Subsurface manure application

Description

In-furrow subsoil application of a liquid organic manure-based fertiliser under pressure is a measure aimed at reducing the time of contact between fertilisers and the open air and at their immediate spread in the root zone within the plow layer. The spread of fertilisers within the soil helps accelerate its infiltration and the binding of nutrients through microbiological processes, which substantially reduces the risk of their surface runoff to ground waters and surface water bodies, while cutting gas emissions (of ammonia, hydrogen sulfide etc.) to the atmosphere.

In-furrow subsoil application of a liquid organic manure-based fertiliser under pressure is a measure intended to enhance soil fertility and improve the structure of soil regardless of its type. In liquid organic fertilisers, nitrogen is more available to plants than in solid ones, and by placing it in the root zone one can make a more effective use of the potential of fertilisers. Subsurface application to the less dense soil layers, under the surface crust, accelerates fertiliser infiltration, preventing the accumulation of the fertiliser on the surface and, hence, reducing the risk of biogens draining from the surface to water bodies. Surface runoff of fertilisers into water bodies makes one of the main sources of biogens.

In-furrow subsoil application of a liquid organic fertiliser under pressure is beneficial from the point of view of cutting emissions both to the atmosphere and to water bodies, and provides farmers with certain preferences by sparing them the need to buy mineral fertilisers, enhancing soil fertility and ensuring larger crop yields, including in meadows and pastures. Liquid organic fertilisers can also serve as an additional source of moisture during dry spells. This measure shows the best effect in crop production in floodplain areas.

Localisation and implementation

This method is intended to be used at pastures or arable lands with minimum tillage before sowing and after harvesting. It can be applied in nearly all countries, with some restrains, though: it is less effective in highly shallow or compacted soils, where application cannot be done uniformly to the required working depth. Systems for application of liquid organic fertilisers under pressure are more energy-intensive than equipment for surface or band placement. Dosage varies depending on the characteristics of fertilisers, crops and fertility level.

Restrains include high stoniness of soil, since stones can damage the implements, and fields with steep slopes, which can topple the application equipment. Moreover, when slopes are steep, liquid organic fertilisers will not get absorbed through the soil fast enough, leading to surface runoff.

Natural and climatic restrains are as follows:

• sub-zero air temperatures, since the fertiliser can freeze;
• high solar radiation, since the fertiliser can evaporate to a greater extent than seep through the soil, which increases emissions to the atmospheric air (this effect is less apparent in the case of this method compared to surface application);
• abundant rainfall and waterlogged soil, since the speed of infiltration of liquid fertilisers goes down and they can drain away to water bodies together with rainwater.

The implements used to form the furrows commonly include a disc (one or two), different types of cultivators (duck foot blades etc.) (Figure 2). To make the method more effective, rollers can be used to cover the furrows after placement.

Effects, duration and maintenance

A faster nutrient uptake by plants and soil, coupled with the prevention of surface runoff, reduces nitrogen emissions and escape of phosphorus into water bodies. The main potential of subsoil application is enhancing capability and cutting emissions.

Major investment costs for implementing this method are related to the purchase of a tractor and a fertiliser application machine. Depending on the manufacturer, performance and lifting capacity of the type of the implements used, average unit prices in Russia vary from EUR 25,000 to 130,000 and higher. The mean service life established by the manufacturer is up to 10 years, and annual expenses generally comprise operational expenses, notably on repair and maintenance of equipment, payroll, fuel etc. The frequency and scope of repairs is determined by the manufacturer.

• The use of liquid organic fertilisers in the root zone increases populations of microorganisms.
• The use of rational doses of fertilisers in optimal weather conditions prevents the release of nutrients into ground waters and slashes emissions to water bodies compared to surface placement.
• The application of this method helps reduce atmospheric emissions arising from the use of organic fertilisers compared to surface placement.

The effect is long-term if soil condition during implementation is optimal. After incorporation, no maintenance is needed.

Pamphlets, reports, videos and websites

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Scientific papers

Васильев Э.В. Повышение эколого-экономической эффективности процесса использования жидкого органического удобрения путем автоматизированного выбора рациональных вариантов технологий транспортировки и внесения в условиях Северо-Западного региона (Increasing the ecological and economic efficiency of the process of using liquid organic fertilisers by automated selection of rational options for transportation and application technologies in the conditions of the Northwest region). Bulletin of the All-Russian Scientific Research Institute of Livestock Mechanization: Вестник Всероссийского научно-исследовательского института механизации животноводства: 2013. No. 4(12). pp. 127-133. (In Russian)