Cn 5 th14_inia_mitigatio_of_water_erosion_martinez

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  • Los sitios de estudio están ubicados en el secano interior de la región sub-húmeda, en la Estación Experimental “El Boldo” de INIA-Cauquenes.
    En esta zona existe una amplia diversidad de tipos de relieve, donde predominan pendientes moderadas utilizadas principalmente para cereales y pendientes fuertes, de uso agroforestal. Por esta razón se han seleccionado 2 sitios para la implementación de estrategias de conservación para ambas unidades de relieve.
    ENSAYO 1.
    Cero labranza. Consiste en sembrar directamente, sin romper el suelo.
    Curva desviación.
    Franjas vivas. Son plantaciones en hileras de pastos o arbustos forrajeros. Se construyen siguiendo la curva de nivel y en forma perpendicular a la pendiente, cuyo objetivo es reducir el grado y largo de la pendiente. A largo plazo llegan a constituirse en terrazas, ya que van acumulando el suelo que es transportado por la lluvia desde las zonas más altas.
    Subsolado. Técnica que contribuye a disminuir la compactación, mejorar la porosidad del suelo y aumentar la infiltración disminuyendo el escurrimiento superficial.
    Labranza tradicional.
  • Rainfall during season 2007 and 2009 where a 46% and 22%, respectively, less than the annual average, producing low leves of soil erosion.It was observed in season 2008, that soil erosion is affected principally by rainfall intensities. In this year, more than 300mm occured in one week.
  • IN THE STUDY AREA, DURING GRAIN-FILLING period there is less water in the soil, specially in Ct.
  • Cn 5 th14_inia_mitigatio_of_water_erosion_martinez

    1. 1. Mitigation of water erosion in MediterraneanMitigation of water erosion in Mediterranean climatic zone of central Chile : effects of noclimatic zone of central Chile : effects of no tillage systems and others soil conservationtillage systems and others soil conservation practicespractices Ingrid Martínez, Christian Prat, Carlos Ovalle, Erick Zagal, Neal Stolpe, Alejandro del Pozo, Hamil Uribe Landcom, October 2010
    2. 2. Mitigation of water erosion inMitigation of water erosion in Mediterranean climatic zone of centralMediterranean climatic zone of central ChileChile On behalf of my colleaguesOn behalf of my colleagues
    3. 3. MEDITERRANEAN CENTRAL - CHILE Rainfall mm per yr 0-50 mm 100-300 400-500 600-800 800-1000 >1000 Rainfall Temperature
    4. 4. GGeomorphologieeomorphologie of Central Chile ( at 36° LS)of Central Chile ( at 36° LS)
    5. 5. Low crop yield andLow crop yield and pasturepasture productiproductivityvity LLowow animal stocking rateanimal stocking rate Low profitability of theLow profitability of the farms (farms (cereal and meat productioncereal and meat production)) Crop (yr 2)Crop (yr 2) Unsown pasture (yr 3)Unsown pasture (yr 3) Fallow (yr 1)Fallow (yr 1) The land use systemThe land use system
    6. 6. Precipitación Evaporación En Fe Mar Ab May Jun Jul Ag Se Oc No Di 0 50 100 150 200 250 Precipitación-Evaporación(mm) (a) Título Precipitación Evaporación Concentrated period of rainfall and intensity of the events Unstable fragile Granitic soils What causes soil erosion in Chile? Traditional Tillage practices( With iron- tipped plow reversing soil) Steep slopes
    7. 7. But at the heart of the problem is the man. Indeed, the small farmer is required to plow the land, because on it depends their livelihood and the support of his family
    8. 8. Objectives • To asses the effects of Soil Conservation Tillage Systems on: •Runoff •Soil and nutrient losses •Soil compaction •Temporal and spatial variation of Soil Water Content (SWC) in the soil profile •Yield and phenological development of the crops In Chile, like in others parts of the world, impropriated agricultural practices had contributed to accelerate soil degradation. Soils are highly affected by water erosion, so New tillage systems can be TESTED to improve soil physical and chemical properties and to mitigate water erosion
    9. 9. METHODOLOGY
    10. 10. Horizons Sand Loam Clay Texture   Bulk density Total porosity cm % % % (Mg m3 ) % 0-18 72,6 12,6 14,8 Sandy loam 1,79 28,4 18-36 42,4 13,0 44,5 Clay 1,69 32,4 36-61 34,2 17,6 48,2 Clay 1,75 30,0 61-100 32,2 19,6 48,2 Clay 1,77 29,2 Soil characteristics Very lowVery low porosityporosity Very lowVery low porosityporosity •Soil is an entisol, classified as a Mollic Palexeralfs (CIREN, 1994) •Low organic matter content , (<1,5%) and and macronutrient (N - P and S) •Soil is an entisol, classified as a Mollic Palexeralfs (CIREN, 1994) •Low organic matter content , (<1,5%) and and macronutrient (N - P and S)
    11. 11. • Characteristics of rainfalls • 695 mm mean annual • Strong concentration in autumn and winter • Very intensive events of rain 0 50 100 150 200 250 300 350 400 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Month mm 2007 (372mm) 2008 (768mm) 2009 (536mm) x 44 years (695 mm) Precipitación Evaporación En Fe Mar Ab May Jun Jul Ag Se Oc No Di 0 50 100 150 200 250 Precipitación-Evaporación(mm) (a) Título Precipitación Evaporación
    12. 12. Plot size 1000m2 (20mx50m) Crop rotation from 2007 to 2009: Oat (Avena sativa cv. Supernova-INIA) – wheat (Triticum aestivum L cv Pandora-INIA) Sowing date: May in each year Plot size 1000m2 (20mx50m) Crop rotation from 2007 to 2009: Oat (Avena sativa cv. Supernova-INIA) – wheat (Triticum aestivum L cv Pandora-INIA) Sowing date: May in each year Experimental Site description
    13. 13. NO TILLAGE NT + CONTOUR PLOUGHING NT + BARRIER HEDGES NT + SUBSOILING CONVENTIONAL TITLLAGE 50 m 20 m 12,5 m Treatments
    14. 14. Runoff rate: the water level was measured in each holding tank (1m3 each one) after every rainfall event Runoff rate: the water level was measured in each holding tank (1m3 each one) after every rainfall event Evaluations in crops Monitoring on each season Soil losses and nutrient losses: samples of 100ml were taken from the holding tank and sediments were evaluated. Soil losses and nutrient losses: samples of 100ml were taken from the holding tank and sediments were evaluated. Soil evaluations Grain yield and BiomassGrain yield and Biomass Rainfall were measured in a pluviometer installed in the study siteRainfall were measured in a pluviometer installed in the study site Evaluations season 2007 to 2009
    15. 15. •Soil description in the profile: texture, bulk density, total porosity •Soil compaction was evaluated with a conical tip penetrometer (Field Scout SC900) 2,5 to 20 cm depth (each 2,5cm) •Soil description in the profile: texture, bulk density, total porosity •Soil compaction was evaluated with a conical tip penetrometer (Field Scout SC900) 2,5 to 20 cm depth (each 2,5cm) Soil evaluations Monitoring soil water content (SWC) •Neutron probe (Troxler, 4300 USA) 10-30, 30-50, 50-70, 70-90, 90-110 cm depth every 7 to 15 days During rainy season (August to December), and tensiometers •A pluviometer was installed in 2007 to register rainfall events (1 sec) •Neutron probe (Troxler, 4300 USA) 10-30, 30-50, 50-70, 70-90, 90-110 cm depth every 7 to 15 days During rainy season (August to December), and tensiometers •A pluviometer was installed in 2007 to register rainfall events (1 sec) Evaluations season 2007 to 2009
    16. 16. Map of experimental site ≈15% slope No tillage (Nt) No tillage + contour ploughing (Nt+Cp) No tillage + barrier hedges (Nt+Bh) No tillage + subsoiling (Nt+Sb) Conventional tillage (Ct) 50 m 20 m 12,5 m Tillage direction slope Acces tube location
    17. 17. Statistical analysis •Soil water content was assessed using split-split-splot design SAS software program and Tukey test was use to compare means of significant values (p≤0,05) -Tillage system (main plot) -Monitoring date (split-plot) -Soil depth (split-split-splot) •Soil water content was assessed using split-split-splot design SAS software program and Tukey test was use to compare means of significant values (p≤0,05) -Tillage system (main plot) -Monitoring date (split-plot) -Soil depth (split-split-splot)
    18. 18. RESULTS
    19. 19. Soil losses season 2008 Ct Nt Nt+Cp Nt+Bh Nt+Sb Tillage system 0 25 50 75 100 (%) % Percentaje of soil losses in Ct and No tillage tillage system. Conservation tillage systems lossed less than 25% compared to Ct. % Percentaje of soil losses in Ct and No tillage tillage system. Conservation tillage systems lossed less than 25% compared to Ct.
    20. 20. Lt Cl+Sb Cl+Fv Cl+Cd Cl J un J ul Aug Season 2007 0 10 20 30 40 50 60 70 (%) 59 123 63 (mm) Runoff Lt Cl+Sb Cl+Fv Cl+Cd Cl Ct Nt+Sb Nt+Bh Nt+Cp Nt Jun Jul Aug Sep Season 2008 0 10 20 30 40 50 60 70 (%) 103 102 94 22 (mm) Runoff Ct Nt+Sb Nt+Bh Nt+Cp Nt Jun Jul Aug Sep Season 2009 0 10 20 30 40 50 60 70 (%) 61 148 38 (mm)197 0 50 100 150 200 250 300 350 400 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Monthmm 2007 (372mm) 2008 (768mm) 2009 (536mm) x 44 years (695 mm) Monthly runoff 2007 2009 2008
    21. 21. Total nitrogen 0,0 0,5 1,0 1,5 2,0 2,5 01-jun 16-jun 01-jul 16-jul 31-jul 15-ago 30-ago Season 2008 Ca 0,0 1,0 2,0 3,0 4,0 01-jun 16-jun 01-jul 16-jul 31-jul 15-ago 30-ago Season 2008 Mg+2 0,0 0,5 1,0 1,5 01-jun 16-jun 01-jul 16-jul 31-jul 15-ago 30-ago Season 2008 Ct Soil nutrient losses in Conventional tillage compared to Conservation tillage systems during season 2008 Ct Ct
    22. 22. Nt Nt+Cp Nt+Bh Nt+Sb Ct Tillage systems 0.0 0.6 1.2 1.8 2.4 3.0 Mgha-1 Oat crop yield during season 2008 No tillage with subsoiling (Nt+Sb) showed a higher productivity in driest year compared with the rest of treatments. No tillage with subsoiling (Nt+Sb) showed a higher productivity in driest year compared with the rest of treatments.
    23. 23. 2007 Oat 2008 Wheat 2009 Oat Ct Nt+Sb Nt+Bh Nt+Cp Nt Tillage systems 0,0 1,0 2,0 3,0 4,0 5,0 Mgha-1 2007 Oat 2008 Wheat 2009 Oat Grain yield oat-wheat crop rotation season 2007-2009 •In season 2007, grain yield in Nt+Sb was significantly higher (p<0,01) to the other treatments. Seasons 2007 to 2009, Nt and Nt+Cp obtained the lowest grain yield. •In season 2007, grain yield in Nt+Sb was significantly higher (p<0,01) to the other treatments. Seasons 2007 to 2009, Nt and Nt+Cp obtained the lowest grain yield. 2007200720072007
    24. 24. 10-30cm 30-50cm 50-70cm 4/09 15/09 23/09 2/10 7/10 22/10 20/11 18/12 Season 2008 10 20 30 40 50 60 70 Ct 10-30cm 30-50cm 50-70cm 4/09 15/09 23/09 2/10 7/10 22/10 20/11 18/12 Season 2008 10 20 30 40 50 60 70 Nt+Sb 4/09 15/09 23/09 2/10 7/10 22/10 20/11 18/12 Season 2008 10 20 30 40 50 60 70 Nt+Bh Soil water content (SWC) •Tillage systems, time and depth significantly influenced SWC (p<0,05). •In general, under NT systems SWC was greater than under CT. •Nt+Sb in the 10-30cm showed a rapid superficial drying, but a significant increment of SWC in depth. •At the end of evaluations Ct, SWC decreased in 60% while No tillage systems decreased in 44 to 51% •Tillage systems, time and depth significantly influenced SWC (p<0,05). •In general, under NT systems SWC was greater than under CT. •Nt+Sb in the 10-30cm showed a rapid superficial drying, but a significant increment of SWC in depth. •At the end of evaluations Ct, SWC decreased in 60% while No tillage systems decreased in 44 to 51% No tillage systemsNo tillage systems Conventional tillageConventional tillage 4/09 15/09 23/09 2/10 7/10 22/10 20/11 18/12 Season 2008 10 20 30 40 50 60 70 Nt+Cp 4/09 15/09 23/09 2/10 7/10 22/10 20/11 18/12 Season 2008 10 20 30 40 50 60 70 Nt
    25. 25. Soil compaction •Soils showed a severe compaction (>2000 kPa) at 12,5cm depth, except Nt+Subsoiling, showing positive the effect for crops of subsoiling. •Soils showed a severe compaction (>2000 kPa) at 12,5cm depth, except Nt+Subsoiling, showing positive the effect for crops of subsoiling. 0 2.5 5 7.5 10 12.5 15 17.5 20 0 500 1000 1500 2000 2500 3000 3500 4000 Cone index (Kpa) Depth(cm) Ct Nt+Sb Nt+Bh Nt+Cp Nt
    26. 26. Main conclusions • No tillage systems reduced soil losses in 75% compared to Ct. • Runoff and soil losses was strongly associated to the high-intensity rainfall. The percentage of runoff in relation to the rainfall was between 60-70% in Conventional tillage (CT), while in No tillage was between 20-30% in the first month and less than 7% the following months of the rain season. • The loss of macronutrients were reduced in : Nitrogen (<34%), Ca (<24%) and Mg (<20%) when we compare the Ct with conservation tillage systems.
    27. 27. •Results demonstrated that No tillage systems incremented SWC in deep (50- 110 cm depth) increasing water infiltration compared to CT. All cropping systems showed a severe soil compaction at 12,5cm depth (>2000 kPa) except in NT+SB (≈1500 kPa), between 2,5-20cm depth and a higher yield specially in driest year (2007) •Finally, the choice of conservation tillage system without any modification on soil structure will affect crop yield in compacted soils. MAIN CONCLUSIONS
    28. 28. Runoff Ct: 70% No till: <30% the first month <10% rest of rainfall Conservation tillage systemSoil losses No tillage systems reduced >75% Nutrient losses In No tillage compared to CT N: <34% Ca: <24% Mg: <20% Yield Nt+Sb > 36% to Ct DECREASE INCREMENT Water availability for crops (Nt+ subsoiling) Mitigation of water erosion process Main conclusions Nt+Sb Ct Nt+Sb Ct
    29. 29. Soil water content (SWC) Soil water content (SWC) PHYSICAL INDICATORS AFFECTED CROP PRODUCTIVITY Soil water infiltration Soil water infiltration Soil Compaction Soil Compaction Yield
    30. 30. MUCHAS GRACIAS

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