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ALPS-ADRIA SCIENTIFIC WORKSHOP 28 February - 5 March 2005, Portorož, Slovenia CORELATIONS BETWEEN MOISTURE AND ORGANIC MATTER CONSERVATION IN SOIL TILLAGE Márta Birkás – Katalin Bencsik – Attila Stingli – Attila Percze Szent István University, Gödöllő, Hungary INTRODUCTION water CO2 Despite the negative effects on water and C, this practice has remained attractive to producers through the years INTRODUCTION Land use and tillage impacts on soil damages Land use-induced harms Soil, nutrient and water loss Soil biological mellowing cut Destroying the living site of earthworms Beneficial organisms activity declining Beneficial biochemical processes stagnation Anaerobiosis – pathogenic organisms activity stimulation Promoting unfavourable chemical processes Deterioration in soil culture condition Increasing soil sensitivity and vulnerability Inducing OM/C loss Soil layer toplayer tilled layer root zone s u b s o i l state Tillage-induced harms Extreme water loss – degraded soil drying structure Bare surface – greater vulnerability Clod and dust formation compaction cycles Water and wind erosion and recompaction occurrence and extension Compaction and recompaction Water-logging on natural compacted surface and/or and/or tillage pans human Deterioration in soil induced compaction workability and trafficability Inducing OM/C loss METHODS This study is based on data of monitoring (1976-2001) 31,000 ha; 41 districts (including Hatvan) long-term experiments for tillage impacts on soil quality Gödöllő (1991-2002), sandy loam, brown forest soil (Chromic Luvisol): 5 variants Hatvan (2002-), loam soil (Calcic Chernozem): 6 variants Soil state variants: settled, loosened shallowly, ploughed, loosened. Fertilization Crop sequence: Maize – W. wheat Years: 6 average (1991, 1993, 1995, 1996, 2002, 2004) 6 dry (1992, 1994, 1997, 2000, 2003) 3 rainy (1998, 1999, 2001) Measuring: according to the accepted standards OBJECTIVES to evaluate the long-term tillage effect on soil moisture and organic matter content (tendency) to summarize the factors affecting water and organic matter conservation in any tillage system. RESULTS Soil moisture loss/conservation tendency Soil moisture content rata in average of the years (Gödöllő 1991-2002, Hatvan 2002-2004) rate in ploughed soil = 100% Hatvan 0 Gödöllő 0 50 60 80 100 Loosened 90 110 115 Loosened 80 Loosened shallow ly 118 LSD5%:19,2 100 Soil moisture content rata % Ploughed 120 LSD5%: 10,9 115 Settled Ploughed 40 100 Settled Loosened shallow ly 20 100 Soil m oisture content rata % RESULTS Organic matter management Humus % tendency in the soil (0-40 cm) disturbed differently (Gödöllő 1996, Hatvan, 2003) Gödöllő 0 Original (1977) 0,5 1 Ploughed Loosened 1,5 2 Hum us % LSD5% =0,131 1,35 0 Original (1983) 1,85 Settled Loosened shallow ly Hatvan Humus % 1,34 2,56 Loosened shallow ly 1,46 2,98 2,77 Ploughed 1,3 2,85 Loosened G 2 2,73 Settled LSD5% =0,111 1 H 0-20 0-20 20-40 Total N % 0, 11 0,138 0,103 C% 1,272 1,877 1,437 3 RESULTS Land use impacts on humus content of soil (Hatvan, 1983, 2003) 3 Humus % 2,9 LSD5% :0,131 2,8 2,98 2,7 2,6 2,85 2,77 2,73 2,56 2,5 1st year (1983) Intensive use Ploughed Loosened Maintained Soil disturbance RESULTS Soil condition rank considering water and organic matter content Place Factor Rank (years) Gödöllő Water content (10) Settled = Loosened > Ploughed > Loosened shallowly OM content Settled > Ploughed > Loosened shallowly > Loosened Water content Loosened shallowly > Loosened > Ploughed > Settled OM content Loosened shallowly > Loosened > Ploughed > Settled Hatvan (3) Note: Loosened shallowly = mulching (in Hatvan) RESULTS CO2 emission rata % CO2 emission tendency at different soil condition (Gödöllő 2002, Hatvan 2004) (Emission of ploughed soil = 100 %) 120 100 80 Gödöllő 60 Hatvan 40 Settled Loosened shallowly Ploughed Soil condition Loosened RESULTS Soil tillage impacts on OM/C loss or storage Negative impacts by Positive impacts by Deep and rough disturbance of soil or clean-till or termination of conservation way or conversion of virgin soils Soil condition improvement and maintenance or less intensity with adequate residue management Disrupts soil structure periodically Exposes soil surface to erosive forces Exposes new aggregates to microbial attack Accelerates respiration of CO2 by organisms Accelerates oxidation and aerob microbial activity Dilutes soil C by mixing subsoil with topsoil Structure conservation Physical protection from biodegradation Stimulates soil C loss Managing soil microbial activity Mitigates the effect of increasing atmospheric CO2 Promotes C accumulation or storage CONCLUSIONS Soil tillage may influence water and organic matter dynamics through various mechanisms. There are factors to mitigate both water and organic matter loss: (1) Use water, OM and soil structure conservation tillage, (2) Form the surface of deeply tilled soils, (3) Mulch and recycle stubble residues, (4) Use crops with high biomass, (5) Use cover crops (Hungarian green land program???), (6) Promote soil mellowing, (7) Reduce physical and chemical load of soils, (8) Prevent and alleviate soil harms (compaction and pulverization). Acknowledgements Experiments supported by NKFP-OM-3B/0057/2002, OTKA-34.274, OTKA 32.851, OTKA-46.670, OTKA-049.049 and sponsored by AGRIKON KAM, KVERNELAND Hungária, SZIE GAK Józsefmajor training farm, VÄDERSTAD, VERTIKUM, and Vetőmag 95. Question for future Will a tendency turn to the fact?