No Tillage Challenges and Solutions for Soybeans in Australia

Transcription

1 No Tillage Challenges and Solutions for s in Australia J.D Sykes 1, P. Desborough 2, L. Gaynor 3, M.J. Bell 4, A.L Garside 5 1,2,3 NSW Agriculture, Dubbo, Grafton and Yanco. 4,5 Agency for Food and Fibre Science, QDPI, Kingaroy and Townsville. Abstract Increased acceptance of no-till and controlled traffic has renewed interest in soybeans in Australia. This papers reviews how soybeans are being utilised in three farming systems in Australia that are dominated by sugarcane, perennial pasture and rice. The farming systems, termed tropical coastal sugarcane, subtropical coastal beef and Murrumbidgee irrigated have had complete or extended periods of monoculture. Resultant soil health and disease problems have caused yield decline comparatively to uncultivated soil. s are an attractive break crop that is being used for green manure or grain production. As a grain crop it can provide an alternative income to subsidise the cost of land improvement techniques. With the adoption of no-till techniques establishment costs are reduced, crop frequency increased and land sustainability improved. Introduction Australian soybean production peaked at 130,000 kt in Production has always been variable and well below expectations for an industry that started in the 1970 s. s have never become a dominant crop within a farming system like wheat in dry land areas, cotton or rice in irrigated areas or sugar cane in coastal areas. However in the last 10 years interest in growing soybeans has moved away from a competitive main crop to a complimentary rotation crop. Researchers and leading farmers have always acknowledged the benefits of including legumes in rotations. However, the availability of no-till and controlled traffic techniques has changed the outlook for soybeans as they can be easily established and harvested within a dominant crop rotation. At the same time oil availability in Australia has increased with the development of canola as a break crop in the inland wheat cropping areas of Australia. As a consequence crushing soybean for oil was reduced and centralised to Brisbane and Newcastle. is now a less profitable crop to grow where freight costs have substantially increased. This has necessitated a change in marketing direction and soybeans are now being grown for specialised human food uses. breeding and marketing is now focused on colourless hilum soybeans used for milk, tofu. The industry challenge now is to revitalise grower interest by focusing research and development opportunities in production areas where soybeans are a preferred break crop or where production for a niche market can be sustained over a long period. Specifically, the utilisation of soybeans under no-tillage is reviewed within three farming systems in Australia. See Table 1. 1 TROPICAL SUGARCANE a) Background Sugarcane production is confined to about 450,000 ha of land located along the coast of Queensland and northern NSW. In most districts sugarcane is grown largely as a monoculture. Normally 4-5 ratoon crops are produced before the stool is ploughed out. Since the 1970 s a system of plough out/ replant has been employed, resulting in virtually no fallow period. There is extensive use of inorganic fertilisers, insecticides and herbicides. As well, the technique of green cane harvesting has increased soil compaction through the

2 use of heavy machinery. There is a soil based production constraint referred to as yield decline (Y.D). b) Farming System Rotation In order to improve sugarcane productivity a legume rotation break crop is recommended at the end of the cropping or ratoon cycle to reduce detrimental biota and restore soil fertility. s have proved to be the best legume available to use in terms of both dry matter production and nitrogen input. Very little else changes in the farming system except cane replanting is delayed by 6 months. Adoption of soybean first occurred on the NSW North Coast and more recently on the Southern Qld coast. Research has also clearly shown that in high rainfall environments it is best to leave plant residues on the soil surface that soil incorporate to maximise nitrogen carry-over. Sugarcane yield improvement has ranged between 15-25% in trials. c) Preferred Crop Establishment The adoption of no till and controlled traffic has improved cane profitability and reduced soil compaction caused by green cane harvesting. s can be directly sown into sugarcane stubble which is subsequently removed by herbicides. Leading growers spray out the old cane crop, use minimum cultivation to develop wheel tracks and then direct plant two or three rows of soybeans to one side of the old stool rows. Usually 1.8m beds are formed. Grass and any volunteer cane control is achieved using an initial spray of a pre-emergent herbicide and a post-emergent grass selective herbicide. Alternatively low rates of a knockdown herbicide are applied with a hooded sprayer. Similar methods to establish sugarcane are then used, although light cultivations take place to prepare seedbeds. d) Problems Encountered The monoculture of sugarcane has led to pesticide residues (OC) and heavy metal accumulation (cadmium) putting the alternative legume peanuts at risk. The wetter tropical north Queensland coast (north of Ingham) has proven more difficult to grow soybeans for grain. There is a lack of specialised harvesting equipment and crop management experience in soybeans. There is no focused R&D program on soybeans. 2 SUBTROPICAL BEEF a) Background There is an increasing number of beef producers on the NSW north coast adopting the Beef n Beans scheme and integrating soybeans into their overall farming system. Beef n Beans is a pasture improvement program that utilises no-till soybeans. The concept is not a new one and some innovators have had it in place for the last twenty years with very successful results. Beef n Beans provides an opportunity for beef producers to increase on-farm income and diversification as well as developing a sustainable crop production system. Recent expansion has occurred within the Grafton, Kempsey and Wauchope areas on the NSW north coast. b) Farming System Rotation s are the engine-room in the Beef n Beans program. They are no-tilled into run down or unimproved pasture (mostly on soils with low fertility levels) as part of a pasture improvement program. Due to the high rainfall of the region and the opportunity to double crop, the soybean crop is followed by either a forage crop (ryegrass, oats) or a grain crop (barley or triticale) during the cool season. These can be aerially sown into the soybean crop prior to harvesting or direct drilled after harvest. This program is repeated for a period of 2-3 years and then in the final year returned to an improved pasture mix. The final pasture mix may include setaria, Rhodes grass, kikuyu,

3 white clover, lotus or other long term pasture species. The cropping phase is repeated when the pasture becomes rundown and requires revamping, usually after 5-6 years. All fertiliser, usually phosphorus and potassium, is applied during the soybean cropping phase, which means the return on investment is rapid. c) Preferred Crop Establishment Many of the farms undertaking this program are situated on undulating country and the application of direct drill technology allows cropping to take place in a sustainable manner. With ploughing, this country would be prone to erosion and nutrient decline. Using the Beef n Beans program this scenario is avoided. The no-till technology helps to improve/maintain soil structure. Leading growers will establish a pioneer crop, such as oats, in the winter prior to the first soybean crop. This crop as well as all subsequent crops in the rotation will be no-tilled using mostly coulter/tyne combine planters (sometimes triple disc) with narrow rows, mm apart. Some of the winter crops and pasture mixture will be dropped by aircraft into a senescing soybean crop. At no stage is the ground fully cultivated. d) Problems Encountered Whilst the Beef n Beans scheme has been utilised very successfully for increased profits in these areas of Australia for a long time, the level of adoption has been affected by a number of factors: Low prices for soybean grain and high prices for cattle have a large affect on the new areas under Beef n Beans Cropping skill levels of traditional cattle producers can dampen the enthusiasm of some to commence a Beef n Beans program. However, good advisory services and a large core of experienced soybean growers in the neighbourhood can assist this situation greatly. In newer areas the lack of availability of suitable no-till planting equipment for contract work. 3 IRRIGATED MURRUMBIDGEE a) Background The Murrumbidgee Irrigation Area (MIA) is situated in south west of New South Wales. The Irrigation water is supplied via the Murrumbidgee River and a series of large reservoirs. The main farming enterprise of the MIA has been rice-based farming systems with up to 50,000 hectares been grown in one season. In the past, continuous rice cropping, and rice pasture or winter cereal (followed by a fallow period) were the main rotations used by broad acre irrigators. However in recent times with irrigation water restrictions and thus the effects on price of water/mega-litre, opportunities have arisen for other shorter growing season summer crops such as soybeans. s have not only proved to be a very profitable crop, it has also proved to be complementary to rice and all other winter cropping rotations. has helped break disease cycles, improve soil structure and fertility, reduce weed seed-banks, and improve total water use efficiencies. b) Farming System Rotation Rice is grown in flooded bays following the land contours, where as soybeans (and other summer crops) are best grown on raised beds down the slope (across the contour). This allows rapid drainage after irrigation of excess water, and reduces the detrimental effects of water-logging. Paddocks are usually land formed to an ideal slope factor before summer cropping. Raised beds are generally 1-2 m (depending soil lateral water movement abilities or termed subbing ). Once established, these beds are left permanently for cropping until rice is regrown (on contour layout).

4 s are no-tilled into raised beds, generally 2 or 4 plant rows/bed depending on bed width and soil subbing ability. Following the soybean crop, a winter cereal is again no-tilled into the soybean stubble/ residue. No-till enables the crop to be sown on-time and the paddock cropped 52 weeks a year. Double cropping continues for 2-3 years. Farming implements and equipment size is generally 6 or 8 rows. Implements are generally all the same size for ease of operation and to enable control traffic or tram-lining. Tractors and harvesters are fitted with narrow row-crop tyres to reduce furrow and bed shoulder compaction. ers are fitted with open fronts, ideally flexi-fronts to follow the land contours and prevent yield lose and soil contamination of seed. c) Preferred Crop Establishment s are ideally direct drilled into pre-watered raised beds. Disc-openers are currently the best available cultivating tool for handling large quantities of crop residues and also providing minimal to zero soil disturbance. Either 2 or 4 plant rows per bed depending upon soil subbing abilities. Row-crop tractors for sowing are used by leading farmers to reduce compaction. Volunteer cereals are controlled with lowrate Glyphosate application at post-sowing pre-emergence. Later emerging weeds can be controlled with a range of post-emergent selective herbicides can be applied throughout the entire season with ground coupes or by plane if conditions are unsuitable. commences early April, followed directly by no-tilling planting of winter cereals. d) Few Problems Encountered No-till has improved soybean establishment and suppressed weeds through minimal soil disturbance and residue cover. If cereal stubbles are heavy there is a decreased ability to inter-row cultivate and straw will lodge in furrows and significantly reduce water flow. A cool burn is utilised or straw is baled.

5 Table 1: Three Farming Systems utilising s A. Tropical Coastal Sugarcane Fallow Legume System Years old ratoon crop (Apr) Ratoon Sugar July (Nov) Cane Cane 1 st Ratoon 2 nd Ratoon old Ratoon B. Coastal Beef Inclusion Before Pasture Years Improved Pasture Ryegrass Aerial (Apr) July Winter Oats + N Ryegrass Aerial (Apr) C. Irrigated Riverina Double Crop Years Fallow/rice Cereal Cereal (Apr) (April) (Apr) Fallow/rice July Cereal Cereal

6 References Bell, M.J., Garside, A.L., Cunningham, G., Halpin, N., Berthelsen, J.E. and Richards, C.L. (1998). Grain Legumes in Sugarcane Farming Systems. Proc.Aust. Soc. Sugarcane Technol., 20: Garside, A.L and Bell, M.J. (2001). Fallow Legumes in the Australian Sugar Industry: Review of Recent Research Findings and Implications for the Sugarcane Cropping System. Proc Aust. Soc. Sugarcane Technol., 23: Nobile, A.D and Garside, A.L. (2000). Influence of Residue Management on Nitrogen Mineralisation and Leaching and Soil PH in a Wet Tropical Environment. Proc. Soc. Sugarcane Technol., 22: A.W. Wood. (1985). Soil Degradation and Management under Intensive Sugarcane Cultivation in North Queensland. Soil Use and Management, 1: Bell, M.J, Halpin, N.V., Garside, A.L., Stirling, G.R., Moody, P.W. and Robtham, B.J. (2004). Evaluating combinations of Fallow Management, controlled traffic and tillage options in protype sugarcane farming systems at Bundaberg. Submitted, Aust. Soc. Sugarcane Tecnol. Pankhurst, C.E., Magarey, R.C., Stirling, G.R, Blair, B.L., Bell, M.J. and Garside, A.L. (2003). Soil and Tillage Research, 72: Wallis, D. Northern Growers point the way to sustainable, more profitable farm systems, BSES Bulletin, Spring 03. Morley, M. and Desborough, P.J. (1998). Beef n Beans Integrating soybeans and pasture improvement. Proc. Tenth Aust. Conf., Brisbane, Sept. 1998, Production of Quality Rice in South Eastern Australia. Chapter 2 - Rice in the Irrigated Environment.(2002). Rural Industries Research & Development Corporation. Colton, R.T. and Rose, I.A. (2000). The Australian Industry-Past, Present and Future. 11th Australia Conference Proceedings.