Nourishing Plants and People Welch Presentation 19 Nov 10

Soils For Health: Enhancing Human Nutrition from the Ground Up
Ross M. Welch
USDA-ARS Robert Holley Center for Agriculture & Health
Department of Crop & Soil Sciences
Cornell University

Why Does Agriculture Exist?
To produce food and fiber and provide livelihoods to farmers and profits to the agricultural and food industries alone?
Why do we need “food”? – Nutrients!
Agriculture is the primary source of all essential minerals and vitamins required for human life!
Farmers are nutrient providers!
If food systems, based in agriculture, cannot provide all the essential nutrients in adequate quantities to sustain human life during all seasons, diseases ensue, societies suffer and development efforts stagnate.

Global Food Systems’ Problems
Agriculture’s primary focus has been on production alone, with little concern for nutritional or health-promoting qualities of products
Nutritionists tend to emphasize unsustainable medical approaches to solve malnutrition problems
supplements
food fortificants
These strategies do not address the underlying causes of malnutrition - dysfunctional food systems based in agricultural systems that do not have a goal of promoting human health
Simplistic views are the norm – looking for “silver bullet” approaches for solutions
Agriculture and human health have never been generally recognized as closely linked disciplines

Soil-Plant Factors Effecting the Micronutrient Quality of Plant Foods
Factors effecting available essential element supplies in soils
Soil type (pH, organic matter, parent material, etc.)
Root-soil interactions & rhizosphere effects
Agronomic practices (fertilizers, amendments, organic matter, cropping systems, variety selection, etc.)
The available supplies of essential minerals (as influenced by genetic & environmental variables) also affect the accumulation of numerous other nutrients (e.g., vitamins) and other health promoting factors accumulated in edible portions of plant foods

Fertilizer Approaches to "Healthier" Food Crops
Fertilizer Practices
Macronutrient fertilizers (form and application method)
N, P, K, S, Ca, Mg
effects protein, fats, vitamins, antinutrients, promoters, etc.
Micronutrient & trace element fertilizers (form and application method)
Zn, Se, Co, I, Ni, Mo, Li, Cl - effective in increasing amount in plant seeds and grains
Fe, Cu, Mn, B, Cr, V, Si - not very effective in increasing seed or grain levels

Agronomic Benefits of Micronutrient Element-Enriched Seeds (e.g. Zn, Mo)
Better seed viability
Greater seedling vigor
Denser stands (less soil erosion)
Lower seeding rates (lower seeding cost to farmers)
Larger root absorptive surface (better water & nutrient use efficiency)
Better resistance to disease
Better plant survival
Increased plant & seed yield

Before I
After I
Importantly: also ≈ 30% increase in livestock productivity!
Data from Cao, et al., 1994
Fertilizer Approach to IDD

Effect of Foliar Applied Selenate and Selenite on the Se Level in Field Grown Polished Rice Grain
Se applied Grain yieldaSe in graina
Se treatment(Se g ha-1) (kg plot-1) (g g-1)
Control 0 24.05 ± 2.16a 0.071 ± 0.002a
Selenite 20 24.54 ± 5.15a 0.471 ± 0.134b
Selenate 20 23.78 ± 0.45a 0.640 ± 0.191c
aValues are means of three determinations ± standard deviation. Values followed by a different letter in each column are significantly different (P < 0.05).
Consumption of 400 g per day of the high-Se rice would provide 200 g Se.
(Data from Chen et al., J. Agric. Food Chem. 50: 5128-5130, 2002)

Effect of Se Fertilization (6 or 16 mg kg-1) in Finland on Serum-Se Levels in 21year-old Finish Students
YearSerum-Se (µmole L-1)
1985 (baseline) 1.05
1989 1.60
1991 1.58
< 1 mole L-1 serum-Se related to increased cancer risk.
(Data from Makela et al., Biol. Trace Element Res. 36: 151-157, 1993)

Effects of Zinc Fertilization on Wheat Yield & Grain-Zn Level
Zn application
Zn concentration
Increases in yield by Zn Fertilizer
methods
Whole shoot
Grain
Whole
shoot
Grain
-
1
(mg kg
(%)
)
100
Control
10
10
-
Soil
19
18
109
265
Seed
12
10
79
204
Foliar
60
27
40
124
69
35
92
250
Soil + foliar
73
29
83
268
Seed + foliar
Using both soil and foliar Zn fertilizers
can maximize grain yields and grain-zinc
Yilmaz et al., 1997

Agriculture’s Agenda For Better Health
(Congressional Briefing)
Item 1:Declare a goal of agriculture to produce high quality food that promotes human health and well-being in sustainable ways.
Item 2: Design seeds,cropping & livestock systems that help achieve primary goal—design for maximum nutrient output of farming systems.
Item 3:Genetically modify food crops, increasing nutritional and health while promoting crop productivity (biofortification).
Item 4:Use agronomic practices (e.g., fertilizers and cropping systems)to improve nutrient output of farming systems.
Item 5:Define sustainable agriculture, as agriculture that yields “healthy foods” for healthy and productive people!

Nourishing Plants and People Welch Presentation 19 Nov 10

by International Food Policy Research Institute (IFPRI)

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