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Diversification of crop species and minimum mechanical soil disturbance are the interlinked principles of conservation agriculture that are beneficial in improving soil physical and hydrological properties, and hence crop productivity. The present study was conducted to assess the long-term impacts of crop rotational diversity and tillage on soil water infiltration ([q.sub.s]), soil water retention (SWR), pore size distribution (PSD), bulk density ([[rho].sub.b]) and soil penetration resistance (SPR). The study was established in 1991 at Beresford, South Dakota, and included three crop rotation systems (2-year, maize (Zea mays L.)-soybean (Glycine max L.); 3-year, maize-soybean-wheat (Triticum aestivum L.); and 4-year, maize-soybean-wheat-oat (Avena saliva L.)) and two tillage systems (NT, no-tillage; and CT, conventional tillage). Soil samples were collected only under maize and soybean phases of the crop rotations. Our results showed that NT with 4-year rotation had the lowest [[rho].sub.b] under maize and soybean phases (1.21 and 1.19 g [cm.sup.-3] respectively) compared with the CT system. Similarly, NT with 4-year rotation decreased SPR by 20% compared to CT with 4-year rotation in the soybean phase. Soils managed under NT with 4-year rotation in the soybean phase retained 27, 28, 28,32,33,31 and 26% more water compared with CT and 4-year system at 0-7.5 cm depth at 0, -0.4, -1.0, -2.5, -5.0, -10 and -30 kPa matric potentials respectively. A similar trend was observed for [q.sub.s] under the same treatments, in which it was 31 % higher under NT than under CT, both with 4-year rotation. Data from this study showed that diversified crop rotation under NT enhanced soil physical and hydrological properties compared with CT with less diverse systems (e.g. maize-soybean). Additional keywords: chisel plow, diverse crop rotations, maize-soybean rotation, soil bulk density, soil penetration resistance, soil water retention, water infiltration rate. Received 29 August 2018, accepted 11 September 2019, published online 2 October 2019, Introduction Conservation management practices are being adopted to protect soil and enhance soil moisture conservation. The main conservation practices involve minimal soil disturbance, maintaining soil cover and enhancing crop productivity [...]

Aggregate re‐formation after a disturbance is important for maintaining soil hydraulic status and carbon stabilization. A study investigating the re‐formation of aggregates after disturbance by spring tillage was conducted at a site located on a south‐facing (6%) slope with a silt‐loam soil at Arlington‐Wisconsin in 2018 and 2019. Treatments were conventional tillage (CT) and no‐tillage (NT) with winter application of solid manure (SM) and no manure in a complete randomized design. Soils under NT had a higher proportion of larger aggregates (>1 mm), whereas the proportion of smaller (<1 mm) aggregates was greater under CT. Soil organic carbon, total nitrogen, bulk density, soil water retention, and micropores of NT treatments were higher compared to CT systems at 0‐ to 5‐cm depth. However, the impacts of manure application on soil properties were not significant, except for those of soil organic carbon (SOC) and total nitrogen. Harvesting in 2018 decreased the relative proportion of aggregates smaller than 1 mm and hydraulic conductivity of saturated soil. These results indicate that the immediate effect of tillage is to decrease larger aggregates, SOC, and total porosity, whereas harvesting decreases the proportion of smaller aggregates. Comparatively, aggregates smaller than 1 mm were mainly influenced by the long‐term effects of the management operations. It appears that larger aggregates can recover on an annual basis, but aggregates smaller than 1 mm do not. In long‐term studies, there is a need to monitor aggregates, including their size distribution and pore structures, to identify aggregate turnover time and rate, which will augment our understanding of aggregate formation. Core Ideas: No‐till developed larger aggregates while conventional tillage lead formation of smaller aggregates.The greater proportion of larger aggregates was linked to higher soil organic carbon (SOC), nitrogen, and bulk density (ρb).Immediate effects of management reduced soil structure due to higher ρb and lower SOC.Note that 1‐ to 4‐mm aggregates were not maintained after tillage disruption.Aggregates <1 mm cannot re‐form annually since they are related to long‐term effect. [ABSTRACT FROM AUTHOR]

Frequency and efficiency of freeze-thaw cycles (FTTCs - freezing and thawing treated cycles) are increasing over soils of cold regions or high altitudes as a natural outcome of global warming. Such cases result in significant changes in available macro and micro nutrient contents of soils. Very little information is available about the effects freeze-thaw cycles have on the availability of soil micronutrients. Therefore, the present study was conducted to determine the effects of frequency of freeze-thaw cycles on available micro nutrient contents of Pellustert, Argiustoll, Haplustept, Fluvaquent and Calciorthid large soil orders of Northern Turkey. Results revealed significant effects of freeze-thaw cycles on available micro nutrient contents of soils mostly based on soil characteristics. The highest Fe content was observed in step 3 of Pellustert soil order (Step 3; each soil was kept at -10, -15, and -20 °C for a month, at -10 °C for 15 days, -5 °C for 15 days, 0 °C for 15 days, then thawed at +2.5, +5, +7.5 and 10.0 °C for 18 hours. This freeze-thaw cycle was repeated 3, 6, and 9 times). It was concluded that the effects of freeze-thaw cycles on Fe availability varied mainly based on soil characteristics and increased frequency of freeze-thaw cycles increased Fe-fixation to soil. [ABSTRACT FROM AUTHOR]

Turkey has diverse climate zones and therefore, number of the freeze-thaw process (FTCS) varies from one region to another. The number is increasing especially in high shear and cold regions and such cycles have significant impacts on available nutrients for plants. The present study was carry out with 5 major soil groups (Vertisol, Chernozem, Andosol, Leptosol and Calcisol) under field conditions to determine the effects of repeated freeze- thaw processes on available nitrogen (ammonium and nitrate) (NH4-N and NO3-N) levels of the soils. Five different nitrogen doses (0, 100, 200, 300 and 400 mg kg-1) were applied to 5 major soil groups in three replications. While the first freeze-thaw process usually increased the ammonium and nitrate nitrogen, the second and further freeze-thaw processes usually reduced available N contents of soils for plants. Current findings revealed that available NH4-N and NO3-N levels greatly depended on number of freeze-thaw cycles and increasing number of cycles decreased available soil nitrogen levels for plants, thus required higher nitrogen fertilizer levels to supply sufficient nitrogen during the plant-growth periods. [ABSTRACT FROM AUTHOR]

The transformation of agro-industrial wastes into value-added commodity is among the best approches to a greener and more sustainable future. The aim of in this study was to examine the effects of phosphogypsum waste (PGW) as fertilizer to improve yield and nutrient content in the grain, stem and leaves of com (Zea mays L.). A randomized experiment via a complete plot design was applied using four different triplicated doses of PGW (0, 1, 5 and 10 tons ha-1). It was shown that improvement in corn yield was proportional to the increase in PGW dose, corresponding to 46.19%, 38.76% and 39.65% for 1, 5, and 10 ton ha-1 of PGW, respectively. A 5.85 ton ha-1 PGW dose was optimal in yielding a 8.63 ton ha-1 of com despite a 8.26 ton ha-1 the production yield using 5 ton ha-1 PGW, as the latter was statistically borderline significant. The approach adopted here also yielded corns with higher macro- and micronutrient contents compared to the control. The analysis of variance data illustrated that the improved contents of N, P, K, Ca, Zn and B per 1 ton ha-1, and Mg per 5 ton ha-1 were also significant (P<0.05). It can be construed that the recommended dose of PGW as fertilizer between 1-5 tons ha-1 can lead to substantial improvements in yield and nutrient contents in corn. [ABSTRACT FROM AUTHOR]

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Dry bean (Phaseolus vulgaris L.) is a widely grown and important food legume which is a major source of mineral nutrition. The present study digs in determining differences in nutrients, organic-amino acid and hormone concentrations of Ispir bean genotypes under different land use conditions. The study sites (32 locations) were identified according to the stratified sampling method in the Ispir district, Erzurum, Turkey, under consideration of bean-cultivated lands and the number of villages. The seed weights were higher for genotype no. 4 (137.5 g) than for genotype no. 14 (131.5 g) and following by all other genotypes. Moreover, values for crude protein content were significantly higher for genotype no. 14 (263.1 g/kg) in comparison to genotype no. 4 (256.9 g/kg) and other genotypes. Therefore, it is concluded that land use impacts seed weight, nutrient, crude protein, amino acid, organic acid and hormone contents of Ispir dry bean. Land use can result economic improvements in crop yields and yield components. Dry bean seed weights were impacted by other crop yield components such as amino acid, organic acid and hormone contents of dry bean. [ABSTRACT FROM AUTHOR]