Contrasting soil microbial abundance and diversity on and between pasture drill rows in the third growing season after sowing

Changed spatial configurations at sowing have been investigated as a strategy to minimize interspecific competition and improve the establishment and persistence of multi-species plantings in pastures, but the impact of this practice on the soil microbiome has received almost no previous research attention. Differences in populations of bacteria and fungi in the surface 10 cm of soil in the third year following pasture establishment were quantified using quantitative polymerase chain reaction and terminal restriction fragment length polymorphism methods. Populations were compared on, and between, drill rows sown to either the perennial grass phalaris (Phalaris aquatica L.), perennial legume lucerne (alfalfa; Medicago sativa L.) or the annual legume subterranean clover (Trifolium subterraneum L.). Results showed that soil microbial abundance and diversity were related to plant distribution across the field at the time of sampling and to soil chemical parameters including total carbon (C), mineral nitrogen (N), pH, and available phosphorus (P), potassium (K) and sulfur (S). Despite the 27-month lag since sowing, pasture species remained concentrated around the original drill row with very little colonization of the inter-row area. The abundance and diversity of bacterial and fungal populations were consistently greater under drill rows associated with higher total C concentrations in the surface soil compared with the inter-row areas. Our results showed that the pH and available nutrients were similar between the subterranean clover drill row and the inter-row, suggesting that soil microbial populations were not impacted directly by these soil fertility parameters, but rather were related to the presence or absence of plants. The abundance of bacteria and fungi were numerically lower under phalaris rows compared to rows sown to legumes. The richness and diversity of fungal populations were lowest between rows where lucerne was planted. Possible explanations for this observation include a lower C:N ratio of lucerne roots and/or a lack of fibrous roots at the soil surface compared to the other species, illustrating the influence of contrasting plant types on the soil microflora community. This study highlights the enduring legacy of the drill row on the spatial distribution of plants well into the pasture phase of a cropping rotation and discusses the opportunity to enhance the microbiome of cropping soils on a large scale during the pasture phase by increasing plant distribution across the landscape

Cytoplasmic Skp2 Expression Is Increased in Human Melanoma and Correlated with Patient Survival

BACKGROUND: S-phase kinase protein 2 (Skp2), an F-box protein, targets cell cycle regulators via ubiquitin-mediated degradation. Skp2 is frequently overexpressed in a variety of cancers and associated with patient survival. In melanoma, however, the prognostic significance of subcellular Skp2 expression remains controversial. METHODS: To investigate the role of Skp2 in melanoma development, we constructed tissue microarrays and examined Skp2 expression in melanocytic lesions at different stages, including 30 normal nevi, 61 dysplastic nevi, 290 primary melanomas and 146 metastatic melanomas. The TMA was assessed for cytoplasmic and nuclear Skp2 expression by immunohistochemistry. The Kaplan-Meier method was used to evaluate the patient survival. The univariate and multivariate Cox regression models were performed to estimate the hazard ratios (HR) at five-year follow-up. RESULTS: Cytoplasmic but not nuclear Skp2 expression was gradually increased from normal nevi, dysplastic nevi, primary melanomas to metastatic melanomas. Cytoplasmic Skp2 expression correlated with AJCC stages (I vs II-IV, P<0.001), tumor thickness (≤2.00 vs >2.00 mm, P<0.001) and ulceration (P = 0.005). Increased cytoplasmic Skp2 expression was associated with a poor five-year disease-specific survival of patients with primary melanoma (P = 0.018) but not metastatic melanoma (P>0.05). CONCLUSION: This study demonstrates that cytoplasmic Skp2 plays an important role in melanoma pathogenesis and its expression correlates with patient survival. Our data indicate that cytoplasmic Skp2 may serve as a potential biomarker for melanoma progression and a therapeutic target for this disease

Benefits of conservation agriculture on soil and water conservation and its progress in China

Conservation agriculture has been practised for three decades and has been spread widely. There are many nomenclatures surrounding conservation agriculture and differ to each other lightly. Conservation agriculture (CA) is a system approach to soil and water conservation, high crop productivity and profitability, in one word, it is a system approach to sustainable agriculture. Yet, because conservation agriculture is a knowledge-intensive and a complex system to learn and implement, and also because of traditions of intensive cultivation, adoption rates have been low, since to date, only about seven percent of the world's arable and permanent cropland area is farmed under conservation agriculture. The practice and wider extention of conservation agriculture thus requires a deeper understanding of its ecological underpinnings in order to manage its various elements for sustainable intensification, where the aim is to conserve soil and water and improve sustainability over the long term. This paper described terms related to conservation agriculture, presented the effects of conservation agriculture on soil and water conservation, crop productivity, progress and adoption of CA worldwide, emphasized obstacles and possible ways to increase CA adoption to accelerate sustainable development of China agriculture

Long-term liming changes pasture mineral profile

Abstract There is limited information on changes of pasture mineral concentrations over the long-term in response to liming. A long-term field experiment was conducted to assess the influence of lime application on (a) changes in pasture mineral composition over time; and (b) key pasture mineral concentrations and ratios important to animal health. Perennial and annual pastures with or without lime application were sampled annually over 12 years and analysed for macro- and micro-minerals. Mineral ratios and indices were calculated to assess the potential impact on animal health. Liming increased the concentrations of calcium, sodium and silicon, but decreased the concentrations of micro-nutrients including copper, zinc and manganese. The same trend was found in both annual and perennial pastures although there were some fluctuations between years. Liming increased the calcium:phosphorus ratio and the dietary cation–anion difference but reduced the tetany index on both annual and perennial pastures. These findings suggest a potential benefit to improve animal health outcomes for some disorders on the limed pastures. However, the reduced concentrations of some trace elements following liming potentially decreases antioxidant capacity and requires further research

Financial risk analysis of lucerne pasture establishment: Under-sowing vs Direct sowing

Over the past 80 years an unresolved issue in rain-fed crop-pasture rotations by scientists and farm advisors has been whether to recommend sowing a perennial pasture either alone or with a cereal cover crop. Researchers and agronomists have typically advocated sowing pastures alone to improve pasture productivity, but a large proportion of farmers continue to sow pastures under a cover crop suggesting a perceived financial advantage with the latter establishment method. Whether there is a real financial benefit of establishing pastures under a cover crop presents a practical Farm Financial Risk problem. Our study is based on four years of field experiment results (2008 to 2012) along a 200 km transect running north and south of Wagga Wagga, New South Wales, Australia. Analysis of these results with information on local weather and price variations using “The Intensive Farming (IF) model” (Hutchings et al, 2016), suggests the following: (1) sowing the pasture alone is a more reliable method of establishing lucerne (Medicago sativa L.) pasture than sowing under a cover-crop; and (2) the additional costs of sowing a lucerne pasture alone are met in the majority of years by its increased productivity compared with pastures sown with cover-crops. Comparing median decadal cash balance values for pastures with stocking rates of 10, 15 and 20 dse/ha, our results show an advantage with direct-sowing for farms with high equity. Farms with low equity may not be helped by agronomic improvements, but find it best to focus on reducing debts

A framework for modelling financial risk in Southern Australia: the intensive farming (IF) model

Australian farmers operate in a financial environment, which is many times more variable than their competitors in the developed world, yet make decisions using static systems which ignore risk. This paper examines the use of dynamic modelling, using the Intensive Farming (IF) model, which can quantify and compare the physical and financial risks associated with various management scenarios on dryland farms in south-eastern Australia. In this paper the Intensive Farming (IF) model is used to simulate the whole-farm, 10-year cashflow for a typical 1,000 ha farm in the region, with a farming system based on dryland crops and breeding Merino sheep. It shows that conventional budgets, based on annual average yields and prices at 80% equity, produce outcomes with similar median values to the more complex dynamic budgets, and predict a positive margin for average years. In contrast dynamic analysis shows that the 10-year cash margins are 38% more likely to be negative than positive. Such a farming system was therefore unlikely to be viable in the long term. Dynamic budgeting also shows that the cropping enterprise is three times more variable (CV 50%) than the sheep enterprise (CV 18%). The effect of including risk reduces the crop gross margin by 14% and the sheep gross margin by 7% compared to static budgeting, which is based on annual average rainfall and prices. Further analysis showed that whole-farm cash margins are very sensitive to debt, with the cost of a 20% increase in debt reducing the 10-year cash margin by 19%. Within-year tactical adjustments had little significant effect on the long-term margin, because such adjustments are usually made in years of low income, where the marginal dollar effect was small. This paper concludes that conventional budgets could encourage sub-optimal, and even loss-making farming practices, and should be replaced with whole-farm, long-term, dynamic budgeting systems, which explicitly account for the natural variability of key inputs

Sowing configuration affects competition and persistence of lucerne (Medicago sativa) in mixed pasture swards

Spatial separation of species at sowing has been proposed as a means of managing interspecific competition in mixed swards. This study examined the effect of row configuration on persistence of lucerne (Medicago sativa L.) in pastures and pasture–cover crop mixtures at three sites in the Central West, and in pasture mixtures at three sites in the Riverina, New South Wales, Australia. Lucerne density, taproot diameter, groundcover, and spatial distribution relative to the original drill row were measured at all sites, and plant-available soil water and light interception during spring were assessed at some sites. Row configuration (alternate or mixed drill rows) did not affect lucerne persistence; however, where lucerne seed was concentrated in every third drill row, intraspecific competition led to increased lucerne mortality. This was estimated to occur at densities >28 plants/m drill row. A lucerne density of ~55 plants/m2 in every or alternate drill rows (at row spacings of 250 mm) would likely achieve maximum lucerne production in the semi-arid environments tested, subject to the chance event of favourable conditions in the period after sowing that would maintain that density (e.g. cumulative summer rainfall >100 mm and summer day degrees <2160°C in 2 years at Cowra). The presence of a cover crop in the establishment year reduced lucerne density by 39% compared with pasture only, regardless of row configuration. Changed row configuration did not reduce competition for light under a cover crop, but there was a small increase in available soil water of up to 4.9 mm in the 0–1.15 m depth, mainly during the first summer, where pasture was sown in alternate compared with mixed drill rows with a cover crop. Soil was drier in pasture-only treatments than those with a cover crop, attributable to increased lucerne density and lower levels of litter cover on the soil surface. Pasture species remained largely confined to the original drill row, especially in drier environments, highlighting the importance of narrower row spacings for pasture establishment. In addition, we determined a mathematical relationship between lucerne density and the non-destructive measure of basal frequency; this relationship could be applied in mature lucerne stands with densities ≤80 plants/m2