Advances in soils

1. Advances in soils Increasing Human sustainability through applied knowledge and technology

2. 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

3. 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.

4. Ultimate goal of agriculture • Production of enough food and fiber to feed and clothe humanity

5. 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

6. 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

7. 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

8. 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

9. 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

10. 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

11. 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!

12. 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.

13. 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

14. 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

15. 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

16. 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)

17. 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

18. 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

19. 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

20. Structure • Crumb • Subangular blocky • Angular blocky • Platy • Massive • Easiest for water to pass through; greatest macropore space • Most difficult for water to pass through; fewest macropores

21. 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

22. 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)

23. 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

24. 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

25. 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

26. 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

27. 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

28. 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!

29. 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