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Appendix A. Individual conceptual networks representing agricultural
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management and ecosystem services provision.
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The relationships between agricultural management and eight ecosystem
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services (ES) provided by Pampean agroecosystems were represented in individual
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conceptual networks (Figs. 1 to 8). The eight conceptual networks developed in this
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work contained five types of nodes, and four types of logical links between nodes (see
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Section 2.3.). These logical links present capital letters in order to easily explain each
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conceptual network.
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1. Supporting Service: Elements cycling - C Balance
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Fig. 1 Conceptual network representing functional relationships between agricultural management and
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provision of the Supporting service: Elements cycling - C balance. Capital letters represent the logical
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links between nodes. Legend: circles meaning input variables; rounded-squares meaning decision
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variables; squares meaning state variables; triangles meaning ecosystem processes and diamond meaning
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ecosystem service provision indicators. Tº: temperature, and Pp: rainfall
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It is generally known that C inputs in soils consist of crop residues and roots,
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and sometimes additions of soil organic amendments; while C loss is caused by humus
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and residue mineralization, in conditions where soil erosion and C leaching are minimal
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(C leaching is not an important cause of soil organic carbon (SOC) losses in Pampean
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agroecosystems (Roberto Álvarez, personal communication)) (Oorts and others 2006).
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The interaction between temperature and rainfall regulates SOC through the influence
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of soil organic matter (SOM) mineralization (Fig. 1, Relations A and B) (Roberto
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Álvarez and Raúl Lavado, personal communication). High temperature reduces SOC
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because of intense SOM mineralization, while there is no linear answer for rainfall (Fig.
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1, Relations A, B and F) (Álvarez and Lavado 1998). However, it is widely accepted
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that, in general, rainfall has the same effect as temperature (Fig. 1, Relations B and F)
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(Roberto Álvarez and Raúl Lavado, personal communication). Additionally, crop
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species, their growth rate and yield determine the amount and type (i.e., quality) of crop
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residue (including crop roots) (Fig. 1, Relations D and I) (Ernst and others 2002) which
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change SOC in surface soil layers, specially in no-tillage systems (Álvarez and Lavado
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1998). Surface soil layers have greater C amounts because of the input of crop residue
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from harvested plants (Álvarez and Lavado 1998). Generally, legume species (e.g.,
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soybean) have higher mineralization rates than gramineous species (e.g., wheat, maize)
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due to lower C/N relations (Fig. 1, Relation E) (Ernst and others 2002).
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Another conditioning factor of SOC reduction is erosion vulnerability which is
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higher in continuous cropping systems, principally by 1) removing C from one site and
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depositing it elsewhere, and 2) promoting soil degradation and then reducing
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productivity (Fig. 1, Relation G) (Martínez-Mena and others 2008). However, it can be
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assumed that SOC movement is dependent on the topographic position (Haydée
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Steinbach and Roberto Álvarez, personal communication). Soils under no-tillage reduce
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both eolic erosion in semiarid sites, and hydric erosion in sites with great slopes
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(Monzon and others 2006).
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2. Supporting Service: Elements cycling - N Balance
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Fig. 2 Conceptual network representing functional relationships between agricultural management and
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provision of the Supporting service: Elements cycling - N balance. Capital letters represent the logical
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links between nodes. Legend: circles meaning input variables; rounded-squares meaning decision
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variables; squares meaning state variables; triangles meaning ecosystem processes and diamond meaning
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ecosystem service provision indicator. Tº: temperature, and Pp: rainfall
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Soil nitrogen (N) availability is modulated by four main factors: SOM
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mineralization, crop residue, fertilization regime and N losses (Cassman and others
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2002). N mineralization through SOM is a very important supply source due to its usage
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availability (Fig. 2, Relation G), increasing or decreasing crop yield (Fig. 2, Relation J)
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(Bono and Álvarez 2007). The increase in soil moisture content increases mineralized N
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(Fig. 2, Relations B and F) (Helena Rimski-Korsakov, personal communication). This
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increase is a direct consequence of higher microbial activity, until the concentration of
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oxygen in the soil becomes a limitation for the microorganisms (Navarro and others
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1991). Moreover, SOM is not only affected by mineralization but also by crop residue
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disposal on soil surface layers (Fig. 2, Relation E) (Ernst and others 2002), as it occurs
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for SOC in no- and reduced tillage systems. N fertilization can increase the amount of
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soil N pools which will be available for crops (Fig. 2, Relation K) (Abril and others
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2007). However, N excedent can also be immobilized by microorganisms, resulting in a
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non linear effect (i.e., increase or reduce) of the application (Fig. 2, Relation K)
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(Cassman and others 2002; Portela and others 2006). Furthermore, N losses by
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denitrification, volatilization or leaching are the main causes for the low efficiency in
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the use of N, and therefore they affect available N in soil (Fig. 2, Relation L) (Abril and
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others 2007). Because of the low degree of these losses during the whole crop growth
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cycle (Álvarez and Grigera 2005), they can be grouped all together under the name of N
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losses (Roberto Álvarez, personal communication).
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3. Supporting Service: Water cycling - Soil water balance
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Fig. 3 Conceptual network representing functional relationships between agricultural management and
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provision of the Supporting service: Water cycling - Soil water balance. Capital letters represent the
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logical links between nodes. Legend: circles meaning input variables; rounded-squares meaning decision
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variables; squares meaning state variables; triangles meaning ecosystem processes and diamonds meaning
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ecosystem service provision indicators. Tº: temperature, and Pp: rainfall
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In Pampean agroecosystems, water supply for crops is determined by nine
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variables: 1) evaporation, 2) runoff, 3) soil structural stability, 4) soil texture, 5) aquifer
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depth, 6) soil depth, 7) presence of weeds/fallow/cover crops, 8) irrigation, and 9)
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rainfall (Fig. 3, Relations M, N, O, P, Q, R, S, T and C). These variables, in general,
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increase or affect water supply for crops. For instance, no-tillage systems leave crop
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residue on the soil surface and, therefore, soil evaporation is clearly decreased (Fig. 3,
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Relations E and F) (Monzon and others 2006). Relative soil evaporation rates directly
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influence the amount of soil water retained which will be used by the crop (Fig. 3,
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Relation M) (O´Leary and Connor 1997). Stubble mulch protects the surface soil from
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erosion and runoff, and increases water storage by minimising surface sealing and
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enhancing infiltration, as well as by directly reducing evaporation (Fig. 3, Relations G,
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J, N and O) (O´Leary and Connor 1997). Moreover, irrigation not only increases water
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supply for crops (Fig. 3, Relation T) but also affects runoff, depending on the amount of
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water irrigated and crop residue on soil surface (Fig. 3, Relation L) (Olga Heredia,
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personal communication). Systems under no-tillage can increase soil water
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accumulation during fallows (Fig. 3, Relation S), and thereby offer the potential for
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affecting crop yield in Pampean agroecosystems (Olga Heredia and Francisco Bedmar,
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personal communication) (Fig. 3, Relation U).
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Soil depth is related with the ability of roots to explore soil profile and to absorb
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water stored there (Fig. 3, Relation R); on the other hand, aquifer depth can be defined
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by characterizing the average depth fluctuation of water table in different regions (Fig.
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3, Relation Q) (Esteban Jobbágy, personal communication). This is specially important
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in sandy soils (Claudia Sainato, personal communication). Finally, weeds can be burned
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to avoid evaporation as well as the establishment of cover crops (Fig. 3, Relation S)
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(Olga Heredia and Silvina Portela, personal communication).
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4. Supporting service: Soil conservation – Soil structural maintenance
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Fig. 4 Conceptual network representing functional relationships between agricultural management and
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provision of the Supporting service: Soil conservation – Soil structural maintenance. Capital letters
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represent the logical links between nodes. Legend: circles meaning input variables; rounded-squares
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meaning decision variables; squares meaning state variables; triangles meaning ecosystem processes and
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diamonds meaning ecosystem service provision indicators. Tº: temperature, and Pp: rainfall
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Structural stability is defined as soil capacity to preserve the system of solids and
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pore space, when subjected to different external disturbances (e.g., tillage) (Taboada
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and Micucci 2002). Its loss is the critical factor which determines structural
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deterioration. This deterioration is evidenced by the formation of surface crusts, higher
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rates of runoff and soil loss due to erosion, as well as reduced water storage (Taboada
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and Micucci 2002). Soil structural stability is clearly affected by land use, which is in
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turn positively associated with crop residue, total organic C concentration and the forms
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of organic C (Fig. 4, Relations I and J) (Caravaca and others 2004). The close
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association found between structural stability, labile carbon and microbial biomass
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confirms both their importance in the mineralization process and their ability as
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aggregate cementitious (Fig. 4, Relations G and H) (Urricarriet and Lavado 1999).
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According to the first statement, SOM decomposition may be limited by pore size
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distribution due to the localization of SOM in pores inaccesible to microorganisms, a
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limited nutrient supply to microorganisms and restricted predation of those
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microorganisms (Miguel Taboada and Roberto Casas, personal communication).
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Furthermore, soil structural stability is one of the most important characteristics
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affecting crop yield (Fig. 4, Relation K) because it affects root penetration, water
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storage capacity, and air and water movement in soil (Fig. 4, Relation O) (Aparicio and
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Costa 2007).
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5. Regulating Service: Climate regulation – N2O emission control
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Fig. 5 Conceptual network representing functional relationships between agricultural management and
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provision of the Regulating service: Climate regulation – N2O emission control. Capital letters represent
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the logical links between nodes. Legend: circles meaning input variables; rounded-squares meaning
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decision variables; squares meaning state variables; triangles meaning ecosystem processes and diamonds
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meaning ecosystem service provision indicators. Tº: temperature, and Pp: rainfall
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Although denitrification is only part of direct N2O emissions from soils, it is the
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most studied process in contrast with nitrification occurring in unsaturated soils, among
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other conditions (Fig. 5, Relation P) (Laura Yahdjian, personal communication). Thus,
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the main factors controlling denitrification are: soil pH, soil texture, nitrate
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concentration, C availability, aeration and moisture content (Guo and Zhou 2007).
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However, the major factors to consider, in terms of N2O production in Pampean
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agroecosystems, are available N in soil and moisture content (in this case, rainfall) (Fig.
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5, Relations N and O) (Palma and others 1997; Ciampitti and others 2005). For instance,
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it is known that the presence of actively growing plants limits the denitrification process
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in comparison with those treatments without plants, due to reduced water availability
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and to lower levels of nitrates in soil, to a lesser extent (Sainz Rozas and others 2004).
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Once the crop is harvested and crop residue remains on the surface, soluble C
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concentration is associated with denitrification (Fig. 5, Relation E); this is because
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bacteria biomass capable of denitrification is probably controlled primarily by C
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availability under aerobic conditions (Fig. 5, Relation M) (Miguel Taboada, personal
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communication), while emissions occur mainly during anaerobic conditions (Fig. 5,
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Relation O).
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6. Regulating Service: Water purification - Groundwater contamination control
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Fig. 6 Conceptual network representing functional relationships between agricultural management and
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provision of the Regulating service: Water purification - Groundwater contamination control. Capital
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letters represent the logical links between nodes. Legend: circles meaning input variables; rounded-
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squares meaning decision variables; squares meaning state variables; triangles meaning ecosystem
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processes and diamonds meaning ecosystem service provision indicators. Tº: temperature, and Pp: rainfall
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Nitrate (NO3) leaching is one of the main causes for groundwater contamination
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(Fig. 6, Relations N and O) (Abril and others 2007; Claudia Sainato and Olga Heredia,
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personal communication). However, Mugni and others (2005) measured NO3
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concentration in four Pampasic streams and concluded that it was relatively modest
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compared to intensively cultivated basins in Europe and North America. Consequently,
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there is a slow N enrichment of water resources in Pampean agroecosystems (Portela
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and others 2006). Water quality is reduced not only by N fertilization (Fig. 6, Relation
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J) (Rimski-Korsakov and others 2004; Abril and others 2007), but also SOM
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mineralization through several years removes great amounts of NO3 towards aquifers
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(Portela and others 2006; Helena Rimski-Korsakov and Raúl Lavado, personal
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communication) (Fig. 6, Relation G). N fertilization could also be indirectly inducing
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soil NO3 leaching, by altering the ability of plants root system to acquire N from soil
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and net mineralization rate from organic N pools (Cassman and others 2002).
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Furthermore, fertilization in excess of crop requirements or water excedent, such as
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rainfall events (Fig. 6, Relation M) or irrigation (Fig. 6, Relation K), increase the
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probability of soil NO3 leaching (Costa and others 2002; Rimski-Korsakov and others
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2004; Vergé and others 2007). It is important to clarify that the Pampa region has low N
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inputs through rainfall (Portela and others 2006). Other factors affecting soil NO3
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leaching are particle size distribution, soil porosity and the ocurrence of preferential
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flow paths. These causes can be grouped under soil texture, which is another important
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factor because of its ability for retaining water (Fig. 6, Relation L) (Taboada and
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Micucci 2002).
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7. Regulating Service: Regulation of biotic adversities
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Fig. 7 Conceptual network representing functional relationships between agricultural management and
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provision of the Regulating service: Regulation of biotic adversities. Capital letters represent the logical
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links between nodes. Legend: circles meaning input variables; rounded-squares meaning decision
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variables; squares meaning state variables; triangles meaning ecosystem processes and diamonds meaning
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ecosystem service provision indicators
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In Pampean agroecosystems, crop environment is determined by: 1) tillage
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system, 2) crop protection, 3) sowing density, 4) sowing date, 5) fertilization, 6)
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genotype selection, and 7) irrigation (Fig. 7, Relations B, A, C, D, E, F and G). These
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variables affect not only crop yield but also species composition and abundance of plant
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and animal community, and beneficial species (Fig. 7, Relations H, J and L) (Emilio
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Satorre and Elba De la Fuente, personal communication). Beneficial species as well as
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crop environment and crop changes affect species composition and
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abundance/incidence of pests, diseases and weeds (Fig. 7, Relations K, L and N). The
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latter reduces crop yield and affects natural pest mitigation of ecosystems (Fig. 7,
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Relations I and O). The presence of weeds influences the presence of diseases and
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diversity and abundance of two insect types: pests, with negative consequences for
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cropping systems, and their natural enemies (Altieri 1999). Generally, a high density of
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weeds is counter-productive because they reduce crop yield and its quality (Albrecht
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2003).
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8. Biodiversity maintenance
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Fig. 8 Conceptual network representing functional relationships between agricultural management and
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Biodiversity maintenance. Capital letters represent the logical links between nodes. Legend: circles
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meaning input variables; rounded-squares meaning decision variables; squares meaning state variables;
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triangles meaning ecosystem processes and diamond meaning ecosystem service provision indicator
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Biological diversity or biodiversity is defined as the wide variety of plants,
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animals, microorganisms and their genetic variations (Altieri 1999). In agroecosystems,
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the variety of crops are also considered as biodiversity components (María Elena
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Zaccagnini, personal communication). However, the type and abundance of biodiversity
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may differ across agroecosystems in relation to their crop protection (i.e.,
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phytotherapics application) and tillage system (Fig. 8, Relations A, B and C) (María
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Elena Zaccagnini, personal communication).
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Other management strategies for increasing biodiversity involve the 1)
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manipulation of undisturbed areas within agroecosystems, 2) preservation of weeds, or
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3) introduction of mixtures containing grasses, legumes, flowering and/or aromatic
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plants. These strategies offer alternative food sources (i.e., pollen, nectar) to different
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organisms, and places for hibernation and reproduction (Fig. 8, Relation D) (Carmona
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and Landis 1999; Carmona and others 1999; Landis and others 2000). Furthermore,
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areas functioning as shelters act as biological corridors in the mobility of natural
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enemies (decreasing, in some cases, phytotherapic application) and their non-
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fragmentation is fundamental to the establishment of these organisms and the rapid
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recolonization of agroecosystems after a disturbance (Fig. 8, Relation D) (Carmona and
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Landis 1999; Landis and others 2000; Jonsson and others 2008; Gardiner and others
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2009; Rufus and others 2009).
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Sequences, rotations and landscape structure provide two types of
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agroecosystems heterogeneity (Fig. 8, Relations E and F). On the one hand,
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sequences/rotations are recognized as temporal heterogeneity even though they are
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planned biodiversity (e.g., crops, pastures); on the other hand, landscape structure can
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be identified as spatial heterogeneity (Elba De la Fuente, personal communication).
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Landscape structure plays a crucial role in the survival of species by offering different
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kinds of habitat (Claudio Ghersa, personal communication).
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References
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253
Abril A, Baleani D, Casado-Murillo N, Noe L (2007) Effect of wheat crop fertilization
254
on nitrogen dynamics and balance in the Humid Pampas, Argentina. Agriculture,
255
Ecosystems & Environment 119:171-176.
256
Albrecht H (2003) Suitability of arable weeds as indicator organisms to evaluate species
257
conservation effects of management in agricultural ecosystems. Agriculture,
258
Ecosystems & Environment 98:201-211.
259
260
Altieri MA (1999) The ecological role of biodiversity in agroecosystems. Agriculture,
Ecosystems & Environment 74:19-31.
261
Álvarez R, Grigera S (2005) Analysis of soil fertility and management effects on yields
262
of wheat and corn in the Rolling Pampa of Argentina. Journal of Agronomy & Crop
263
Science 191:321-329.
264
265
266
267
Álvarez R, Lavado RS (1998) Climate, organic matter and clay content relationships in
the Pampa and Chaco soils, Argentina. Geoderma 83:127-141.
Aparicio V, Costa JL (2007) Soil quality indicators under continuous cropping systems
in the Argentinean Pampas. Soil & Tillage Research 96:155-165.
268
Bono A, Álvarez R (2007) Mineralización de nitrógeno del suelo en la región semiárida
269
pampeana. Instituto Nacional de Tecnología Agropecuaria, Publicación Técnica Nº
270
69:65-76.
271
Caravaca F, Lax A, Albaladejo J (2004) Aggregate stability and carbon characteristics
272
of particle-size fractions in cultivated and forested soils of semiarid Spain. Soil &
273
Tillage Research 78:83-90.
274
Carmona D, Landis D (1999) Influence of refuge habitats and cover crops on seasonal
275
activity-density of ground beetles (Coleoptera: Carabidae) in field crops.
276
Environmental Entomology 28:1145-1153.
13
277
Carmona D, Menalled F, Landis D (1999) Northern Field Cricket Gryllus pensylvanicus
278
Burmeister (Orthoptera: Gryllidae): Weed seed predation and within field activity-
279
density. Journal Economic of Entomology 92:825-829.
280
281
Cassman KG, Dobermann A, Walters DT (2002) Agroecosystems, nitrogen-use
efficiency, and nitrogen management. Ambio 31:132-140.
282
Ciampitti IA, Ciarlo EA, Conti ME (2005) Emisiones de óxido nitroso en un cultivo de
283
soja (Glycine max (L.) Merrill): efecto de la inoculación y de la fertilización
284
nitrogenada. Ciencia del Suelo 23:123-131.
285
Costa JL, Massone H, Martínez D, Suero EE, Vidal CM, Bedmar F (2002) Nitrate
286
contamination of a rural aquifer and accumulation in the unsaturated zone.
287
Agricultural Water Management 57:33-47.
288
Ernst O, Betancur O, Borges R (2002) Descomposición de rastrojos de cultivos en
289
siembra sin laboreo: trigo, maíz, soja y trigo después de maíz o de soja. Agrociencia
290
6:20-26.
291
Gardiner MM, Landis DA, Gratton C, Difonzo C, O´Neal M, Chacon JM, Wayo MT,
292
Schmidt NP, Mueller EE, Heimpel,GE (2009) Landscape diversity enhances
293
biological control of an introduced crop pest in the north-central USA. Ecological
294
Applications 19:143-154.
295
296
297
298
Guo J, Zhou C (2007) Greenhouse gas emissions and mitigation measures in Chinese
agroecosystems. Agricultural and Forest Meteorology 142:270-277.
Jonsson M, Wratten SD, Landis DA, Gurr GM (2008) Recent advances in conservation
biological controls of arthropods by arthropods. Biological Control 45:172-175.
299
Landis D, Menalled FD, Lee J, Carmona DM, Perez Valdez A (2000) Habitat
300
management to enhance biological control in IPM. In: Kenedy GG, Sutton TB (eds)
14
301
Emerging technologies for Integrated Pest Management: Concepts, Research and
302
Implementation. APS PRESS. St. Paul, Minesota, pp. 226-239.
303
Martínez-Mena M, Lopez J, Almagro M, Boix-Fayos C, Albaladejo J (2008) Effect of
304
water erosion and cultivation on the soil carbon stock in a semiarid area of South-
305
East Spain. Soil & Tillage Research 99:119-129.
306
Monzon JP, Sadras VO, Andrade FH (2006) Fallow soil evaporation and water storage
307
as affected by stubble in sub-humid (Argentina) and semi-arid (Australia)
308
environments. Field Crops Research 98:83-90.
309
Mugni H, Jergentz S, Schultz R, Maine A, Bonetto C (2005) Phosphate and nitrogen
310
compounds in streams of Pampean Plain areas under intensive cultivation (Buenos
311
Aires, Argentina). In: Serrano L, Golterman HL (eds) Proceedings of the 4th
312
International Symposium Phosphates in Sediments. Backhuys Publishers, The
313
Netherlands, pp. 163-170.
314
Navarro C, Echeverría H, Fonalleras M, Manavella F (1991) Efecto de los contenidos
315
de humedad sobre la mineralización del nitrógeno en suelos del sudeste bonaerense.
316
Ciencia del Suelo 9:13-19.
317
318
O´Leary GJ, Connor DJ (1997) Stubble retention and tillage in a semi-arid environment:
1. Soil water accumulation during fallow. Field Crops Research 52:209-219.
319
Oorts K, Nicolardot B, Merckx R, Richard G, Boizard H (2006) C and N mineralization
320
of undisrupted and disrupted soil from different structural zones of conventional
321
tillage and no-tillage systems in northern France. Soil Biology & Biochemistry
322
38:2576-2586.
323
324
Palma RM, Rímolo M, Saubidet MI, Conti ME (1997) Influence of tillage system on
denitrification in maize-cropped soils. Biology and Fertility of Soils 25:142-146.
15
325
Portela SI, Andriulo AE, Sasal MC, Mary B, Jobbágy EG (2006) Fertilizer vs. organic
326
matter contributions to nitrogen leaching in cropping systems of the Pampas: 15N
327
application in field lysimeters. Plant Soil 289:265-277.
328
Rimski-Korsakov H, Rubio G, Lavado RS (2004) Potential nitrate losses under different
329
agricultural practices in the pampas region, Argentina. Agricultural Water
330
Management 65:83-94.
331
Rufus I, Tuell J, Fiedler A, Gardiner M, Landis D (2009) Maximizing arthropod-
332
mediated ecosystem services in agricultural landscapes: the role of native plants.
333
Frontiers in Ecology and the Environment 7:196-203.
334
Sainz Rozas H, Echeverría HE, Barbieri P (2004) Denitrification in a soil under no-
335
tillage as a function of presence of maize plant and nitrogen rate. Ciencia del Suelo
336
22:27-35.
337
338
339
340
Taboada MA, Micucci FG (2002) Fertilidad física de los suelos. Editorial Facultad
Agronomía, Universidad de Buenos Aires. Buenos Aires, Argentina.
Urricarriet S, Lavado RS (1999) Indicadores de deterioro en suelos de la Pampa
Ondulada. Ciencia del Suelo 17:37-44.
341
Vergé XPC, De Kimpe C, Desjardins RL (2007) Agricultural production, greenhouse
342
gas emissions and mitigation potential. Agricultural and Forest Meteorology
343
142:255-269.
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