A Meeting of the Minds on Orchard Systems and Production

Transcription

1 A Meeting of the Minds on Orchard Systems and Production Stuart Tustin Plant and Food Research Ltd Hawke s Bay Research Centre, Havelock North, New Zealand Two ISHS Symposia in 214 Physiological Principles and their application to Fruit Production - Geneva, NY, March 214 Physiology of Perennial Fruit Crops and Production Systems in a changing Global Environment - IHC Symposium 8, Brisbane, Australia, August 214 1

2 A 2 to 5 year horizon What are the research issues for the new generation of fruit physiologists and horticultural scientists? What is the global context that our research has to address? My presentation draws on perspectives from both symposia, together with the insights guiding our NZ fruit production research The Global Context Unifying World Issues - by 23* Population will increase by 1.7 billion The proportion of arable land will decline by up to 3-4% Environmental degradation, water scarcity, climate dynamism Food supply and security *Revisiting the Green Revolution: Seeking innovations for a changing World. Rodomiro Ortiz, 211. Chronica Hort 51 2

3 What do these forecasts mean for fruit industries? Water resources become limiting Soil natural capital protecting the capacity to support crop growth Farmed land will need to be twice as productive as today to meet food demand! For Apples = productivity of 15-2 t/ha (bins per acre) Future rules for fruit growing? Orchard Eco-credentials... an initiative, co-chaired by the European Commission and food supply chain partners, which aims to establish the food chain as a major contributor towards sustainable consumption and production in Europe. 3

4 The big question What is the theoretical limit of productivity of crops and what are the major factors preventing this being realized? * Will it be possible to achieve the increases in crop production that are foreshadowed? * New Phytologist, Aug 211. One Hundred important questions facing plant science research Focus on two functions of the orchard system The crop physiology of production systems Soil natural capital providing ecosystem services 4

5 Crop physiology of orchard production systems Two fundamental aspects to productivity»light utilization»resource (growth) allocation Light Interception and productivity of apple orchards Apple yields (t/ha) In mature apple orchards 6-7% light interception is the practical upper limit Lakso, 1994 and revised % Total light interception 5

6 Light Interception and productivity of modern apple orchards Apple yields (t/ha) In mature apple orchards 6-7% light interception is the practical upper limit Lakso, 1994 and revised % Total light interception What is the theoretical limit of productivity of apple intensive orchard systems? Three cultivars in Nelson, NZ Palmer et al. 22. The theoretical yield at 9% light interception would be 169 tonnes per hectare. 6

7 Orchard system yield has the theoretical potential to double. if. Achieve >85% light interception Canopy design that ensures canopy irradiance properties for fruit quality High biological efficiency = high harvest index Simpler canopies - labour efficient and amenable to mechanisation, automation, even robotics Total seasonal light interception and total dry matter production: Palmer et al. 22 7

8 Growth allocation and Harvest Index of orchard systems Harvest Index = the proportion of the seasonal total growth allocated to the fruit product Total growth = fruit + shoots + leaves + stems + roots Harvest index = fruit mass / total growth mass (%) Understanding growth processes that enhance HI provides insight to the function and efficiency of planting systems What is the physiological upper limit of HI? HI has increased as tree management has reduced pruning and increased manipulation slender spindle tall spindle Simpler tree architecture Less growth Lower pruning weights More and better fruit Smaller tree dry mass? 8

9 Manipulating harvest index by changing crop management Envy / M.9, 6 th year, tall spindle Left tree: artificial spur extinction from 3rd year on Right tree: conventional crop management Metrics: fruit per tree, 95 t/ha Mfw ~26g Crop load set each year according to branch size (bca) Annual crop production - fruit dry weight per tree (kg) Kg dm/tree Con Ase Year from planting into orchard 9

10 Crop management can manipulate floral processes Total flower cluster density (number / cm 2 BCA) ns *** ns 3rd 4th 5th 6th Year or leaf from planting Unmodified ASE Within a single year only, ns = non significant, *** significant at P <.1. *** Cumulative pruning dry weight per tree (g) 12 Cumulative pruning dwt (g) Con Ase Year from planting into orchard 1

11 Cumulative trunk cross-sectional area (cm 2 ) 25 2 TCA (cm2) 15 1 Con ASE Year from planting into orchard Annual increment in trunk crosssectional area (cm 2 ) 6 5 Delta TCA (cm 2 ) Con ASE Year from planting into orchard 11

12 What is the upper limit for harvest index? Year 6 Year 7 Dry mass removed as crop = 1.5 kg (23 lbs) Dry mass removed in pruning = 15g (6 ozs) Increment in TCA = 2.7cm 2 Summarising opportunities in crop physiology of orchard systems Theoretical biological yield potential of apple orchard systems is between 16-2 t/ha Will require re-thinking the whole system Productivity and fruit quality potential are driven by - resource acquisition (light, minerals) AND - resource allocation (growth, harvest index) Optimistically there are still multiple strings to our crop physiology bow 12

13 Soil : The Natural Capital providing ecosystem services within the orchard system Dr Brent Clothier, Science Leader, Production Footprints Group Natural Capital: Our stocks of natural materials & energy Ecosystem Services: The beneficial flows of goods between natural capital stocks, or stocks & humans Provisioning services Regulating services Investing Carbon into the Ecological Infrastructures of Orchards C new =f(r,t,w,n) Y R C root a R Y L C leaf a L Y S C shoot a S a C Y C C fruit + compost C litter Organic: Integrated: 3.8 kg-c m kg-c m -2 Next-door neighbours Changed Natural Capital & different Soil Ecosystem Services 13

14 Organic: Integrated: 3.8 kg-c m kg-c m -2 X-ray Tomography Valuable Provisioning The New Zealand & Regulating Institute for Plant & Food Research Services Limited Macro & Microbiological Changes Earthworm FW [g/m 2 ] Microbial biomass C [g C/m2] Organic Integrated January April July October Organic Integrated January March May July September November... Lead to Soil Structural Changes. Soil Macropores Macroporosity (Vol%) Integrated orchard, core 1 Organic orchard, core 9 The Institute for Limited New Zealand 1 Plant & Food Research Depth (mm) 14

15 Supporting Services & Nitrogen; Regulating Services & Macropores Nitrogen mineralisation (R n : mg-n kg -1 d -1 ) depends on temperature (T), water potential (Ψ) and labile carbon (C hw ) Profile generation: 15 kg-n ha -1 y mm 15 mm 5 mm 1 mm Rootzone 5 mm Wick L 6 mm Nitrate loss [kg-n/ha] 2 1 Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 15 mm Buffering efficiency: 9% retained Regulating Services of Macropores : Buffering of Endogenous Solutes Rain/Irrigation Highly buffered runoff Surface Ponding Free-water surface Endogenous mineralisation of nitrogen Macropore Buffered leaching of NO 3 Some 9% retained 15

16 Carbon manipulation in the orchard system - an impressive list of potential eco-credentials Increasing soil carbon (OM) appears quite feasible Higher soil carbon: - increases macro and microbiological functions - increases macroporosity - increases N supply by > mineralisation - buffers N leaching and water run-off Tree roots sequester carbon deep in the soil profile, increasing soil macroporosity when roots die Truly Sustainable Orchard Systems - the only future! This is not a Tree-huggers concept of environmental nirvana Truly sustainable is the most pressing long term issue The challenge of the long range goal: The integration of all orchard systems functions to:..reach the biological limit of productivity + quality..in ways that conserve the natural capital of the production ecosystem in perpetuity 16

17 Thank you for your interest 17