Valuation of ecosystem services in South Africa, 2001–2019

Please read abstract in the article.The Department of Environmental Affairs (South Africa) and the joint National Research Foundation (NRF) of South Africa and the National Natural Science Foundation of China (NSFC).https://www.mdpi.com/journal/sustainabilityam2022Agricultural Economics, Extension and Rural Developmen

Dietary knowledge, attitude and practice among type 2 diabetes mellitus patients in Sudan: a hospital-based cross-sectional study

Background: In Sudan, the prevalence of diabetes in adults was estimated at 19.1% in 2015. This study assessed dietary knowledge, attitude, and practices (KAP) of type 2 diabetes mellitus (T2DM) patients in Sudan. Methods: We randomly selected 238 T2DM patients from a list of 2460 patients from the Jabber Abulizz Hospital. We interviewed them face-to-face using a structured questionnaire. Multivariate logistic regression analyses were performed to investigate the determinants of KAP regarding the recommended diets for T2DM patients. Results: Majority of the patients demonstrated good knowledge (54.6%), positive attitude (79%); and good practice (58%). The result revealed that patients with formal education had 3.0 (95% CI: 1.6-5.7) times higher odds of having good diabetic dietary knowledge than those with informal education. While patients who had good knowledge and a positive attitude were respectively 4.7 (95% CI: 2.4-8.9) and 3.2 (95% CI: 1.5-6.7) times more likely to follow dietary recommendations than the patients with poor knowledge and negative attitudes. Conclusion: Irrespective of the socio-demographic position, the good knowledge and the positive attitude towards the recommended diet, all the T2DM patients complied with the dietary recommendations. These findings highlight the need for improving knowledge and promoting positive attitudes towards the recommended diet among T2DM patients

Determination of soil electrical conductivity and moisture on different soil layers using electromagnetic techniques in irrigated arid environments in South Africa

DATA AVAILABILITY : Available on request.Precise adjustments of farm management activities, such as irrigation and soil treatment according to site-specific conditions, are crucial. With advances in smart agriculture and sensors, it is possible to reduce the cost of water and soil treatment inputs but still realize optimal yields and highprofit returns. However, achieving precise application requirements cannot be efficiently practiced with spatially disjointed information. This study assessed the potential of using an electromagnetic induction device (EM38-MK) to cover this gap. An EM38-MK was used to measure soil apparent electrical conductivity (ECa) as a covariate to determine soil salinity status and soil water content θ post irrigation at four depth layers (Hz: 0–0.25 m; Hz: 0–0.75 m; Vz: 0.50–1 m). The inverse distance weighting method was used to generate the spatial distribution thematic layers of electrical conductivity. The statistical measures showed an R2 = 0.87; r > 0.7 and p ≤ 0.05 on correlation of ECa and SWC. Based on the South African salinity class of soils, the area was not saline ECa < 200 mS/m. The EM38-MK can be used to estimate soil salinity and SWC variability using ECa as a proxy, allowing precise estimations with depths and in space. These findings provide key information that can aid in irrigation scheduling and soil management.The Agricultural Research Council-Natural Resources and Engineering, Department of Science and Innovation; National Research Foundation and the Water Research Commission of South Africahttps://www.mdpi.com/journal/waterGeography, Geoinformatics and Meteorolog

Characterisation of Coastal Sediment Properties from Spectral Reflectance Data

Remote sensing of coastal sediments for the purpose of automated mapping of their physical properties (grain size, mineralogy and carbonate content) across space has not been widely applied globally or in South Africa. This paper describes a baseline study towards achieving this aim by examining the spectral reflectance signatures of field sediment samples from a beach–dune system at Oyster Bay, Eastern Cape, South Africa. Laboratory measurements of grain size and carbonate content of field samples (n = 134) were compared to laboratory measurements of the spectral signature of these samples using an analytical spectral device (ASD), and the results interrogated using different statistical methods. These results show that the proportion of fine sand, CaCO3 content and the distributional range of sediment grain sizes within a sample (here termed span) are the parameters with greatest statistical significance—and thus greatest potential interpretive value—with respect to their spectral signatures measured by the ASD. These parameters are also statistically associated with specific wavebands in the visible and near infrared, and the shortwave infrared parts of the spectrum. These results show the potential of spectral reflectance data for discriminating elements of grain size properties of coastal sediments, and thus can provide the baseline towards achieving automated spatial mapping of sediment properties across coastal beach–dune environments using hyperspectral remote sensing techniques

Enhancing Water Infiltration through Heavy Soils with Sand-Ditch Technique

Enhancing rainwater infiltration into heavy soils is an important strategy in arid regions to increase soil water storage and meet crop water demand. In such soils, water infiltration and deep percolation can be enhanced by constructing deep ditches filled with permeable materials, such as sand. Laboratory experiments were conducted to examine the effect of sand ditch installed across the slope of a soil box, 50 &times; 20 &times; 20 cm3, on runoff interception and water infiltration of clay soil packed at two bulk densities, 1240 and 1510 kg/m3. The experiments were carried out under laboratory conditions using simulated steady flow of about 20 cm/h for a duration of 60 min. Results showed that sand ditches highly reduced runoff and largely enhanced water infiltration into soils. In low-density soil, the average runoff was 15% of inflow volume but reduced to zero in the presence of sand ditches thus increasing soil water storage by 15%. In high-density soil, the presence of sand ditches was more effective; infiltration volume increased by 156% compared to control. The WASH_2D model was used to simulate water flow in the presence of sand ditches; it showed to increase water infiltration and soil-moisture storage thus improving crop production in drylands

Root System Development of Prosopis Deedlings under Different Soil Moisture Conditions

Prosopis juliflora (Swartz) DC is one of the most economically and/or ecologically important legumes in arid and semi-arid regions of the world. Prosopis was introduced into Sudan in early 20^ century, and succeeded in controlling the expansion of desert in northern Sudan. Recently, however, this species distributes widely and rapidly in eastern Sudan, and induces many problems in human subsistence. To clarify the mechanism of rapid invasion of Prosopis, we investigated the response of seedling roots to different soil moisture conditions. Prosopis seedlings were cultivated twice (seven weeks each) in Desertification Mechanism Analysis System of Arid Land Research Center, Tottori University. Seedlings were cultivated in columns with sandy soils and dripping irrigation once per day. Second experiment was done in columns with four drip irrigations (top, top and middle, middle and bottom, or bottom of columns). Seedlings were carefully harvested, and dry weight and root structure were analyzed. Results were (1) seedlings developed two root systems, one was horizontal root just below the soil surface, and the other was tap root penetrated beyond 1m depth, (2) water supply on the surface increased dry weight and total root length of seedling, (3) seedling developed lateral roots vigorously at higher soil moisture areas. These results suggest that seedling responds sensitively to the increase of soil moisture after the rain, and develops root system flexibly against patches of soil moisture. These properties may enable Prosopis to invade easily into new habitats and distribute widely and rapidly in eastern Sudan