Organic Soil Management:common mistakes & misperceptions Dr. Joel Gruver School of Agriculture Western Illinois University (309) 298 – 1215 email@example.com
Ten common mistakes & misperceptions Organic = neglect or omission Organic = input substitution Plants don’t know the difference Rush without consequence Organic systems require pre-plant tillage Traditional tillage tools will do the trick Haphazard cover cropping Precision ag is incompatible with organics Artificial drainage is incompatible with organics Balanced farming = cation balancing
Franklin Hiram King (1848-1911) One of the early agricultural scientists in the Midwest region who was very concerned by therapid degradation of Midwest soils during the 19th century“ We desired to learn how it ispossible, after twenty andperhaps thirty or even fortycenturies, for their soils to bemade to produce sufficiently forthe maintenance of such densepopulations.. “Farmers of Forty Centuries, 1911
FIRST SENTENCE: It is an old saying that "any fool can farm," and this was almost the truth when farming consisted chiefly in reducing the fertility of new, rich land secured at practically no cost from a generous government.http://www.soilandhealth.org/01aglibrary/010134hopkins/010134toc.html
Famous photo of Cyril Hopkins Wheat harvested Wheat harvested from 1 ac treated from 1 ac treated with manure, lime with manure and rock phosphateOnly manure produced on the farm
Why were FH King and CG Hopkins so concerned? -523,000 tons of N/yr ! N budget for Illinois (units are 1000 metric tons N / yr) (David et al., 2001)
+1 ton of N/yr !N budget for Illinois (units are 1000 metric tons N / yr) (David et al., 2001)
From ―Soil Erosion: A National Menace (1928) What would be the feeling of this Nation should a foreign nation suddenly enter the United States and destroy 90,000 acres of land, as erosion has been allowed to do in a single county? To visualize the full enormity of land impairment and devastation brought about by this ruthless agent is beyond the possibility of the mind. An era of land wreckage destined to weigh heavily upon theHugh Hammond Bennett welfare of the next generation is at hand. (1881-1960)
What do I do now? Organic weed management by omissionhttp://biology4.wustl.edu/olsen/images/briana_field.jpg
Input substitution NOP allows 20% of total crop N to be supplied by “Bulldog soda”Can this stuff be used on organic farms?
Guano was mined intensively off the west coast of S. Americaduring the mid-to late 1800s. During the peak years of guanomining, Great Britain imported over 150,000 tons annually. PERU
Mountain of guanoGuanothe coast of intensively off the west coast of S. America off was mined Peruduring the mid-to late 1800s. During the peak years of guanomining, Great Britain imported over 150,000 tons annually. PERU
Do you regularly apply chicken litter on your farm? If so, how do you decide whatrate to apply and have you ever estimated the P balance for your farm?
Broiler Litter BasicsWhat does a ton of litter currently cost in NC? http://hubcap.clemson.edu/~blpprt/Aub+244.html
The nutrient content of manure varies with animal diet
Compost or manure management based on N normally results in excessive applications of P Compost = 1.7% N 1.2% P2O5 Cumulative P build up in lbs/acre 3000 2000 Most crops remove 2.5-10 times as much N 1000 as P2O5 3 6 9 12 YEARSCompost applied at optimal rate to supply crop with N(2004) Adapted from Magdoff and Weil
We applied4000 gallons per acre. How many lbs of N didwe supply to our corn crop?
Historically crop rotationsrevolved around LEGUMES
Amount of nitrogen fixed by various forage legumes N fixed Crop (lb/A/year) Alfalfa 150-300+ Red clover 70-200 White clover 75-150 Other annual forage 50-150 legumesLegume biomass contains a lot more than N!
Many vegetable crop residues arecomparable to a legume cover crop http://res2.agr.ca/stjean/publication/bulletin/n
The soil food web digestive serves as a system for plants • Bacteria • Fungi Microflora “The Soil • • Algae Protozoa Microfauna Stomach” • Nematodes Mesofauna • Microarthropods • Enchytraeids • Earthworms Macrofauna
Plants take up mostly inorganic forms of N when inorganic forms of N are readily availableIn some natural ecosystems (e.g., tundra), direct uptake of organic forms of N is very important
―Our data show that all grass species wereable to take up directly a diversity of soil amino acids of varying complexity. Moreover, we present evidence of marked inter-species differences in preferential use of chemical forms of N of varying complexity. L. perenne was relatively more effective at using inorganic N and glycine compared to the most complex amino acid phenylalanine, whereas N. stricta showed a significant preference for serine over inorganic N.‖
Dissolved organic matter is animportant part of the soil soup! Fe+3 Ca+2 DOM Ca+2 NO3- NO3- Mg +2 Ca +2 H2PO4- Cu+2 DOM K+ K+ NO3 - Ca+2 Mg +2 Zn+2 DOM Mg+2 NO3- Fe+3 DOM Ca+2 SO4-2 Adapted from Brady and Weil (2002)
Jethro Tull invented the grain drill and manycomplementary technologies that resulted in large increases in grain yields during the 18th century. Jethro Tull, 1731
―All sorts of dung and compost containsome matter, which, when mixt with thesoil, ferments therein; and by such fermentdissolves, crumbles, and divides the earthvery much; This is the chief, and almostonly use of dung... This proves, that its(manure) use is not to nourish, but todissolve, i.e., divide the terrestrial matter,which affords nourishment to the mouthsof vegetable roots.‖Jethro Tull, 1731
Adoption of Tull’s tillage intensive row cropping system increased yields across Europe ―All sorts of dung and compost contain some matter, which, when mixt with the soil, ferments therein; and by such ferment dissolves, crumbles, and divides the earth very much; This is the chief, and almost only use of dung... This proves, that its (manure) use is not to nourish, but to dissolve, i.e., divide the terrestrial matter, which affords nourishment to the mouths of vegetable roots.‖ Jethro Tull, 1731 even though it was based on an incorrect theory of crop nutrition
Symptoms of planting when soils are too moistRushing withoutconsequences?
Do these views look familiar?Slow emerging seedlings in cold soil Frosted corn
These situations are less common on organic farmsbecause most experienced organic farmers plant later to:• Increase speed and uniformity of stand establishment• Allow a flush of weeds to be terminated before planting• Avoid contamination with GMO pollenSlow emerging seedlings in cold soil Frosted corn
Most organic farmers use tillage to stimulate and then kill 1 or more flushes of weeds before planting summer crops
Terminating spring planted oats with a soil finisher ~ 3 weeks before planting corn
Converting old sod to rowcrops is much easier if thesoil is allowed to ―mellow‖between tillage operations
Organic farmers who want their tillage tools to perform non-traditional tasks may need to purchase or build non-traditional tillage tools
Haphazard use of cover crops Cover CropsCover crops have many effects! Adapted from Magdoff and Weil (2004)
Haphazard use of cover crops Host pests Tie up N ? ? Become a weed Interfere w/ equipment performance Suppress crop growth Cover Crops Dry out soil Prevent excessively soil Add cost drying Increase management Not all are positiveCover crops have many effects! Adapted from Magdoff and Weil (2004)
Be realistic about potential cover crop challenges
Key considerations How will I seed the cover crop?What will soil temperature and moisture conditions be like? What weather extremes and field traffic must it tolerate? Will it winterkill in my area? Should it winterkill, to meet my goals? What kind of regrowth can I expect? How will I kill it and plant into it? Will I have the time to make this work? What’s my contingency plan—and risks—if the cover crop doesn’t establish or doesn’t die on schedule? Do I have the needed equipment and labor?
Cover crops should be viewed as part of a crop rotation! : http://www.ncl.ac.uk/tcoa/files/breakcrops_orgagr.pdf
Using cover crops to improve soil fertility generally requires more management thanusing manure or purchased nutrient amendments
Finding the right times to fit in cover crops Summer Fallow Spring Summer Fall Broccoli LettuceABC = cover crop A = cover crop seeded after spring crop harvested, tilled in before fall crop B = cover crop overseeded into spring crop, tilled in before fall crop C = Cover crop allowed to grow in strips when fall crop is young Adapted from Sarrantonio (1994)
Cereal rye, hairy vetch, andcrimson clover over seeded into collards
How much overlap occurs when you work a field?
Guidance before GPS The best tool for precision ag is not the latest GPS samples or satellite image. Your observations during harvest (or other field operations) can tell a far more accurate story. Pay attention!30’ wide strips The very best precision ag tool inyou! managed using ridge till is Iowa
No wheeltraffic on beds http://www.avanzi.unipi.it/researchactiviti_file/Agricultural_mechanisation_ENG.htm
The best tool for precision ag is not thelatest GPS samples or satellite image. Your observations during harvest (or other field operations) can tell a far more accurate story. Pay attention! The very best precision ag tool is you!
Artificial drainage has greatly increased the number of days when soils are suitable for field operations but has also contributed Pollution of to manywater resources environmental Loss of SOM problems
Days Suitable for Field Work in Missouri http://agebb.missouri.edu/mgt/fieldwork.htm Timely field operations are especially important in organic farming systems How much would it be worth to you if you could increase the # of days suitable for field work?
Farmers agree that improved drainage is a big advantage
Why do crops on tiled-drained land tend to be more drought resistant ?Ontario Ministry of Ag and Food
SUMMARYThe interaction of rainfall with the soil surface has a major effect on agricultural productivity and environmental quality in the Southeastern U. S. High-intensity rainfall during the summer months often causes surface crusting, which inhibits seedling emergence, decreaseswater infiltration into the soil, and causes accelerated soil erosion.Dispersion of soil clays and associated aggregate breakdown have been implicated in the process of soil crusting. The application of gypsum has the potential to flocculate soil clays into micro-aggregates, and thereby delay or decreasecrust formation, provided that ionic strength of the soil solution is the primary factor responsible for de-flocculation.The studies reported here show that gypsum does increase water intake rate and reduce soil loss, and that the mechanism is primarily an ionic strength effect.
Figure 1. Varying degrees of clay dispersion in soils. The higher amounts of dispersal(4 and 5) indicate a soils suitability for gypsum application. No.0 displays slaking(breaking off of soil particles), compared to 1 to 5 which show clay dispersion
Soil fertility is >>chemical fertility+ cation balance is onlypart of chemical fertility
Biological Fertility Soil + Chemical Fertility + Physical FertilityFertility
Healthy root functiona balance of inward and outward processes H20 NO3- Root exudates N, S, P activate soil microbes Transpirational stream H20 Ca+2 + Diffusion Root growth K+ H2PO4-
Healthy root functiona balance of inward and outward processes H20 NO3- Root exudates N, S, P activate soil microbes Transpirational stream H20 Ca+2 + Diffusion Root growth K+ H2PO4-A balance of O2 andH2O is important for most of these processes
Both strategies are important ! Soils with low OM and poor structure tend to grow unhealthy roots which use nutrients inefficiently & healthy roots need available nutrients !
Easily misinterpreted Easily detected Acute root disease Chronic root is a common cause of drought stress malfunction and nutrient deficiency symptoms
A balanced approach to soil management Well adapted crop Building (or maintaining) SOM a good circulatory and respiratory system Nutrient Water Management Management Adapted from Bailey and Lazarovits (2003)
Small increases in OM can improve crumb structure Superior air/water relationships Healthier root growth and function (justification statement)NC STATE UNIVERSITY DEPARTMENT of SOIL SCIENCE
Biological inoculants can be helpful but are less important than SOM and good soil structure