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Healthy soils contribute to a wide range of ecosystem services and virtually all of the UN Sustainable Development Goals, but most of the world's soil resources are in only fair, poor, or very poor condition, and conditions are getting worse in more cases than they are improving. A total of 33% of all soils are moderately to highly degraded as a result of erosion, loss of organic matter, poor nutrient balance, salinization and alkalinization, contamination, acidification, loss of biodiversity, sealing, compaction, and poor water status. Best management practices are available to limit or mitigate threats to soil health, and many of them mitigate multiple soil threats. In many regions of the world, policies or initiatives to protect or enhance the status of soils are in place, and they need to be strengthened and enforced. The Food and Agriculture Organisation will publish its second comprehensive assessment of the status of the world's soils in 2025, and this review provides an interim update on world soil status and offers an accessible overview of the topic. [ABSTRACT FROM AUTHOR]

Learning styles represent an integral component of the learning environment, which has been shown to differ across institutions and disciplines. To identify learner preferences within a discipline would aid in evaluating instructional resources geared toward active learning. The learning profiles of second-year soil science students (n = 62) were investigated using the VARK and index of learning styles (ILS) questionnaires, at the mid-semester stage. Student performance was measured using quality points (course work and final exam), which was also compared with to learning style preferences. The results showed that students were mostly multimodal (25%) and kinaesthetic (25%) for the VARK instrument. An almost balanced student profile was seen among the four dimensions for the ILS except between sequential and global preferences, which differed significantly (p less than 0.05). Learning preference was not related to course performance. Students performed significantly better in course work compared with the final exam. Grouping students into "strong" and "balanced" profiles resulted in lower quality points for students labeled as having a strong preference. The data supported using a diverse set of instructional resources and complementary assessment, but how these and other attributes of the learning environment interact to facilitate better learning leaves much to be researched. (Contains 3 figures and 3 tables.)

The concentration of strongly fixed-ammonium (N[H.sub.4f] in soil is not high enough to allow direct injection of soil digests into automated [sup.15]N analyzers. Investigations were therefore conducted to develop microdiffusion protocols primarily as a preconcentration step in N[H.sub.4f]-[sup.15]N analysis of soils using continuous flow-isotope ratio mass spectrometry (CF-IRMS). The 5 M HF:1 M HCI soil digest containing N[H.sub.4f] was treated with 10 M KOH in a 140-mL polypropylene specimen container, modified to collect N[H.sub.3]-N in a petri dish containing [H.sub.3]B[O.sub.3] indicator solution which was then quantified by acidimetric titration. For [sup.15]N analysis, however, acidified Whatman GF-D filter paper discs substituted for the [H.sub.3]B[O.sub.3] indicator solution trap, which were subsequently processed for direct analysis via CF-IRMS. With the modifications described, analyses (quantitative and [sup.15]N) were performed on 5- to 20-mL samples of 5 M HF:1 M HCI soil digests. Recovery was quantitative in 48 to 96 h with up to ~525 [micro]g N[H.sub.4]-N and was more dependent on digest volume than on its N content. Fractionation of [sup.15]N was effectively nonexistent within the diffusion periods used except only for immediately (a few hours) into the diffusion; suggesting that the need to optimize diffusion is not that critical to the accuracy of the [sup.15]N results provided a sufficient quantity of N is obtained for the CF-IRMS. Additionally, diffusion times were slightly affected by soil type, indicating a mild matrix effect probably because of mineralogical variation among soils. These diffusion methods therefore proved to be very accurate and reliable for practical use as a preconcentration step prior to [sup.15]N analysis of the N[H.sub.4f] fraction in soils.

High-rate composting studies on green waste, i.e. banana leaves (BL) and lawn clippings (LC), were conducted in 0.25-m3rotary barrel composters to evaluate and model changes in key physico-chemical parameters during composting. Time to compost maturity and antagonistic effects and relationships of composts againstPythium ultimumwere also investigated. Higher temperatures were achieved in LC compost (LCC), which did not translate to higher total organic carbon (TOC) loss but resulted in lower carbon to nitrogen ratio (C:N) and a more mature compost. With the exception of electrical conductivity (EC), net decreases were observed in pH, TOC and C:N across compost types. Total Kjeldahl nitrogen (TKN) showed a net increase in LCC and a net decrease in BLC. With the exception of TOC and pH, the results showed that compost type and time had a significant effect on the respective TKN, EC and C:N models. Compost temperature and TOC were best described by the critical exponential and rectangular hyperbola functions, respectively. Whereas TKN, C:N and pH were described using double Fourier functions and EC using Fourier functions. Composts achieved maturity within 19 days and significantly inhibited the growth ofP. ultimum. Bacterial population was positively related to growth inhibition (GI) across compost types, whereas total microbial population had a positive relationship with GI in LCC. Evidence suggests that multiple groups of microorganisms contributed to GI through antibiosis and competition for resources. Composts were determined to be suitable for use as components of plant growth substrates based on compost maturity indices. [ABSTRACT FROM AUTHOR]