Change the timing of ploughing

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 2
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How is the evidence assessed?

Effectiveness

46%
Certainty

38%
Harms

33%

Calculating overall effectiveness category

Background information and definitions

Nitrate leaching is when nitrates (or other nutrients) are lost from the soil.

Study locations

Key messages

Two replicated site comparison studies from Denmark and Norway (one also randomized) found reduced soil loss and nitrate leaching when ploughing was delayed until spring.

SOIL TYPES COVERED: sandy, sandy-loam, silty-clay loam.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A randomized, replicated site comparison study in 1989-1995 on coarse sand and sandy-loam soils in Denmark, found that nitrate loss from soil (leaching) was lower when ploughed in spring (81.5 kg N/ha) compared to winter (106.4 kg N/ha). Nitrate leaching was higher on coarse sand (160-254 kg N/ha) compared to sandy loam (129-233 kg N/ha) soils. Wheat Triticum aestivum, barley Hordeum vulgare and rye Secale cereal were grown at two locations. A ryegrass Lolium perenne/clover Trifolium repens ley mix was used, undersown with spring barley on areas 126 m². Within these were two sampling plots 11 m² (at Jyndevad) and 15 m² (Foulum). There were five treatments: autumn ploughing with wheat followed by rye; autumn ploughing – wheat/barley; autumn ploughing – barley/rye; autumn ploughing – barley both years, spring ploughing – barley/rye. Soil samples were taken at the start and end of each treatment. Soil water, organic carbon and total nitrogen were measured.
Study and other actions tested
Referenced paper
Djurhuus J & Olsen P (1997) Nitrate leaching after cut grass/clover leys as affected by time of ploughing. Soil Use and Management, 13, 61-67.
A replicated site comparison study, from 1984 to 1996 on silty clay loam soils in southern Norway, found that spring tillage reduced annual soil loss by 90% compared with autumn tillage. Variations in winter climate (e.g. rainfall) also influenced soil loss. There were six sites, with varying plot size: Bjørnebekk (144m², 11 replicates), Syverud (210m², 12), Askim (147 and 267 m², 6), Øsaker (176 m², 8), Hellerud (180, 720, 816 m², 8), Holt (2.7 ha catchment, not replicated). The tillage treatments were autumn ploughing, spring ploughing, autumn harrowing, spring harrowing, and direct drilling. Runoff and amount of eroded soil was measured.
Study and other actions tested
Referenced paper
Lundekvam H & Skøien S (1998) Soil erosion in Norway: an overview of measurements from soil loss plots. Soil Use and Management, 14, 84-89.

Please cite as:

Key, G., Whitfield, M., Dicks, L.V., Sutherland, W.J. & Bardgett, R.D. (2020) Enhancing Soil Fertility. Pages 613-634 in: W.J. Sutherland, L.V. Dicks, S.O. Petrovan & R.K. Smith (eds) What Works in Conservation 2020. Open Book Publishers, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Soil Fertility

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