MUHAMMAD FAHAD ANSARI 12IEEM 14Characteristics& efficient Useof fertilizers
Characteristi cs & efficient Use of fertilizersPotash & Phosphate Institute/Potash & Phosphate Institute of Canada
Fertilizer Use Efficiency: An Old Topic but With New Importance International Nitrogen Initiative (INI) Goal: to optimize N’s beneficial role in sustainable food production and minimize N’s negative effects on human health and the environment resulting from food and energy production. Will focus attention on improving fertilizer N efficiency at a global scale Multiple Level Nutrient Management NRCS program under development to subsidize farmer practices that improve nutrient use efficiency Will test our collective understanding of nutrient use efficiency for N and P
Traditional Nutrient Efficiency Terms Recovery efficiency (RE) = Increase in uptake per unit nutrient added usually expressed as % Agronomic efficiency (AE) = Crop yield increase per unit nutrient added such as bu/lb or kg grain/kg nutrient
Agronomic efficiency of fertilizer N used on corn grain in the U.S., 1964-2002 75 70Kg grain per kg N . 65 59 60 55 43 50 45 40 35 30 1960 1965 1970 1975 1980 1985 1990 1995 2000 39% increase in N efficiency Since 1975: 12% increase in fertilizer N per ha 40% increase in corn yields
N fertilizer recovery efficiency using on-farm measurements Opportunity for improvement Crop Region Number Avg N Recovery, of farms rate, % kg/ha Maize NC USA 56 103 37 Rice Asia-farmer 179 117 31 Asia-researcher 179 112 40 Wheat India-poor weather 23 145 18 India-good weather 21 123 49Cassman et al., 2002
Areas of opportunity for improvement in fertilizer N efficiency Continued improvement in cropping system management Realisticestimation of attainable yield Yield potential protection – pest management and other cultural practices Balanced nutrition
Balanced nutrition in the U.S. Ohio State University – dryland corn 80 ppm soil test K 45% N recovery 139 ppm soil test K 80% N recovery Kansas State University – irrigated corn No P applied 35% N recovery 45 kg ha-1 75% N recovery
Balanced nutrition in China TreatmentReference Crop N NPK N recovery by crop,%Zhu, 1994 Barley 28 51Jin, 2001 Wheat (11 yrs) 31 70 Corn (5 yrs) 35 66
Areas of opportunity for improvement in fertilizer N efficiency Continued improvement in cropping system management Use of site-specific precision ag technologies
Site Specific Management:Accounting for spatial variability
Spatial variability in fertilizer N efficiency Year 1 Soybeans Year 3 Uniform N rate In year 2 Variable N rate 11.1 t/ha average yield 11.3 t/ha average yield Indiana; two N rates based on soil type N Efficiency, kg grain/kg N 28-39 39-50 50-62 62-73Murrell and Murrell, 2002
Variable N rate contributed to increased N efficiency 40 ha field divided into 10 zones 9 8 Whole field year 1, 47 kg grain/kg N 8 Frequency of zones 7 Variable rate year 3, 53 kg grain/kg N 6 13% increase in fertilizer N efficiency 5 4 4 3 2 2 2 2 1 1 1 0 0 28-39 39-50 50-62 62-73 N use efficiency, kg grain/kg applied NMurrell and Murrell, 2002
Areas of opportunity for improvement in fertilizer N efficiency Continued improvement in cropping system management Use of site-specific precision ag technologies Better prediction of soil N mineralization Improved timing of N application Improved manure management and crediting Improved fertilizers Biotechnology?
Is the concept of fertilizer useefficiency the same for P and K as it is with N?
The result of applying the definition of agronomic efficiency for N to P The highest “efficiency” occurs when inadequate amounts are applied at low soil test levels Building soil test levels to optimum reduces “efficiency” 120 “Efficient” P use means reduced profitability, water useP use efficiency, kg corn/kg P 100 * efficiency, N use efficiency, and land use efficiency 80 60 ** 40 20 0 ** * 5 10 15 20 25 Bray P-1, ppm Low High
We need to view P and K efficiency as different than N efficiency A.E. Johnston and P Poulton “The difference method (RE) is appropriate for N … but is less useful for P and K where plant available reserves of these nutrients can accumulate in the soil from past applications of fertilizer.” Sustainable efficiency (for P&K) – Nutrient input needed to sustain the system at optimum productivity expressed as a removal to use ratio
P and K Sustainable Efficiency in N. America Review current crop removal to use ratios Review current soil test levels Combine the two to assess efficiencyInformation Sources:• Soil Test Levels in North America, PPI/PPIC/FAR Technical Bulletin 2001-1.• Plant Nutrient Use in North American Agriculture, PPI/PPIC/FAR Technical Bulletin 2002-1.
Partial K budgets for the U.S. (average of 1998-2000) Crop Applied Recov. Removal to use Region removal fertilizer manure* fertilizer fert+man ------- K2O, billion kg ------ U.S. 8.8 4.6 1.7 1.91 1.396 corn states 3.0 1.9 0.5 1.62 1.30* USDA-NRCS, 2000; Due to manure distribution problems relative to crop demand,this likely overestimates the agronomic contribution.
Ratio of K removal by crops to fertilizer applied plus recoverable manure BC AB MB SK ON PQ PEI WA NB ME MT ND NS OR MN R/(F+M) VT ID NH 0.00-0.89 NY WI SD MI MA 0.90-1.09 CT WY RI 1.10-1.49 IA NE PA 1.50-4.99 NV OH NJ IL IN MD > 5.00 UT WV DE CO MO VACA KS KY NC AZ NM OK TN AR SC MS AL GA TX LA FL
Percent of Soils Testing Medium or Lower in K in 2001North America 43%
Partial P budgets for the U.S. (average of 1998-2000) Crop Applied Recov. Removal to use Region removal fertilizer manure* fertilizer fert+man ------- P2O5, billion kg ------ U.S. 5.2 4.0 1.5 1.30 0.95 6 corn states 2.3 1.4 0.4 1.71 1.33*USDA-NRCS, 2000; Due to manure distribution problems relative to crop demandand unavailability of a portion of manure P, this likely overestimates the agronomiccontribution.
Ratio of P removal by crops to fertilizer applied plus recoverable manure BC AB MB SK ON PQ PEI WA NB ME MT ND NS R/(F+M) OR MN VT ID NH 0.00-0.49 NY WI SD MI MA 0.50-0.89 CT WY RI 0.90-1.09 IA NE PA 1.10-1.49 NV OH NJ IL IN MD >1.50 UT WV DE CO MO VACA KS KY NC AZ NM OK TN AR SC MS AL GA TX LA FL
Percent of Soils Testing Medium or Lower in P in 2001North America 47%
Viewing removal to use in light of soil test levels Large regional differences exist across North America in both current removal to use ratios and soil test levels “1” is often not the appropriate removal to use ratio target for a state or for a field Soil test levels < optimum: ratio should be < 1 Soil test levels > optimum: ratio should probably be > 1 Starter fertilizer needs are often independent of soil test levels or removal to use ratios
Est. crop removal / (fertilizer + manure use) State level P assessment: R/(F+M) 1.8 1.6 Low and SD IA High but decreasing 1.4 decreasing WI 1.2 1.0 AR 0.8 0.6 0.4 GA 0.2 Low and increasing High and increasing 0.0 -15 -10 -5 0 5 10 15 20 25 State median soil test level - target level, ppmTarget level = lower end of high category
Estimating target removal/use ratio for a field Target K test = 150 ppm Current test = 130 Build: (150 - 130) x 9 kg K2O/ppm = 180 kg K2O/ha To spread build over 4 yrs = 180/4 = 45 kg K2O/ha Avg crop removal per year = 67 kg K2O/ha Total to apply = 45 + 67 = 112 kg K2O/ha Target removal to use ratio = 67/112 = 0.60
Examples of apparent recovery efficiency of P fertilizer in long term studies Soil(s) Applied No. of Recovery P2O5, kg/ha Crops % Calcareous clay 67 5 F 28 Clay loam, pH 7.3 29 9 F 54 28 soils, pH 6.2-7.9 152 8 GH 74 4 soils, pH 6.7-7.6 230 19 GH 87 Sandy loam, non-calcareous 118 4 F 100 GH = Green house; F = Field.Fixen, 1992
If a field is at its optimum soil test level, and replacement of the P and K removed by crops maintains that optimum level, what is the efficiency of P or K? 100%If use must exceed removal to maintain optimum productivity,soil erosion or fixation are often the cause: Reduce erosion losses Utilize banding and annual fertilizer application
Impact of Improving Efficiency on Fertilizer Demand Critical to properly define efficiency for the nutrient in question Nitrogen Good progress has been made in improving agronomic efficiency Will be significant pressure to further improve agronomic efficiency without sacrificing yield potential Research shows there is room for improvement Yields will likely continue to increase faster than N use
Impact of Improving Efficiency on Fertilizer Demand (continued) Phosphorus and potassium Will be increasing pressure to improve system efficiency by reducing P levels where excessive Sustainable efficiency will translate into increased P and K demand in some major production regions Pressure to improve N efficiency should result in increased support for balanced nutrition with P and K Higher future crop yields could require higher target soil test levels and temporarily impact demand The thermodynamic need to replace P and K removal at some soil level sets a lower limit for P and K use As food needs increase … fundamentals of natural systems indicate a permanent and expanding role for fertilizers in food production