Providing evidence to improve practice

Action: Water: Use no tillage in arable fields Mediterranean Farmland

Key messages

Water use (1 study): One replicated, randomized, controlled study from Spain found that barley used water more efficiently in plots without tillage, compared to plots with tillage, in some comparisons.

Water availability (14 studies): Nine controlled studies (eight replicated and randomized) from Spain and the USA found more water in soils without tillage, compared to soils with tillage, in some or all comparisons. One replicated, randomized, controlled study from Lebanon found less water in soils without tillage, compared to soils with tillage, in some comparisons. Three replicated, controlled studies (two randomized) from Spain and the USA sometimes found more water, and sometimes found less water, in soils without tillage, compared to soils with tillage. One replicated, randomized, controlled study from Spain found lower porosity in soils without tillage, compared to soils with tillage, in some comparisons.

Pathogens and pesticides (0 studies)

Nutrients (0 studies)

Sediments (0 studies)

Supporting evidence from individual studies

1 

A replicated, controlled study in 1996–1998 in an irrigated tomato field in the San Joaquin Valley, California, USA, found that tillage (and cover crops) had inconsistent effects on water in soil. Water availability: In the tomato-growing season, more water was found in plots that had cover crops in winter and no tillage in spring, compared to plots that had bare soil in winter and tillage in spring, in some comparisons (when irrigated, data not clearly reported), but less water was found in winter and spring, in some comparisons. Methods: There were 12 plots (4.5 x 27.5 m plots) for each of two treatments (two grass-legume mixtures as winter cover crops, sown in October 1996–1997, killed and retained as mulch, with no tillage, in March 1997–1998) and there were 12 control plots (bare-soil fallow in winter, with herbicide, and conventional tillage in spring). Soil water was measured throughout the year with hydroprobes (0–6 feet depth until autumn 1997, then 0–7 feet depth). It was not clear whether these results were a direct effect of cover crops or tillage.

 

2 

A controlled study in 1994–1999 in a rainfed legume-cereal field near Barcelona, Spain, found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage (33 vs 26 mm mean topsoil water content in February–May). Methods: No tillage or conventional tillage was used on one plot each (90 x 30 m plots). A cultivator (August), a mouldboard plough (September), and a harrow and a roller (November) were used for conventional tillage (depth not reported). Herbicide was used for no tillage (August). Herbicide was used in both plots in September and January, and fertilizer was added in October. Seeds were sown with a seed drill in December and crops were harvested in July. Crop residues were removed from all plots before tillage. Water was measured weekly (February–May, two time-domain reflectometer probes/plot, 20 cm depth).

 

3 

A replicated, randomized, controlled study in 1992–1997 in a rainfed barley field in the Ebro river valley, Spain, found lower porosity in soils with no tillage, compared to subsoil tillage. Water availability: Lower porosity was found in soils with no tillage, compared to subsoil tillage, in some comparisons (e.g., in subplots with continuous cropping, in one of two years: 5.0 vs 15.5 cm/day, hydraulic conductivity). Methods: No tillage or subsoil tillage was used on four plots each (each with 10 m x 6 m subplots, with continuous cropping or fallow). A cultivator and a subsoil plough were used for subsoil tillage (15–40 cm depth), in October. Herbicide was used for no tillage, in October. Crop residues were removed from all plots. Hydraulic conductivity was measured in July 1996 and August 1997 (tension infiltrometer, 250 mm diameter, seven tensions from 0 to 20 cm water, in subplots with continuous cropping).

 

4 

A replicated, randomized, controlled study in 2003–2005 on rainfed farms in the Ebro river valley, Spain, found that tillage had inconsistent effects on water in soils. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in 11 of 24 comparisons, in the two days after tillage (0.04–0.26 vs 0.02–0.20 g water/g soil), but less water was found in 3 of 24 comparisons (0.08–0.11 vs 0.09–0.14). Methods: No tillage or conventional tillage was used on ten plots each (33–50 x 7–10 m plots), on a total of three farms, with multiple crops. A mouldboard or subsoil plough was used on plots with conventional tillage (25–40 cm depth). Herbicide was used on plots with no tillage. Water was measured in soil samples (5 cm depth), at three times (0, 24, and 48 hours after tillage).

 

5 

A replicated, randomized, controlled study in 2002–2004 in an irrigated maize field in southwest Spain found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in two of nine comparisons (0–10 cm depth, in 2004: 0.23–0.31 vs 0.14–0.19 cm3 water/cm3 soil). Methods: Conventional tillage or no tillage was used on four plots each (20 x 10 m plots). A mouldboard plough (0–30 cm depth, in October 2001–2003 and March and April 2002–2004) was used for conventional tillage, and maize residues were burned in September–October 2002–2004. Herbicide was used for no tillage (April and May–June 2002–2004), and maize residues were not burned.

 

6 

A replicated, randomized, controlled study in 1996–2008 in a rainfed barley field in the Ebro river valley, Spain (same study as (8,9)), found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage (0.09–0.25 vs 0.05–0.18 g water/g dry soil). Methods: No tillage or conventional tillage was used on nine plots each (50 x 6 m). A mouldboard plough or a disk plough was used for conventional tillage (25–30 cm depth, 100% incorporation of crop residues). Two-thirds of the plots were fertilized (60 or 120 kg N/ha). Water content was measured in soil samples (0–5 cm depth).

 

7 

A replicated, randomized, controlled study in 2005–2007 in a rainfed field in the central Bekaa Valley, Lebanon, found less water in soils with no tillage, compared to conventional tillage, in one of 10 comparisons. Water availability: Less water was found in soils with no tillage, compared to conventional tillage, in one of 10 comparisons (water content not reported). Methods: No tillage or conventional tillage was used on four plots each (14 x 6 m), in October. Conventional plots were ploughed (25–30 cm depth) and then shallowly disk-cultivated. Barley, chickpeas, and safflower were planted in November. Barley and safflower were fertilized (60–100 kg N/ha). Soil water was measured at two depths (25 and 50 cm), on five dates from 30 March 2005–16 August 2006, with a time-domain reflectometer.

 

8 

A replicated, randomized, controlled study in 1996–2009 in a rainfed barley field in the Ebro river valley, Spain (same study as (6,9)), found that barley used water more efficiently in plots with no tillage, compared to conventional tillage, in two of three comparisons. Water use: Higher water-use efficiency was found in plots with no tillage, compared to conventional tillage, in two of three comparisons (5.7–6.0 vs 1.8–2.1 kg barley grain/mm rainfall). Methods: No tillage or conventional tillage was used on nine plots each (50 x 6 m plots). A mouldboard plough was used for conventional tillage (25–30 cm depth, 100% 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). Soil samples were collected five times/year (two samples/plot, 4 cm diameter soil auger, 0–100 cm depth) in 2005–2009. Mature barley was harvested in June 2006–2009.

 

9 

A replicated, randomized, controlled study in 1996–2009 in a rainfed barley field in the Ebro river valley, Spain (same study as (6,8)), found that tillage had inconsistent effects on water in soils. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in 11 of 16 comparisons (110–240 vs 90–215 g water/g soil), but less water was found in one of 16 comparisons (100 vs 115). Methods: No tillage or conventional tillage was used on nine plots each (50 x 6 m plots). A mouldboard plough was used for conventional tillage (25–30 cm depth, 100% 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). Soil samples were collected four times/year in 2005–2009 (0–100 cm depth).

 

10 

A replicated, randomized, controlled study in 2009–2010 in a wheat-maize field in the San Joaquin Valley, California, USA, found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage (20–23% vs 12–14% volumetric water content). Methods: No tillage or conventional tillage was used on three plots each (1.5 x 91 m plots). A disk plough and a chisel plough (30 cm depth) were used for conventional tillage, in April 2009–2010 (after harvesting the wheat). In plots with no tillage, soils were not disturbed after harvesting the wheat. Wheat and maize were grown in rotation. Soil water content was measured after tillage (0–20 cm depth, about 12 reflectometer readings/plot and 4–6 soil cores/plot, 7.5 cm diameter).

 

11 

A replicated, randomized, controlled study in 2008–2013 in a rainfed wheat-sunflower-pea field near Seville, Spain, found more water in soils with no tillage, compared to conventional tillage, in one of three comparisons. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in one of three comparisons (0–5 cm depth, in early May 2013: 19.1 vs 7.42% soil moisture). Methods: No tillage or conventional tillage was used on three plots each (6 x 33.5 m plots). A mouldboard plough (25–30 cm depth), a chisel plough (25 cm depth, twice/year), and a disk harrow (12 cm depth) were used for conventional 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. Soil moisture was measured in May 2013 (0–5 cm depth, time-domain-reflectrometry probes) and early June (0–10 cm depth, gravimetric).

 

12 

A replicated, randomized, controlled study in 1987–2010 in rainfed cereal fields in the Ebro river valley, Spain, found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in three of 15 comparisons (in Agramunt: 140–240 vs 100–210 mm volumetric water content). Methods: No tillage or conventional 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). In Peñalba, a disk plough (20 cm depth) and a cultivator (10 cm depth) were used for conventional tillage. In Agramunt, a mouldboard plough (25 cm depth) and a cultivator (15 cm depth) were used for conventional tillage. In Selvanera, a subsoil plough (40 cm depth) and a chisel plough (15 cm depth) were used for conventional 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. Soil samples were collected two times (at tillering and flowering, four samples/plot, 0–90 cm depth).

 

13 

A replicated, randomized, controlled study in 1996–2013 in two rainfed barley fields in northeast Spain found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage (32–44% vs 18–20% water-filled pore space). Methods: No tillage or conventional tillage was used on three plots each, in each of two fields (from 2010–2013 in the short-term field, and from 1996–2013 in the long-term field; plots size not clearly reported). A mouldboard plough (25 cm depth) and a cultivator (15 cm depth) were used for conventional tillage in the long-term field, and a chisel plough was used in the short-term field (depth not reported), in September–October. For no tillage, the residues were chopped and spread, and pre-emergence herbicide was used. Some plots were fertilized (0–150 kg N/ha). Soil samples (0–5 cm depth) were collected every 2–3 weeks in 2011–2013 (2011–2012 in the short-term field).

 

14 

A replicated, randomized, controlled study in 1994–2013 in a rainfed wheat field near Madrid, Spain (same study as (15)), found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in one of six comparisons (November 2011: 180 vs 128 g water/kg soil). Methods: No tillage or conventional tillage was used on four plots each (in which a total of 24 subplots, 10 x 25 m each, were used in this study). A mouldboard plough was used for conventional tillage (25 cm depth). Pre-emergence herbicide was used for no tillage. The subplots had wheat monocultures or fallow-wheat-vetch-barley rotations. The cereals were fertilized (NPK, 200 kg/ha, twice/year, in October and March). The crop residues were shredded and retained. Soil samples were collected in October 2010, April 2011, November 2011, May 2012, October 2012 and April 2013 (50 mm diameter, 0–15 cm depth).

 

15 

A replicated, randomized, controlled study in 1994–2011 in a rainfed cereal-legume field near Madrid, Spain (same study as (14)), found more water in soils with no tillage, compared to conventional tillage. Water availability: More water was found in soils with no tillage, compared to conventional tillage, in some comparisons (amounts of water and numbers of comparisons not reported). Methods: No tillage or conventional tillage was used on three plots each (10 x 25 m). A mouldboard plough and a cultivator were used for conventional tillage (20 cm depth) in October. A seed drill and herbicide were used for no tillage.  Soil samples were collected 1–12 times/month, in November 2010–October 2011 (0–15 cm depth, 2.5 cm diameter).

 

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.