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 7639 IREC Farmers' Newsletter No. 195 ­ – Rice R&D 2016 are inherently slow at a time when farm labour is directed to establishing winter crops; and fields can be difficult to traffic with heavy machinery due to wet ground. Stubble incorporation is rarely achieved in a single working and the resultant soil surface is usually left in a rough state that will require subsequent grading. PTO-driven disc ploughs Powered discs (i.e. driven by the tractor PTO to give a positive drive relative to ground speed) are used commercially in many parts of Asia to incorporate stubbles between rice crops. Indian researchers reported on the design and performance optimisation of PTO-driven discs when incorporating stubbles: l  increasing forward speeds and decreasing depth of tillage reduced fuel consumption from 4.4 to 2.9 L/ha. l  increasing forward speed and increasing depth of tillage increased the percentage of stubble inverted from 86 to 97%. In early 2015, Agropraisals imported two PTO-driven linkage disc ploughs to determine if they would offer improved incorporation of rice stubble immediately after harvest, as an alternative to burning. The experience with this equipment proved disappointing as a consistent pattern of disc blockage occurred at all sites where testing occurred. Variations in PTO speed, forward speed or operational depth did not appear to influence the propensity of the plough to block with straw and mud. An exception to this failure was when operating the equipment in a fully inundated field where the plough did not block; however the tractor required steel narrow track wheels to avoid excessive rolling resistance and bogging. By June 2015 it was concluded that incorporation of freshly harvested rice stubbles into moist soil was both impractical and undesirable, given the rough surface that resulted required subsequent levelling. Broadcast seeding Whilst testing the PTO-driven plough in 2015, seed for a range of forage legume species was broadcast onto cultivated (stubble incorporated) and undisturbed (stubble standing) plots. Intriguingly, it was noted that establishment of the legumes was improved where the stubble was retained and the ground left undisturbed. In what proved to be a relatively dry autumn, the retained moisture beneath the rice stubble, enhanced germination and establishment of five different legumes (subterranean, balansa, Persian and arrowleaf clovers and common vetch). Seeding subterranean clover into rice stubbles using aircraft or drop seeders has been practiced successfully since the 1950s. The technique largely lapsed as livestock returns plummeted during the late 1980s. Forage legume options have broadened since this period, thus it is timely now to re-examine the suitability and productivity of forage legumes given improved returns for livestock enterprises relative to grain production. How do forage legumes perform when sown into standing rice stubbles? Early seeding around rice harvest produced some spectacular results in the 2015 season. Demonstrations and replicated trials at Old Coree, Tongaboo and Cobram in 2015 compared the establishment and growth of five forage legumes (subterranean clover, balansa clover, Persian clover, arrowleaf clover and vetch). Early spring growth was outstanding with Rasina vetch and Shaftal Persian clover. Late spring rain produced an additional flush of growth in Viper balansa clover and arrowleaf clover. Quadrat cuts from demonstration plots at Old Coree in early September produced fresh weight equivalents of between 21 and 29 t/ha of silage at 15–19% protein. Subterranean clover performance was poor and insufficient to harvest, whilst vetch, Table 1. Ground cover (%) ratings, on two dates, of five forage legumes broadcast seeded into rice stubble, Cobram, 2015 Legume Seeding rate Ground cover rating* (kg/ha) 23 Aug 15 9 Oct 15 Fallow 0 c 0 d Subterranean clover 10 8 c 45 c Balansa clover (Viper) 5 6 c 48 bc Persian clover (Shaftal) 10 30 b 65 b Arrowleaf clover 5 9 c 51 bc Vetch (Rasina) 30 57 a 90 a LSD (P=.05) 12.6 18.3 Standard Deviation 9.6 13.9 CV 42% 28% * Treatment means with the same letter do not differ significantly l Trafficability is limited by the wettest spot in the field. l Vetch established by broadcast seeding after rice harvest, May 2015. l Blocking of PTO-driven plough after cultivating a rice stubble,Jerilderie,April 2015. l Vetch broadcast seeded after harvest into a rice stubble, August 2015.