Advances in Soils: Enhancing Human Sustainability Through Knowledge and Technology
Delve into the world of soil science through the lens of Jim Akin, with a focus on environmental soil science and the goal of sustainable agriculture. Explore the challenges posed by population growth and the historical advances that have shaped modern soil science practices. Discover the traditional research philosophy and its impact on agricultural innovations over time.
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ADVANCES IN SOILS INCREASING HUMAN SUSTAINABILITY THROUGH APPLIED KNOWLEDGE AND TECHNOLOGY
JIM AKIN BS in Agriculture, SFASU, 1978 MS in Soil Science, Texas A&M, 2001 Emphasis: Environmental Soil Science 23 years of research and practice in soil science
DISCLAIMER The views expressed in this presentation are my own and do not represent the views of any company or governmental agency. This presentation is given in my personal capacity based on the totality of my training and experience.
ULTIMATE GOAL OF AGRICULTURE Production of enough food and fiber to feed and clothe humanity
THE CHALLENGE Population growth Increasing but at a decreasing rate Yield must increase as population increases Norman Borlaug Wheat breeding to double amount of grain per stalk Saved Third World from starvation Nobel Laureate
TRADITIONAL RESEARCH PHILOSOPHY Limit variables to as few as possible and preferably only one Identify correlations Exploit the correlations that increase yield Sets all other variables and conditions as constants If adverse results are noted in another area as a result, that becomes future research
EXAMPLE OF TRADITIONAL PHILOSOPHY Breeding wheat to significantly increase yield No other factors considered in initial research Stalks were noted as too weak to hold the grain (broken stalks prior to harvest) Additional breeding done to increase strength of stalks to prevent lodging or broken stalks
HISTORICAL ADVANCES IN SOIL SCIENCE Mesopotamia or prior If ground is broken, more seeds germinate, and yield increases Bronze Age Europe Land continuously farmed loses yield over time Addition of animal manure increases yield 1920 s Europe IG Farben synthesizes Urea Chemical fertilizer affordable and available
HISTORICAL ADVANCES IN SOIL SCIENCE Modern day: Correlations are made between Nitrogen, Phosphorus, Potassium relative to plant growth Crops tested for their response to additions of fertilizer Soil tests for N, P, and K correlated to yield Optimum additions for soil conditions, specific crop and yield goals established based on soil testing
EMERGING PHILOSOPHY An Holistic Approach (Soil Health/Sustainability) Considers additional factors beyond yield Effects of fertilization of soil biota Effects of plowing on available water, water holding capacity Effects of management practices on soil organic carbon and its relationship to soil biota, structure, water regime, nutrient fate and transport, erosion As it is new, it is incomplete No correlations to yield No economic correlations Expect changes, improvements, and refinements over the coming years
SUSTAINABILITY The continual use of the soil resource without damage to the soil resource or other resources In a larger sense it must do this while increasing yield to keep up with projected population growth AND be economically feasible on decreasing acres of land A very tall order indeed!
LARGE FARM TECHNOLOGY Sub-meter soil mapping by aerial drones NDVI (Normalized Difference Vegetative Index) on sub-meter scale 1 inch accuracy GPS locations onboard harvesters to achieve high resolution yield maps Yield maps and soil maps correlated to provide high seeding rates in high yield areas, low seeding rates in low yield areas Computer controlled additions of water and nutrients to plants based on soil water availability in real time, plant growth stage, etc.
LARGE FARM RESULTS Waste not, want not Efficiency Water and Fertility = Money spent that could be used to support the family Use of excess water is eliminated as much as practicable Minimizes the nutrients added to the fields Field soil tests are often showing nutrients being mined (lower nutrient levels) Limits nutrients in runoff Use of seed drills reduces sediment load in streams, limits losses in soil structure
SOIL HEALTH METHODOLOGY Establish cover crops Use rotational flash grazing of cover crops Seeding using no till methods Allow harvested plants to stand until cover crop is established
ESTABLISHMENT OF COVER CROPS Cover crop shades ground, significantly reduces soil temperatures, reduces evaporation Use of deep rooted cover crops Assists in destruction of historic plow pans Provides channels for water to access soil at greater depths Especially important given the 7 to 10 year drought cycle Severe droughts occur about every 50 years 2 years in 12 will be normal Conservation of water at greater depths provides a reserve of water for crops in dry years
USE OF SEED DRILLS Minimal disturbance of soil Existing structure of soil preserved Losses of organic carbon added to soil by cover crop and standing stubble are minimized Minimization of organic carbon losses allows net increase in organic carbon which promotes improved structure, increases in CEC, and biota (bacteria, beneficial fungi, worms (earthworms and nematodes)
FLASH GRAZING Reduces use of diesel fuel to lower the cover crop in advance of seeding Converts plant material into a more readily available form of fertilizer Provides a secondary operation and business for the farm Trampling of cover begins its degradation into organic matter while retaining its protection of the soil against rain, wind, and heat
RETENTION OF PLANT STUBBLE Plant stubble (stems) are retained primarily to reduce consumption of fuel and compaction of the soil Retention of stubble leaves roots in the ground A major pathway that water follows into the soil is by flowing down the stems and roots
WATER, MICROPORES, AND MACROPORES Peds have micropores Very small pores having capillary properties These must be satiated before water moves by gravity through the soil Macropores are larger pores that do not have capillary properties Includes root channels, the spaces between peds
STRUCTURE Crumb Easiest for water to pass through; greatest macropore space Subangular blocky Angular blocky Platy Most difficult for water to pass through; fewest macropores Massive
CLIMATE One of the 3 active soil forming factors Climate changes Cyclic Can be extreme Models are most generally over simplified and not able to be used to predict known past events. All models are based on statistics All models contain error We cannot mitigate climate change but we can mitigate the effects of climate change
CAUTIONS RELATIVE TO CLIMATE MODELS Peer reviewed papers are the best representation of the model(s) Someone with a degree in Journalism is likely not a good interpretive source Always carefully read the materials and methods Keep lots of coffee available while doing this to prevent head and neck injury Always identify the assumptions being made and determine if they are valid in the real world Consider information from outside the climate community that have a bearing on the subject (Solar/Earth interactions, Geology)
CLIMATE CYCLES Severe droughts lasting 7 10 years recur on an approximate 50 year cycle Tropical cyclones generally end the droughts and usher in several really wet years Only 2 of 12 years is normal Houston floods duh!!! Ice Age coming: All deep ocean currents moved to their ice age positions before the year 2000
TAKE HOME MESSAGES All science, even soil science grows and changes Accepted science is dangerous, if you disagree. Ask Galileo about his stand on the Copernican doctrine Challenge students to practice the trivium Grammar or rote memory Logic the use of good rational thought Rhetoric the expression of logical thought unemotionally and to express disagreements without being disagreeable
TAKE HOME MESSAGES Sustainability is a laudable goal, but it will take time, effort, and treasure to achieve it without devolving into a hunter-gatherer society Soil health, as it currently exists, is not successful on large scale operations Soil health has been shown to be very effective at improving the soil condition, its water regime, sediment loads in runoff water, and improving nutrient availability on smaller farms where family provides the labor
CLASSROOM ACTIVITIES Physics Demonstrate Stokes Law: Need a 1 L cylinder, Sodium Hexametaphosphate, soil, hydrometer In a liquid larger suspended particles hit the bottom first Finest particles (clays) don t fall out as they are colloids Chemistry pH of soil; 2 parts water, 1 part soil, shake and measure with pH meter CaCO3(limestone) buffers soil solution to about 8.3 Electrical conductivity: make a saturated slurry of soil, filter it with a vacuum pump, and use an Ec meter to measure its conductivity (inverse of resistance); correlates to the amount of salts in the soil
CLASSROOM ACTIVITIES Biology Compare a healthy soil to one that has been annually disturbed Note the number of earthworms in each From a mixture of soil and earth take samples and place on Agar plates to identify the types of colonies that grow Climatology Explore the weather data for your area for rainfalls, frequency of hurricanes, droughts, and then compare to sun spot activity
LAST SLIDE Books: Nature and Properties of Soils, Brady, Niles C. and Weil, Ray R. Publisher: Prentice Hall. Weatherman s Guide to the Sun, Davidson, Ben. ISBN-13: 978-1483588988 ISBN- 10: 148358898X Soil is a dynamic natural body having properties due to the combined effects of climate and biotic activity, as modified by topography, acting on parent material over time. Dirt is a four letter word. Dirt is on the kitchen floor. We deal with soil!
THANKS All y all for listening Dr. Murray H. Milford, Professor Emeritus, Texas A&M University and according to his students, a consultant to God on the creation of soils Dr. Joe B. Dixon, Professor Emeritus, Texas A&M University; a consummate professional, fine teacher, and expert on clay mineralogy Dr. Sam Feagley, Professor Emeritus, Texas A&M University for guidance in nutrient management
