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Perennial systems, such as switchgrass have been shown to improve soil hydraulic properties on degraded soils relative to annual cropping systems; however, studies of the effects on thermal properties are limited. Therefore, the objectives of this study were to determine the effects of topsoil thickness on soil thermal properties under switchgrass (Panicum virgatum L.) and row crop production systems. The experiment was carried out at the University of Missouri South Farm Research Center (38°54′ N, 92°16′ W). Research plots were re-established in 2009 with selected topsoil thickness categorized into two treatments (shallow [4 cm] and deep [36 cm]) on a Mexico silt loam (Vertic Epiaqualfs). Plots were planted to either switchgrass or a corn (Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation with four replicates. Undisturbed soil cores (7.6 by 7.6 cm) and bulk soil were collected from two depths (10 cm increments) to determine thermal properties. Thermal conductivity (λ), volumetric heat capacity (C v), and thermal diffusivity (D) were measured at 0, −33, −100 and − 300 kPa soil water pressures. In addition, soil organic carbon (SOC), bulk density (D b) and water content (θ) were also determined. The results showed that the switchgrass treatment had 23% higher SOC, 5–8% greater θ, and 11% lower D b than the row crop treatment. In turn, switchgrass plot exhibited a 5–7% reduction in λ, an 8–9% reduction in D, and a 2–3% increase in C v. Shallow topsoil thickness demonstrated increased thermal properties (λ, D and C v) relative to the deep topsoil thickness, likely due to higher clay content in the surface soil horizon and associated higher θ. This study contributes to a better understanding of the impact of topsoil loss and perennial vegetation on the thermal properties of soils in degraded landscapes. • Switchgrass reduced soil thermal conductivity but increased heat capacity. • Switchgrass has the potential to buffer heat transport within the soil profile. • Management that influences bulk density also affects soil thermal conductivity. [ABSTRACT FROM AUTHOR]

Conversion of annual grain crop systems to biofuel production systems can restore soil hydrologic function; however, information on these effects is limited. Hence, the objective of this study was to evaluate the influence of topsoil thickness on water infiltration in claypan soils for grain and switchgrass ( Panicum virgatum L.) production systems. The experiment was performed at the University of Missouri South Farm (38°54′N, 92°16′W) on a Mexico silt loam (Vertic Luvisols) soil. Since 2009, plots were planted with either switchgrass or a corn ( Zea mays L.)-soybean (Glycine max (L.) Merr.) rotation. Infiltration rates were measured using ponded infiltrometers during two years (2014 and 2015) under switchgrass and grain crop management each with two levels of topsoil thickness (0 and 37.5 cm). Physically-based Parlange and Green-Ampt infiltration models were used to estimate saturated hydraulic conductivity ( K s ) and sorptivity ( S ) parameters. Switchgrass planted on degraded soil (shallow topsoil treatment) resulted in greater K s , S , q s (quasi-steady infiltration rate) and K fs (field-saturated hydraulic conductivity) values than with row crop management for both 2014 and 2015 measurement years. Results for selected 24-hour mean frequency (11.8, 14.2, and 16.2 cm) storms showed that switchgrass production systems enhanced estimated water infiltration, reduced estimated runoff, and decreased estimated time from water ponding to end of ponding compared with row crop management. Switchgrass is recommended to be planted on degraded soils especially in claypan landscapes for improved water use. [ABSTRACT FROM AUTHOR]

Loss of productive topsoil by erosion with time can reduce the productive capacity of soil and can significantly affect soil physical and hydraulic properties. This study evaluated the effects of reduced topsoil thickness and perennial switchgrass (Panicum virgatum L.) vs. a corn (Zea mays L.)--soybean [Glycine max (L.) Merr.] rotation on soil bulk density (pb), saturated hydraulic conductivity (K(sat), soil water retention and pore size distributions. The experiment was conducted at the University of Missouri South Farm on a Mexico silt loam (a Vertic Epiaqualf). Plots with the corn--soybean rotation and switchgrass were established in 2009 with four replicates. Twenty-seven years after establishment, plots with selected topsoil thickness were grouped into four treatments (TopA [4 cm], TopB [11 cm], TopC [22 cm] and TopD [36 cm]). Undisturbed soil cores, 76 by 76 mm, were collected by 10- cm depth increments from the surface to the 40-cm depth. Results showed that soil under switchgrass had 53 and 27% higher macroporosity (>1000- mm diameter) and coarse mesoporosity (60--1000-mm diameter), respectively, than row crop management. This led to 73% greater Ksat and 11% higher water content at saturation than row crop management. Thicker topsoil treatments (TopC and TopD) had consistently lower rb and greater Ksat than the shallow topsoil treatments (TopA and TopB) for all sampling depths. These results imply that switchgrass production systems significantly improve soil hydraulic properties, particularly in eroded claypan landscapes. [ABSTRACT FROM AUTHOR]

The central part of the country in the world classified Maize as their staple and essential crop, but this crop cannot cultivate appropriately in acidic soil. Thus, biochar, silicon and phosphorus observation can act as an agent to improve the growth of Maize in acidic soil. Additionally, biochar, well known for its alkaline properties, can reduce soil acidification and, at the same time, improve crop production. This low pH condition was caused by aluminium, manganese and low of phosphorus. Thus, silicon and phosphorus can improve crop productivity. Using biochar as a soil amendment raises the pH value, alone or in combination. Maize (Zea mays L.) and the acidity of the soil are much related to the application of biochar combined with silicon and phosphorus. Biochar simply can reduce exchangeable soil acidity, but when combined with silicon and phosphorus, it can have a greater influence on reducing soil Al toxicity. The importance of biochar with different rates combined with silicon and phosphorus to increase the pH of soil is still an inconsistent result by various studies. This review summarizes the properties of biochar, silicon and phosphorus and provides the scientific reference for its application to archive high yield of maize and reduce the acidification effect on soil. [ABSTRACT FROM AUTHOR]

The production cost of chili in the fertigation system has increased recently due to the high cost of water-soluble fertilizers used in the system. Laundry greywater and biodegradable vegetable waste are rich in nutrients essential for plant growth. Thus, this research aims to investigate the effects of greywater organomineral fertilizer (OMF) on the chili plants’ growth and yield performance in the fertigation system. The experiment was laid out in a completely randomized design under the rain shelter. OMF produced from laundry water and vegetable waste was applied with chemical fertilizer (CF) in different ratios, including 100% CF (T1, control), 75% CF + 25% OMF (T2), 50% CF + 50% OMF (T3), 25% CF + 75% OMF (T4), and 100% OMF (T5). Results showed that the combined use of CF and OMF produced non-significantly different chili plants from those solely treated by CF. Interestingly, chili plants treated with 50% CF and 50% OMF increased the yield by 4.71% compared to CF. Chili plants treated with 25% and 50% OMF showed nonsignificantly different plant height, stem diameter, plant dry weight, fruit number, and proximate composition of fruits over those treated with 100% CF. Solely application of OMF produced similar chili as CF in terms of fruit quality. The present study shows that plant performance and yield of chili were improved after the application of CF and OMF at a ratio of 50:50. It can be concluded that OMF has the potential to be used as an alternative for replacing 50% of chemical fertilizer in chili fertigation system without affecting its growth and yield. [ABSTRACT FROM AUTHOR]

Heat transport is an important factor that can influence the soil environment. The objective of this study was to determine if perennial biofuel and cover crops could alter soil thermal properties. Experimental treatments included two levels of cover crops (cover crops [CC] vs. no cover crops) [NC], collectively called row crops (RC) and two biofuel crop treatments. Cover crops used included cereal rye (Secale cereale L.), hairy vetch (Vicia villosa subsp. villosa) and Austrian winter pea [Pisum sativum subsp. arvense (L.) Asch. & Graebn]. The two biofuel treatments included perennial biofuel crops (PB): giant miscanthus (Miscanthus x giganteus J.M. Greef & Deuter ex Hodkinson & Renvoize) and switchgrass (Panicum virgatum L.). Soil samples were collected at 10-cm depth increments from the soil surface to a depth of 30 cm. Soil thermal properties (thermal conductivity [λ], volumetric heat capacity [CV], thermal diffusivity [D]) and volumetric water content (θ) were determined at 0, -33, -100 and -300 kPa soil water matric potentials. Additionally, bulk density and soil organic C (SOC) were determined. Results showed that PB had 11% higher CV at saturation, probably because they had significantly higher θ and SOC than RC management. Cover crops had 13% higher CV at saturation probably because they had significantly higher θ and SOC than no cover crop management. Row crops had significantly higher λ and D than PB. The results from the current study imply that CC and PB can change soil thermal properties by reducing λ and D and increasing CV under laboratory conditions. [ABSTRACT FROM AUTHOR]