The genus Dorycnium L. consists of a number of species of perennial leguminous shrubs known to be relatively drought tolerant. Low rainfall areas (i.e <600 mm annually) of Australia under agricultural use are subject to periods of feed shortage during summer and autumn, and hence animal production is limited at this time. Dorycnium spp. have been identified as having the potential to be integrated into Australian grazing systems as a source of forage when little or no other feed is available. This project was established to further investigate a number of key issues related to the agronomic and forage characteristics of this potentially important genus. Research was undertaken into Dorycnium spp. to examine three important factors associated with the evaluation of a legume, seed germination characteristics, the nutritional value of the forage, and rhizobial associations. Dorycnium hirsutum Ser. accessions TAS1002 and TAS2001 were subjected to a range of germination experiments examining the level of pod maturity, harvest season, and the effect of pre-germination treatments. The seed coat of D. hirsutum was found to influence germination behaviour, with the use of pre-germination scarification treatments improving germination behaviour by increasing the percentage germination (PG) and lowering the mean time to complete germination (MTG) and percentage hard seed. Mechanical scarification of TAS2001 for 20 seconds was found to increase (P<0.05) PG from 86 to 96 %, lower the MTG from 6.0 to 2.7 days, and reduce the percentage hard from 13.6 to 1.9 % in relation to untreated seed. Mechanical and chemical scarification techniques were found to be the most effective in promoting rapid and uniform germination, were simple to apply and were repeatable. In general, inherent differences in seed lot germination characteristics were believed to be associated with the influence of environmental factors and the natural characteristics of selected accessions with indeterminate flowering. Established plots of D. rectum Ser., D. hirsutum and D. pentaphyllum Scop. were sampled along with an area of lucerne (Medicago sativa L.) on a regular basis throughout the spring/summer period of 2001/2002. Samples were analysed using near infrared reflectance spectroscopy (NIRS) and wet chemistry for crude protein (CP), neutral detergent fibre (NDF) and dry matter digestibility (DMD) and metabolisable energy (ME). Over the course of the sampling period forage of Dorycnium spp. generally displayed decreases in CP, ME, DMD and increases in NDF. Typical CP values ranged from 4 - 18 % of dry matter (DM), NDF 21 - 72 % of DM, DMD 32 - 75 %, and ME 4.1 - 11.0 MJ/Kg/DM. The nutritive value of Dorycnium spp. forage appeared to be influenced by environmental and developmental characteristics, with the growth stage identified as a useful tool for predicting forage quality. Although Dorycnium plants were of lower forage value than lucerne, their forage can provide livestock with an important source of nutrition in areas of low rainfall and during periods where there are feed gaps. Experimental plots of Dorycnium spp. at three Tasmanian sites were sampled every six weeks throughout the spring/summer period of 2002/2003 and analysed using a modified butanol-HCl method for condensed tannins (CT). The CT content of D. hirsutum was found to fluctuate from 3.2 to 16.6 % of the DM. Dorycnium rectum and D. pentaphyllum were found to contain CT levels of at least 7.7 and 6.8 % of DM respectively during the sampling period. The CT levels observed were considered to be high in general, with only D. hirsutum containing levels that may be considered to be low and possibly beneficial at certain stages of development. Increases in CT levels were associated with the initiation of flowering, and interactions between the environment and species were observed, although no common factor was identified as influencing CT levels. A glasshouse experiment was undertaken to assess the nitrogen fixing ability of the commercial Lotus corniculatus L. inoculant SU343 with Dorycnium spp. against a range of alternative inoculants. The host/rhizobia interactions of Dorycnium spp. along with six important pasture legumes and a range of inoculants was assessed. Strains WSM1284, WSM2323 and WSM2338, along with SU343 were found to be suitable inoculants for Dorycnium spp. examined. However, negative interactions between these inoculants and important pasture legumes were identified. Inoculant strains, WSM1284, WSM2323, WSM2338 and SU343 were selected to undergo evaluation under Tasmanian field conditions with D. hirsutum and D. rectum. In the field all strains were found to fix adequate amounts of atmospheric nitrogen. Inoculant SU343 was confirmed to be a suitable inoculant for D. rectum in terms of performance and commercial viability, however, WSM2338 and WSM1284 were found to be equally suitable. The inoculation of Dorycnium hirsutum with the Tasmanian isolate WSM2323, was found to be a significantly (P<0.05) superior strain to SU343 in terms of nitrogen fixation. The inoculation of D. hirsutum did not affect (P>0.05) plant DM production in the field. The ability of the inoculants to compete with a background population of root nodule bacteria was found to be of concern, and may have serious implications for the long-term performance from a single inoculation event. It was proposed that a combination of rhizobial strains may be more effective as a commercial inoculant rather than relying on the single L. corniculatus inoculant SU343.

No description available.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

Population dynamics of plants is the study of the recruitment and longevity of plants. Of the many tropical pasture legumes now in use, only Siratro (Macroptilium) is understood in simple mixtures. Walker (1980) found that rapid changes occurred in the populations of some tropical perennial legumes in response to grazing by cattle. The study investigated initial effects of cattle grazing on the dynamics of five perennial, tropical legumes in association with two contrasting grass species.

The prospects of sustainable crop production technologies in East Timor were discerned with relevant case studies and experimental data. An overview of the agricultural development in East Timor with particular emphasis on the traditional farming and cropping systems was presented complemented by the discussion on the aspects of agricultural mechanization and technological change and their socioeconomic ramifications on food security. Empirical data from tillage trials, established both in East Timor and New Zealand, were gathered and discussed in the quest for a better understanding of tillage effects on soil structure and crop production environment. The agro-climatic zones of East Timor provide a well-defined set of ecological boundaries upon which further collaborative research work can be developed. Given land resources as one of the major capital investments in agriculture development, the drive towards improvement and technical change in agriculture should be directed in a balanced combination, whenever appropriate, between technologies of land-saving (hybrid seeds, irrigation, and drainage) or labour-saving (mechanization, herbicides, varieties and cropping techniques) characteristics. Moreover, the justification for acquiring an improved technology for traditional farmers, to some extent, needs to conform to the features of their subsistence mode of farming. The emphasis in technology dissemination, therefore, will have to shift from communication to education. Experimental results of this study on the effects of tillage, and no-tillage in Particular as a form of conservation tillage, on the edaphic changes affecting cropping environment generally concur with the findings known in the literature. Organic carbon levels are generally restored with cropping in East Timor. In addition, soil bulk density and crop grain and biomass yield were not affected by tillage treatments. Soil compaction was significantly affected by tillage as shown by data from the Palmerston North experiment. Soil aggregate stability in the 0-10 cm topsoil was similar under all the tillage treatments. Manual tillage (MT) had the greatest number of soil aggregates on sieve after a 30-minute wet-sieving (68.3%) followed by no-tillage (NT) (65.1), permanent pasture (PP) (62.6) and conventional tillage (CT) (56.5). Similarly, the top 0-10 cm soil under MT had significantly larger macroporosity (16.4%) than CT (9.23), NT (11.5), and PP (10.6). MT and CT significantly reduced the total C whereas N levels were significantly decreased by tillage (CT, MT and NT) compared to permanent pasture at the top 0-10 cm soil layer. Barley grain and biomass were unaffected by tillage whereas potato tuber yield and biomass were significantly less under no-tillage. Conventional tillage significantly increased water runoff but produced less leachate compared to no-till and permanent pasture. Total soil sediment loss was significantly lower under PP (95.8 kg/ha) and NT (132.9) compared to CT (3556.7) and MT (4652.2). pH of water runoff was significantly reduced under tillage treatments compared to that from permanent pasture whereas nitrogen losses were unaffected. There are at least four major public policy components that will play vital roles in the development of sustainable crop production technologies in East Timor: (i) Agricultural research and development (ii) Agricultural extension (iii) International and regional networking (iv) Shift of policy focus. The policy approach needs to be decentralized and broad-based and conservation agriculture should be promoted as opposed to conventional production agriculture. Three major areas for the future research agenda include: (i) Integrated Farming Systems (ii) Soil tillage and erosion (iii) Applied science and technology. The last component may cover disciplines such as: food policy analysis, farm machinery selection and testing, soil testing and mapping, land evaluation and GIs, bio-energy technologies, improved local seed varieties, adaptive fodder crops for improved grazing and pasture management, appropriate agro-forestry and soil and water conservation technologies and cash crop initiatives.

No description available.

No description available.

No description available.

The effect of continuous monoculture of sorghum, mungbean, oats, greenpanic and luceren on the nitrogen status of a brown clay soil from Narayen, South East Queensland was studied using biological and chemical methods. the soil nitrogen status was estimated by using indices of nitrogen availability i.e. waterlogged incubation method as the biological method and 2 M KCL, phosphate-borate buffer and 0.01 M CaCl_2 as rapid chemical methods. Total soil nitrogen and organic carbon were also included as estimates of soil nitrogen status. The results obtained by the waterlogged (WL) method were used to evaluate the results obtained by the three rapid chemical methods. The results show that of the three rapid chemical methods 2 M KCL was the most closely correlated with the waterlogged incubation method. Total N and organic C were also highly correlated with the WL method and they may have value as indices of nitrogen availability. The available N, total N and organic C contents in the 0-5 cm and 5-15cm layer soils were consistently higher under greenpanic and lucerne than for the annual crop treatments. The available N contents as determined by the WL method in the 0-5 cm and 5-15 cm soil layers under greenpanic and lucerne ranged from 75.6 to 126.5 ug N/g soil and 53.2 to 106.7 ug N/g soil, respectively, whereas the values under the annual crop treatments ranged from 13.2 to 75.3 ug N/g soil and 25.6 to 66.1 ug N/g soil, respectively. The total N contents in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 0.29 to 0.38 % and 0.20 to 0.33 %, respectively, whereas the values under the annual crop treatments ranged from 0.17 to 0.31 % and 0.17 to 0.25 %, respectively. The availability of the total N as indicated by the available N as a percentage of the total N in the 0-5 cm and 5-15 cm layer soils under the greenpanic and lucerne ranged from 2.6 to 4.0 % and 2.1 to 3.2 %, respectively, whereas the values under the annual crop treatments ranged from 0.8 to 3.8 % and 1.5 to 2.4 %, respectively. In addition the organic C contents in the 0.5 cm and 5-15 cm layer soils under the greenpanic and lucerne range from 2.4 to 4.0 % and 2.0 to 3.5 %, respectively, whereas the values under the annual crop treatments ranged from 1.4 to 3.3 % and 1.7 to 2.7 %, respectively.

The study undertaken was carried out in the montane tussock grassland region which in the South Island comprises some six million acres. Field trials were established at Mt Somers, Mid Canterbury. This study attempts to elucidate some of the factors connected with the sulphur nutrition of grasses. For the particular trial area it was hoped to determine four key aspects ; 1. Whether the response of the grass to nitrogen is governed by the sulphur level available. 2. A determination of what level of nitrogen was likely to be provided by clover fixation and transferred to the grass component under improved grassland conditions in the area. 3. What the optimum level of sulphur for the association is, allowing adequate sulphur for maximum possible nitrogen fixation as well as for utilization by the grass of the nitrogen transferred. 4. The effects of nitrogen and sulphur on plant chemical composition and any possible relationships between plant and soil as infuenced by these factors. Following a review of literature, a summary of experimental work is presented, with results, discussion and conclusions.