Efficient Nutrient Management

Transcription

1 DI&INSW Integrated advanced fertigation (IAF) of citrus VC HAL CT741 Steven Falivene 1,3 Knowledge and tools to manage fertigation technologies in highly productive citrus orchards for minimal environmental footprint LWA DAN527 Michael Treeby 1,2,3 Steven Falivene 1,3 Mark Skewes 2 Karen Connolly 1 1 NSW Industries and Investment 2 SARDI 3 CRC Irrigation Futures Project Structure & Presentations IAF HAL VC funded May 28 VC contributors listed later Fertigation Knowledge tools Funded by National Program Sustainable Irrigation IAF S.Falivene Efficient Nutrient Management M.Treeby I&I NSW / SARDI SSET Modelling M.Skews SARDI Preliminary in progress discussion of results Specific results are limited to Dareton, different site may have different responses Trial results may not deliver the final conclusion, but provide a better understanding to help you select onfarm tool and practice to suit your circumstances Western Australia 3 rd February 21 2 DI&INSW Efficient Nutrient Management Michael Treeby (I&I NSW / SARDI) Rootstocks & nutrient uptake trials Current 6 rootstocks N responses mm NH 4 NO 3 ( N ppm / mg L -1 ) Next fewer rootstocks K/Ca balance 4 Rootstock growth & N supply Assessing orchard N supply Growth maximised more N same growth Different stocks different water ppm N Height (cm) Macrophylla BC A A D-F C-E BC F-H D-F CD Troyer IJ E-G ppm N (as ammonium nitrate) in nutrient solution J G-I J HI D-F D-F D-F Volkameriana J F-H E-G 5 Real time leaf N sensor non-destructive readings reflect N supply early days Reading ppm N (as ammonium nitrate) in nutrient solution 6

2 DI&INSW SSET Nutrient Modelling Water & nutrient movement below rootzone Mark Skews (SARDI) Formerly conducted by Tapas Biswas (SARDI) Solution extraction tubes Logging capacitance probe Weighing scales Logging tensiometers Drainage Time taken to establish plants in tubs Data collection commenced Jan 21 8 DI&INSW Integrated Advanced Fertigation Steven Falivene (I&I NSW) Aim & design Five year trial comparing drip irrigation & fertiliser practices on young citrus Commenced in October 28 on 4yo Fischer navel on citrange in a sandy loam soil Drip irrigation management Conventional* OH Fertiliser Pulse Continuous management X 3 per year - Daily * Industry best practice : tensiometers and ETo 1 1 st year establishment phase Irrigation vs Nutrition Drip emitter spacing was reduced Using best knowledge a water program was chosen Water stress occurred in highly efficient regime Estimate under watered by 2% and/or exasperated by numbers of drip emitter per tree Water use estimation calculation now improved (4yo +) 11 Tree on left suffered about 2% less water for 3 months tree stress evident Trees on right have had no nutrition for over 18 months No significant signs of tree stress & 29 March leaf tests showed no significant difference 12

3 Soil moisture monitoring How representative? Tensiometer readings from trees irrigated exactly the same May the correct tensiometer reading please stand forward????? worse on small trees? Very important to gain confidence that a single probe installed on a 3-5 ha block is representative. Calibration is required Eto, visual symptoms etc Tensiometers need maintenance Temperature affects reading Warming up readings drop & vica versa (2-5 cb) Thermal sun shielding significantly helps Take reading morning & before tubes in direct sunlight st year establishment phase Drip emitter Wet soil Soil evaporation 33x28cm basin 2.5 hours (hot windy Jan day) Sun ~ 27ml Shade ~17ml Shade + mulch ~ 6ml Irregular wetting & rooting patterns Can cause irrigation and soil probes to give false readings Probably due to soil structure (i.e. old wheel track) Hourly Fruit Growth Data Two Phytec15-7mm hourly fruit growth data loggers Seen used by Israeli grower in 24 ~ $13 each 17 Fruit diameter (mm) Jan - 9 Jan - 12 Hourly Fruit Growth Pulse (7791) Conv (779) 1 Jan - 1 Jan Jan - 11 Jan Jan - 12 Jan Jan - 13 Jan Jan - 14 Jan Jan - 15 Jan Jan - 16 Jan Jan - No visible short term difference between pulse & conventional Fruit loose water during the day and rehydrate at night Trees & fruit need to physiologically dehydrate slightly so they can pull up water 18

4 Fruit Growth :Can be used as a irrigation management tool 2xSap flow sensors (5,12,21,32mm) 58 Water applied Fruit diameter (mm) Feb Fruit growth slowed; water should have been applied 2-Feb 3-Feb 4-Feb 5-Feb 6-Feb 7-Feb 8-Feb 9-Feb 1-Feb Hourly fruit measurements can be a indicator to water stress Fruit rehydrated to normal size once water applied Short term ( one off ) water stress may have little effect on tree health ; continual/regular water stress is the problem 19 2 Sap flow no mid day shut down Sap flow L/hr : 1: 2: 3: Sap flow of Two Five Year Old Fischer Navel Trees 5th January 21 4: 5: 6: 7: 8: 9: 1: 11: 12: 13: Time (24hr, not daylight saving) 14: 15: 16: 17: 18: 19: 2: 21: 22: 23: Tree 1 Tree 2 Solar Trees self regulate during peak demand (hot : 9am-5pm) not to transpire more water than that can move up the trunk Self regulation is by frequently closing and opening stomata (leaf pores) i.e. turning a tap on and off regularly to regulate flow Solar Radiation W/m2 21 Soil Solution Soil solution extraction tubes (SSET) & full stop 28-9 Regular high nitrate (1ppm + ) & EC spikes (5dS/m) 29-1 More stable Spikes probably mainly due reduced water = compact rootzone + some excessive fertiliser 22 Full stop vs SSET NO 3 : 2cm OH slow dripper Full stop vs SSET NO 3 : 2cm Conventional 18 Average Orange 2cm SSET Vs 3cm FS : Average White 2cm SSET Vs 3cm FS : Jul-9 1-Aug-9 1-Sep-9 1-Oct-9 1-Nov-9 1-Dec-9 Orange S 2 Orange F 3 3cm Full stop shows similar pattern to 2cm soil solution Jul-9 1-Aug-9 1-Sep-9 1-Oct-9 1-Nov-9 1-Dec-9 White S 2 White F 3 Urea slug may have set within/on top the funnel of full stop or SSET missed the slug? 24

5 Nitrate 2 cm soil solution extraction tube Nitrate 9 cm soil solution extraction tube 35 Average SSET 2cm : Average SSET 9cm : Jul-9 1-Aug-9 1-Sep-9 1-Oct-9 1-Nov-9 1-Dec-9 1-Jan-1 Blue Orange Red White Yellow Blue = OH pulse, Orange = OH slow dripper, White = Best practice conventional Red = Pulse & conv. Fert., Yellow = conv. Irr. & prop. fert Jul-9 1-Aug-9 1-Sep-9 1-Oct-9 1-Nov-9 1-Dec-9 1-Jan-1-5 Blue Orange Red White Yellow Blue = OH pulse, Orange = OH slow dripper, White = Best practice conventional Red = Pulse & conv. Fert., Yellow = conv. Irr. & prop. fert 26 Extension: irrigation scheduling tool No practical guidelines for young trees A tool to predict water needs: making it easier for growers to use all the information Information difficult to integrate Spreadsheets: Crop coefficient Based on site characteristics Average monthly water use Monthly water use based on historical ETo data Current ETo data Calculate RAW ETo & water needs (hours day -1 ) prediction Extension Workshops (Mastery Technical Series) Nutrition Workshop Empowerment in confidence through knowledge & understanding Nutrition 2 day course (4 ½days) Content based on citrus literature Fertigation/nutrition management spreadsheet tool Delivered Planned 1 Riverina Sunraysia (Mar 21) 2 Sunraysia Riverina (Mar 21) 1 Mid Murray 1 x Riverland 29 3

6 Nutrition Workshop Soil Solution Workshops Crop load estimation Delivered 2 CRC-IF (Canberra & Adelaide) 1 Riverina 1 x Sunraysia Planned Riverina & Riverland (Oct 21) Vic CRCIF (April 21) Leaf sampling for tree nutrient status measurements Other Planned Workshops Extension: Planned Factsheets Soils understand the soil & how to interpret soil tests Crop water use & drip irrigation calculation & estimation of irrigation needs (use spreadsheet tools) Some examples Fertigation Interpreting soil solution analysis, Advanced irrigation (Fertigation book) Fertigation equipment, mixing fertilisers Physiology how trees operate Questions & thoughts work in progress Is the compact rootzone seen in OH systems partly a result of pulse watering? reduced soil wetted volume Is claimed increase in production of OH a statement of current practices? OH forces the user to keep trees well watered, can a well watered conventional do the same? Is conventional estimation of irrigation needs underestimated Overestimate soil water holding capacity, soil water delivery & root density for high demand conditions ; grower practices have potential to improve with more informed & accurate irrigation Questions & thoughts work in progress Field observations : OH Significant improvements in young tree establishment Overestimation of the extent (volume) and capacity of young tree roots to extract water & nutrients Can a well managed conventional syste that recognises a small root zone and more regular nutrition application perform similar to OH? Easy to encourage a water shoot tree with excess nutrition 35 36

7 Suggestions on dealing with saline water Acknowledgements 1. Monitor water, soil solution & leaf tests 2. Do not use trifoliata 3. Maintain soil moisture at higher that usual moisture levels 4. Calcium will help to reduce sodium uptake and push sodium ion off clay particles so it can be leached away 5. Sulphate, nitrate can reduce chloride uptake 6. Leach salts when water quality best - follow up on rain 7. Incorporate some gypsum and/or potassium sulphate & calcium nitrate and go back to step 1 Twin line drip increase soil volume dilutes salt THE END..for now! Thanks to Moora Citrus, Lawrence Kirton & Helen Ramsay for initiating & facilitating my WA visit It s a pleasure to present you Please provide any comments or feedback 39