Soil recovery following landslides at Whatawhata Research Station, Waikato, New Zealand: preliminary results

This research investigates soil recovery following landslides at the Whatawhata Research Station 20 km west of Hamilton. Six landslides were studied, ranging in age from pre-1953 to 2014. The landslides were divided into four zones: shear zones (mean of 25% of landslide area), intact accumulation zones (20%), transition zones (40%), and re-deposition zones (15%), along with a control. Soils were well-developed in the control and intact accumulation zones and least recovered in the shear and re-deposition zones. Mean A horizon depths ranged from 2 cm in the shear and re-deposition zones to 7 cm in the transition zone, 17 cm in the intact accumulation zone, and 20 cm in the control. Mean soil carbon contents were lower (P</jats:p

The joy of teaching soil science

The fundamental purposes of teaching are to impart knowledge, insight, and inspiration. Around the world, university teaching principles are changing as students also gain knowledge and inspiration in ways other than in the class room. Likewise, the soil science discipline is evolving as there is a new set of tools and techniques available by which we investigate soils, and the foci are shifting toward other disciplines and changing research questions. In many universities, the teaching of undergraduate soil science increasingly takes place to non-soil science majors. All these forces require some thinking about how we teach the subject and here we present some of our experiences and ideas of teaching soil science in different parts of the world. Some 15 examples are presented from Australia, Canada, France, Germany, New Zealand, Russia, Taiwan, The Netherlands, and the USA. As the research is widening so is our teaching. The examples are diverse and, despite cultural and personal differences, they show several trends. The cases represent vibrant and creative ways to teach soils, and the initial focus is to create a sense of wonder about the soil and its utilitarian and scientific value. Published by Elsevier B.V

Pore size distribution in soils irrigated with sodic water and wastewater Distribuição de poros em solos irrigados com água salina e com água residuária

Soil porosity, especially pore size distribution, is an important controlling factor for soil infiltration, hydraulic conductivity, and water retention. This study aimed to verify the effect of secondary-treated domestic wastewater (STW) on the porosity of a sandy loam Oxisol in the city of Lins, state of São Paulo, Brazil. The two-year experiment was divided into three plots: soil cultivated with corn and sunflower and irrigated with STW, soil cultivated and irrigated with sodic groundwater, and non-irrigated and non-cultivated soil (control). At the end of the experiment, undisturbed core samples were sampled from 0 to 2.0 m (8 depths). The water retention curves were obtained by tension plates and Richard's pressure plate apparatus, and the pore size distribution inferred from the retention curves. It was found that irrigation with treated wastewater and treated groundwater led to a decrease in microporosity (V MI), defined as the pore class ranging from 0.2 to 50 &#956;m diameter. On the other hand, a significant increase in cryptoporosity (V CRI) (< 0.2 &#956;m) was identified throughout the soil profile. The presence of Na+ in both waters confirmed the role of this ion on pore size distribution and soil moisture (higher water retention).<br>A porosidade do solo, principalmente a distribuição dos poros, é um fator importante que controla a infiltração de água, condutividade hidráulica e retenção da água no solo. Este estudo teve como objetivo verificar os efeitos do efluente de estação de tratamento de esgoto (TSE) na porosidade de um Latossolo de textura média. A área experimental foi dividida em três parcelas: solo cultivado com milho e girassol e irrigado com TSE (STW); solo cultivado e irrigado com água subterrânea sódica (W); e solo não cultivado e não irrigado (C-controle). No final de dois anos de experimento, amostras não deformadas de solo foram coletadas de 0 a 2,0 m (oito amostras). As curvas de retenção de água no solo foram obtidas com mesas de tensão e câmara de Richards, e a distribuição de poros no solo foi calculada a partir da derivação dessas curvas. Foi observado decréscimo da microporosidade V MI (poros com diâmetro entre 0,2 e 50 &#956;m) no solo irrigado com TSE e água tratada. Por outro lado, observou-se aumento significativo da criptoporosidade V CRI (< 0,2 &#956;m). A presença de Na+ nos dois tipos de água confirmou o papel desse íon na distribuição dos poros e na umidade do solo (maior retenção de água no solo)