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Research Challenges from and for High Yield Growers. Scientists and farmers. International Conference on Precision Agriculture Minneapolis, MN July 26, 2004 Paul Fixen Potash & Phosphate Institute. Is this session appropriate for a precision agriculture conference?.
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Research Challenges from and for High Yield Growers Scientists and farmers International Conference on Precision Agriculture Minneapolis, MN July 26, 2004 Paul Fixen Potash & Phosphate Institute
Is this session appropriate for a precision agriculture conference? Precision in management gets more critical as yield potential climbs … - agronomic reasons - environmental reasons
Summary:Research challenges from high yield growers • A large gap exists between maximum attainable and typical yields • Observing the practices of high yield growers through the lens of scientific principles and controlled research can be revealing and lead to researchable questions for scientists and farmers • Modern technologies should facilitate narrowing the gap between attainable and typical yields
* F. Childs Manchester, IA 20 bu/A/yr H. Warsaw Saybrook, IL Exploitable yield potential in corn Iowa example * * * * * * * 1965-1991 2.0 bu/A/yr * IA Contest Winners * * * IA State Average 1.7 bu/A/yr
Top corn yields from researchers in 1982 Dr. Roy Flannery New Jersey 338 bu/A Dr. Sterling Olsen Colorado 332 bu/A
From Saybrook, IL to Manchester, IA Manchester, IA Growing season precip: very similar at 27-28” Growing degree Days: Manchester - 2980 Urbana – 3513 PropertyChildsWarsaw Soil type Kenyon loam Parr silt loam Taxonomy Typic Hapludolls Oxyaquic Argiudolls Org. mat., % 5.5-6.0 4.5-5.8 pH 5.3-6.1 6.0 P1, ppm 126 (VH) 81 (VH) K, ppm 374 (VH) 400 (VH) Source: Childs – Murrell and Childs, 2000; Smith,2000; Dobermann, 2002; Warsaw – PPI, 1986. Saybrook, IL
Depth, In Childs Warsaw-light Warsaw-dark Organic matter, % 0-6 5.6 5.8 4.5 6-12 4.5 4.9 3.9 12-18 3.0 3.2 4.3 18-24 --- 1.4 4.3 24-30 --- 0.8 3.8 30-36 --- 0.6 3.6 Source: Childs data – Dobermann, 2002. Warsaw data – PPI, 1977. From Saybrook, IL to Manchester, IA: Soil OM Manchester, IA Warsaw: 20 years of intensively managed continuous corn Childs: 35 yearsof intensively managed continuous corn Saybrook, IL
From Saybrook, IL to Manchester, IA: Practices Manchester, IA Practice Childs Warsaw Fall tillage Mini MP 14” deep CH 14” deep Hybrid 2001-34M95; 2002-34N44 FS 854 Harv. Population 34,000 - 40,000 36,000 Row spacing 2001-30”; 2002-20” 28” Manure High rates in past 20 T/A annually Fall P2O5+K2O none 250+250 Fall N, lb/A 50(UAN) 45(DAP) Preplant N 250(NH3 + sep. stab.) 300(UAN)+ 100(AS) Starter, N+P2O5+K2O6+15+15+ACA 26+26+26 Popup, N+P2O5+K2O 4+9+4 none Postplant N 50(UAN) 75(UR) 2.5-4’ tall N 50(UAN+Guardian) None Fert N, lb/A 410(1.0 bu/lb) 546(0.7 bu/lb) Other nutrients Boron Sulfur Saybrook, IL
Research challenges: Which practices are critical and at what level? • Determination of site-specific attainable yield estimates (crop models) • Carbon cycling – crop and environmental impacts • Crop rotation vs monoculture • Tillage requirements … no till/strip till • Minimum N requirements, NH4+ vs NO3-, timing • Minimum soil test P and K requirements • Role of subsoil fertility, organic matter, etc. (P. Nowak) • Role of manure application • Role of secondary and micronutrients • Importance of starter fertilizer (0.5% P at V3-V4 for max kernel initiation/ear)
Better Crops (2004, No. 1) http://www.hybridmaize.unl.edu/
Real time yield prediction of current season U. of Nebraska EI Study - Lincoln July 25, 2004 349 279 251
Soil Test P and K requirements for very high yields: Classical theory • For soil immobile nutrients like P or K, the STL vs % yield relationship should not vary with site yield potential unless plant population increases enough for adjacent roots to compete with each other for P and K (Bray, 1954; Bray, 1963). • Roots normally occupy less than 1% of soil volume (Barber, 1984) … an increase in size of the root system translates into a greater volume of soil P or K being available for uptake. • As long as the size of the root system increases proportionally with yield, a higher yielding crop should not need a higher P or K concentration at the root surface … should not require a higher soil test level.
Soil Test P and K requirements for very high yields: Conditions that could lead to higher requirements • Shoot growth increases that exceed root growth increases as yields climb • Redistribution of roots from the surface soil to a low P or K subsoil • soil factors (organic matter, pH, structure, etc.) • varietal factors – vertical vs lateral rooting tendencies • Each % increase in yield has greater economic value … want to be further up the response curve
8 Weeks Mature 36 Days Source: Weaver, 1926 Is “subsoil” fertility more important to today’s high yield potential “stay-green” hybrids? • Probably taking up nutrients later in the season when surface soils are dryer • Higher % of active roots located deeper in profile Is manure important because it moves P into subsoils?
27K vs 38K 39K vs 46K Impact of hybrid on the influence of N rate on yield response to plant population Colorado S.R. Olsen, reported by W. M. Stewart, 2000
Summary:Research challenges from high yield growers • A large gap exists between maximum attainable and typical yields • Observing the practices of high yield growers through the lens of scientific principles and controlled research can be revealing and lead to researchable questions for scientists and farmers. • Modern technologies should facilitate narrowing the gap between attainable and typical yields • Simulation models to help define attainable yields and researchable questions • Improved weather data and management tools • Site-specific technologies for greater efficiency • Biotechnology for yield protection … and building
Research Challenges from High Yield Growers InfoAg 2003 Indianapolis, IN August 1, 2003 Paul Fixen Potash & Phosphate Institute