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 Conservation tillage techniques (left-hand side) were compared with mouldboard ploughing (right-hand side) where the soil is inverted
The results presented in this section are from 25 fields of varying soil types growing a range of arable crops on 18 farms across the 3 countries. The cost of a particular operation e.g. spraying, ploughing, was standardised within a particular country by using nationally published contractor costs, allowing an objective comparison between farms. Therefore the costs resulting from this analysis may differ from the farmers' real costs or benefits
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Conservation tillage reduces crop establishment costs |
- Conservation tillage, especially no-tillage, can substantially reduce crop establishment costs compared to mouldboard ploughing
Conservation tillage almost always lowered the cost of crop establishment, due to reducing the number of operations required (Figure 1). No-tillage in particular reduced costs by up to 70%. In Hungary , conservation tillage reduced crop establishment costs by almost 40%; in Belgium and the UK cost savings from the practice of conservation tillage were on average 20% compared to mouldboard plough costs. |
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Figure 1: Effect of soil management on crop establishment costs (relative to mouldboard ploughing so a value above 0 represents the % saving on establishment costs under conservation tillage)
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| Conservation tillage can reduce crop yield |
- Yields of a range of arable crops were often lower from conservation tillage than from mouldboard ploughing
- Cereal and maize yields were more sensitive to soil management than broad-leaved crops
- Conservation tillage did not impact crop quality
- The presence of difficult-to-control weeds like blackgrass ( Alopecurus ) and cleavers (Galium) in conservation tillage areas may have contributed to the impact on yield of winter-sown crops
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| In general, yields from conservation tillage fields were lower but frequently within 10% of that achieved by the conventionally established crop (Figure 2). The results suggest that the yield of broad-leaved crops like oilseed rape and beans were less affected by the practice of conservation tillage than cereals and maize. Perhaps surprisingly, on the Belgian farms the root crops like sugar beet often benefited from growing in conservation tillage soils. |
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Figure 2: Yields of all crops grown in all three countries during the SOWAP project. The yield expressed is that of conservation tillage crops relative to that of mouldboard ploughed crops set at 0 i.e. a value above 0 represents an increase in yield under conservation tillage when compared to mouldboard ploughing
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| Yields of winter wheat in Hungary were on average 50% of that achieved in Belgium and the UK , regardless of soil management practice. |
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| The variability in yields of a particular crop is likely to be a complicated function of climate, soil type, variety, the state of the soil and the crop rotation. Figure 3 demonstrates this variability over the duration of the SOWAP project. Yields of winter wheat in 2003/2004 appeared to be more sensitive to establishment method than at other times during the project. Conversely, maize and sugar-beet established by conservation tillage did not perform as well in 2005/2006. |
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Figure 3: Variability in yields over time. Results for any one crop are from different fields. The yield expressed is that of conservation tillage crops relative to that of mouldboard ploughed crops set at 0%, i.e. a value above 0 represents an increase in yield under conservation tillage when compared to mouldboard ploughing
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There was no evidence of an effect of soil management on various crop quality indicators like moisture content and protein content in wheat, moisture content and dry matter content of maize or sugar content and dirt tare in sugar beet (Figure 4). |
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Figure 4: Impacts of soil management on sugar content and tare of Belgian sugar-beet. MP = mouldboard ploughing, CT= conservation tillage . |
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 In the UK , weed surveys undertaken in the 2005-2006 season when the majority of fields investigated were in winter wheat, showed that there were clear differences in the weed populations between the two soil management treatments. Cleavers ( Galium aparine ), blackgrass ( Alopecurus myosuroides ), sterile brome ( Bromus sterilis ) and groundsel ( Senecio vulgaris ) were typical of conservation tillage areas on the fields surveyed. Cleavers was common on all farms; groundsel more prominent in Somerset and charlock ( Sinapis arvensis ) at Loddington. Each farm had its own troublesome grass weed, e.g. blackgrass at Loddington (a competitive weed species) that may well have contributed to the reduction in yield seen under conservation tillage. |
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The crops grown over the duration of the project were representative of European arable systems. Winter wheat and winter oilseed rape were typical of UK rotations whereas sugar-beet and maize dominated in Belgium . On the two farms in Hungary , winter wheat and maize were grown almost exclusively. This may be of concern in the longer-term if the farmer continues with this practice as there is evidence from the UK and France of increased mycotoxin risk in wheat after maize in conservation tillage systems. |
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Conservation tillage can be more profitable |
- The reduction in crop establishment costs using conservation tillage often offsets the decrease in yield to increase overall profitability
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| There was considerable variability in the profit made by different farms between different cropping seasons (Figure 5). In general for these farms, the profit was increased under conservation tillage but at times there was insufficient decrease in the cost of soil management to offset the yield reduction. When crop prices were low as at the start of the project (in 2003), little profit was made on any farm regardless of the crop establishment method. |
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| However, the values calculated and obtained during the project may not be a true representation of the profit experienced by the farmer, e.g. the labour costs utilised by the project were general contractor costs while the farmer's actual costs may be lower (or higher). In addition, the profitability of the entire rotation on these farms was not assessed. A reduction in external inputs (fertiliser and pesticide) costs may be possible in the longer term but this was not tested during the project. |
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Figure 5: Effect of soil management on profit (all relative to mouldboard ploughing so that a point 0 represents an increase in profit under conservation tillage when compared to mouldboard ploughing).
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| A limited number of examples from SOWAP suggest that the additional cost of buying and planting a cover crop to protect the soil and prevent nutrient leaching over-winter can turn profit in a conservation tillage system into loss, at least in the short-term. An over-winter mustard cover crop planted before spring beans, turned a 17% profit into a 4% loss on the bean crop and a rye cover crop before maize, turned a 2% profit into a 7% loss. |
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| Impact of costs and yields on uptake of conservation tillage |
| SOWAP results have demonstrated that conservation tillage is an effective means of reducing farmers' crop establishment costs. Such results along with the ability to save time and labour and improve timeliness during the busy spring and autumn periods reported elsewhere are the key factors that have driven uptake of conservation tillage across Europe to date. Many other factors influence the uptake of conservation tillage, e.g. the effect of agricultural policies such as CAP Reform and Rural Development, so it is important that conservation tillage is also evaluated in terms of these factors covering its wider contribution to the environment and society. |
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This report is based on the work of Katleen Gillijns at K.U.Leuven in Belgium; Balazs Madarasz of the Hungarian Academy of Sciences and Ceris Jones of Agronomica in UK. |
