User:Cassiville/Cover crop

Soil fertility management
Of the various nutrients, the impact that cover crops have on nitrogen management has received the most attention from researchers and farmers, because nitrogen is often the most limiting nutrient in crop production.

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The catch crops take up surplus nitrogen remaining from fertilization of the previous crop, preventing it from being lost through leaching, or gaseous denitrification or volatilization. Because of this ability, cover crops help the subsequent target crops uptake nutrients more efficiently, even after the cover crops themselves are terminated. Non-legume cover crops, such as ___, reduce leaching more than legume cover crops. And long-term cover crops, such as ___, improve soil organic carbon over time, increasing nitrogen availability.

Soil quality management
''Cover crops can also improve soil quality by increasing soil organic matter levels through the input of cover crop biomass over time. Increased soil organic matter enhances soil structure, as well as the water and nutrient holding and buffering capacity of soil. It can also lead to increased soil carbon sequestration, which has been promoted as a strategy to help offset the rise in atmospheric carbon dioxide levels. ''

''Soil quality is managed to produce optimum circumstances for crops to flourish. The principal factors of soil quality are soil salination, pH, microorganism balance and the prevention of soil contamination.''

types of microbes: protozoa, nematodes, microarthropods

Water management
By reducing soil erosion, cover crops often also reduce both the rate and quantity of water that drains off the field, which would normally pose environmental risks to waterways and ecosystems downstream. Cover crop biomass acts as a physical barrier between rainfall and the soil surface, allowing raindrops to steadily trickle down through the soil profile. Also, as stated above, cover crop root growth results in the formation of soil pores, which in addition to enhancing soil macrofauna habitat provides pathways for water to filter through the soil profile rather than draining off the field as surface flow. With increased water infiltration, the potential for soil water storage and the recharging of aquifers can be improved.

Just before cover crops are killed (by such practices including mowing, tilling, discing, rolling, or herbicide application) they contain a large amount of moisture. When the cover crop is incorporated into the soil, or left on the soil surface, it often increases soil moisture. In agroecosystems where water for crop production is in short supply, cover crops can be used as a mulch to conserve water by shading and cooling the soil surface. This reduces evaporation of soil moisture. In other situations farmers try to dry the soil out as quickly as possible going into the planting season. Here prolonged soil moisture conservation can be problematic.

While cover crops can help to conserve water, in temperate regions (particularly in years with below average precipitation) they can draw down soil water supply in the spring, particularly if climatic growing conditions are good. In these cases, just before crop planting, farmers often face a tradeoff between the benefits of increased cover crop growth and the drawbacks of reduced soil moisture for cash crop production that season. The ratio of carbon to nitrogen is balanced with this application.

Possible sources

 * A functional trait framework for integrating nitrogen‐fixing cover crops into short‐rotation woody crop systems (The Wikipedia Library)
 * Net greenhouse gas balance with cover crops in semi-arid irrigated cropping systems (The Wikipedia Library)
 * Gypsum, crop rotation, and cover crop impacts on soil organic carbon and biological dynamics in rainfed transitional no-till corn-soybean systems (Wikipedia Library)
 * Νarrow Row Spacing and Cover Crops to Suppress Weeds and Improve Sulla (Hedysarum coronarium L.) Biomass Production (Wikipedia Library)
 * Choice of cover crop influences soil fungal and bacterial communities in Prince Edward Island, Canada. (Wikipedia Library) -- choice of cover crop changes soil fertility (ie fungal and bacterial communities)
 * Winter cover crops increased nitrogen availability and efficient use during eight years of intensive organic vegetable production (Wikipedia Library)
 * Elaine Ingham
 * Soil life in reconstructed ecosystems: initial soil food web responses after rebuilding a forest soil profile for a climate change experiment
 * Comparison of soil biota between organic and conventional agroecosystems in Oregon, USA
 * Effect of cover crops and tillage system on symphylan (Symphlya: Scutigerella immaculata, Newport) and Pergamasus quisquiliarum Canestrini (Acari: Mesostigmata) populations
 * Defining climate policies based on soil health (Tufts)
 * Can Dirt Save the Earth? (NYT)
 * A framework for evaluating ecosystem services provided by cover crops in agroecosystems (Rodale Institute)
 * Choosing the Best Cover Crops for Your Organic No-Till Vegetable System (Rodale Institute)
 * Planting Date Impacts on Soil Water Management, Plant Growth, and Weeds in Cover-Crop-Based No-Till Corn Production (Rodale Institute)
 * Plant root-microbe communication in shaping root microbiomes (NIH)
 * Rehydrating the Earth: A New Paradigm For Water Management (Holistic Science Journal Vol 2 Issue 4 <- note to self to check journal quality)

Gaps in the article to fix

 * How cover crops enhance soil structure and water holding capacity of the soil
 * More citations in the water management section
 * Something about barley / nonlegumous cover crops (include photo)
 * Planting cover crops (include photo)
 * How cover crops help biodiversity
 * Additional citation for: “the impact that cover crops have on nitrogen management"
 * Add organic soil fertility practices that aren't cover crops (compost, fish emulsion, etc)
 * Link types of cover crops (is this only US relevant??):
 * sour clover (Melilotus indicus)
 * Phacelia tanacetifolia
 * farro wheat (Triticum turgidum subsp. dicoccum (Schrank ex Schübler) Thell.)
 * common vetch (Vicia sativa L.)
 * white mustard (Sinapis alba L.)
 * More about the connection between cover crops and carbon storage (see succinct explanation you wrote here)
 * Cover crops use for weed supression
 * Add some photos
 * provides "protection of the topsoil from erosion and drought." (and cycles nutrients) -- from Groundcover article