Agriculture waste can be a significant issue in waste management as its impact can be felt far from its place of origin. Post-harvest crop residues require clearance prior to the next planting and a common practice is burning on the field. The uncontrolled burning results in air pollution and can adversely impact the environment far from the burn site. Agriculture waste can also include animal husbandry waste such as from cattle, swine, and poultry. Animal manure not only causes odors but also pollutes water if discharged untreated. However, agricultural activities, particularly on a large scale, are typically at some distance from urban centers. The environmental impacts associated with production may not be well recognized by the consumers. As the consumption terminal of agricultural produce, urban areas in turn generate food waste, which can contribute significantly to municipal solid wastes. There is a correlation between the quantity of food waste generated and a community’s economic progress.
Managing waste carries a cost, which may illustrate cost transfer from waste generators to the public. However, waste need not be seen only as an unwanted material that requires costly treatment before disposal. The waste may instead be perceived as a raw material for resource recovery. For example, the material may have substantial quantities of organic carbon, which can be recovered for energy generation. This offers opportunity for producing and using renewable and environment-friendly fuels. The “waste” may also include quantities of recoverable nutrients such as nitrogen and phosphorus.
Article
Food Waste and Biomass Recovery
Wun Jern Ng, Keke Xiao, Vinay Kumar Tyagi, Chaozhi Pan, and Leong Soon Poh
Article
Tomatoes: A Model Crop of Solanaceous Plants
Raheel Anwar, Tahira Fatima, and Autar K. Mattoo
The modern-day cultivated and highly consumed tomato has come a long way from its ancestor(s), which were in the wild and not palatable. Breeding strategies made the difference in making desirable food, including tomato, available for human consumption. However, like other horticultural produce, the shelf life of tomato is short, which results in losses that can reach almost 50% of the produce, more so in developing countries than in countries with advanced technologies and better infrastructure. Food security concerns are real, especially taking into consideration that the population explosion anticipated by 2050 will require more food production and the production of more nutritious food, which applies as much to the tomato crop as the other crops. Today’s consumer has become aware and is looking for nutritious foods for a healthful and long life. Little was done until recently to generate nutritionally enhanced produce including fruits/vegetables. Also, extreme environments add to plant stress and impact yield and nutritional quality of produce. Recent developments in understandings of the plant/fruit genetics and progress made in developing genetic engineering technologies, including the use of CRISPR-Cas9, raise hopes that a better tomato with a high dose of nutrition and longer-lasting quality will become a reality.
Article
Ancient and Traditional Agriculture, Pastoralism, and Agricultural Societies in Sub-Saharan Africa
Andrew B. Smith
African domesticated animals, with the exception of the donkey, all came from the Near East. Some 8,000 years ago cattle, sheep, and goats came south to the Sahara which was much wetter than today. Pastoralism was an off-shoot of grain agriculture in the Near East, and those herders immigrating brought with them techniques of harvesting wild grains. With increasing aridity as the Saharan environment dried up around 5000 years ago, the herders began to control and manipulate their stands resulting in millet and sorghum domestication in the Sahel Zone, south of the Sahara. Pearl millet expanded to the south and was taken up by Bantu-speaking Iron Age farmers in the savanna areas of West Africa and then spread around the tropical forest into East Africa by 3000 b.p. As the Sahara dried up and the tsetse belts retreated, sheep and cattle also moved south. They expanded into East Africa via a tsetse-free environment of the Ethiopian highlands arriving around 4000 b.p. It took around 1000 years for the pastoralists to adapt to other epizootic diseases rife in this part of the continent before they could expand throughout the grasslands of Kenya and Tanzania. Thus, East Africa was a socially complex place 3000 years ago, with indigenous hunters, herders and farmers. This put pressure on pastoral use of the environment, so using another tsetse-free corridor from Tanzania, through Zambia to the northern Kalahari, then on to the Western Cape, herders moved to southern Africa, arriving 2000b.p. They were followed to the eastern part of South Africa by Bantu-speaking agro-pastoralists 1600 years ago who were able to use the summer rainfall area for their sorghum and millet crops.
Control and manipulation of African indigenous plants of the forest regions probably has a long history from use by hunter-gatherers, but information on this is constrained by archaeological evidence, which is poor in tropical environments due to poor preservation. Evidence for early palm oil domestication has been found in Ghana dated to around 2550b.p. Several African indigenous plants are still widely used, such as yams, but the plant which has spread most widely throughout the world is coffee, originally from Ethiopia. Alien plants, such as maize, potatoes and Asian rice have displaced indigenous plants over much of Africa.
Article
Crop Rotations, Fallowing, and Associated Environmental Benefits
Faisal Nadeem, Ahmad Nawaz, and Muhammad Farooq
Planned crop rotation offers a pragmatic option to improve soil fertility, manage insect pests and diseases, and offset the emission of greenhouse gases. The inclusion of legume crops in crop rotations helps to reduce the use of external nitrogen inputs for legumes and other crops because legumes may fix the atmospheric nitrogen. This also helps to reduce the environmental pollution caused by volatilization and leaching of applied nitrogen. The inclusion of allelopathic crops in rotation may be useful to suppress noxious weeds due to release of the allelochemicals in the rhizosphere. The rotation of tap-rooted crops with shallow rooted crops may result in efficient and productive use of nutrient resources and conservation of soil moisture. Continuous monoculture systems may cause the loss of biodiversity. Land fallowing is an efficient agricultural management technique mostly practiced in arid regions to capture rainwater and store it in the soil profile for later use in crop production. During fallowing, tillage operations are practiced to enhance moisture conservation in the soil. Keeping soil fallow for a season or more restores soil fertility through nutrient deposits; increases organic matter, microbial carbon, and soil microbial diversity; and improves the soil’s physical properties, including aggregation stability and reduced soil compaction due to decreased traffic. In addition, fallowing of land provides biological means of pest (weeds and insects) control by disrupting the life cycle of pests and decreasing reliance on pesticides. Land fallowing can help offset the emission of greenhouse gases from agricultural fields by reducing traffic and increasing carbon sequestration within the soil. Summer fallowing may help to preserve moisture in diverse soil types in the rainfed regions of the world, although it may reduce the carbon sequestration potential of soils over the long term. Energy resources are decreasing, and the inclusion of energy crops in crop rotation may be highly beneficial. Many of the processes, factors, and mechanisms involved in crop rotation and land fallowing are poorly understood and require further investigation.
Article
Soil Tilth and Management
Lars J. Munkholm, Mansonia Pulido-Moncada, and Peter Bilson Obour
Soil tilth is a dynamic and multifaceted concept that refers to the suitability of a soil for planting and growing crops. A soil with good tilth is “usually loose, friable and well granulated”; a condition that can also be described as the soil’s having a good “self-mulching” ability. On the other hand soils with poor tilth are usually dense (compacted), with hard, blocky, or massive structural characteristics. Poor soil tilth is generally associated with compaction, induced by wheel traffic, animal trampling, and/or to natural soil consolidation (i.e., so-called hard-setting behavior). The soil-tilth concept dates back to the early days of arable farming and has been addressed in soil-science literature since the 1920s. Soil tilth is generally associated with soil’s physical properties and processes rather than the more holistic concepts of soil quality and soil health. Improved soil tilth has been associated with deep and intensive tillage, as those practices were traditionally considered the primary method for creating a suitable soil condition for plant growth. Therefore, for millennia there has been a strong focus both in practice and in research on developing tillage tools that create suitable growing conditions for different crops, soil types, and climatic conditions. Deep and intensive tillage may be appropriate for producing a good, short-term tilth, but may also lead to severe long-term degradation of the soil structure. The failure of methods relying on physical manipulation as means of sustaining good tilth has increased the recognition given to the important role that soil biota have in soil-structure formation and stabilization. Soil biology has only received substantial attention in soil science during the last few decades. One result of this is that this knowledge is now being used to optimize soil management through strategies such as more diverse rotations, cover crops, and crop-residue management, with these being applied either as single management components or more preferably as part of an integrated system (i.e., either conservation agriculture or organic farming).Traditionally, farmers have evaluated soil tilth qualitatively in the field. However, a number of quantitative or semi-quantitative procedures for assessing soil tilth has been developed over the last 80 years. These procedures vary from simply determining soil cloddiness to more detailed evaluations whereby soil’s physical properties (e.g., porosity, strength, and aggregate characteristics) are combined with its consistency and organic-matter measurements in soil-tilth indices. Semi-quantitative visual soil-evaluation methods have also been developed for field evaluation of soil tilth, and are now used in many countries worldwide.
Article
Vermiculture in Greenhouse Plants, Field Crop Production, and Hydroponics
Norman Q. Arancon and Zachary Solarte
Vermiculture is the art, science, and industry of raising earthworms for baits, feeds, and composting of organic wastes. Composting through the action of earthworms and microogranisms is commonly referred to as vermicomposting. Vermiculture is an art because the technology of raising earthworms requires a comprehensive understanding of the basic requirements for growing earthworms in order to design the space and the system by which organic wastes can be processed efficiently and successfully. It is a science because the technology requires a critical understanding and consideration of the climatic requirements, nutritional needs, growth cycles, taxonomy, and species of earthworms suitable for vermicomposting in order to develop a working system that supports earthworm populations to process successfully the intended organic wastes. The nature of the organic wastes also needs to be taken into careful consideration, especially its composition, size, moisture content, and nutritional value, which will eventually determine the overall quality of the vermicomposts produced. The quality of organic wastes also determines the ability of the earthworms to consume and process them, and the rate by which they turn these wastes into valuable organic amendments. The science of vermiculture extends beyond raising earthworms. There are several lines of evidence that vermicomposts affect plant growth significantly. Vermiculture is an industry because it has evolved from a basic household bin technology to commercially scaled systems in which economic activities emanate from the cost and value of obtaining raw materials, the building of systems, and the utilization and marketing of the products, be they in solid or aqueous extract forms. Economic returns are carefully valued from the production phase to its final utilization as an organic amendment for crops.
The discussion revolves around the development of vermiculture as an art, a science, and an industry. It traces the early development of vermicomposting, which was used to manage organic wastes that were considered environmentally hazardous when disposed of improperly. It also presents the vermicomposting process, including its basic requirements, technology involved, and product characteristics, both in solid form and as a liquid extract. Research reports from different sources on the performance of the products are also provided. The discussion attempts to elucidate the mechanisms involved in plant growth and yield promotion and the suppression of pests and diseases. Certain limitations and challenges that the technology faces are presented as well.
Article
Well Construction, Cones of Depression, and Groundwater Sharing Approaches
Fidel Ribera Urenda
The importance of groundwater has become particularly evident in the late 20th and early 21st centuries due to its increased use in many human activities. In this time frame, vertical wells have emerged as the most common, effective, and controlled system for obtaining water from aquifers, replacing other techniques such as drains and spring catchments.
One negative effect of well abstraction is the generation of an inverted, conically shaped depression around the well, which grows as water is pumped and can negatively affect water quantity and quality in the aquifer. An increase in the abstraction rate of a specific well or, as is more common, an uncontrolled increase of the number of active wells in an area, could lead to overexploitation of the aquifer’s long-term groundwater reserves and, in some specific contexts, impact water quality. Major examples can be observed in arid or semi-arid coastal areas around the world that experience a high volume of tourism, where aquifers hydraulically connected with the sea are overexploited. In most of these areas, an excessive abstraction rate causes seawater to penetrate the inland part of the aquifer. This is known as marine intrusion. Another typical example of undesirable groundwater management can be found in many areas of intensive agricultural production. Excessive use of fertilizer is associated with an increase in the concentration of nitrogen solutions in groundwater and soils. In these farming areas, well design and controlled abstraction rates are critical in preventing penetrative depression cones, which ultimately affect water quality.
To prevent any negative effects, several methods for aquifer management can be used. One common method is to set specific abstraction rules according to the hydrogeological characteristics of the aquifer, such as flow and chemical parameters, and its relationship with other water masses. These management plans are usually governed by national water agencies with support from, or in coordination with, private citizens.
Transboundary or international aquifers require more complex management strategies, demanding a multidisciplinary approach, including legal, political, economic, and environmental action and, of course, a precise hydrogeological understanding of the effects of current and future usage.
Article
Barley in Archaeology and Early History
Simone Riehl
In 2018 barley accounts for only 5% of the cereal production worldwide, and regionally for up to 40% of cereal production. The cereal represents the oldest crop species and is one of the best adapted crop plants to a broad diversity of climates and environments.
Originating from the wild progenitor species Hordeum vulgare ssp. spontaneum, biogeographically located in the Fertile Crescent of the Near East, the domesticated form developed as a founder crop in aceramic Neolithic societies 11,000 years ago, was cultivated in monocultures in Bronze Age Mesopotamia, entered the New World after 1492 ce, reached a state of global distribution in the 1950s and had reached approximately 200 accepted botanical varieties by the year 2000.
Its stress tolerance in response to increased aridity and salinity on one hand and adaptability to cool climates on the other, partially explains its broad range of applications for subsistence and economy across different cultures, such as for baking, cooking, beer brewing and as an animal feed.
Although the use of fermented starch for producing alcoholic beverages and foods is globally documented in archaeological contexts dating from at least the beginning of the Holocene era, it becomes concrete only in societies with a written culture, such as Bronze Age Mesopotamia and Egypt, where beer played a considerable role in everyday diet and its production represented an important sector of productivity.
In 2004 approximately 85% of barley production was destined for feeding animals. However, as a component of the human diet, studies on the health benefits of the micronutrients in barley have found that it has a positive effect on blood cholesterol and glucose levels, and in turn impacts cardiovascular health and diabetes control. The increasing number of barley-breeding programs worldwide focus on improving the processing characteristics, nutritional value, and stress tolerance of barley within the context of global climate change.
Article
Crop Production Resilience through Biodiversity for Adaptation to Climate Change
Charles A. Francis
Adaptation of cropping systems to weather uncertainty and climate change is essential for resilient food production and long-term food security. Changes in climate result in substantial temporal modifications of cropping conditions, and rainfall and temperature patterns vary greatly with location. These challenges come at a time when global human population and demand for food are both increasing, and it appears to be difficult to find ways to satisfy growing needs with conventional systems of production. Agriculture in the future will need to feature greater biodiversity of crop species and appropriate design and management of cropping and integrated crop/animal systems. More diverse and longer-cycle crop rotations will need to combine sequences of annual row crops such as maize and soybean with close-drilled cereals, shallow-rooted with deep-rooted crops, summer crops with winter crops, and annuals with perennials in the same fields. Resilience to unpredictable weather will also depend on intercropping, with the creative arrangement of multiple interacting crop species to diversify the field and the landscape. Other multiple-cropping systems and strategies to integrate animals and crops will make more efficient use of natural resources and applied inputs; these include systems such as permaculture, agroforestry, and alley cropping. Future systems will be spatially diverse and adapted to specific fields, soil conditions, and unique agroecozones. Production resilience will be achieved by planting diverse combinations of species together in the same field, and economic resilience through producing a range of products that can be marketed through different channels. The creation of local food webs will be more appropriate in the future, as contrasted with the dominance of global food chains today. Materials considered “waste” from the food system, including human urine and feces, will become valuable resources to be cycled back into the natural environment and into food production. Due to the increasing scarcity of fertile land, the negative contributions of chemicals to environmental pollution, the costs of fossil fuels, and the potential for the economic and political disruption of supply chains, future systems will increasingly need to be local in character while still achieving adaptation to the most favorable conditions for each system and location. It is essential that biologically and economically resilient systems become productive and profitable, as well as environmentally sound and socially equitable, in order to contribute to stability of food production, security of the food supply, and food sovereignty, to the extent that this is possible. The food system cannot continue along the lines of “business as usual,” and its path will need to radically diverge from the recognized trends toward specialization and globalization of the early 21st century. The goal needs to shift from exploitation and short-term profits to conservation of resources, greater equity in distribution of benefits, and resilience in food supply, even with global climate change.
Article
Terracing: From Agriculture to Multiple Ecosystem Services
Paolo Socci, Alessandro Errico, Giulio Castelli, Daniele Penna, and Federico Preti
Agricultural terraces are widely spread all over the world and are among the most evident landscape signatures of the human fingerprint, in many cases dating back to several centuries. Agricultural terraces create complex anthropogenic landscapes traditionally built to obtain land for cultivation in steep terrains, typically prone to runoff production and soil erosion, and thus hardly suitable for rain-fed farming practices. In addition to acquiring new land for cultivation, terracing can provide a wide array of ecosystem services, including runoff reduction, water conservation, erosion control, soil conservation and increase of soil quality, carbon sequestration, enhancement of biodiversity, enhancement of soil fertility and land productivity, increase of crop yield and food security, development of aesthetic landscapes and recreational options. Moreover, some terraced areas in the world can be considered as a cultural and historical heritage that increases the asset of the local landscape. Terraced slopes may be prone to failure and degradation issues, such as localized erosion, wall or riser collapse, piping, and landsliding, mainly related to runoff concentration processes. Degradation phenomena, which are exacerbated by progressive land abandonment, reduce the efficiency of benefits provided by terraces. Therefore, understanding the physical processes occurring in terraced slopes is essential to find the most effective maintenance criteria necessary to accurately and adequately preserve agricultural terraces worldwide.
