Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 7640 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 arrowleaf, balansa and Persian clovers all developed substantial and productive swards. Harvest management Crop harvesting techniques produce dramatic contrasts in the density and architecture of rice stubbles. Conventional open front headers leave 20–60 cm of straw standing (less in a lodged crop), with the balance threshed and spread over a lesser width behind the machine. This can result in straw loads of in excess of 40 t/ha in header trails, proving a major challenge to the growth of any plant that may attempt to establish in this zone. Straw spreaders at the back of the header can alleviate this concentration of rice straw. Stripper fronts will leave straw intact to a height of 80–110 cm with a lesser load of flag leaf, stems and empty florets in the header trails. Straw loads across the field tend to be more even, however shading of the ground is increased due to the increased height of standing stubble. Traffic lines will of course be flattened by the passage of wheels. Some Asian-built rice harvesters are fitted with a second knife in order to cut stubbles closer to the ground and reduce straw length for ease of incorporation. Leaving rice stubble undisturbed, then either burning it or incorporating it dry in late spring represents a major lost opportunity for crop production through the winter-growing season. Thus establishing forage legumes for livestock production or as a green manure crop prior to re-cropping rice is desirable and potentially profitable. Wet or dry seasons? In dry autumns rice stubbles offer moist soils and protection from desiccating winds for newly planted forage legumes, and other crops. In wet autumns, rice stubbles are commonly severely waterlogged and hostile to the establishment and productivity of most forage legumes. How often do wet autumns deleteriously affect these crops? Deniliquin has over 150 years of complete rainfall records. Table 2 shows that averaged over the total record, less than one in four autumns is likely to become wet enough to challenge forage legumes with waterlogging; even less frequent (less than one in seven years) when focusing on the last 50 years of data. Most growers would take a punt on these odds to grow a successful forage crop. We do not understand the relative tolerance of many forage legumes to waterlogging, so observations in the 2016–17 season across our demonstrations sites should improve our understanding of this issue. When establishing crops after rice, one has little information with which to confidently predict if the winter season will be wet or dry. In wet years crops may become waterlogged and a complete loss. Field layout, slope and drainage can be considered and steps taken to improve drainage to prevent prolonged waterlogging by connecting drains and toe furrows. Inoculation and sowing Inoculants ought to be applied to forage legume seeds, immediately prior to broadcasting to maximise the potential for nitrogen fixation by the crop. Experience with irrigated pastures shows that optimum growth of annual legumes occurs when the field is watered in February to commence germination. This timing coincides with draining of rice, thus it follows that aerial broadcasting of forage legumes just after water has been removed is likely to result in the best potential production. Costs and techniques Opportunities for ground-based seeding exist using air booms mounted on tractors, however wet areas in fields are likely to prove challenging. Alternatively seed could be distributed beneath the auger table or stripper front of a header using a small air seeded mounted on the harvester. Marking of the field is assured using this method. Systems for achieving this technique were marketed in France during the 1990s using a drive wheel operating on the top of the header main tyres. Contemporary systems could obtain a signal from the ground radar used to measure harvester speed. Aerial seeding can be a cost effective means of establishing forage legumes after rice. Seeding can occur irrespective of ground conditions (wet or dry), is rapid and usually facilitated with an agricultural aviation contractor for under $30/ha. Adding a seed cost of perhaps $50 leaves change out of $100/ha; a price that pales into insignificance compared with the multiple thousands required to grow summer crops such as rice, cotton on maize. A business case for legumes after rice? One cannot determine if a business case exists for growing forage legumes without an understanding of the yield and quality of the forage produced, coupled with knowledge of the value of this production to an enterprise. Will the fodder be grazed (and if so when) or conserved as hay or silage? Forage legumes have the capacity to fix nitrogen for subsequent crops. How much nitrogen fixed will be dependent upon the success of inoculation and the manner in which the legumes are used (grazed versus silage versus hay versus incorporation as green manure). Typical inputs of fixed Table 2. Summary of autumn rain events that could have resulted in waterlogging of a rice stubble at Deniliquin, NSW. Rainfall recording period Number of years with ‘Wet’ autumns as more than 75 mm rain a percentage of April–June (‘wet' autumns) total years 1858–2014 34 22% 1966–2016 6 12% l Straw spreaders can reduce excessive concentration of straw. l Prolonged waterlogging in wet seasons will kill many forage legume species. l Shaftal Persian clover broadcast seeded after rice harvest, August 2015.