Processing Tomato Industry: Soil Priorities for Moving towards 200 t/Ha Yield. • Ba Ag (Hons). University of Melbourne, Dookie College. • Soils of the Riverine Plain. • Soil formation (Butler 1950; Butler 1956; Butler & Hutton, 1956; Butler, 1958). • Soil catenas – sequences • Soil type and variability • Land use capability & suitability • Preferred crop types • Engineering of soils to increase productivity. • Focus primarily on soil physical properties.
Cockroft – Orchard Soils (Not Tomatoes)
Soil Physical Properties – Breakdown into Two Groups. Cockroft & Dillon, 2006. Inherent : Those that are fixed, difficult to change or modify (without engineering): • A horizon topsoil depth • Horizon texture • Depth to hostile or constraining subsoil Set and limit yield potential. Must have a rootzone to support growth. Dynamic : Those that can be modified or changed. • Soil structure • Bulk density, slaking, dispersion • Others previously mentioned. Can be modified to increase yield potential.
Soil Requirements for High Yield Potential in Horticulture: 1. Field drainage. 2. Deep topsoil, or engineer deeper topsoil – mound. • Horsepower • Drainage 3. Full amelioration of the ‘effective’ rootzone • Mound • All topsoil • Upper B horizon 4. Improve water stability – control dispersion, slaking and reduce coalescence (Cockroft & Olsson 2000). 5. Maintain and improve aggregation (structure) by adding and growing organic matter / use management techniques to maintain structure (Tisdall & Oades 1979; 1980a; 1980b). • Ryegrass • Other cover crops • Crop rotations • Cultivation 6. Adequate supply of nutrition to meet yield potential, optimal cycling of nitrogen from organic matter. 7. Irrigation – method, placement, volume.
YIELD POTENTIAL OF 200 t/Ha…??? • We have seen 200 t/Ha yields before in patches. • YES , potential is possible. • Short-medium term (5 years), average yield potential on subsurface drip irrigation: • NO . • Why? - Short term issues: • Soils are too expensive or difficult to ameliorate. • Poor compatibility between irrigation system application rates, placement and soil properties. • Industry does not focus on the ‘key’ factors which drive high yield potential. • How will we get there?
2016 GRDC Conference. Inherent soil properties - what we have to work with Dynamic soil properties – those 200 t/Ha we can change.
2018 study tour – December New Zealand. • 17 t/Ha cereal crops, chasing 20 t/Ha. • Reduce crop stress • Perfect field drainage • Deep rootzone, large area to draw water • Rainfall • Irrigation – light, soft application. • Crop rotation critical. • Several crops in rotation, both summer and winter – more than 1 crop per year.
What this means for processing tomatoes: • Starting conditions is critical. More due diligence on land. • Irrigation system compatibility – must be studied. • Knowing how soils behave and change under irrigation will support hypothesis on yield decline – research required. • Know yield potential before we start. • Must understand and set benchmark parameters around soil physical properties to support desired yields • Use these benchmarks for: • Land selection • Soil amelioration. • May already be achieving maximum yield potential from some soils for the irrigation system that is employed.
Soil physical properties & other measures of soil physical conditions impacting plant growth and yield potential: 1. Horizon depths (cm): Visual assessment of the layers of soil in a profile with similar physical and chemical properties (Butler, 1955; Cockroft & Dillon, 2004) 2. Horizon texture: Texture of each horizon or layer in the profile, understand drainage (McDonald et al 1990; FAO, 2006). 3. Topsoil depth (cm): Zone where crop nutrients are accessed, zone of the profile which can rapidly drain, including the A1 & A2 Horizons, bleached layers (Cockroft & Dillon, 2006). 4. Soil colour: Assess internal and surface drainage, waterlogging potential and impedance to water flow (McDonald et al, 1990, Munsell Colour Charts, 1975). 5. Soil structure & porosity: Level of aggregation, surface tilth, hard panning, water movement and root movement (Freebairn et al, 1997; McDonald et al. 1990; US Dept. Ag, 1951). Bulk density (t/m 3 ): 6. Calculation of the density of a soil, including volume of soil and air space for roots (Brady, 1990; White, 1979) 7. Slaking Class: Breakdown of aggregation and associated consolidation and compaction (Herrick et al 2001; Tisdall & Oades, 1982). 8. Dispersion Class: Clay colloid dispersion and associated consolidation and compaction. (Emerson, 1967; Charman, 1978; Charman & Murphy, 1991; Naudu et al. 1995)
9. Consistence: Field strength, cohesion and plasticity. (Butler, 1955; McDonald et al. 1990). 10. Effective root zone depth (cm): Zone where soil can be efficiently accessed by plants. (Kramer & Boyer, 1995; Schaetzl & Anderson, 2005). 11. Calcium carbonate (free limestone), type of lime (nodules, powder or rubble), the depth to lime: Naturally occurring lime that can impact root growth or influence soil pH rendering nutrients of low availability. (Brady & Weil; 2008; Weatherby, 1992; Cockroft & Dillon, 2004) 12. Calcium sulphate (gypsum) content and depth: Visual inspection, influences soil electrical conductivity, less impact than lime, less impact than NaCl (FAO, 1990). 13. Plant root score, volume and distribution of the plant root system: Scoring the root system in each horizon for available water (McDonald et al, 1990; personal observation). 14. Self-mulching processes in clay dominant soils and subsoils: The influence of shrink-swell process on plant root zone depth, available water and soil chemistry. Discuss dryland and irrigation. (Churchman et al. 1995; McGarity et al, 1984). 15. Crusting and restricted infiltration: Surfaces prone to crusting with restricted water infiltration. Closely related to texture, behaviour when wet and organic matter.
Processing Tomatoes: Summary of Field Observations Limiting Yield Potential: • Germination and poor early growth. • Crusting – slaking, dispersion, intense rainfall. • Paddock variability – variable water use. • Poor profile drainage – heavy sodic clay subsoils. • Poor rooting depth, moisture drawn mostly from the surface. • Soil structural, lack of aggregation. • Soil moisture management – too wet, watered from the bottom up, perched water table development, capillary rise of water. • Amplified irrigation volume • Consolidation around the tape • Poor structure • Limited roots where nutrition is being applied.
Early Growth. Many problems relating to yield are caused from poor early growth and management. • Crop struggles to get established • Mis-match between irrigation requirement and application • ET increases, shallow rootzone, irrigation becomes difficult. • Crop does not flourish in peak ET period. Early growth must secure: • Effective rootzone depth – as deep as possible. • Deeper than tape. • Readily available water – as high as possible, big bucket. • Wetting front from irrigation that takes soil from deficit to moist (field capacity) over a large area, rather than deficit to saturated (small area). Ayres & Westcot, 1989. FAO Irrigation & Drainage Paper No. 29.
Kagome – 2014 Land Development. • Crops on these soils yielded up to 140-160 t/Ha. • Effect short term only – follow up work is required.
Kilter – Soil Physics & Chemistry Around Tape.
Kilter – Soil Physics & Chemistry Around Tape.
FINAL NOTE • Several aspects of soil physics that can be studied to move towards 200 t/Ha. • Major shift in R & D priorities. • Water stability – major focus.
Recommend
More recommend
