is ground to silt-sized particles to increase the availability of its slowly soluble nutrients. Chemical treatment of rock phosphate with acids to manufacture superphosphates is not an organic practice, unless the treatment occurs in some natural process, such as mixing rock phosphate with decaying organic matter or mixing it in acid soils. Wood ashes are organic materials, although they are not naturally occurring in the context in which they are considered organic fertilizers. Hence, it is evident that a lot of judgment goes into the definition of organic fertilizers. The NOP publishes a national list of allowed and prohibited substances for use by certifying agents, and growers who are not seeking certification may want to consult this list.

Organic control of pests involves diverse activities. Generally, sprays or dusts derived from natural sources are considered organic. In some cases, a few manufactured, extracted, or purified products are permitted, as with oils and soaps used in insect control and copper compounds used in disease control. Lack of mammalian toxicity or lack of injury to beneficial organisms is not necessarily a firm characteristic of organic pesticides. Organic sprays and dusts may be highly toxic, abrasive, or otherwise destructive to people, livestock, pets, fish, bees, and other organisms that are not targets for harm.

Organic control may involve cultural practices that limit the spread or growth of pests. These practices may include biological control or natural control of pests. Biological control involves introduction of organisms that eat, kill, or impede the growth of pests. Natural control involves taking advantage of these organisms already existing in the environment without their intentional introduction. Integrated pest management (IPM) is a practice that tries to use naturally occurring organisms in pest control along with the use of conventional pest-controlling chemicals and a combination of cultural practices and use of pest-resistant crop varieties. Use of barriers and traps, rotation of crops, drainage, fertilization, liming, and sanitation are cultural practices for pest control in organic agriculture. Many of these practices are in common with those used in conventional agriculture.

Many myths must be dispelled in discussions of organic agriculture. Organic agriculture is a highly managed system. Production of wild crops can be certified. An abandoned farm is not an organic farm. Failure to fertilize a crop is not an organic practice. Infestation of produce with insects is not a characteristic of organically grown material. Old or ancient practices are not necessary organic ones. One cannot say that once upon a time, all farmers were organic farmers. Once upon a time, the most common practice was to not fertilize crops. Products such as lead or copper arsenate were used formerly for insect control. These products are not organic.

The organic farmer needs to be a scientist more than a philosopher. The organic farmer must separate fact from myth and the occasional occurrence from the rule.

Practices Related to Organic Farming

Biodynamic Farming and Permaculture are systems of agriculture that have practices and concepts contributing to or added to foundations of organic farming. Biodynamic farming in a sense was a forerunner of organic agriculture as it was first outlined in the 1920s by an Austrian philosopher, Rudolph Steiner. For a farmer to be certified as a biodynamic farmer, the farmer must be certified also as an organic farmer. The Demeter Association certifies biodynamic farmers. The system of permaculture was developed by Australians Bill Mollison and David Holmgren, in the 1970s. The word permaculture is derived from permanent agriculture and permanent culture.

Biodynamic Farming

In the 1920s, Rudolph Steiner outlined principles of biodynamic farming. A basic concept of biodynamic farming is the view of a farm as an organized, self-contained entity or as an organism with its own individuality. The farm is viewed as a closed, self-nourishing system. A biodynamic farm has an integration of crops with livestock and includes recycling of nutrients and management practices that involve environmental, social, and financial aspects of the farm. Although organic farming is basic to biodynamics, biodynamics is different in that it has an association with spiritual and astrological factors and emphasizes farming practices that have a balance between physical and higher, nonphysical realms that include the influence of cosmic and terrestrial forces on the farm. A certification system called Demeter was established in about 1924 for biodynamic farming.

Biodynamic farming can be div...