Better Soils for Resilient Agricultural Production

Agriculture plays a pivotal role in improving food security and reducing poverty in Africa, as well as in promoting climate change mitigation and adaptation and general progress on the Sustainable Development Goals (SDGs). In Sub-Saharan Africa (SSA), the agricultural sector employs 70% of the population and is estimated to contribute roughly 15% to GDP. But changing climate conditions and poor agricultural practices lead to soil degradation of up to 65% of agricultural lands in SSA, threatening food security. The “betterSoil” concept is a holistic and systemic approach that stresses the whole, considers essential regional aspects to link economic prosperity and sustainable agricultural practices, and addresses climate change. Its four simple principles – soil management, compost, biochar, and agroforestry – can unlock the potential of soils to restore soil organic matter, to protect soil fertility and biodiversity, and to sequester CO2 for the future build-up of humus in agricultural soils. Better soils can promote economic growth and development, especially in low-income countries hit hardest by climate change. Its four principles support the introduction of climate-positive practices that can be implemented anywhere. To harvest the benefits of large-scale soil improvement, farmers, governments, the African Union, individuals, the private sector, and practitioners must work together to bring theory on better soils into practice.</p

A new empirical ground-motion model for Iran

In this study, we developed a new ground-motion model (GMM) for the 5% damped horizontal spectral accelerations using a newly developed database of strong-motion records for Iran. The newly developed GMM includes peak ground acceleration and 5% damped elastic pseudospectral acceleration ordinates of 0:01 s ≤ T ≤ 4:0 s. We used a database containing 1356 records from 208 events up to 2013, with the moment magnitude range of 4:8 ≤ M ≤ 7:5, and the rupture distances or closest distance to the rupture plane RRUP up to 400 km. The selected database includes a variety of fault mechanisms, for example, strike slip, normal, and reverse.We used Akaike and Bayesian information to determine the validity of the chosen regression model. We introduced random-effect coefficients in our mixed-effect regression model to capture the regional variations among Zagros, Alborz-Azarbaijan, Kope Dagh, and central east Iran and found no statistical variations among these regions. As part of the developed GMMs, we included the nonlinear site effect using VS30 (average shear-wave velocity in the upper 30 m of soil profile). Distribution of residuals obtained considering between-event, site-to-site, and event-station showed no discernable trends for the developed GMM. Furthermore, our proposed model is compared with Kale et al. (2015), which has been a recent and well-established new generation model for Iran and Turkey