The Effects of Particle Gradation on Salinized Soil in Arid and Cold Regions

Particle size grading impacts salt-frost heaving and dissolution collapse events of salinized soil on northwestern China’s arid and cold region highways. However, the influencing mechanisms remain unclear and the impact of varying particle size grading needs further investigation. Hence, this study focused on these effects and the number of freeze–thaw cycles on the characteristic changes in highway salinized soil in arid and cold regions. Three soil columns with different gradations were prepared to explore the gradation and the number of freeze–thaw cycle affects on salinized soil’s salt-frost heaving and dissolution collapse characteristics. The multi-functional physical simulation platform conducted multiple freeze–thaw cyclic tests in the laboratory. Test results confirmed significant and conclusive effects of gradation and the number of freeze–thaw cycles on salinized soil’s salt-frost heaving and dissolution collapse behaviors. Poorly graded salinized soil with high coarse particle content caused repeated freeze and thaw engineering hazards, significantly affecting salinized soil’s displacement and deformation behaviors during freezing. Contrarily, an increased range of fine particles more easily involved the characteristics of salinized soil during thawing. Therefore, the fourth freeze–thaw cycle was a crucial time node. After four freeze–thaw cycles, the displacement and deformation of original salinized soil and B-grade salinized soil samples (poorly graded with high fine particle content) tended to be stable. In contrast, the displacement and deformation of A-grade salinized soil samples (poorly graded with high coarse particle content) increased the growth rate. The present research results contribute to in-depth knowledge of the effects of gradation and freeze–thaw cycles on the characteristics of salinized soil in northwestern China, providing excellent referenced data support for the prevention and control of highway salinized soil failures and other engineering projects in arid and cold regions of northwest China.

Image-based lime size grading using the comparison ratio of the pixel radius and the actual size of lime fruit

Lime is a commercially important fruit in Thailand whose sale price depends on the fruit’s size; hence, farmers must grade limes by size before distribution. However, as lime grading machines are very expensive and each province has different size grading limits, grading is often performed manually, which is time-consuming and error-prone. Agricultural production systems for automatic selection and grading use image processing techniques for extracting key features. Therefore, this study proposes techniques to extract features of limes and to develop analytical methods for grading them. This method can reduce time and cost, and increase accuracy and flexibility for selecting different lime sizes according to each province’s size criteria. To verify our method, we classified limes according to criteria from four Thailand provinces as sample data in an experiment. The focal image feature was the radius or diameter of the lime and the grading conditions were defined by the maximum comparison ratio of the fruit’s radius in pixels to the measured radius of the actual lime in centimeters. The average grading accuracy was 99.59%, which outperformed that of mechanical grading. The processing time was 1.70 seconds per individual fruit.

Influence of Seed Quality Upgrading by Processing Machines in Soybean var. DSb-21

Background: Soybean is the “Miracle crop” of the 21st century due to its nutritional value and multiple uses. Maintenance of soybean seed quality is a major issue as it is more vulnerable to mechanical damage from harvesting to next sowing. Seed processing.by use of individual or combination of machineries will help in getting physically pure, uniform, healthy sound seeds with enhanced planting value. With the advent of new improved varieties, it is advisable to find out the individual or combination of seed processing machines like air screen cleaner, specific gravity and spiral separator to find out the effective and economical seed processing to get maximum recovery with up-graded quality of seeds.Methods: The seeds of soybean var. DSb-21 were used for seed size grading using different sieve sizes and the good seeds obtained from different size grading were processed through specific gravity separator and the good seeds obtained from specific gravity separator were further processed through spiral separator and the processed seeds obtained from these machine combinations were used to assess the seed quality. The seed processing was carried out at Seed Processing Unit and seed quality studies were carried out in the Seed Quality and Research Laboratory, Seed Unit, University of Agricultural Sciences, Dharwad during 2017-18. The experiment was laid in completely randomized design.Result: The influence of sequential processing through seed size grader followed by specific gravity separator and spiral separator on seed quality revealed that, the good seeds obtained from spiral separator after seed grading with recommended sieve size 3.75 mm recorded higher recovery (76.95%), seed germination (89.00%), seedling vigour index (3567) and lower seed mechanical damage (11.67%) followed by 4.00 mm (74.80%, 87.33%, 3418 and 12.33%, respectively) and 4.80 mm (65.64%, 85.00%, 3209 and 13.67%, respectively).

Effect of size grading on the growth of pirarucu Arapaima gigas reared in earthen ponds

Size grading is a common management practice in fish farming to minimize growth variability. Such practice has not been established for pirarucu Arapaima gigas. Therefore, the present study assessed the effect of size grading on the growth of pirarucu. Juvenile pirarucu were divided into three groups: ungraded fish (U: mean initial weight 1.12 kg), small fish (S: mean initial weight 0.81 kg), and large fish (L: mean initial weight 1.36 kg), and reared for 129 days (phase I) and 158 additional days (phase II), consecutively. No significant difference was observed in the final length, specific growth rate, biomass, survival and feed conversion rate between fish groups. Ungraded fish presented a greater decrease in the coefficient of variation for weight in phase I than in phase II. Size sorting resulted in significantly higher growth after 287 days of farming in the L-graded fish (9.49 kg, final weight), followed by the ungraded group (8.80 kg) and S-graded group (8.01 kg). However, the mean weight of pooled S- and L-graded fish was similar to the ungraded fish group in phase I and phase II, indicating that grading did not improve the general performance of pirarucu in captivity.