Economics of managing acid soils in dryland mixed cropping systems: comparing gross margins with whole-farm analysis derived using a business process model

A 12-year experiment designed to show the benefits of applying lime to acid soils when growing annual pasture, perennial pasture, and annual crops in rotations with annual or perennial pastures, provides the context for comparing methods of economic analysis. In this study enterprise gross margins are compared with whole-farm cumulative monthly cash flows derived using a business process model. The current study gave gross margins comparable with those of a recently published study based on the first 12 years of the same field experiment at Book Book near Wagga Wagga in southern NSW (Li et al., 2010). Both gross margin analyses indicated positive results for all treatments. However, because key fixed and capital cost items were not taken into account in the gross margin analysis the financial benefits of the treatments were overstated. In the whole-farm analysis, a full set of accounts (including fixed and capital costs) was developed for the experimental combinations of prime lamb and dryland cropping enterprises and used to generate a monthly cash flow sequence for each treatment over the 12-year term of the experiment. This full financial analysis, where all costs are included, showed all mixed treatments (cropping and grazing) accumulated unsustainable losses over the period of the trial. The grazing-only treatments generated positive cash lows over the 12 year period, but 2 accumulated high levels of debt in the initial years. None of these outcomes were predicted by gross margins, which were consistently positive for all treatments. This paper concludes that the analysis of trial results benefits from interpretation in the context of whole-farm analysis, verified by district experience. Relying on gross margin analysis alone would have supported loss-making outcomes in this trial. This conclusion has important ramifications for analysis of all systems trials.Agribusiness,

Subsoil Acidity Determines Survival of Lucerne on a Highly Acidic Soil

Lucerne (Medicago sativa) is one of most productive perennial species in southern Australia. However, productivity is severely restricted under acid soils (Irwin et al. 2001). Fenton et al. (1996) reported that lucerne performs poorly if soil pH was below 5 and exchangeable aluminium was over 5%. It is estimated that there are 24 m ha of acidic subsoil in southern Australia (Dolling et al. 2001). A long-term liming experiment, 1992 to 2010, aimed to ameliorate subsoil acidity via a vigorous liming program (Li et al. 2001). This paper reports survival of lucerne during the 3rd cycle of the experiment from 2004 to 2009

Lucerne for Acid Soils: A Field Evaluation of Early Generation Aluminium Tolerant Genotypes

The development of lucerne germplasm tolerant of acidic soil conditions has long been a research objective of international significance. Many initiatives have previously failed to produce genotypes with adequate improvement in tolerance to be deemed economically viable and as a consequence, still no cultivar of lucerne exists that has improved adaptation to acidic soils. An Australian research program spanning the previous decade sought to redress this issue by developing lucerne genotypes with significantly enhanced tolerance to aluminium (Al) toxicity. Using recurrent selection in hydroponic solution culture, populations selected comprised individuals which displayed enhanced seedling root growth following a pulse of Al toxic solution (Scott et al. 2008). A subsequent pot experiment showed that these populations exhibited up to 40% increase in seedling root length when grown in an acidic soil with high Al concentration, though there was a differential response observed between the elite populations (Hayes et al. 2011). The current study tested the hypothesis that lucerne establishment in the field would be higher in populations selected in high Al solution culture when grown in an acidic soil environment

Simulating collective behavior in the movement of immigrants by using a spatial prisoner’s dilemma with move option

The movement of immigrants is simulated by using a spatial Prisoner’s Dilemma (PD) with move option. We explore the effect of collective behavior in an evolutionary migrating dynamics. Simulation results show that immigrants adopting collective strategy perform better and thus gain higher survival rate than those not. This research suggests that the clustering of immigrants promotes cooperation

Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, \u3cem\u3eFrankliniella occidentalis\u3c/em\u3e

Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually

Development of Near-Isogenic Lines in a Parthenogenetically Reproduced Thrips Species, \u3cem\u3eFrankliniella occidentalis\u3c/em\u3e

Although near-isogenic lines (NILs) can standardize genetic backgrounds among individuals, it has never been applied in parthenogenetically reproduced animals. Here, through multiple rounds of backcrossing and spinosad screening, we generated spinosad resistant NILs in the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), with a haplo-diploid reproduction system. The resultant F. occidentalis NIL-R strain maintained a resistance ratio over 30,000-fold, which was comparable to its parental resistant strain, Spin-R. More importantly, F. occidentalis NIL-R shared 98.90% genetic similarity with its susceptible parental strain Ivf03. By developing this toolset, we are able to segregate individual resistance and facilitate the mechanistic study of insecticide resistances in phloem-feeding arthropods, a group of devastating pest species reproducing sexually as well as asexually

Pore structure characterization of Chang-7 tight sandstone using MICP combined with N2GA techniques and its geological control factors

Understanding the pore networks of unconventional tight reservoirs such as tight sandstones and shales is crucial for extracting oil/gas from such reservoirs. Mercury injection capillary pressure (MICP) and N(2) gas adsorption (N(2)GA) are performed to evaluate pore structure of Chang-7 tight sandstone. Thin section observation, scanning electron microscope, grain size analysis, mineral composition analysis, and porosity measurement are applied to investigate geological control factors of pore structure. Grain size is positively correlated with detrital mineral content and grain size standard deviation while negatively related to clay content. Detrital mineral content and grain size are positively correlated with porosity, pore throat radius and withdrawal efficiency and negatively related to capillary pressure and pore-to-throat size ratio; while interstitial material is negatively correlated with above mentioned factors. Well sorted sediments with high debris usually possess strong compaction resistance to preserve original pores. Although many inter-crystalline pores are produced in clay minerals, this type of pores is not the most important contributor to porosity. Besides this, pore shape determined by N(2)GA hysteresis loop is consistent with SEM observation on clay inter-crystalline pores while BJH pore volume is positively related with clay content, suggesting N(2)GA is suitable for describing clay inter-crystalline pores in tight sandstones

the Portuguese case

BACKGROUND: Portugal has one of the most severe HIV-1 epidemics in Western Europe. Two subtypes circulate in parallel since the beginning of the epidemic. Comparing their transmission patterns and its association with transmitted drug resistance (TDR) is important to pinpoint transmission hotspots and to develop evidence-based treatment guidelines. METHODS: Demographic, clinical and genomic data were collected from 3599 HIV-1 naive patients between 2001 and 2014. Sequences obtained from drug resistance testing were used for subtyping, TDR determination and transmission clusters (TC) analyses. RESULTS: In Portugal, transmission of subtype B was significantly associated with young males, while transmission of subtype G was associated with older heterosexuals. In Portuguese originated people, there was a decreasing trend both for prevalence of subtype G and for number of TCs in this subtype. The active TCs that were identified (i.e. clusters originated after 2008) were associated with subtype B-infected males residing in Lisbon. TDR was significantly different when comparing subtypes B (10.8% [9.5-12.2]) and G (7.6% [6.4-9.0]) (p = 0.001). DISCUSSION: TC analyses shows that, in Portugal, the subtype B epidemic is active and fueled by young male patients residing in Lisbon, while transmission of subtype G is decreasing. Despite similar treatment rates for both subtypes in Portugal, TDR is significantly different between subtypes.publishersversionpublishe