Proper Manure Application to Land

Objectives Proper application of manure to the land with the objective to prevent pollution of land, ground and surface water and to prevent evaporation of ammonia and greenhouse gases. Timely application of manure in accordance with the nutrient requirements of the crops will result in improved crop production. | Objectives Techniques Costs Targeted Livestock System Impact Context of Application Monitoring: EIA, Indicators Reference

Techniques

- Restrict manure spreading on the land to the growing season of the crop, do not apply manure on the land when there is no crop.

- Balance the quantity of manure with the nutrient requirements of the crop. The quantity of manure which can be applied per ha depends on the soil type and should be limited to not more than the equivalent of 150 kg N per hectare.

- Evaporation of ammonia and greenhouse gases will be reduced when manure is not or only for a short time exposed to fresh air. The manure should be covered with soil (e.g. by harrowing) immediately after spreading or should be injected into the soil directly.

Manure application techniques to reduce the emissions of ammonia include machinery for decreasing the surface area of slurries and burying slurry or solid manure through incorporation into the soil. The techniques included are:

- Band-spreading.
- Trailing shoe or ‘sleigh-foot’ machines.
- Injection - open slot.
- Injection - closed slot.
- Incorporation of surface applied manure and/or slurry into soil.

Band-spreading. Band-spreaders discharge slurry at or just above ground level through a series of hanging or trailing pipes. The width is typically 12 m with about 30 cm between bands. The technique is applicable to grass and arable land e.g. for applying slurry between rows of growing crops. Because of the width of the machine, the technique is not suitable for small, irregularly shaped fields or steeply sloping land. The hoses may also become clogged if the straw content of the slurry is too high.

Trailing shoe. This technique is mainly applicable to grassland. Grass leaves and stems are parted by trailing a narrow shoe or foot over the soil surface and slurry is placed in narrow bands on the soil surface at 20 - 30 cm spacings. The slurry bands should be covered by the grass canopy so the grass height should be a minimum of 8 cm. The machines are available in a range of widths up to 7 - 8 m. Applicability is limited by size, shape and slope of the field and by the presence of stones on the soil surface.

Injection - open slot. This technique is mainly for use on grassland. Different shaped knives or disc coulters are used to cut vertical slots in the soil up to 5 - 6 cm deep into which slurry is placed. Spacing between slots is typically 20 - 40 cm and working width 6m. Application rate must be adjusted so that excessive amounts of slurry do not spill out of the open slots onto the surface. The technique is not applicable on very stony soil nor on very shallow or compacted soils where is impossible to achieve uniform penetration of the knives or disc coulters to the required working depth.

Injection - closed slot. This technique can be shallow (5 - 10 cm depth) or deep (15 - 20 cm). Slurry is fully covered after injection by closing the slots with press wheels or rollers fitted behind the injection tines. Shallow closed-slot injection is more efficient than open-slot in decreasing ammonia emission. To obtain this added benefit, soil type and conditions must allow effective closure of the slot. The technique is, therefore, less widely applicable than open-slot injection. Deep injectors usually comprise a series of tines fitted with lateral wings or ‘goose feet’ to aid lateral dispersion of slurry in the soil so that relatively high application rates can be achieved. Tine spacing is typically 25 -50 cm and working width 2 - 3 m. Although ammonia abatement efficiency is high, the applicability of the technique is severely limited. The use of deep injection is restricted mainly to arable land because mechanical damage may decrease herbage yields on grassland. Other limitations include soil depth and clay and stone content, slope and a high draught force requiring a large tractor. There is also a greater risk of nitrogen losses as nitrous oxide and nitrates, in some circumstances.

Incorporation. Incorporating manure spread on the surface by ploughing is an efficient means of decreasing ammonia emissions. The manure must be completely buried under the soil to achieve the efficiencies given in Table 1. Lower efficiencies are obtained with other types of cultivation machinery. Ploughing is mainly applicable to solid manures on arable soils. The technique may also be used for slurries where injection techniques are not possible or unavailable. Similarly, it is applicable to grassland when changing to arable land (e.g. in a rotation) or when reseeding. Ammonia loss is rapid following spreading manures on the surface so greater reductions in emissions are achieved when incorporation takes place immediately after spreading. This requires that a second tractor be used for the incorporation machinery which must follow close behind the manure spreader. A more practical option might be incorporation within the same working day as spreading the manure, but this is less efficient in reducing emissions.

Table 1 Category 1 Techniques for Manure Application to Land

Abatement measure | Type of manure | Land use | Emission reduction (%) | Applicabilitya | Costs1) ECU per m3
Band-spreading | Slurry | Grassland | 10 | Slope (tankers <10 %, umbilical < 20 %), not for slurry that is viscous or has a high straw content, size and shape of field | 0.68
Band-spreading | Slurry | Arable | 30 | Slope (tankers < 10 %, umbilical < 20 %), not for slurry that is viscous or has a high straw content, size and shape of the field, possibility of applying to growing crop between rows | 0.68
Trailing shoe | Slurry | Mainly grassland | 40 | Slope (tankers < 20 %, umbilical < 30 %), not viscous slurry, size and shape of the field, grass height should be about 8 cm | 1.33
Injection (open slot) | Slurry | Grassland | 60 | Slope < 12 %, greater limitations for soil type and conditions, not viscous slurry | 2.51
Injection (closed slot) | Slurry | Mainly grassland, arable land | 80 | Slope < 12 %, greater limitations for soil type and conditions, not viscous slurry | 2.51
Incorporation - immediate (costs for < 4h) | Solid manure and slurry | Arable land | 80 | Only for land that can be easily ploughed | Slurry: 0.67 dairy 0.53 other cattle 1.05 pigs Manure: 1.32 dairy, other cattle, sheep & goats 1.47 pigs 3.19 layers 6.19 broilers
Incorporation - within same working day | Solid manure and slurry | Arable land | 50-90 for manure depending on type 40 for slurry | Only for land that can be easily ploughed | As above

Source: Hendriks, H.J.M. and van de Weerdhof, A.M. 1999. Dutch notes on BAT (Best Available Techniques) for pig and poultry intensive livestock farming. National Reference Centre Agriculture.

Costs

Proper application of the manure to the land involves the cost for transportation, injecting into the soil or spreading and covering with soil. Benefits are the reduced cost of fertilizer and the improved yields.

Targeted Livestock System

Grazing System

LGA | LGS1 | LGS2 | LGS3 | LGH1 | LGH2 | LGH3 | LGT1 | LGT2 | LGT3
N | Y | Y | Y | Y | Y | Y | Y | Y | Y

Mixed System

MCG | MCR | MCC | MFF | MEF
Y | Y | Y | Y | Y

Industrial System

IFP | IPL | IPG | IRM | IDU | ISL | ITN | IMP
N | Y | Y | Y | Y | Y | N | N

Industrial livestock production systems Mixed, cut and carry; and mixed, external feed resources.

Impact

- Positive Environmental Impact

- Reduced pollution of land, and ground and surface water.
- Reduced ammonia emissions.
- Reduced evaporation of greenhouse gases.
- Increased crop yields.

- Negative Environmental Impact

- Incorporation of manure into the soil compared to spreading of manure over the soil could possibly result in increased loss of minerals due to leaching.
- The relation is unknown between the manure application system and the emission of NOx (an obnoxious greenhouse gas) produced in small quantities in the denitrification process.

- Livestock Productivity Impact

- Improved application of manure has an indirect benefit on livestock production through a better recycling of manure and improved fodder crop yields

Context of Application

- Policy context:

- Regulations for the application of manure in terms of period of the year and quantities per hectare according to the soil type.

- Institutional context:

- Research into manure application techniques.
- Research of crop and fodder-crop response to manure application.
- Research into interactions of manure and fertilizer.
- Research into the relation of manure application techniques and NOx emissions.

- Education/training:

- Explanation to the farmers of the need for proper manure application

Monitoring : EIA; Indicators

- Legislation on manure application (times and quantities)

References

Information on application rates of manure on land: http://hubcap.clemson.edu/~blpprt/manure.html

Land application of liquid manure: http://www.gov.on.ca/OMAFRA/english/livestock/dairy/facts/92-164.htm

Nutrient management plan: http://www.agnr.umd.edu/users/agron/nutrient/outlinnm/0utline.html

Hendriks, H.J.M. and van de Weerdhof, A.M. 1999. Dutch notes on BAT (Best Available Techniques) for pig and poultry intensive livestock farming. National Reference Centre Agriculture.

Mineral policy in the Netherlands; Dutch policy to reduce undesired effects of mineral losses to the environment. Published in 1999 by the Ministry of Agriculture, Nature Management and Fisheries and the Ministry of Housing, Spatial Planning and the Environment. Available from: Ministry of Agriculture, Infotiek, P.O. Box 20401, 2500 EK, The Hague, The Netherlands.

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