Biochar Amended Soils and Water Systems: Investigation of Physical and Structural Properties

There are significant regional differences in the perception of the problems posed by global warming, water/food availability and waste treatment recycling procedures. The study illustrates the effect of application of a biochar (BC) from forest biomass waste, at a selected application rate, on water retention, plant available water (PAW), and structural properties of differently standard textured soils, classified as loamy sand, loam and clay. The results showed that soil water retention, PAW, and aggregate stability were significantly improved by BC application in the loamy sand, confirming that application of BC to this soil was certainly beneficial and increased the amount of macropores, storage pores and residual pores. In the loam, BC partially improved water retention, increasing macroporosity, but decreased the amount of micropores and improved aggregate stability and did not significantly increase the amount of PAW. In the clay, the amount of PAW was increased by BC, but water retention and aggregate stability were not improved by BC amendment. Results of the BET analysis indicated that the specific surface area (BET-SSA) increased in the three soils after BC application, showing a tendency of the BET-SSA to increase at increasing PAW. The results obtained indicated that the effects of BC application on the physical and structural properties of the three considered soils were different depending on the different soil textures with a BET-SSA increase of 950%, 489%, 156% for loamy sand, loam and clay soil respectively. The importance of analysing the effects of BC on soil water retention and PAW in terms of volumetric water contents, and not only in terms of gravimetric values, was also evidenced.

TERENGGANU SOIL SERIES TEXTURAL CLASSIFICATION AND ITS IMPLICATION ON WATER CONSERVATION

The updated Terengganu soil series has been made known to the public in 2018 by the Department of Agriculture, Malaysia. One of the most important physical aspects not quantify is the parameter relating to soil’s ability to contain water and allow water infiltration. This information is necessary to help farmers to know the soil suitability characteristics. In the current study, we retrieve the soil particle size of the soil series for further investigation. A pedotransfer function was used to estimate the soil water retention. The properties were then used to estimate the field capacity (FC), permanent wilting point (PWP), and the plant available water (PAW). In this study, we found twelve soil series in Terengganu state. The soil series were categorized into clay, sand, loamy sand, silty clay loam, and clay loam. Batu Hitam, Tasik, Lubok Kiat, Kampong Pusu, Tok Yong, Jerangau, and Tersat Series were found as clay soil. Jambu and Rhu Tapai Series as sand soil. Rudua, Gondang, and Kuala Brang Series corresponded to clay loam, silty clay loam, and loamy sand. Among the soil series, Gondang Series appeared to be the most preferred soil for plantation due to its ability to give the highest plant available water, a lower water infiltration duration than clay, and it required lesser water for irrigation than the clay soil.

Guidelines for surfactant selection to treat petroleum hydrocarbon-contaminated soils

The present study determined the most effective surfactants to remediate gasoline and diesel-contaminated soil integrating information from soil texture and soil organic matter. Different ranges for aliphatic and aromatic hydrocarbons (> C6–C8, > C8–C10, > C10–C12, > C12–C16, > C16–C21, and > C21–C35) in gasoline and diesel fuel were analyzed. This type of analysis has been investigated infrequently. Three types of soils (silty clay, silt loam, and loamy sand) and four surfactants (non-ionic: Brij 35 and Tween 80; anionic: SDBS and SDS) were used. The results indicated that the largest hydrocarbon desorption was 56% for silty clay soil (SDS), 59% for silt loam soil (SDBS), and 69% for loamy sand soil (SDS). Soils with large amounts of small particles showed the worst desorption efficiencies. Anionic surfactants removed more hydrocarbons than non-ionic surfactants. It was notable that preferential desorption on different hydrocarbon ranges was observed since aliphatic hydrocarbons and large ranges were the most recalcitrant compounds of gasoline and diesel fuel components. Unlike soil texture, natural organic matter concentration caused minor changes in the hydrocarbon removal rates. Based on these results, this study might be useful as a tool to select the most cost-effective surfactant knowing the soil texture and the size and chemical structure of the hydrocarbons present in a contaminated site.

Urban stormwater nutrient and metal removal in small-scale green infrastructure: exploring engineered plant biofilter media optimisation

The present study evaluated engineered media for plant biofilter optimisation in an unvegetated column experiment to assess the performance of loamy sand, perlite, vermiculite, zeolite and attapulgite media under stormwater conditions enriched with varying nutrients and metals reflecting urban pollutant loads. Sixty columns, 30 unvegetated and 30 Juncus effusus vegetated, were used to test: pollutant removal, infiltration rate, particulate discharge, effluent clarity and plant functional response, over six sampling rounds. All engineered media outperformed conventional loamy sand across criteria, with engineered attapulgite consistently among the best performers. No reportable difference existed in vegetation exposed to different material combinations. For all media, the results show a net removal of NH3-N, PO43−-P, Cd, Cu, Pb and Zn and an increase of NO3−-N, emphasizing the importance of vegetation in biofilters. Growth media supporting increased rate of infiltration whilst maintaining effective remediation performance offers the potential for reducing the area required by biofilters, currently recommended at 2% of its catchment area, encouraging the use of small-scale green infrastructure in the urban area. Further research is required to assess the carrying capacity of engineered media in laboratory and field settings, particularly during seasonal change, gauging the substrate's potential moisture availability for root uptake.

Does Soybean Yield and Seed Nutrient Content Change Due to Broiler Litter Application?

Broiler litter (BL) has the potential to be used as an alternative multi-nutrient source for soybean (Glycine max L.) production. While previous research on soybean yield response to BL has reported inconsistent results, the effects of BL application on soybean seed nutrient concentrations are largely unknown or less studied. The objective of this two-year field study was to investigate the effect of BL application on soybean yield and seed nutrient content in three different soil types and production environments. To pursue the objective, a field experiment was established in 2018 in a Compass loamy sand with four BL rates (0, 2.2, 5.6, and 11.2 Mg BL ha−1). In 2019, the study was expanded to include two additional soil types (Decatur silty clay loam and Dothan fine sandy loam) totaling four site years. The experimental design at each site was a randomized complete block with four replications. Application of BL had no impact on soybean yield in the first year, regardless of application rate and soil type. In the second year of BL application, soybean yield was 43% higher overall compared to no BL plots on a Compass loamy sand. However, soybean yield with the application of 5.6 or 11.2 Mg BL ha−1 was not statistically different from that at 2.2 Mg BL ha−1. Soybean seed Ca and B concentrations changed significantly among the treatments; however, the change was not consistent across the sites. Consecutive year application of 11.2 Mg BL ha−1 yr−1 produced the highest seed K and Cu concentrations. The results of this research suggest that repeated BL application can boost soybean yield and potentially enrich seed with selected nutrients.

Soil Textural Inactivation of Residual Faecal Indicator Organisms in Bio Slurry Used for Carrot Production

A screen house pot study using bio-slurry at the rate of 7.8 t N / ha was conducted at Makerere University Agricultural Research Institute (MAURIK) Kabanyolo, Uganda. This was monitored using fecal indicator organisms (coliforms, Escherichia coli and Enterococci) in loamy sand, sandy loam and sandy clay loam texture obtained at the study site within 5litres pots under a Complete Randomized Design under a screenhouse. The different textures significantly (p<0.05) reduced the fecal indicator organisms. Conditions within the loamy sand texture reduced the pathogenic microorganisms within 90 days due to its high sand content. In this soil texture, E. coli and enterococci were reduced to undetectable levels within 90 days unlike the coliforms. Fecal, Bio slurry, coliforms, Escherichia. coli, Enterococci