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Providing evidence to improve practice

Action: Crop production: Use no tillage instead of reduced tillage Mediterranean Farmland

Key messages

Crop yield (15 studies)

  • Cereals (7 studies): Three replicated, randomized, controlled studies from Spain found higher cereal yields in plots with no tillage, compared to reduced tillage. One of these studies also found lower cereal yields in some comparisons. One replicated, randomized, controlled study from Spain found lower cereal yields in plots with no tillage, compared to reduced tillage, in some comparisons. Three replicated, randomized, controlled studies from Australia, Lebanon, and Spain found similar cereal yields in plots with no tillage or reduced tillage, in all comparisons.
  • Fruits and vegetables (3 studies): Three replicated, randomized, controlled studies from Italy found lower fruit or vegetable yields in plots with no tillage, compared to reduced tillage, in some comparisons. Two of these studies also found higher yields, in some comparisons.
  • Legumes (3 studies): Two replicated, controlled studies from Italy and Spain found higher legume yields in plots with no tillage, compared to reduced tillage, in some or all comparisons. One replicated, controlled study from Lebanon found similar legume yields in plots with no tillage, compared to reduced tillage.
  • Oilseeds (1 study): One replicated, randomized, controlled study from Spain found lower sunflower seed yields in plots with no tillage, compared to reduced tillage, in some comparisons.
  • Crop residues (6 studies): Three replicated, controlled studies from Lebanon and Spain found higher straw yields in plots with no tillage, compared to reduced tillage, in some or all comparisons. One replicated, randomized, controlled study from Spain found lower straw yields in plots with no tillage, compared to reduced tillage. Two replicated, controlled studies from Italy and Spain found similar straw yields in plots with no tillage or reduced tillage.

Crop quality (3 studies): One replicated, randomized, controlled study from Spain found larger peas, and more peas in a pod, in plots with no tillage, compared to reduced tillage, in one of four comparisons. One replicated, controlled study from Italy found similarly sized faba beans, and similar numbers of beans in a pod, in plots with no tillage, compared to reduced tillage. One replicated, randomized, controlled study from Spain found differences in the nutritional values of sunflower seeds in plots with no tillage, compared to reduced tillage.

· Crop yield (15 studies)

o Cereals (7 studies): Three replicated, randomized, controlled studies from Spain2,4,13 found higher cereal yields in plots with no tillage, compared to reduced tillage. One of these studies10410417Angás, P.Lampurlanés, J.Cantero-Martínez, C.Tillage and N fertilization: Effects on N dynamics and Barley yield under semiarid Mediterranean conditionsSoil and Tillage ResearchSoil and Tillage Research59-71871Conservation tillageNitrogen fertilizationN fertilizer efficiencyPhysiological N use efficiency20065//0167-1987http://www.sciencedirect.com/science/article/pii/S0167198705000991http://dx.doi.org/10.1016/j.still.2005.02.0362 also found lower cereal yields in some comparisons. One replicated, randomized, controlled study from Spain868617López-Garrido, R.Madejón, E.León-Camacho, M.Girón, I.Moreno, F.Murillo, J. M.Reduced tillage as an alternative to no-tillage under Mediterranean conditions: A case studySoil and Tillage ResearchSoil and Tillage Research40-47140Tillage systemsSoil conditionsCrop performanceSeed qualitySunflower20147//0167-1987http://www.sciencedirect.com/science/article/pii/S0167198714000300http://dx.doi.org/10.1016/j.still.2014.02.00811 found lower cereal yields in plots with no tillage, compared to reduced tillage, in some comparisons. Three replicated, randomized, controlled studies from Australia19119117Manalil, SudheeshFlower, KenSoil water conservation and nitrous oxide emissions from different crop sequences and fallow under Mediterranean conditionsSoil and Tillage ResearchSoil and Tillage Research123-129143AustraliaDroughtFallowNitrous oxide201411//0167-1987http://www.sciencedirect.com/science/article/pii/S0167198714001214http://dx.doi.org/10.1016/j.still.2014.06.00612, Lebanon777717Yau, S. K.Sidahmed, M.Haidar, M.Conservation versus Conventional Tillage on Performance of Three Different CropsAgronomy JournalAgronomy Journal269-2761022010Madison, WIAmerican Society of Agronomyhttp://dx.doi.org/10.2134/agronj2009.024210.2134/agronj2009.0242English3, and Spain848417Hernanz, J. L.López, R.Navarrete, L.Sánchez-Girón, V.Long-term effects of tillage systems and rotations on soil structural stability and organic carbon stratification in semiarid central SpainSoil and Tillage ResearchSoil and Tillage Research129-141662Long-term effectTillageCrop rotationAggregate stabilitySoil organic carbonSemiarid conditions20027//0167-1987http://www.sciencedirect.com/science/article/pii/S0167198702000211http://dx.doi.org/10.1016/S0167-1987(02)00021-11 found similar cereal yields in plots with no tillage or reduced tillage, in all comparisons.

o Fruits and vegetables (3 studies): Three replicated, randomized, controlled studies from Italy9,10,15 found lower fruit or vegetable yields in plots with no tillage, compared to reduced tillage, in some comparisons. Two of these studies9,15 also found higher yields, in some comparisons.

o Legumes (3 studies): Two replicated, controlled studies from Italy10710717Giambalvo, DarioRuisi, PaoloSaia, SergioDi Miceli, GiuseppeFrenda, Alfonso SalvatoreAmato, GaetanoFaba bean grain yield, N2 fixation, and weed infestation in a long-term tillage experiment under rainfed Mediterranean conditionsPlant and SoilPlant and Soil215-227360120122012//1573-5036http://dx.doi.org/10.1007/s11104-012-1224-510.1007/s11104-012-1224-57 and Spain838317Santín-Montanyá, M. I.Zambrana, E.Fernández-Getino, A. P.Tenorio, J. L.Dry pea (Pisum sativum L.) yielding and weed infestation response, under different tillage conditionsCrop ProtectionCrop Protection122-12865DiversityLegume-cropsSemi-arid conditionsYieldWeeds201411//0261-2194http://www.sciencedirect.com/science/article/pii/S0261219414002373http://dx.doi.org/10.1016/j.cropro.2014.07.017

Supporting evidence from individual studies

1 

A replicated, randomized, controlled study in 1983–1996 in a rainfed wheat field in the Henares river valley, Spain, found similar crop yields in plots with no tillage or reduced tillage. Crop yield: Similar wheat yields were found in plots with no tillage or reduced tillage (2.7 vs 2.6 Mg/ha). Methods: No tillage or reduced tillage was used on four plots each. Each plot had two subplots (20 x 30 m, with or without crop rotations). A chisel plough (20 cm depth, in autumn) and a tine cultivator (10–15 cm depth, two passes, in spring) were used for reduced tillage. A seed drill and pre-emergence herbicide were used for no tillage. Fertilizer and post-emergence herbicide were used on all plots. Wheat was harvested at maturity (July 1996), and yield was measured in two strips/subplot (1.4 x 30 m strips).

 

2 

A replicated, randomized, controlled study in 1996–1999 in three rainfed barley fields in the Ebro river valley, Spain, found that tillage had inconsistent effects on crop yields. Crop yield: Higher grain yields were found in plots with no tillage, compared to reduced tillage, in one of nine comparisons (3,645 vs 2,507 kg/ha), but lower grain yields were found in two of nine comparisons (770–1,247 vs 1,043–1,749 kg/ha). Methods: No tillage or reduced tillage was used on 27 plots each (50 x 6 m plots). A cultivator (10–15 cm depth, 1–2 passes) was used for reduced tillage, in September. Herbicide was used for no tillage. Two-thirds of the plots were fertilized (50–75 or 100–150 kg N/ha). Barley was sown, with a seed drill, in October–November (month of harvest not reported).

 

3 

A replicated, randomized, controlled study in 2005–2007 in a rainfed field in the central Bekaa Valley, Lebanon, found higher seed and straw yields in plots with no tillage, compared to reduced tillage. Crop yield: Higher seed and straw yields were found in plots with no tillage, compared to reduced tillage, in one of three crops (safflower seed: 2,600 vs 1,900 kg/ha; safflower straw: 9,950 vs 7,450). Methods: No tillage or reduced tillage (shallow disc cultivation, 10 cm depth) was used in four plots each (14 x 6 m), in October. Barley, chickpeas, and safflower were planted in November. Barley and safflower were fertilized (60–100 kg N/ha). Mature crops were collected in three quadrats/plot (0.25 m2 quadrats).

 

4 

A replicated, randomized, controlled study in 1996–2009 in a rainfed barley field in the Ebro river valley, Spain (same study as (5,6)), found higher barley yields in plots with no tillage, compared to reduced tillage. Crop yield: Higher barley yields were found in plots with no tillage, compared to reduced tillage (2,062 vs 1,792 kg/ha). Methods: No tillage or reduced tillage was used on nine plots each (50 x 6 m plots). A cultivator was used for reduced tillage (10–15 cm depth, 50% incorporation of crop residues), in October or November. A seed drill and herbicide were used for no tillage. Two-thirds of the plots were fertilized (60 or 120 kg N/ha). Mature barley was harvested in June 2006–2009.

 

5 

A replicated, randomized, controlled study in 1996–2009 in a rainfed barley field in the Ebro river valley, Spain (same study as (4,6)), found similar crop yields in plots with no tillage or reduced tillage. Crop yield: Similar barley yields were found in plots with no tillage, compared to reduced tillage (1,350–4,400 vs 1,050–4,100 kg/ha). Methods: No tillage or reduced tillage was used on nine plots each (50 x 6 m plots). A cultivator was used for reduced tillage (10–15 cm depth, 50% incorporation of crop residues), in October or November. A seed drill and herbicide were used for no tillage. Two-thirds of the plots were fertilized (60 or 120 kg N/ha). Mature barley was harvested in June 2006–2009.

 

6 

A replicated, randomized, controlled study in 1996–2009 in a rainfed barley field in the Ebro river valley, Spain (same study as (4,5)), found less barley straw in plots with no tillage, compared to reduced tillage, in one of nine comparisons. Crop yield: Less barley straw was found in plots with no tillage, compared to reduced tillage, in one of nine comparisons (321 vs 456 g/m2). Methods: No tillage or reduced tillage was used on nine plots each (50 x 6 m plots). A cultivator was used for reduced tillage (10–15 cm depth, 50% incorporation of crop residues). A seed drill and herbicide were used for no tillage. Two-thirds of the plots were fertilized (60 or 120 kg N/ha). Mature barley was harvested in June 2006–2009 (three samples/plot, 50 cm of one row/sample).

 

7 

A replicated, controlled study in 1991–2009 in a rainfed faba bean field in Sicily, Italy, found higher crop yields, and no differences in crop quality, in plots with no tillage, compared to reduced tillage. Crop yield: Higher faba bean yields were found in plots with no tillage, compared to reduced tillage (2.36 vs 1.91 Mg grain/ha), but no differences in straw yields were found (3.93 vs 3.80 Mg straw/ha). Crop quality: No differences were found in faba bean seed weight (99 g/100 seeds), or number of seeds/pod (2.7 vs 2.6), in plots with no tillage, compared to reduced tillage. Methods: No tillage or reduced tillage was used on two plots each (18.5 x 20 m plots). A chisel plough (40 cm depth), a mouldboard plough (15 cm depth, in 1991–1998), and a harrow (depth not reported; before sowing) were used for reduced tillage. Herbicide (before sowing) and a seed drill were used for no tillage. In all plots, a hoe was used to control weeds (depth not reported; 1–2 times/year). Faba beans were grown in rotation with durum wheat. During durum wheat growth, herbicide was used in all plots. All plots were fertilized (46 kg P2O5/ha). Faba beans were sown in December and harvested at maturity (month not reported). Yield and quality were measured in three samples/plot (four rows/sample, 3 m rows).

 

8 

A replicated, randomized, controlled study in 1996–2008 in a rainfed barley field in the Ebro river Valley, Spain, found more barley straw in plots with no tillage, compared to reduced tillage, in two of three comparisons. Crop yield: More barley straw was found in plots with no tillage, compared to reduced tillage, in two of three comparisons (2,083–2,265 vs 1,612–1,679 kg/ha). Methods: There were nine plots (50 x 6 m) for each of two tillage treatments (no tillage: pre-emergence herbicide and seed drill; reduced tillage: cultivator, 10–15 cm depth). Plots were tilled in October or November. Two-thirds of the plots were fertilized (60 or 120 kg N/ha/year). Barley was harvested in June.

 

9 

A replicated, randomized, controlled study in 2009–2011 in two irrigated pepper fields in central Italy found that tillage had inconsistent effects on crop yields. Crop yield: Higher pepper yields were found in plots with no tillage, compared to reduced tillage, in four of eight comparisons (18–38 vs 7–18 t/ha, fresh weight), but lower yields were found in one of eight comparisons (10 vs 15). Methods: A mouldboard plough (30 cm depth) was used on all plots in autumn, before winter cover crops were planted. Cover crops were mown or chopped in spring, before tillage. No tillage or reduced tillage was used on 12 plots each (6 x 12 m plots), in May 2010–2011. A rotary hoe (10 cm depth) was used for reduced tillage (which incorporated the cover crop residues into the soil). Cover crop residues were mulched and herbicide was used for no tillage. Pepper seedlings were transplanted into the plots in May, and fruits were harvested twice/year in August–October 2010–2011. All plots were fertilized before the cover crops, but not after. All plots were irrigated.

 

10 

A replicated, randomized, controlled study in 2009–2012 in two irrigated vegetable fields in central Italy found lower crop yields in plots with no tillage, compared to reduced tillage. Crop yield: Lower crop yields were found in plots with no tillage, compared to reduced tillage, in one of six comparisons (in plots with oilseed rape as the winter cover crop: 5 vs 11 t/ha endive, fresh weight). Methods: Reduced tillage or no tillage was used on nine plots each (6 x 4 m plots). Each plot had a winter cover crop (hairy vetch, oats, or oilseed rape). Cover crops were sown in September 2009–2010 and suppressed in May 2010–2011. A rotary hoe was used for reduced tillage (incorporating the cover crop residues to 10 cm depth). The cover crop residues were gathered into strips of mulch (50 cm wide, along crop rows) in plots with no tillage. Pepper seedlings were transplanted into these plots in May 2010–2011 and were last harvested in October 2010 and September 2011. After the pepper harvest, endive and savoy cabbage seedlings were transplanted into these plots, and they were harvested in December 2010 and November 2011 (endive) or March 2011 and February 2012 (cabbage). No fertilizer was added while the crops were growing, but the plots were irrigated. It was not clear whether these results were a direct effect of tillage or mulch.

 

11 

A replicated, randomized, controlled study in 2008–2013 in a rainfed wheat-sunflower-pea field near Seville, Spain, found lower crop yields and differences in crop quality in plots with no tillage, compared to reduced tillage, in some comparisons. Crop yield: Lower crop yields were found in plots with no tillage, compared to reduced tillage, in two of five comparisons (sunflower seeds in 2013: 105 vs 3,839 kg/ha; wheat grain in 2012: 2,940 vs 3,985 kg/ha). Crop quality: Less oil, more zinc, more saturated and polyunsaturated fatty acid, and less monounsaturated fatty acid were found in sunflower seeds in plots with no tillage, compared to reduced tillage (34% vs 50% oil; see publication for other results). Methods: No tillage or reduced tillage was used on three plots each (6 x 33.5 m plots). A chisel plough (25 cm depth), a disc harrow (5 cm depth), and herbicide were used for reduced tillage. A seed drill and herbicide were used for no tillage. Wheat, sunflowers, and peas were grown in rotation. Wheat was fertilized, but sunflowers and peas were not. Sunflowers were sown in May 2013 (three months later than usual) and harvested in September. Yield and quality were measured in 16 sunflower heads/plot.

 

12 

A replicated, randomized, controlled study in 2010–2011 in a rainfed wheat field in Australia found similar crop yields in plots with no tillage or reduced tillage. Crop yield: Similar wheat yields were found in plots with no tillage or reduced tillage (2,600 kg/ha). Methods: No tillage or reduced tillage was used on three plots each (1.4 x 40 m plots) in 2010, when the plots were fallow. A rotary hoe (12 cm depth) was used for reduced tillage. Herbicide was used for no tillage. Wheat was grown on all plots in 2011. Fertilizer (150 kg/ha) and herbicides were used on all plots in 2011.

 

13 

A replicated, randomized, controlled study in 1987–2010 in rainfed cereal fields in the Ebro river valley, Spain, found higher crop yields in plots with no tillage, compared to reduced tillage. Crop yield: Higher grain yields were found in plots with no tillage, compared to reduced tillage (4,449 vs 3,923 kg/ha). Methods: No tillage or reduced tillage was used on ten plot each (Peñalba: three plots each, 34 x 175 m plots, established in 2005; Agramunt: four plots each, 9 x 50 m plots, established in 1990; Selvanera: three plots each, 7 x 50 m plots, established in 1987). A cultivator (Peñalba: 10 cm depth; Agramunt: 15 cm) or a chisel plough (Selvanera: 15 cm) was used for reduced tillage. Herbicide was used for no tillage. Barley (Peñalba) or wheat (Agramunt and Selvanera) was planted in November 2009 with a seed drill (2–4 cm depth) and harvested in June–July 2010.

 

14 

A replicated, randomized, controlled study in 1994–2009 in a rainfed pea-cereal field near Madrid, Spain, found higher pea yields, larger peas, and/or more peas/pod in plots with no tillage, compared to reduced tillage. Crop yield: Higher grain and straw yields were found in plots with no tillage, compared to reduced tillage, in one of four comparisons (peas, grain: 0.6 vs 0.08 t/ha; straw: 2.9 vs 1.5 t/ha). Crop quality: Larger peas and more peas/pod were found in plots with no tillage, compared to reduced tillage, in one of four comparisons (154 vs 80 g/1,000 peas; 5.4 vs 4.8 peas/pod), but no difference in the length of pea pods was found (5.9–7.0 vs 5.7–7.0 cm). Methods: No tillage or reduced tillage was used on four plots each (each with three 10 x 25 m sub-plots, with different pea-cereal rotations), in October or November. A chisel plough was used for reduced tillage (10 cm depth). A seed drill and herbicide were used for no tillage. Peas were planted in November 2005–2008 and harvested in June 2006–2009. The peas were not fertilized.

 

15 

A replicated, randomized, controlled study in 2009–2011 in an irrigated eggplant field in central Italy found that tillage had inconsistent effects on crop yield. Crop yield: Higher eggplant yields were found in plots with no tillage, compared to reduced tillage, in one of four comparisons (18 vs 7 Mg/ha fresh weight), but lower yields were found in two of four comparisons (11–18 vs 21–25). Methods: A mouldboard plough (30 cm depth) was used on all plots in autumn, before winter cover crops were planted. Cover crops were mown or chopped in spring, before tillage. No tillage or reduced tillage was used on 12 plots each (6 x 4 m plots). A rotary hoe (10 cm depth) was used for reduced tillage (which incorporated some of the cover crop residues into the soil). Cover crop residues were mulched and herbicide was used for no tillage. Eggplant seedlings were transplanted into the plots in May, and fruits were harvested four times/year in July–September 2010–2011. All plots were fertilized before the cover crops were grown, but not after. All plots were irrigated.

 

Referenced papers

Please cite as:

Shackelford, G. E., Kelsey, R., Robertson, R. J., Williams, D. R. & Dicks, L. V. (2017) Sustainable Agriculture in California and Mediterranean Climates: Evidence for the effects of selected interventions. Synopses of Conservation Evidence Series. University of Cambridge, Cambridge, UK.