Crop residue

There are two types of agricultural crop residues. Field residues are materials left in an agricultural field or orchard after the crop has been harvested. These residues include stalks and stubble (stems), leaves, and seed pods. The residue can be ploughed directly into the ground, or burned first. In contrast, no-till, strip-till or reduced till agriculture practices are carried out to maximize crop residue cover. Good management of field residues can increase efficiency of irrigation and control of erosion. Simple line transect measurements can be used to estimate residue coverage.[1] Process residues are materials left after the crop is processed into a usable resource. These residues include husks, seeds, bagasse, molasses and roots. They can be used as animal fodder and soil amendment, fertilizers and in manufacturing.

Stubble field in Brastad
Stubble field in Brastad, Sweden

Economic value

Most discussions about the economic value of crop residues focus on the equivalent fertilizer cost of the nutrients within. Although crop residues contain both macro- and micro nutrients, only values for the macro nutrients nitrogen, phosphorus, potassium and sulfur are economically significant.

Biofuel production from crop residues

Because of the high carbohydrate content, crop residues can be considered as an appropriate feedstock to produce biofuels. Some algorithms have been developed to estimate the potential capacity of biofuel production from agricultural residues.[2][3] Based on the experimental data obtained from a study that used ethanol organosolv pretreated rice straw to produce biohydrogen using Enterobacter aerogenes, the annual global amount of collectable rice straw (not total produced straw) for biofuel production was estimated about 249 million tonnes, that could approximately produce 355.78 kilotonnes of hydrogen and 11.32 million tonnes of lignin by the proposed organosolv technology and it was found that China contributes to about 32% of global potential capacity to produce biohydrogen from rice straw.[4]


Nutrients in most crop residue are not immediately available for crop use. Their release (called mineralization) occurs over a period of years. The biological processes involved in soil nutrient cycles are complex. As a rough guide, cereal straw releases about 10 to 15 per cent of its nutrients and pea residues release about 35 percent of their nutrients by the next year.

The speed of mineralization depends on the nitrogen and lignin (fiber) content, soil moisture, temperature, and degree of mixing with the soil. N is released fairly quickly from residue when the content is higher than 1.5 per cent (such as in pea residues). In contrast, below 1.2 per cent (such as cereal residue), soil-available N is fixed (called immobilization) by the microbes as they decompose the residue.

Thus pea residue would have short- and long-term benefits to soil fertility, whereas cereal straw would reduce next year's soil supply of available nutrients. Over time, the nutrients fixed by soil microbes and humus are released and available to crops. Nutrients from residue are not fully recovered by crops. Just like fertilizer nutrients, nutrients released from crop residue into the soil are susceptible to losses such as leaching (N and S), denitrification (N), immobilization (N, P, K and S), and fixation (P and K).

Efficiency of nutrient uptake

The efficiency of nutrient uptake by crops from fertilizers or residue release is generally thought to be similar. For example, about 50 percent recovery of N in the above-ground plant in the first year. There is some residual benefit of fertilizers as the crops take up a small amount of the nutrients two and three years later. Fertilizer placement can significantly affect the efficiency of crop uptake. The impact of residue placement (buried by tillage or left on the surface in zero tillage) on nutrient cycling and efficiency is under study.

Thus, the practice of calculating the fertilizer equivalent value of the nutrients in crop residue is a reasonable guide to estimating the partial value of crop residues.

See also


  1. ^ Richards, B. K.; Muck, R. E.; Walter, M. F. (1 January 1984). "Variation in line transect measurements of crop residue cover". Journal of Soil and Water Conservation. 39 (1): 60–61. ISSN 0022-4561.
  2. ^ Asadi, Nooshin; Karimi Alavijeh, Masih; Zilouei, Hamid. "Development of a mathematical methodology to investigate biohydrogen production from regional and national agricultural crop residues: A case study of Iran". International Journal of Hydrogen Energy. doi:10.1016/j.ijhydene.2016.10.021.
  3. ^ Karimi Alavijeh, Masih; Yaghmaei, Soheila. "Biochemical production of bioenergy from agricultural crops and residue in Iran". Waste Management. 52: 375–394. doi:10.1016/j.wasman.2016.03.025.
  4. ^ Asadi, Nooshin; Zilouei, Hamid (March 2017). "Optimization of organosolv pretreatment of rice straw for enhanced biohydrogen production using Enterobacter aerogenes". Bioresource Technology. 227: 335–344. doi:10.1016/j.biortech.2016.12.073.
  • Alemayehu Mengistu. 1985. Feed resources in Ethiopia. A paper presented at the Workshop on Animal Feed Resources for Small Scale livestock Producers, 11–15 November 1985, Nairobi, Kenya. 12 pp.
  • Butterworth, M.H. and Mosi, A.K. 1986. The voluntary intake and digestibility of combinations of cereal crop residues and legume hay for sheep. ILCA Bulletin 24:14-17.

External links

Air pollution in India

Air pollution occurs when harmful or excessive quantities of substances including gases, particles, and biological molecules are introduced into the Earth's atmosphere. Air pollution in India is a serious issue, ranking higher than smoking, high blood pressure, child and maternal malnutrition, and risk factors for diabetes. At least 140 million people breathe air 10 times or more over the WHO safe limit and 13 of the world's 20 cities with the highest annual levels of air pollution are in India. Air pollution contributes to the premature deaths of 2 million Indians every year. In urban areas, most emissions come from vehicles and industry, whereas in rural areas, much of the pollution stems from biomass burning for cooking and keeping warm. In autumn and winter months, large scale crop residue burning in agriculture fields – a low cost alternative to mechanical tilling – is a major source of smoke, smog and particulate pollution. India has a low per capita emissions of greenhouse gases but the country as a whole is the third largest after China and the United States. A 2013 study on non-smokers has found that Indians have 30% lower lung function compared to Europeans.The Air (Prevention and Control of Pollution) Act was passed in 1981 to regulate air pollution and there have been some measurable improvements. However, the 2016 Environmental Performance Index ranked India 141 out of 180 countries.In 2015, Government of India, together with IIT Kanpur launched the National Air Quality Index. In 2019, India launched 'The National Clean Air Programme' with tentative national target of 20%-30% reduction in PM2.5 and PM10 concentrations by 2024, considering 2017 as the base year for comparison. It will be rolled out in 102 cities that are considered to have air quality worse than the National Ambient Air Quality Standards.

Ascochyta pisi

Ascochyta pisi is a fungal plant pathogen that causes ascochyta blight on pea, causing lesions of stems, leaves, and pods. These same symptoms can also be caused by Ascochyta pinodes, and the two fungi are not easily distinguishable.

Bacterial blight (barley)

Bacterial blight is a disease of barley caused by the bacterial pathogen Xanthomonas campestris pv. translucens (syn. X. translucens). It has been known as a disease since the late 19th century. It has a worldwide distribution.

Controlled burn

A controlled or prescribed burn, also known as hazard reduction burning, backfire, swailing, or a burn-off, is a wildfire set intentionally for purposes of forest management, farming, prairie restoration or greenhouse gas abatement. A controlled burn may also refer to the intentional burning of slash and fuels through burn piles. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for foresters. Hazard reduction or controlled burning is conducted during the cooler months to reduce fuel buildup and decrease the likelihood of serious hotter fires. Controlled burning stimulates the germination of some desirable forest trees, and reveals soil mineral layers which increases seedling vitality, thus renewing the forest. Some cones, such as those of lodgepole pine and sequoia, are serotinous, as well as many chaparral shrubs, meaning they require heat from fire to open cones to disperse seeds.

In industrialized countries, controlled burning is usually overseen by fire control authorities for regulations and permits.


A crop is a plant or animal product that can be grown and harvested extensively for profit or subsistence. Crop may refer either to the harvested parts or to the harvest in a more refined state. Most crops are cultivated in agriculture or aquaculture. A crop is usually expanded to include macroscopic fungus (e.g. mushrooms), or alga (algaculture).

Most crops are harvested as food for humans or fodder for livestock. Some crops are gathered from the wild (including intensive gathering, e.g. ginseng).

Important non-food crops include horticulture, floriculture and industrial crops. Horticulture crops include plants used for other crops (e.g. fruit trees). Floriculture crops include bedding plants, houseplants, flowering garden and pot plants, cut cultivated greens, and cut flowers. Industrial crops are produced for clothing (fiber crops), biofuel (energy crops, algae fuel), or medicine (medicinal plants).

Crop destruction

Crop destruction is the deliberate destruction of crops or agricultural products to render it useless for consumption or processing. It can be made by burning, grinding, dumping into water, or application of chemicals. It should not be confused with crop residue burning, which burns useless parts of the crop.

Related to crop destruction is alternate, low-price use of agricultural products. A large portion of the wine lake (European Union wine surplus) is converted to industrial ethanol.

There can be numerous reasons for crop destruction. In scorched-earth strategy, crops and other useful materials are destroyed to prevent the enemy from gaining hold of them. The strategy of destroying the food supply of the civilian population in an area of conflict has been banned under Article 54 of Protocol I of the 1977 Geneva Conventions.

In government-regulated agriculture, farmers can be required to destroy crops that exceed their production quota. Crops can also be dumped in the street during a public protest; this custom has been common in the European Union. Also, illegal crops, such as opium and cannabis, can be destroyed by law enforcement.

Note that this term does not apply to the burning of crops which are or can be usefully harvested by this means, such as sugar cane.

Cyathus olla

Cyathus olla is a species of saprobic fungus in the genus Cyathus, family Nidulariaceae. The fruit bodies resemble tiny bird's nests filled with "eggs" – spore-containing structures called peridioles. Like other bird's nest fungi, C. olla relies on the force of falling water to dislodge peridioles from fruiting bodies to eject and disperse their spores. The life cycle of this fungus allows it to reproduce both sexually, with meiosis, and asexually via spores. C. olla is a relatively common fungus, with a worldwide distribution. It is the subject of agricultural research to determine its potential as a means to accelerate the breakdown of crop residue, and reduce the population of plant pathogens. The specific epithet is derived from the Latin word olla, meaning "pot".

Energy in India

Energy in India describes energy and electricity production, consumption and import in India. Energy policy of India describes the policies and strategies of India for achieving sustainable energy security to its people. Electricity sector in India is the main article of electricity in India. The Ministry of New and Renewable Energy provides data regarding progress in the non-conventional energy sector.

Since 2013, total primary energy consumption in India has been the third highest in the world (see world energy consumption) after China (see energy in China) and the United States (see energy in the United States). India is the second top coal consumer in the year 2017 after China. India ranks third in oil consumption with 221 million tons in 2017 after the United States and China. India is net energy importer to meet nearly 45% of its total primary energy.


Forage is a plant material (mainly plant leaves and stems) eaten by grazing livestock.

Historically, the term forage has meant only plants eaten by the animals directly as pasture, crop residue, or immature cereal crops, but it is also used more loosely to include similar plants cut for fodder and carried to the animals, especially as hay or silage. The term forage fish refers to small schooling fish that are preyed on by larger aquatic animals.While the term forage has a broad definition, the term forage crop is used to define crops, annual or biennial, which are grown to be utilized by grazing or harvesting as a whole crop.

IAME Rastrojero

The Rastrojero was a small utility pickup truck (taxis were also developed) with a capacity of half-ton designed by Raúl Gómez and built by the Argentine government-owned airplane (and vehicle) manufacturer IAME (Industrias Aeronáuticas y Mecánicas del Estado) from 1952 to 1980. It owes its name to its purpose of being driven on crop residue (rastrojos). Over 33,000 of these trucks were manufactured.

Indoor air pollution in developing nations

Indoor air pollution in developing nations is a significant form of indoor air pollution (IAP) that is little known to those in the developed world.

Three billion people in developing countries across the globe rely on biomass, in the form of wood, charcoal, dung, and crop residue, as their domestic cooking fuel. Because much of the cooking is carried out indoors in environments that lack proper ventilation, millions of people, primarily poor women and children face serious health risks. Globally, 4.3 million deaths were attributed to exposure to IAP in developing countries in 2012, almost all in low and middle income countries. The South East Asian and Western Pacific regions bear most of the burden with 1.69 and 1.62 million deaths, respectively. Almost 600,000 deaths occur in Africa,

200,000 in the Eastern Mediterranean region, 99,000 in Europe and 81,000 in the Americas. The remaining 19,000 deaths occur in high income countries.Even though the rate of dependence on biomass fuel is declining, this dwindling resource will not keep up with population growth which could ultimately put environments at even greater risk.

Over the past several decades, there have been numerous studies investigating the air pollution generated by traditional household solid fuel combustion for space heating, lighting, and cooking in developing countries. It is now well established that, throughout much of the developing world, indoor burning of solid fuels (biomass, coal, etc.) by inefficient, often insufficiently vented, combustion devices results in elevated exposures to household air pollutants. This is due to the poor combustion efficiency of the combustion devices and the elevated nature of the emissions. In addition, they are often released directly into living areas. Smoke from traditional household solid fuel combustion commonly contains a range of incomplete combustion products, including both fine and coarse particulate matter (e.g., PM2.5, PM10), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), and a variety of organic air pollutants (e.g., formaldehyde, 1,3-butadiene, benzene, acetaldehyde, acrolein, phenols, pyrene, benzopyrene, benzo(a)pyrene, dibenzopyrenes, dibenzocarbazoles, and cresols). In a typical solid fuel stove, about 6–20% of the solid fuel is converted into toxic emissions (by mass). The exact quantity and relative composition is determined by factors such as the fuel type and moisture content, stove type and operation influencing the amount.While many pollutants can evolve, most measurements have been focused on breathing-zone exposure levels of particulate matter (PM) and carbon monoxide (CO), which are the main products of incomplete combustion and are considered to pose the greatest health risks. Indoor PM2.5 exposure levels have been consistently reported to be in the range of hundreds to thousands of micrograms per cubic meter (μg/m3). Similarly, CO exposure levels have been measured to be as high as hundreds to greater than 1000 milligrams per cubic meter (mg/m3). A recent study of 163 households in two rural Chinese counties reported geometric mean indoor PM2.5 concentrations of 276 μg/m3 (combinations of different plant materials, including wood, tobacco stems, and corncobs), 327 μg/m3 (wood), 144 μg/m3 (smoky coal), and 96 μg/m3 (smokeless coal) for homes using a variety of different fuel types and stove configurations (e.g., vented, unvented, portable, fire pit, mixed ventilation stove).

Lake Sugema

Lake Sugema [Pronounced sōō•jē’•mə](+40° 41' 22.85", -91° 59' 39.01") is a man-made 574-acre (2.32 km2) lake 3 miles (4.8 km) southwest of Keosauqua, Van Buren County, in southeast Iowa, United States. It is located south of the Des Moines River, west of State Highway 1 and north of State Highway 2.

The maximum depth of the lake is 34 feet (10 m), with a mean depth 9.3 feet (2.8 m), and drainage of 11,480 acres (46.5 km2). The lake was designed as a high quality fishing lake. Facilities include parking lots, and 3 hard surface boat ramps with no motor size limit at no wake. There are fishing jetties, an accessible fishing pier for the handicapped, accessible facilities, a picnic area, restrooms, camping facilities, floating boat docks, and wildlife islands.An asphalt road leads off of Hwy 2 to a large camping area with a shelterhouse, sewer dump station, handicapped-accessible showerhouse, playground, 23 hard-surfaced 50 ft (15 m). camp pads, 8 primitive campsites, 8 slip boat docks, and a boat trailer parking area. Cabins located in the campgrounds are available for rental throughout the year.Lake Sugema is stocked with largemouth bass, walleye, bluegill, black crappie, channel catfish, and saugeye. The lake has fishing jetties and good shore fishing access. Special fishing regulations require for 12-inch (300 mm) to 18-inch (460 mm) black bass to be immediately released alive.Extensive planning was done by the Iowa Department of Natural Resources to establish underwater structure that helps fish survive and reproduce. When the lake was constructed, steps were taken to prevent siltation. Besides the hundreds of farm ponds, crop rotations, crop residue management, and other soil saving practices farmers have established in the lake's drainage area, the lake is protected by a series of smaller sediment-control dams.Approximately 3,000 acres (12 km2) immediately surrounding the lake was purchased by the Iowa Department of Natural Resources and Van Buren County to be managed as a wildlife area. That management is helping to build on the number of wild turkey, deer, squirrel, geese, quail, rabbits, songbirds, and other wild animals. Habitat is also being developed for raccoon, fox, mink, muskrats, and bald eagles, among other wildlife.The Indian Creek Wildlife area is intended for public hunting, fishing, hiking, bird watching, cross country skiing, picnicking, nature study, primitive camping and other fun in the outdoors.

Shimek State Forest is managed as a multiple-use area for timber products, wildlife habitat and recreation. The 900-acre (3.6 km2) forest includes hiking trails and is available for public hunting.

All those activities are available to the public at Lake Sugema and the 3,000-acre (12 km2) Indian Creek Wildlife Area. The Iowa Department of Natural Resources and the Van Buren County Conservation Board are managing the lake, wildlife, and recreation areas.

No-till farming

No-till farming (also called zero tillage or direct drilling) is a way of growing crops or pasture from year to year without disturbing the soil through tillage. No-till is an agricultural technique that increases the amount of water that infiltrates into the soil, the soil's retention of organic matter and its cycling of nutrients. In many agricultural regions, it can reduce or eliminate soil erosion. It increases the amount and variety of life in and on the soil, including disease-causing organisms and disease organisms. The most powerful benefit of no-tillage is improvement in soil biological fertility, making soils more resilient. Farm operations are made much more efficient, particularly improved time of sowing and better trafficability of farm operations.

Tillage remains relevant in agriculture today, but the success of no-till methods in many contexts keeps farmers aware that multiple options exist. In some cases low-till methods combine aspects of till and no-till methods. For example, some approaches may use a limited amount of shallow disc harrowing but no plowing.

Residue-to-product ratio

In climate engineering, the residue-to-product ratio (RPR) is used to calculate how much unused crop residue might be left after harvesting a particular crop. Also called the residue yield or straw/grain ratio, the equation takes the mass of residue divided by the mass of crop produced, and the result is dimensionless.The RPR can be used to project costs and benefits of bio-energy projects, and is crucial in determining financial sustainability. The RPR is particularly important for estimating the production of biochar, a beneficial farm input obtained from crop residues through pyrolysis. However, it is important to note that RPR values are rough estimates taken from broad production statistics, and can vary greatly depending on crop variety, climate, processing, and residual moisture content.


Stover is the leaves and stalks of field crops, such as corn (maize), sorghum or soybean that are commonly left in a field after harvesting the grain. It is similar to straw, the residue left after any cereal grain or grass has been harvested at maturity for its seed. It can be directly grazed by cattle or dried for use as fodder. Stover has attracted some attention as a potential fuel source, and as biomass for fermentation or as a feedstock for cellulosic ethanol production. Stover from various crops can also be used in mushroom compost preparation.The word 'stover' derives from the English legal term 'estovers', referring to the right of tenants to cut timber.


Stubble may mean:

The short stalks left in a field after crops have been harvested: see crop residue

Short stumps of hair that grow back on a man's face after shaving.

Designer stubble: shaving stubble of a type that became popular in the 1980s


Stubble-mulching refers to leaving the stubble (agriculture) or crop residue essentially in place on the land as a surface cover during a fallow period. Stubble-mulching can prevent soil erosion from wind or water and conserve soil moisture.


Tillage is the agricultural preparation of soil by mechanical agitation of various types, such as digging, stirring, and overturning. Examples of human-powered tilling methods using hand tools include shovelling, picking, mattock work, hoeing, and raking. Examples of draft-animal-powered or mechanized work include ploughing (overturning with moldboards or chiseling with chisel shanks), rototilling, rolling with cultipackers or other rollers, harrowing, and cultivating with cultivator shanks (teeth). Small-scale gardening and farming, for household food production or small business production, tends to use the smaller-scale methods, whereas medium- to large-scale farming tends to use the larger-scale methods.

Tillage that is deeper and more thorough is classified as primary, and tillage that is shallower and sometimes more selective of location is secondary. Primary tillage such as ploughing tends to produce a rough surface finish, whereas secondary tillage tends to produce a smoother surface finish, such as that required to make a good seedbed for many crops. Harrowing and rototilling often combine primary and secondary tillage into one operation.

"Tillage" can also mean the land that is tilled. The word "cultivation" has several senses that overlap substantially with those of "tillage". In a general context, both can refer to agriculture. Within agriculture, both can refer to any kind of soil agitation. Additionally, "cultivation" or "cultivating" may refer to an even narrower sense of shallow, selective secondary tillage of row crop fields that kills weeds while sparing the crop plants.

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