Elsevier

Soil and Tillage Research

Volume 174, December 2017, Pages 221-230
Soil and Tillage Research

Long-term no-till as a means to maintain soil surface structure in an agroecosystem transformed into irrigation

https://doi.org/10.1016/j.still.2017.07.012Get rights and content

Highlights

Abstract

The aim of this study was to determine the most appropriate soil management to reduce the structural degradation of soils susceptible to crusting in Mediterranean areas recently transformed into irrigation. A long-term field experiment (LTE) under rainfed conditions was established in 1996 in NE Spain to compare three tillage systems (no-tillage, NT; reduced tillage, RT; conventional tillage, CT). The experiment was transformed to irrigated corn in 2015. In 2015, an adjacent experiment with the same layout was created (short-term experiment, STE) in an area previously managed under long-term NT. The study was carried out during the second corn growing season (i.e. year 2016). Soil samples were collected from 0 to 5 cm depth at different dates during corn season. Dry and water-stable macroaggregates and their C concentration, soil organic carbon (SOC) and labile C concentration, soil respiration, bulk density, penetration resistance (PR), water infiltration, macroporosity, microporosity, amount of crop residues and ground cover, corn development, aerial biomass, and grain yield were measured. In LTE and STE tillage led to a breakdown of dry sieved aggregates (of 2–4 and 4–8 mm size) in RT and CT, being slowly reconsolidated throughout the corn growing season. However, macroaggregate water-stability did not increase in CT and RT compared to NT due to a lower SOC concentration, making the soil more susceptible to its degradation by the action of water. SOC differences between treatments were more pronounced in LTE than STE given the long-term differential management in the first, which allowed greater accumulation of SOC under NT. In LTE, PR between corn rows was greater under NT than CT and RT and non-significantly different between treatments within the row. In the case of STE, PR increased over time after tillage (CT and RT) to match NT in the last sampling. Crop establishment was slower in CT than NT in LTE highlighting the impact of soil surface degradation on crop development. However, contrarily to the differences in corn yield in 2015, a careful planting in 2016 led to a lack of differences between tillage systems on corn yield. Our results indicate that in areas transformed into irrigation intensive tillage leads to greater susceptibility to soil structural degradation. Thus, in these areas the adoption of conservation agriculture practices such RT and NT enhances soil resilience to degradation processes and ensures an adequate development of the crop.

Introduction

Soil management practices affect both soil surface characteristics and crop productivity. Tillage exposes soil to erosive agents such as wind and water, inducing its degradation. Under severe erodible forces, soils are exposed to the impact of water-drops, either produced by irrigation or by rainfall. This last process results in the release of organic matter and, generally, in soil crusting (Awadhwal and Thierstein, 1985). In bare soils, structural crusts are a major problem facing many agricultural areas worldwide (Mbuvi et al., 2009). Structural crusts, developed on soil surface, negatively affect seedling emergence and reduce infiltration, favoring runoff and soil erosion (Fox et al., 2004). Furthermore, crusting is closely related to soil aggregation. In that sense, Bouaziz et al. (1990) found a linear relationship between soil aggregate size and the proportion of non-emerged wheat seedlings due to soil crusting.

In Mediterranean climate regions, an increasing number of rainfed areas are transformed into irrigation to stabilize or increase crop yields (Apesteguía et al., 2015). This conversion generates significant consequences in agroecosystems. Greater biomass production by irrigation leads to an increase in crop residues which can be returned to the soil. The increase of organic C inputs to the soil usually entails an increase in soil organic carbon (SOC) (Franzluebbers, 2005) and, concomitantly, an improvement in soil quality (Wick et al., 1998, Dexter et al., 2008). Moreover, C inputs play an essential role in the formation of soil aggregates, which physically protect SOC from microbial degradation (Beare et al., 1994) boosting SOC sequestration and climate change mitigation (Lal, 2011).

C-enriched aggregates are more stable to alterations such as rainfall, irrigation or tillage. Furthermore, crop residues protect the soil surface, preventing the formation of crusts (Jordán et al., 2010). Besides its importance in the Mediterranean climate regions, the impact of rainfed into irrigation transformation on soil surface characteristics (e.g., soil aggregation, soil organic carbon, bulk density, infiltration, penetration resistance and soil porosity) has been scarcely studied. Regarding to this, Apesteguía et al. (2015) observed an increase of the proportion of large macroaggregates under corn and wheat cropping systems managed under conventional tillage (chisel plow) when transforming a Mediterranean rainfed area into irrigation in north of Spain. Also, in Central Great Plains, Denef et al. (2008) found greater SOC storage in the surface soil layer (0–20 cm) in pivot-irrigated areas compared to dryland areas.

Tillage operations that incorporate crop residues into the soil increase soil susceptibility to degradation. When intensive tillage systems are adopted, soil remains bare until the next planting. Bare soils are more exposed to erosive agents and to drop impact promoting soil surface sealing and crusting and, at the end, water runoff (Pagliai et al., 2004). Tillage generally decreases soil bulk density compared to no-tillage (NT) (Lal, 1999) and it can negatively influence soil water infiltration, depending on soil type and properties (Dexter et al., 2004). For instance, Chan and Heenan (1993) and McGarry et al. (2000) reported lower infiltration rates under conventional tillage (CT) compared to NT. The adoption of NT systems has been identified as an optimal practice to reduce soil degradation and to improve soil aggregation in rainfed Mediterranean areas (Álvaro-Fuentes et al., 2009; Plaza-Bonilla et al., 2010). Moreover, it has been proved that long-term use of NT increases soil organic carbon (SOC) sequestration (Plaza-Bonilla et al., 2015). Similarly, Follett et al. (2013) showed that CT induced greater losses of old organic matter than NT in irrigated corn systems influencing soil physical properties. Soil organic matter plays a fundamental role in the formation and maintenance of aggregates, positively influencing the soil water retention capacity, water infiltration, and avoiding the formation of superficial crusts which improves seed germination and crop emergence.

In Mediterranean irrigated agroecosystems, typical soil management strategies include intensive tillage with deep subsoilers and mouldboard ploughs. However, unlike in irrigated systems, in Mediterrenan rainfed areas an increasing adoption of reduced tillage (RT) or NT techniques has been taking place over the last 30 years (Lampurlanés et al., 2016). In Mediterranean irrigated areas, the limited knowledge associated to the use of MT or NT systems, makes farmer adoption difficult and jeopardizes the soil quality benefits attained with long-term NT. As a consequence, the aim of this study was to determine to what extend soil management practices affect soil surface characteristics and crop establishment when transforming a rainfed area into irrigation in Mediterranean conditions.

Section snippets

Experimental design

A field experiment was conducted in Agramunt, NE Spain (41°48′ N, 1°07′ E, 330 m asl), where the soil was classified as Typic Xerofluvent (Soil Survey Staff, 2014). Soil characteristics are presented in Table 1. The climate is semiarid Mediterranean with a mean annual precipitation of 430 mm and a potential evapotranspiration of 855 mm. Mean annual air temperature is 13.8 °C.

A rainfed long-term field experiment (LTE) was established in 1996 to compare three tillage systems (no-tillage, NT; reduced

Results

Rainfall, irrigation events and air temperature during the entire experimental period are shown in Fig. 1. Air temperature increased from the beginning of the experimental period, reaching a maximum in summer months (July-August), to decrease later during autumn months. Total rainfall during the crop cycle was 140 mm with the greatest rainfall recorded in May (43 mm), which was far from the evapotranspiration needs. The amount of water applied by irrigation was 672 mm, 80% of this considered

Effect of long-term and short-term management practices on soil surface and corn development

The different historical management of the two experiments tested had a great impact on the results obtained. In the LTE, soil inversion with moldboard plough for the last 20 years (CT treatment) led to soil crusting (Fig. 6b). However, NT for 20 years provided greater resilience to soil degradation and crust formation, enhancing water infiltration, with almost two-fold greater water infiltration in NT compared to CT.

In the STE, tillage treatments significantly affected PR between corn rows,

Conclusions

Our study shows that the long-term use of intensive tillage in areas recently transformed into irrigation leads to a greater susceptibility to soil crust formation, and structural degradation. The results of this study have shown that the main process behind soil crusting was the breakdown of dry-sieved aggregates.

Although the proportion of dry-sieved aggregates increased after tillage (even reaching similar values than NT at the end of corn growing season) their water stability was lower.

Acknowledgements

We would like to thank the field and laboratory technicians Javier Bareche, Carlos Cortés and Silvia Martí. This research work is financially supported by the Ministerio de Economía y Competitividad of Spain (project AGL2013-49062-C4-1-R; PhD fellowship BES-2014-070039). Daniel Plaza-Bonilla received a Juan de la Cierva postdoctoral grant from the Ministerio de Economía y Competitividad of Spain (FJCI-2014-19570).

References (61)

  • D.M. Fox et al.

    Changes in pore characteristics with depth for structural crusts

    Geoderma

    (2004)
  • A.J. Franzluebbers

    Soil organic carbon sequestration and agricultural greenhouse gas emissions in the southeastern USA

    Soil Tillage Res.

    (2005)
  • A. Jordán et al.

    Effects of mulching on soil physical properties and runoff under semi-arid conditions in southern Spain

    Catena

    (2010)
  • J. Lampurlanés et al.

    Long-term analysis of soil water conservation and crop yield under different tillage systems in Mediterranean rainfed conditions

    Field Crops Res.

    (2016)
  • E. Martínez et al.

    Soil physical properties and wheat root growth as affected by no-tillage and conventional tillage systems in a Mediterranean environment of Chile

    Soil Tillage Res.

    (2008)
  • E. Martínez et al.

    Chemical and biological properties as affected by no-tillage and conventional tillage systems in an irrigated Haploxeroll of Central Chile

    Soil Tillage Res.

    (2013)
  • D. McGarry et al.

    Contrasting soil physical properties after zero and traditional tillage of an alluvial soil in the semi-arid subtropics

    Soil Tillage Res.

    (2000)
  • D. Moret et al.

    Dynamics of soil hydraulic properties during fallow as affected by tillage

    Soil Tillage Res.

    (2007)
  • M. Neave et al.

    A field investigation into the effects of progressive rainfall-induced soil seal and crust development on runoff and erosion rates: the impact of surface cover

    Geomorphology

    (2007)
  • J.A. Osunbitan et al.

    Tillage effects on bulk density, hydraulic conductivity and strength of a loamy sand soil in southwestern Nigeria

    Soil Tillage Res.

    (2005)
  • M. Pagliai et al.

    Soil structure and the effect of management practices

    Soil Tillage Res.

    (2004)
  • M. Panettieri et al.

    Moldboard plowing effects on soil aggregation and soil organic matter quality assessed by 13C CPMAS NMR and biochemical analyses

    Agric. Ecosys. Env.

    (2013)
  • D. Plaza-Bonilla et al.

    Soil aggregation and organic carbon protection in a no-tillage chronosequence under Mediterranean conditions

    Geoderma

    (2013)
  • D. Plaza-Bonilla et al.

    Identifying soil organic carbon fractions sensitive to agricultural management practices

    Soil Tillage Res.

    (2014)
  • J. Six et al.

    Soil macroaggregate turnover and microaggregate formation: a mechanism for C sequestration under no-tillage agriculture

    Soil Biol. Biochem.

    (2000)
  • J. Álvaro-Fuentes et al.

    Soil aggregation and soil organic carbon stabilization: effects of management in semiarid Mediterranean agroecosystems

    Soil Sci. Soc. Am. J.

    (2009)
  • M. Apesteguía et al.

    Effect of the conversion to irrigation of semiarid Mediterranean dryland agrosecoystems on soil carbon dynamics and soil aggregation

    Arid Land Res. Manage.

    (2015)
  • G.H. Baker et al.

    Seasonal changes in the abundance of earthworms (Annelida: lumbricidae and Acanthodriliadae) in soils used for cereal and lucerne production in South Austraia

    Aust. J. Agric. Res.

    (1993)
  • J. Balesdent et al.

    Effects on tillage on soil organic carbon mineralization estimated from 13C abundance in maize fields

    J. Soil Sci.

    (1990)
  • M.H. Beare et al.

    Aggregate-protected and unprotected organic-matter pools in conventional-tillage and no-tillage soils

    Soil Sci. Soc. Am. J.

    (1994)
  • Cited by (50)

    View all citing articles on Scopus
    View full text