N fertilization decision support systems for WOSR based on a predictive balance sheet method

Transcription

1 N fertilization decision support systems for WOSR based on a predictive balance sheet method Hubert Hebinger CETIOM European rapeseed and N Workshop Berlin March 2009

2 Plan The principles underlying our approach What s the engine behind the different DSS? A broad choice of DSS made available to the WOSR growers for optimizing their N application rates Special focus on the most sophisticated : Farmstar Colza, based on satellite images

3 The principles underlying our approach Aim : developing an easy method to evaluate the nitrogen amount best suited for each WOSR crop. Based on a simplified forecasting N balance method suited to WOSR (COMIFER, 1996) Basic idea : need to take into account the crop s nitrogen uptake during autumn (winter) for establishing the right N fertiliser dose to WOSR Why? : these nitrogen is as efficient in elaborating the crop s yield than nitrogen applied through fertilisers or coming from soil mineralization. This way of thinking is now well established in France where it was introduced at WOSR growers level at the end of the nineties.

4 The simplified forecasting N balance method suited to WOSR (COMIFER, 1996) (the engine) F = (b x Y) + Rf Nh Rh-M F : optimal rate of nitrogen to apply to the crop (kg N/ha) b : total N crop requirement to produce a ton of seeds (kg N/ha per t) Y : yield target (t/ha at 9% moisture and 2 % impurities) Rf : soil N mineral content at harvest (kg N/ha) Nh : crop s total N content (kg N/ha aerial + root parts) at the end of winter Rh : soil N mineral content (kg N/ha) at the end of winter M : spring soil N mineralization potential (kg N/ha)

5 An other way to present our approach balancing the N budget BEFORE Global Nitrogen needs 6,5 kg N / 0,1 t x Expected Yield = Total crop s N requirement SMN after harvest N application rate Soil mineralization SMN after winter

6 An other way to present our approach balancing the N budget SINCE THE END OF THE NINETIES Global Nitrogen needs 6,5 kg N / 0,1 t x Expected Yield = Total crop s N requirement SMN after harvest N application rate Soil mineralization Crop s N uptake After winter SMN after winter Limited to 330 kg/ha

7 How to easily assess the crop s N uptake needed for our calculation? Trying to find a relation between a parameter easy to measure at field level without to resort to N analyses, complicated plant samplings or dry matter measurements The way wee followed was to derive the N uptake from a green biomass (kg / m²) measurement at field level by multiplying it by a multiplying factor (65 to 70) The DSS, Cetiom or other bodies developed, differ in the way the green biomass is assessed, some parameters are determined and in their bodywork. N absorbé pe (k g /ha) avec coeff rac = 1.35 Tout : y = x ; R 2 = : y = x ; R 2 = : y = x ; R 2 = : y = x ; R 2 = : y = x ; R 2 = : y = x ; R 2 = : y = x ; R 2 = France entière à Poids de matière verte pa (kg/m2) 1994 (n=144) 1995 (n=322) 1996 (n=213) 1997 (n=86) 2006 (n=81) 2007 (n=60) Tout (n=906)

8 From biomass N uptake N application rates N application rate = (6,5 kg / 0.1 t x expected yield) N soil mineralization ((green biomass bw x 65/70 + green biomass aw x 65/70))/ 2 * Green biomass expressed in kg / m² Opportunity to switch from previous parameters to new ones is still under discussion but approach will remains the same

9 Different tools (DSS) to assess N uptake pre and post winter and calculate the optimal N dressing Cost Usage complexity Visual (ancestor) weighing method Règlette azote Precision

10 Weighing method illustration 2 to 4 m²/field pre and post winter

11 Different tools (DSS) to assess N uptake pre and post winter and calculate the optimal N dressing Cost Usage complexity On line DSS Visual (ancestor) weighing method Règlette azote Precision

12 Free on line version Règlette azote 40 dt 1,2 0,8

13 Different tools (DSS) to assess N uptake pre and post winter and calculate the optimal N dressing Farmstar colza Cost Usage complexity Geosys On line DSS Satellite based DSS Visual (ancestor) weighing method Règlette azote Precision

14 The Farmstar colza service Focus on a satellite image based Hubert Hebinger CETIOM European rapeseed and N Workshop Berlin March 2009 DSS to optimize WOSR N fertilization

15 Farmstar colza service production chain involving infoterra Cetiom coop/private dealers - agriculture chambers Cooperatives Agricultural Chambers

16 Focus on Farmstar colza, a remote sensing based DSS to optimize spring N dressing Crop Canopy reflectance model : SAIL + PROSPECT Atmospheric model : MODTRAN Calculation pixel by pixel (Technology Infoterra) N = GBW. C C varying from 65 to 75 depending on the region (CETIOM, réglette azote colza). Taking into account of leaf loss during winter due to frost periods : Nh = (N.bw + N.ew) / 2. Satellite reflectance data GLAI.bw, GLAI.aw GBW.bw, GBW.aw N.bw, N.aw F* = (b.y) + Rf Rh M - Nh Simplified forecasting N balance equation FMW estimed from satellite measurement (g.m -2 ) Centre Bourgogne Poitou-Charentes y=x FMW estimated from ground measurement (g.m -2 ) Validation : Relation between GBW of aerial part at the beginning of the winter estimated from ground and satellite measurements (beginning of winter, 2005).

17 Farmstar colza service production chain involving infoterra Cetiom coop/private dealers - agriculture chambers Cooperatives Agricultural Chambers

18 Fields associated with a data file (2008) permitting zoned nitrogen adjustments (IPF) on WOSR

19 Farmstar colza calendar First crop status map BW Second crop status map BW Recommendation Map

20 Farmstar remote sensing green biomass assessed before winter (first crop status map) Straw Ploughed in Straw withdrawn

21 Farmstar remote sensing green biomass assessed after winter (second crop status map) Straw ploughed in Straw withdrawn

22 Farmstar remote sensing Nitrogen requirements map Straw ploughed in Straw withdrawn

23 Over ha WOSR managed under Farmstar colza Cost of Farmstar Colza service, 6 to 12 / ha

24 Biomass differences through the years well reflected by Farmstar colza But Farmers stick at their yield targets whatever the year and that s a real limit to our approach

25 Do the farmers trust Farmstar colza N application recommendations and brave enough to apply them? Survey 2008 Total N applied Farmstar advise

26 Farmstar users seem to better manage their Nitrogen applying without damage to their yield Farmstar user Farmstar non user With OM Without OM With OM Without OM Number of fields Average N kg / ha Average yield t / ha Caution : survey covers different growing conditions and regions

27 Some final reflections The French WOSR growers have plenty of well-tested DSS to better adapt their N fertilization rates to their growing and field conditions. In fact they now understand and accept that a well developed WOSR crop needs less nitrogen than a small one and more and more of them evaluate the GB in one way or another. It has permitted to reduce the mean nitrogen fertilization rate by 10 to 20 kg / ha over the past ten years in France but in far greater proportions in case of farms applying organic fertilisers (170 kg N / ha) But improvements are still necessary : On farmers side, by better sticking at the advises and accepting more realistic yield targets On Cetiom and research side, by improving the accuracy of the different factors taken into account in the calculation. Technology improvements are also required in terms of remote sensing technology to gain in flexibility and precision Better nitrogen efficiency is probably one of the most important challenges the agriculture industry as to taken up in a Hot, flat and crowded world (quoted : Thomas L. Friedman).

28 To go further : réglette azote (in french) Champolivier L., Fourty T., Poilvé H., Sigel G., Charbonnaud J., and Pilorgé E Farmstar-rapeseed: a decision support system for rapeseed nitrogen fertilization based on satellite data. p In: Proc. 12th Int. Rapeseed Congress, Vol. III, Wuhan, China. GCIRC, Paris, France. Lagarde F., and Champolivier L Le raisonnement et les avancées techniques permettent de réduire la fertilisation azotée : le cas de farmstar-colza. OCL, 13 :

29 Thanks for listening and your questions are welcome