Building healthy soils for healthy crops LORI HOAGLAND ASSISTANT PROFESSOR PURDUE UNIVERSITY

Building healthy soils for healthy crops LORI HOAGLAND ASSISTANT PROFESSOR PURDUE UNIVERSITY

Outline v What is soil health and why is organic ma7er so important? v How do management prac:ces influence soil health and what are the implica:ons for vegetable crop produc:vity? v How can you determine how your management prac:ces are influencing soil health on your farm?

What is soil health? Organic Ma*er Aggregate Stability Organic Ma*er Soil Strength Available Water Chemical Organic Ma*er ph Nutrients Organic Ma*er Disease Suppression Drought tolerance (Charlie White, PSU)

Soil organic mader v Key component of soil health - glues soil aggregates together - contributes to soil CEC - absorbs and holds soil water - source of plant nutrients - energy and food for soil organisms v Formed over millennia from plant, animal and microbial residues v Must be con:nually renewed to maintain soil health

Change in SOM with culhvahon (Brady and Weil, 2002) SOM is made up of different pools with variable rates of decomposi9on

HOW DO MANAGEMENT PRACTICES INFLUENCE SOIL HEALTH AND WHAT ARE THE IMPLICATION FOR VEGETABLE CROP PRODUCTIVITY?

Specialty crop systems trial (2011-2015) Intensive conven1onal system - Inorganic fer:lizers Intensive organic system - Winter cover crop - Compost fer:lizer Soil- building organic system - Winter cover crop - Compost fer:lizer - Cash crop alternates with summer cover crop - Soil health declined - Soil health improved slowly - Soil health improved rapidly v Crop rota:on: popcorn, soybean, tomato, and carrot v Few differences in yield v What if we introduce stress?

How does crop systems management influence mycorrhizal communihes and drought tolerance? Lisseth Zubieta v Arbuscular mycorrhizal fungi

How does crop systems management influence mycorrhizal communihes and drought tolerance? v In the absence of water stress, AMF improved water status and increased soybean growth regardless of source v In the presence of water stress, plants grown with AMF from the organic system had greater drought tolerance and yield

High tunnel soil management project (2011-2014) v Intensively managed (heavy food traffic, mul:ple crops/growing season, high nutrient needs) v Limited crop rota:on v High evapotranspira:on/limi:ng leaching events Ma* Rudisill Pepper Treatments: Control (no amendment), Urea, Chicken Manure, Green Manure (vetch/alfalfa)

ImplicaHons for soil health v Soil quality declines in urea and control treatments in high tunnel v Green manure treatment improves soil health in both systems v Soil EC higher in high tunnel regardless of treatment v Pepper yield greater in high tunnel/not affected by amendment v What if we introduce crop stress?

Bioassays with snap bean and Rhizoctonia solani v Drama:c reduc:on in health of plants grown in high tunnel rela:ve to open field v Green manure mi:gates nega:ve impact of high tunnel v Nega:ve effects eliminated with soil steriliza:on - > biologically mediated 1 2 3 4 1.60 1.40 1.20 1.00 0.80 0.60 0.40 0.20 0.00 OF a a a B a CNT UR GM CM CNT UR GM CM Dry Shoot b HT b a A b 0.60 0.50 0.40 0.30 0.20 0.10 0.00 OF B HT A a a a a a b b b CNT UR GM CM CNT UR GM CM Dry Root

Soil biocontrol project (2014-2015) v Phytophthora blight v Biological control: control of pathogen with beneficial microorganisms v Biocontrol op:ons - cover crops (brassica, cereal rye, wheat) - vermicompost - biochar v Greenhouse trials with infected soil h7p://www.nature.com/nrmicro/ journal/v3/n4/full/nrmicro1129.html

Soil biocontrol project results v Biochar and wheat cover crops altered soil microbial community composi:on and reduce root infec:on by P. capsici v Biochar amendment and wheat cover crops improved pepper produc:vity Penewawa Soil B 25 20 15 10 5 * * * * Soil B (high OM) * * * * * * * * * * * * * * * 0 Change in soil microbial community Root weight Shoot weight

How can you build soil health and increase resilience on your farm? v Plant cover crops v Apply organic amendments v Reduce soil :llage v Rotate crop families v Provide con:nuous plant cover Plant rhizosphere (E. Brennan) h7ps://microbewiki.kenyon.edu/index.php/plant_growth_promo:ng_bacteria

HOW CAN YOU DETERMINE HOW MANAGEMENT PRACTICES ARE INFLUENCING SOIL HEALTH ON YOUR FARM?

Standard soil test v Es:mates nutrients available for plant uptake v Total soil organic ma*er, soil ph, and Ca1on Exchange Capacity (CEC) v Advantage: - rela:vely inexpensive v Limita:on: - no or very limited informa:on on biological or physical proper:es

Soil health test v Standard nutrient analysis plus physical and biological indicators v Advantage: - informa:on on soil chemical, physical and biological status of soil - many provide management recommenda:ons for iden:fied constraints v Limita:on: - Cost: $50- $240 - Some need access to equipment on the farm like a penetrometer - Interpreta:on of results are a bit fuzzy indicators (not absolute) Valuable for tracking changes over 9me

Soil health indicators v Soil texture: propor:on of sand, silt and clay - func:on of soil parent material - virtually unchangeable except for erosion important for soil test interpreta9on

Soil health indicators v Aggregate stability - ability of soil aggregates to resist erosion, slaking, crus:ng healthy soils s9ck together

Soil health indicators v Surface and subsurface hardness - measure of penetra:on resistance - important for water infiltra:on and crop roo:ng

Soil health indicators v Ac1ve soil carbon - organic ma7er that is readily available for microbial use - simple compounds that have not been stabilized by associa:on with mineral par:cles Mineral Associated Organic Ma7er Ac:ve Carbon Mineral Par:cle Figure Source: M. Kleber et al. Biogeochemistry (2007) 85:9-24.

Soil health indicators v Microbial ac1vity and community composi1on - What types of microbes are present? - How ac:ve are they? - Important for nutrient mineraliza:on and availability for crop uptake - Important for media:ng bio:c and abio:c stress

Soil health indicators v Poten1ally mineralizable nitrogen - Nitrogen expected to be released from organic ma7er by soil microbes - Func:on of ac:ve organic ma7er pool and soil microbial ac:vity

Soil health indicators v Pathogen pressure - pathogen counts (direct) - bean root assay (indirect)

Soil health indicators v Salinity: soluble salt content of the soil - electrical conduc:vity (EC) - affects soil :lth and crop produc:vity

Soil health indicators v Heavy metal screening - recommended for urban areas

RecommendaHons Cornell Soil Health Test v Value provided for each physical, biological and chemical indicator v Color coded ra:ng/score for each indicator v Overall score provided v Site- specific constraints iden:fied v Specific management prac:ces suggested to address constraints h7p://soilhealth.cals.cornell.edu/extension/test.htm

Management recommendahons Cornell Soil Health Test - Biological concerns linked to NRCS prac1ce codes Short term Long term NRCS Code h7p://soilhealth.cals.cornell.edu/extension/pdfs/nh_nrcs_soilhealthmanagementop:onstable.pdf

Summary v Soil health is important for maintaining crop produc:vity and environmental health v Soil organic ma7er must be con:nually replenished to build and maintain soil health v Management prac:ces can alter soil health and impact crop produc:vity par*cularly under stress v Many for tracking changes in soil health using soil chemical, physical and biological indicators

QuesHons???