Stop Treating Soil Like Dirt! Soil Workshop Soil is living! There - PowerPoint PPT Presentation

Too much of a good thing The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Yield curves to fert recommendations The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Yield curves to fert recommendations The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

An empirical estimate Yield curves / fertiliser recommendations are too often considered to be highly precise and accurate They are in fact very fuzzy The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Real yield curves are fuzzy The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Real yield curves are fuzzy The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

P availability index (PAI) fits and uncertainties 1.0 Observed P availability index (PAI) 0.8 E = 0.34 Predicted 95 % CIs 95 % PIs 0.6 0.4 0.2 0.0 0 50 100 150 200 250 300 350 400 450 Data from Vadas and White. 2010. TASABE 53: 1469-1476. Slide from: Model Parameter Uncertainty Analysis for an Annual Field-Scale P Loss Model. Carl H. Bolster, Peter A. Vadas, & Debbie Boykin USDA-ARS. LuWQ 2015

Impact of biology on a yield curve The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Wrapped up in a value judgment Yield maximisation is not a scientific objective It is a value judgement You cant design an experiment that shows you ought to increase yield Only an experiment to show you how to increase yield Maximising yield is a moral / ethical judgement therefore outside of science The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Hume's guillotine David Hume, Scottish philosopher and historian 1711-1776 The is – ought problem You cant logically get from what is to what ought (should) to be That we can maximise yield does not mean we ought to, even have to Could just as well aim for crop quality or any other measure of plant performance

Justus von Liebig Invented the Liebig condenser, marmite and oxo ! The founder of organic chemistry One of the greatest chemistry teachers of all time The father of agricultural chemistry / fertilizer industry Popularized Carl Sprengel’s the ‘law of the minimum’ The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Law of the Minimum The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Soil tests as a guide not an oracle Tests are a guide not God Long term trends using exactly the same lab and test are the real gold - make a chart Coupled with YOUR observations of plant reaction to applied nutrients - i.e., are test recommendations over or under YOU need to build your own experience of your vines needs The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

FFC Bulletin article www.bhu.org.nz/future-farming- centre/information/bulletin/2015-v1/fundamentals-of-soil- nutrient-management-soil-testing-and-fertiliser- recommendations The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Stop Treating Soil Like Dirt Zespri Soil Workshop 2019 Part 3: Nitrogen Dr Charles ‘Merf’ Merfield MRSNZ charles@merfield.com The Future Farming Centre Permanent Agriculture and Horticulture Science and Extension www.bhu.org.nz/future-farming-centre The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Overview Understanding why N is the joker of the pack of plant nutrients / chemical elements How N (mis)behaves - the N cycle Practical organic, N management techniques – In situ N fixation – Importing N The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Nitrogen - the joker / wildcard Nitrogen Nitrogen To understand nitrogen you need to understand why it is different The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

The three nutrient classes C,O,H delivered free by the atmosphere – CO 2 and H 2 O ‘atmospheric nutrients’ P,Ca,K,Mg,S,Fe, etc only come from the soil / rocks of the planet – The ‘lithospheric nutrients’ Nitrogen ‘is’ the atmosphere - 80% but plants can only absorb it from the soil – atmospheric + lithospheric nutrient The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Nutrient cycles Atmosphere gas Lithosphere (rocks) + Hydrosphere pedosphere (soil) = solid & liquid Geosphere The Future Farming Centre solid & liquid Permanent Agriculture and Horticulture: Science and Extension

Carbon cycle CO 2 Soil - major carbon reservoir - 3 x the atmosphere The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Lithospheric nutrients Cycles are the same for all lithospheric nutrients Atmosphere Geological sediment uplift Rock weathering The Future Farming Centre 10 - 50,000,000 years + Thousands of years Permanent Agriculture and Horticulture: Science and Extension

Nitrogen cycle N 2 N 2 N 2 Nr Nr Nr The Future Farming Centre Geosphere - very small amounts of N Permanent Agriculture and Horticulture: Science and Extension

Nitrogen (spaghetti) cycle!

Atmospheric, un-reactive di-nitrogen (N 2 ) gas Biological nitrogen fixation by bacteria, cyanobacteria and actinomycetes in symbiosis with higher plants especially the Fabaceae (legumes) Reactive nitrogen stored in living plants and animals Denitrification by soil dwelling bacteria Assimilation Reactive nitrogen in Biological nitrogen fixation by plants by free living bacteria and soil organic matter cyanobacteria in the soil - Nitrates NO 3 Decomposers Assimilation Aerobic and anaerobic Nitrifying by plants fungi and bacteria bacteria Ammonia NH 3 Ammonification Nitrification by nitrifying - + Nitrites NO 2 Ammonium NH 4 bacteria

Practical orchard N management Nitrogen is the flip side of carbon C N N+C+O+H = soil organic matter (SOM) N sorbed onto organic matter N is therefore both in and on organic matter N management flip side of SOM management The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing or fixing N N comes from - and returns to - the atmosphere To get N into the orchard it has to either be: – Imported i.e. as fertiliser, compost, manure – Fixed in-situ, by legumes The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N Difficult under organic standards Only biological-organic forms are permitted The main N compound in living things is protein Protein is 6.25% N (Jones factor) i.e., max N content of bio-ferts without fortification or concentration is 6% The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N Need data (not guess) on: – Total N content of material – How much of the total N is available per year All bio-organic ferts contain a wide (all) range of the other nutrients – Need to include all other nutrients in fert calculations to make sure they are not over applied – Other nutrients may be higher than N The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N - compost Is a very poor source of N - 1-2% total N Has much more P & K on a plant needs basis Using compost to supply N will result in excess P & K A good soil conditioner It is not soil ‘food’ A literature review on the availability of phosphate from compost in relation to the Nitrate Regulations SI 378 of 2006. 2009 Prasad A literature review on the availability of nitrogen from compost in relation to the nitrate regulations SI 378 of 2006. 2009 Prasad The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N - compost Need both total N and C:N ratio % of total N mineralised after application Compost Over 3 C:N ratio years In year 1 In year 2 In year 3 10 25.0 12.5 7.0 5.5 13 17.5 8.0 5.0 4.5 15 10.0 5.0 3.0 2.0 18 5.0 2.5 1.5 1.0 20 0.0 0.0 0.0 0.0 Wallace, P. (2006) Production of Guidelines for Using Compost in Crop Production- A Brief Literature Review

Importing N - Vermicompost Compost made by worms – quite different to hot compost Higher nutrient levels than hot compost – depends on feed stock N as nitrate more than ammonium Need nutrient analysis of each batch - varies Cost and supply – fewer vermicomposters than hot composters The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N - manure If you can find organic certified manure… Total N – Sheep manure 2% – Cow manure 0.7% – Pig manure 1.0% – Chook manure • Cage (banned) 1.4% • Litter 2.4% from Practical Soil Management, Ian Cornforth The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N - Foliar sprays Importing N into organic orchards, and getting into the plant via the soil, is slow If vines are N deficient then N needs to be got directly into the plant…. Foliar sprays The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N - Foliar sprays Not recommended as the main N supply route - due to cost (materials and application) There are foliar sprays and foliar sprays – Some are based on good science – Some are not – Caveat emptor Ask to see research results / strong evidence Get good independent advice The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N – Wool and feathers? Wool and feathers contain up to 12% N Is there potential to use them as an N source? Issues: – Certification rules • Uncertified has to be composted – N lost • Certified products – supply issues? • Would they be allowed to be used as fertiliser? – Decompose slowly – resistant to decay – Other issues? Research project? The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Importing N – biodigestate? Anaerobic digestion / biodigestion Giant steel rumen Unlike composting no N lost Biodigestate high in mineral N (ammonium) Grow high N feedstock – certified clover pasture Convert to biodigestate + methane – energy ??? The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Making your own: Fixing N Importing N in organic ag is difficult and expensive Fixing N in-situ is the dominant route A few key concepts underpin the process The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Biologic zero The absolute zero of soil biology 5 - 10 ° C, average ~ 8 ° C Below this soil organisms, including diazotrophs (N fixing ‘bacteria’) are inactive → Little N fixation during winter → Most N fixation occurs during summer The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Serving up N and biologic zero N in soil is in the form of organic matter To become available to plants it has to be mineralised into ammonium This is done by fungi and bacteria The release of soil N is therefore determined by microbial activity Which is determined by soil temperature The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Serving up N and biologic zero If temps are close or below to biologic zero – Zero N release If other soil conditions suppress microbial activity, e.g., too dry, to hot – Zero N release Spring is the time when organic systems struggle for nitrogen - crops start growing and need N, soil microbes are still in bed The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Loosing N The main form of Nr loss in healthy soils is leaching Mainly as nitrate NO₃− There has to be soil drainage Soil has to be above biologic zero so SOM can be mineralised to nitrate Spring and mainly autumn are the main loss periods The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Green manures and catch crops Cover crops is the overarching term – Green manures to fix N. – Catch crops to hold N Basic concepts pretty straight forward Lots and lots of permutations The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

N fixed and remaining after harvest Lucerne (silage) Red clover (silage) White clover/grass (silage) White clover/grass (grazed) Field bean (grain crop) Forage peas Lupin (grain crop) N fixed N after harvest Vetch (cut & mulched) (including roots) Soya (grain crop) 0 100 200 300 400 500 600 kg N/ha/year Compendium of international figures

What causes the variability Fixing N is very hard and very energy intensive Legumes are lazy They wont fix N, if there is available soil N If there is little soil N, they will fix N flat out Biologic zero – soil temperatures The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

N catch crops It is easy to loose 50 – 100 kg N / ha over autumn- winter-spring when leaching is high Quite possible to catch 50 - 100 kg N / ha over autumn-winter-spring with catch crops Mustard and cereals are the best Need to be well established before N leaching occurs The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Growing catch crops & green manures When Where? – Summer – Undervine – Autumn – Interrow – Winter – Both – Spring What kind? – Perennials – Annuals The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

http://www.sare.org/Learning-Center/Books/ Managing-Cover-Crops-Profitably-3rd-Edition

OSCAR Optimising Subsidiary Crop Application in Rotations www.covercrops.eu The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Wrapping up N You need to understand the N cycle and how N behaves in the soil Importing N is expensive in organics Fix your own is the best and cheapest long term option (Un)fortunataly the options and permutations are many - and often highly site specific The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Stop Treating Soil Like Dirt Zespri Soil Workshop 2019 Part 4: Soil Health Dr Charles ‘Merf’ Merfield MRSNZ charles@merfield.com The Future Farming Centre Permanent Agriculture and Horticulture Science and Extension www.bhu.org.nz/future-farming-centre The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Soil health = soil biology Soil health is physical, chemical and biological / ecological – all are required But soil biology is a key driver of physical and chemical health Physical and chemical health is the foundation for biological health A healthy soil is a biologically active soil How to make a soil biologically active? The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

163 pages The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

http://www.bhu.org.nz/future-farming-centre/future-farming- centre/information/bulletin/2013-v1/make-soil-organisms-work-for-you-mythbusting- The Future Farming Centre practices-that-do-and-don-t-work Permanent Agriculture and Horticulture: Science and Extension

The living soil Soil is the most complex ecosystem on the planet It is typically 10 times as complex and contains 10 times the amount of life (weight and species) than the above ground biomass Looking after all this complexity is surprisingly straight forward The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension

Looking after your soil Your soil Organic matter Feed The Future Farming Centre Permanent Agriculture and Horticulture: Science and Extension