Nitrogen dynamics in agricultural systems under Mediterranean climate

Transcription

1 Nitrogen dynamics in agricultural systems under Mediterranean climate Luis Lassaletta Rennes 25 th 27 th June 2018

2 Mediterranean type climate areas worldwide California The Mediterranean basin MEDITERRANEIZATION Chile South Africa Australia Highly populated areas Hot spot of biodiversity Unique agriculture High risk of soil degradation Highly vulnerable to climate change Water scarcity

3 The Mediterranean climate Water scarcity Gap: Water availability Max. Irradiation Water availability Range precipitation: mm Precipitation Temperatures Evapotranspiration

4 Response to irrigation Net irrigation requirements Relative yields for different irrigation strategies and crop regions < 100(mm/y) Yield change Irrigation strategies Climate-Region > 1000 (mm/y) Wriedt et al (J. Hydrol.)

5 Percentage irrigated area Temperate Mediterranean Tn grain /ha Surface under irrigation Wheat yield 2015 (FAOSTAT) Temperate Mediterranean Cyprus Greece Italy Portugal Spain Austria Belgium Germany Sweden United Kingdom

6 Tn grain /ha Tn grain /ha Tn grain /ha Diversity: Climatic gradient, different agronomic performance Fertilization kgn/ha Cuenca Annual precipitation Temperate La Rioja Mediterranean Rainfed Irrigated Rainfed Irrigated Murcia Rainfed Irrigated Wheat yield 2015 (National Stat)

7 Nitrogen inputs to agricultural soils Leip et al (European Nitrogen Assessment)

8 Yield kgn/ha/y Yield kgn/ha/y Tn grain /ha Climatic gradient, different agronomic performance: Spatial & 160 Interannual vartiability Fertilization 200 kgn/ha/y 400 Irrigated Spatial variability Small distance Rainfed Interannual variability Annual precipitation Temperate Mediterranean Rainfed Irrigated Irrigated High distance Rainfed 0 100Fertilization 200 kgn/ha/y High inefficiency

9 Interaction water-nitrogen in Mediterranean cropping systems Co-limitation water-nitrogen Quemada & Gabriel (2016) Global Food Security

10 Output (kgn/ha/y) Interaction water-nitrogen in Mediterranean cropping systems % 46% Irrigated Strat. 2 Irrigated Strat. 1 Rainfed 850 mm Rainfed 550 mm Rainfed 280 mm Input (kgn/ha/y) 11% 22% 32% Fertilization rate: 140 kgn/ha/y

11 Soil Organic Carbon Low organic concentration

12 Tn / ha Organic matter management in arid regions a a a Vineyard Effect only on rainfed: Water retention a ab b Rainfed Irrigated Control Inorgánic Mulching Intrigliolo et al. (pers comm)

13 The effect of climate change: warmer, drier and extreme Projected : Changes in runoff García-Ruiz el al (Proc. IAHS)

14 Some key messages Large inter-annual variability Large spatial variability from Mediterranean arid to M. humid Fertilization adjusted to highly variable needs Organic matter low but relevant Water-nitrogen interaction crucial N management We need to mitigate climate change We need to save water So, we will see now some specificities of the dynamics of the main N compounds under Mediterranean conditions We also need to protect the scarce water Imperative need for adaptation to climate change NH 3 NO 3 - N 2 O

15 Gg N/y Challenge to accomplish Gothenburg protocol Lassaletta et al (Reg. Environ. Change) Increasing ammonia pollution: the case of Spain Production vs Import NH Crops Net imp-exp Percentage urea use 35% 30% 25% 20% 15% 10% 5% 0%

16 Food and feed fate (GgN) Similar trends in other Mediterranean countries Huge and increasing amount of crops (imported or local) transformed in manures Imported food Local food Imported feed NH Local feed Permanent grass Lassaletta et al. (in prep) North Med.

17 Significant net import of protein-rich crops for feed NH 3 Sanz-Cobena et al (Agric. Ecosyst. & Environ.)

18 Emissions from urea lower than expected: i) high atm. stability and ii) clay soils and dry summers NH 3 Synthetic fertilizers (urea). Urea: 10.1 and 5.3% N applied CORINAIR: 20% Sanz-Cobena et al. (2008) AGEE; Ábalos et al. (2012) Chemosphere. Sanz-Cobena et al. (2014) ERL Organic fertilizers (pig slurry). Mitigation by slurry incorporation NH 3 kgn ha cumulative emissions of volatilized ammonia Surface Injected 1.0 Higher risk of nitrate leaching?: Pollution swapping time (h) Sanz-Cobena et al., in prep.

19 Nitrogen pollution in continental waters NO 3 - Ebro River Basin Mediterranean Sea Lassaletta et al (STOTEN) Lassaletta et al (Env. Sci. Policy)

20 Management strategies in irrigated areas: mean effect size on nitrate leaching NO 3 - Water management Fertilizer management Use of cover crops Fertilizers technology Water management largest effect size: 58% Quemada et al (Agric. Ecosyst. & Environ.)

21 N 2 O emissions: as systematic review N 2 O 2016 Footer; wijzig via View > Header and Footer Cayuela et al (Agric. Ecosyst. & Environ)

22 Again a strong interaction with water Rainfed (62) Rainfed <450 mm (38) N 2 O IPCC Tier I default value 0.3 ± ± 0.3 Rainfed >450 mm (24) 0.3 ± 0.3 Irrigated (138) 0.6 ± 0.1 Flood (14) Furrow (27) Drip (52) Sprinkler (45) 0.2 ± ± ± ± 0.2 Mean EF for Mediterranean crops (223) 0.5 ± 0.1 Cayuela et al (Agric. Ecosyst. & Environ) Emission factor (%)

23 Application rate Fertilizer type Fertilizer type + application rate IPCC Tier I default value N 2 O Organic liquid (30) 0.8 ± 0.3 Organic solid (24) 0.2 ± 0.3 Mixture (22) 0.5 ± 0.4 Synthetic (124) 0.5 ± 0.1 Inhibitors (23) 0.1 ± 0.3 <100 kg N/ha (40) 0.2 ± kg N/ha(145) 0.5 ± 0.1 >400 kg N/ha (15) 0.8 ± 0.5 Cayuela et al (AGEE) Emission factor (%)

24 Non-linear responses to application rate? France N 2 O 170 kgn/ha/y North Med. Shcherbak et al. (2014) PNAS East Med. Egypt South Med. Lassaletta et al. (in prep)

25 GgN/y N2O (Gg N-N 2 O) The importance of a Tier-2 transition in the national inventories N 2 O Input to Mediterranean crops N 2 O Tier 1 vs Tier Total To crops Liquid Solid Synthetic GgN 47 GgN Tier 1 Tier 2 Lassaletta et al. (in prep)

26 Indirect and induced GHG emissions N 2 O Direct emissions can be small! But other emissions can be high! Sanz-Cobena et al (Agric. Ecosyst. & Environ.)

27 Nitrogen retention in river basins 5000 km channels 208 dams 10% irrigated land Demanding 7623 hm 3 /y Transport to pollutants to the sea 9216 hm 3 /y Mediterranean sea Inland contamination Mediterranean Sea Lassaletta et al (Biogeosciences)

28 Nitrogen retention in river basins Retention 76 % in temperate catchments Retention 95 % in Mediterranean catchments Romero et al (STOTEN)

29 Research gaps Number of papers considering N 2 O emissions in Mediterranean areas per Tg N 2 O emitted (CO 2 eq) by crop type in Spain 160 Papers/Tg CO2eq No scientific information E.g. Total emissions in Spanish grain legumes lower than in olive orchards Aguilera et al. (In prep.)

30 AGEE Special Issue on GHG mitigation in Mediterranean cropping systems Special Issue: "Mitigation and Quantification of GHG in Mediterranean cropping systems Alberto Sanz-Cobena, Luis Lassaletta, Josette Garnier and Pete Smith. Eds. Agriculture, Ecosystems & Environment Vol 238 (Feb-2017) 14 contributions

31 Alberto Sanz-Cobeña Mediterranean landscape in an unusually humid spring

32 Eduardo Aguilera Systems Mariluz Cayuela N 2 O Diego Intrigliolo Water Estela Romero Basins Margarita Ruiz-Ramos Adaptation Miguel Quemada Leaching Antonio Vallejo Gases Alberte Bondeau Wolfgang Cramer Integrated modelling Gilles Billen Josette Garnier Julia le Noe The temperate contrast

33 Conclusions Nitrogen dynamics deeply depend on the water input and management and on the climatic variability Rainfed and irrigated systems represent two contrasted worlds that do not match with the knowledge gained in temperate systems Strong water regulation highly affect N cycle at the basin scale Mitigation, adaptation and water quality strategies have to be constructed in coordination and tailored at the regional scale

34 Conclusions Nitrogen dynamics deeply depend on the water input andthe management Mediterranean and onglasses the climatic variability Rainfed and irrigated systems represent two contrasted worlds that do not match with the knowledge gained in temperate systems Strong water regulation highly affect N cycle at the basin scale Mitigation, adaptation and water quality strategies have to be constructed in coordination and tailored at the regional scale

35 Thank you very much