Towards a farmer-feasible soil health assessment that is globally applicable

Globally, agriculture has had a significant and often detrimental impact on soil. The continued capacity of soil to function as a living ecosystem that sustains microbes, plants, and animals (including humans), its metaphorical health, is of vital importance across geographic scales. Healthy soil underpins food production and ecosystem resilience against a changing climate. This paper focuses on assessing soil health, an area of increasing interest for farming communities, researchers, industry and policy-makers. Without accessible and reliable soil assessment, any management and interventions to improve soil health are likely to be sub-optimal. Here we explore available soil health assessments (SHAs) that may be feasible for farmers of varying income levels and suitable for broad geographic application. Whilst there is a range of existing approaches to SHA, we find that no one framework currently meets these broad aims. Firstly, reliance on expensive and logistically complex laboratory methods reduces viability and accessibility for many farmers. Secondly, lack of defined indicator baselines and associated thresholds or gradients for soil health prevents the assessment of soil measurements against achieving optima for a given set of local soil-climate conditions. Since soils vary greatly, these baselines and thresholds must be defined considering the local biogeographic context; it is inappropriate to simply transfer calibrated information between contexts. These shortcomings demand progress towards a feasible, globally applicable and context-relevant SHA framework. The most feasible SHAs we identified were developed locally in conjunction with farmers, who have been repeatedly found to assess the health of their soils accurately, often using relatively simple, observable indications. To progress, we propose assessment of which indicators add information to a SHA in local contexts, with a focus on sufficiency, to reduce data burden. Provision of a standardised protocol for measurement and sampling that considers the reliability and accuracy of different methods would also be extremely valuable. For greatest impact, future work should be taken forward through a cross-industry collaborative approach involving researchers, businesses, policy makers, and, above all, farmers, who are both experts and users.

Multimode dynamics and emergence of a characteristic length scale in a one-dimensional quantum system

We study the nonequilibrium dynamics of a coherently split one-dimensional Bose gas by measuring the full probability distribution functions of matter-wave interference. Observing the system on different length scales allows us to probe the dynamics of excitations on different energy scales, revealing two distinct length-scale-dependent regimes of relaxation. We measure the crossover length scale separating these two regimes and identify it with the prethermalized phase-correlation length of the system. Our approach enables a direct observation of the multimode dynamics characterizing one-dimensional quantum systems.

[Posterolateral retroperitoneal approach and exclusion technique in therapy of infrarenal aortic aneurysm: initial experiences]

Although the infrarenal aorta is a retroperitoneal structure, the surgical access has been transperitoneal especially when dealing with infrarenal aneurysms. After the opening of the sack a tube-or bifurcated graft is implanted. With the posterolateral retroperitoneal (RP) approach described by G.M. Williams in 1980 access to the aorta can be gained without opening the peritoneal cavity. With the non resective exclusion technique the intraoperative blood loss is minimized. This method is routinely used in Albany N.Y. for the treatment of infrarenal aneurysms. We describe here our first experiences with 44 RP excluded aortic aneurysms. Despite the small number of cases we can confirm the advantages described in the larger series of Sicard et al. and Leather and Shah: the RP approach and the exclusion technique can be routinely used for infrarenal aneurysms. It is associated with a smoother and shorter postoperative period (8 to 10 days).