SOYBEANS IN THE SUGARCANE CROPPING SYSTEM

Transcription

1 SOYBEANS IN THE SUGARCANE CROPPING SYSTEM Alan Garside 1, Mike Bell 2, Neil Halpin 2, John Berthelsen 1 1 BSES LTD and 2 QDPI & F Sugar Yield Decline Joint Venture The SYDJV was largely funded by SRDC

2 Australian Sugar Industry Productivity plateau (sugar yield/harvested ha) Fig. 1 - Area ( ha), sugar production ( t) and sugar yield (10 t/ha) for the Australian sugar industry Data are averages for consecutive five year periods. Source: SRDC, Area Sugar Production Sugar Yield Year Sugar yield per harvested hectare did not increase between 1970 and 1990

3 Productivity plateau co-incided with changes to the sugarcane cropping system in the 1960 s and 1970 s. CHANGES INCLUDED: Removal of assignment restrictions. Reduced desire to include legume fallow. Encouraged PO/RP. Expansion onto poorer quality soils. Mechanical harvesting with heavy machinery causing compaction. Necessitated increased tillage to remove compaction.

4 POOR SOIL HEALTH RESULTING IN POOR ROOT HEALTH AND POOR YIELDS WAS A CONSEQUENCE OF THESE CHANGES

5 Effect of different soil histories on sugarcane root systems Untreated Fumigated Monoculture Pasture Rainforest

6 WE NEEDED TO FOCUS ON IMPROVING SOIL HEALTH Healthy soil. has well balanced chemical, physical and biological properties

7 HOW CAN WE IMPROVE SOIL HEALTH? Breaking the monoculture with a legume fallow (rotations/fallow). Reducing or eliminating tillage (min/zero tillage). Controlling traffic by matching wheel and row spacing and using permanent beds (controlled traffic/ permanent beds).

8 LEGUMES (SOYBEANS) IN THE SUGARCANE CROPPING SYSTEM

9 HISTORY PRE 1970 Legumes were traditionally an integral part of sugarcane cropping systems Assignment restrictions - farmers forced to fallow 25% of assigned land. Many different species used including mungbean, velvet bean, cowpea, gambia pea, lablab etc. BUT NOT SOYBEANS

10 HISTORY Assignment restrictions reduced to 15% fallowing in 1964 and to nil in Many farmers adopted plough-out/re-plant (PO/RP) Many growers decided that little benefit was being derived from legumes Legume fallow declined and husbandry was neglected

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12 SYDJV REVIVED LEGUME PROGRAM FROM POST 1993 Evaluated a number of legumes and their management but concentrated on soybean (green manure/grain) and peanuts (grain)

13 OVERALL OUTCOMES FROM INCLUDING LEGUMES IN THE SYSTEM Our research has consistently shown short term legume breaks lift cane productivity. PO/RO SOYBEAN BREAK Effects through reduced cane pathogens, better balanced biology, healthier cane stools and symbiotically fixed nitrogen

14 NITROGEN BENEFITS

15 INITIAL STUDIES AT TULLY Temporal Dry Matter (kg/ha) for several legume species in a short term rotation experiment at Tully DM (kg/ha) Date Peanut Cow pea Soybean Mungbean FF

16 INITIAL STUDIES AT TULLY FROM (N CONTENT) Temporal Changes in N Content for a number of legumes in a short term rotation experiment at Tully N Content (kg/ha) Date PEANUT COWPEA SOYBEAN MUNGBEAN F.F (ALL)

17 CANE YIELDS FOLLOWING LEGUME BREAKS Fig. 2 - Cane yield (t/ha) following seven different fallow histories fertilised with either 0 or 140 kg/ha N {LSD 5% = 11.4 for histories x nitrogen} 0 N 140 N Cane Yield (t/ha) Cane Bare Fallow Farmer Fallow Cow pea Mungbean Peanut Soybean Fallow Histories No response to nitrogen following a soybean fallow In this research all the soybean material was fully incorporated no grain harvested

18 THIS OUTCOME SUGGESTED THAT SOYBEANS WERE LIKELY TO BE A VERY BENEFICIAL LEGUME A NUMBER OF TRIALS, DEMONSTRATIONS AND COMMERCIAL EVALUATIONS SINCE HAVE SHOWN NO RESPONSE TO N WHEN THE SEED IS HARVESTED

19 DURATION OF SOYBEAN BREAK EFFECT

20 CANE YIELD FOLLOWING SOYBEAN BREAK MACKAY ROTATION EXPERIMENT Cane Yield following a soybean break in the Mackat Rotation Experiment PO/RP Soybean Break Cane Yield (t/ha) Plant R1 R2 R3 Stage in Cycle Positive effect of soybean break lasts for plant and several ratoons Conventional cultivation

21 SUMMARIZED OVER A CROP CYCLE MACKAY Total cane grown in 5 years (plant + 4R under PO/RP) = 388 t/ha Total cane grown in 5 years (plant + 3R with soybean fallow) = 383 t/ha plus return from soybean crop

22 Grain yield from various plantings of Leichhardt soybean in the Mackay rotation experiments. Site Year Planting Date Harvest Date Grain Yield (t/ha) Mackay 1995/ /97 Dec.12, 1995 Dec 16, 1996 May 16, 1996 April 30,

23 Crop of Leichhardt soybean grown by Steve Arbila, Mackay in Yield 3.5 t/ha

24 SOIL HEALTH BENEFITS

25 Effect of breaking the monoculture on soil biology Microbial biomass Microbial activity Beneficial bacteria Beneficial fungi Mycorrhizal fungi Beneficial nematodes Earthworms Pasture Legume Bare fallow Pachymetra Parasitic nematodes Change relative to continuous cane increase no change decrease

26 EARTHWORMS Worms/m Trash Burnt, Bare Fallow, Tilled Trash Burnt, Soybean, Tilled GCTB, Bare Fallow, DD GCTB, DD soybean, Tilled GCTB, DD soybean, DD Cane

27 Earthworms have a big impact on 330 macroporosity and infiltration - especially in a plant crop Total soil water (mm) Dec 4-Jan 14-Jan 24-Jan 3-Feb 13-Feb 23-Feb CT, BAREFALL DD, SOYMANURE

28 RESPONSE EXCLUSIVE OF NITROGEN SOIL HEALTH RESPONSE Effect of four rates of applied nitrogen (0, 70, 140, 280 kg/ha) on the yield of sugarcane following PO/RP or a soybean fallow. History Sugarcane Yield (t/ha) N rate (kg/ha) PO/RP Soybean Fallow NSD between N rates within histories. Fall outyielded PO/RP by 28%

29 INTEGRATING SOYBEANS INTO THE SUGARCANE CROPPING SYSTEM

30 SOYBEAN RESIDUE MANAGEMENT

31 Release of Mineral N over Time fr om Incorporated Soybean Fallow (T1...T5 = 0, 33, 50, 83, and 137 DAI) Concentration NO 3 - N (mg kg -1 ) Depth (cm) T1 T2 T3 T4 T

32 DIFFERENT SOYBEAN RESIDUE MANAGEMENT Standing Surface Incorporated

33 Soil NO 3 - N (mg/kg) at Time 0 (2 weeks prior to residue management being applied) NO 3 - N (mg/kg) Depth (cm) Incorporated Surface Standing

34 Soil NO 3 - N (mg/kg) at 70 DAYS AFTER imposing residue management and just prior to planting sugarcane NO 3 - N (mg/kg) Depth (cm) Incorporation Surface Standing Surface management slows mineralisation and movement down the soil profile

35 Plant Cane Yields Treatment Cane Yield (t/ha) ccs Sugar Yield (t/ha) Tully Plant Cane Incorporated Surface Managed Left Standing Positive response to not incorporating legume residue Stalk numbers were not affected differences were due to individual stalk weight.

36 Relationship between Cane Yield and Individual Stalk Weight 1.2 Individual Stalk Wt (kg) CANE YIELD = X ISW (p < 0.001, R 2 = 0.95) Cane Yield (t/ha)

37 Relationship between mineral N in the top 50 cm at 10 months after cane planting and ISW ISW = X NFEB (p= 0.006, R 2 = 0.64) ISW (kg) Mineral N (kg/ha) The availability of nitrogen late in the growing season promotes stalk size and ultimate crop yield. Surface management promotes N available late in the growing season.

38 NO ADVERSE EFFECTS OF SURFACE MANAGING SOYBEAN RESIDUE IDEALLY SUITS A MIN/ZERO-TILL SYSTEM

39 SYNERGISTIC EFFECTS OF SOYBEANS AND REDUCED TILLAGE IN A CONTROLLED TRAFFIC PERMANENT BED SYSTEM

40 EXPERIMENT DETAILS 6 cane trash management treatments. 2 legume/cc residue management treatments (incorp/left standing) 2 nitrogen rates (0 &150 kg/ha). 3 replications. Beds were established in Expt. established in 2003 after R1. R1 was not fertilised with N.

41 CANE YIELDS (t/ha) Cane Trash Management Direct Planted Soy/cc residue NOT INCORP. Till Planted Soy/cc residue INCORP. No soybean PO/RP -N +N -N +N CC CTB 2M CTI 2M CTI 1M CTI 1W CTR All planted to soybean N = 150 kg/ha

42 SOYBEAN FALLOW EFFECT

43 Cane trash incorporated No soybean Cane trash incorporated Soybean left standing

44 CANE YIELDS (t/ha) Cane Trash Management Direct Planted Soy/cc residue NOT INCORP. Till Planted Soy/cc residue INCORP. No soybean PO/RP -N +N -N +N CC CTB 2M CTI 2M CTI 1M CTI 1W CTR All planted to soybean N = 150 kg/ha

45 SOYBEAN FALLOW EFFECT CC 75 t/ha Mean of soybean fallow 96 t/ha Planting a soybean fallow increased cane yield by 27%.

46 TILLAGE EFFECTS WITHOUT SOYBEAN

47 TILLAGE EFFECTS (t/ha) Cane Trash Management Direct Planted Soy/cc residue NOT INCORP. Till Planted Soy/cc residue INCORP. No soybean PO/RP -N +N -N +N CC CTB 2M CTI 2M CTI 1M CTI 1W CTR All planted to soybean N = 150 kg/ha

48 TILLAGE EFFECTS Tilled 66 t/ha Direct Planted 85 t/ha Direct planting in CC increased cane yield by 29%

49 COMBINATION OF SOYBEAN AND DIRECT PLANTING VS NO SOYBEAN (CONTINUAL CANE) AND CULTIVATION

50 DP & LEGUME vs. TILL & CC Cane Trash Management Direct Planted Soy/cc residue NOT incorp. Till Planted Soy/cc residue incorp. No soybean PO/RP -N +N -N +N CC CTB 2M CTI 2M CTI 1M CTI 1W CTR All planted to soybean N = 150 kg/ha

51 COMBINATION OF DIRECT PLANT & LEGUME BREAK vs. CONTINUAL CANE &CULTIVATION CC & Cultiv. 66 t/ha DP & Soybean Break 97 t/ha DP & Soybean break increased cane yield by 46%

52 SUMMARY Soybean breaks can provide sustained benefits to the sugarcane cropping system. Benefits include fixed nitrogen, soil health improvements and improved cane yields. They are ideally suited to the new sugarcane cropping system now being developed. They offer opportunities for diversification of income and improved cash flow.

53 Expansion in Soybean Area in Isis (source: J. Area Harvested (ha) Plath) 2003/ / / /07 NB. 2006/07 area is the expected harvest area. Harvest is due to commence in April.

54 Soybean Overview - Isis (source: J. Plath) Size of District Crop (t) ~40% Food Grade 2003/ / /06 67% Food Grade Avg Yield: 2.74 t/ha 2.98 t/ha 3.67 t/ha