Productivity of Short-Rotary Crop Cultivation under Different Systems of Basic Tillage in Organic Agriculture of the Steppe of Ukraine

Long-term reform of the agricultural sector in Ukraine is taking place under difficult economic and natural conditions. In modern agriculture, the most relevant ones are biologized measures and technologies for growing crops and resource- and energy-economic restoration of soil fertility. Studies of the impact of the system of basic tillage and the use of straw bio-decomposers and postharvest residues in organic farming were conducted in the most common and typical for the southern region of the steppe of Ukraine short- rotation crop cultivation with the following alternation of crops: peas – winter wheat – winter barley – ½ sunflower fields + ½ corn fields. During the years of the first cultivation, the experiment showed the advantages of a system of differentiated tillage, where even without the use of bio-decomposers, the highest yield of cereals was obtained – 3.64 tons/ha and sunflower – 2.20 tons/ha (check experiment). The application of the planar-free system combined with multi-depth and especially planar-free shallow soil processing, main tillage caused a decrease in grain yields by 0.11-0.39 tons/ha and sunflower by 0.28-0.42 tons/ha, respectively. With the use of bio-decomposers provided by brands Ecostern and Cellulad, yields’ growth is in the range of 0.13-0.25 t/ha or 4.5-8.7% for cereals and 0.10-0.23 t/ha or 5.4-12.4% for sunflower. The application of the Ecostern bio-decomposer 1.5 l/ha provided an increase in the yield from 1 ha of crop rotation area of grain, fodder, fodder-protein units and digestible protein on average in all systems of basic tillage by 4.7, respectively; 4.5; 4.3 and 5.4%, and with the introduction of Cellulad 2.0 l/ha, these figures increased by 9.5, respectively; 8.9; 8.6 and 10.8% compared to options without the introduction of bio-decomposers

Performance of Chickpea Varieties Based on Growth and Yield Parameters Influenced by Different Sowing Dates at Toke Kutaye District, Ethiopia

One of the basic agronomic practices to improve the yield of chickpea are ideal sowing date and high yielding varieties. Thus, a field experiment was conducted to assess the effect of different sowing dates on yield and yield components of chickpea varieties in the main cropping season of 2019 at Toke Kutaye District. Four sowing dates (September 4th, September 14th, September 24th, and October 5th) and four kabuli varieties. Four Kabuli types of chickpea varieties were Dalota, Ejere, Teji and Dube (local check). Experiment was laid out in split plot design using factorial arrangement with three replications and sowing date treatments were assigned to the main plots and varieties to sub plots. The main effect of sowing date showed highly significant effect on days to emergence, days to 50% flowering and physiological maturity. Highest days to emergence (12.4 days) were recorded from a plot sown on October 5th, while longest days to 50% flowering (54.92 days) and physiological maturity (122.5 days) were recorded from a plot sown on September 14th. Moreover, varieties had significant effect on days to physiological maturity of chickpea. Longest days to physiological maturity (133 days) were recorded from local variety and early days to physiological maturity (113.3 days) was recorded from Dalota variety. The main effects of sowing date and variety were significant on plant height, as the tallest plant height (42.75 cm) was recorded from September 24th sown plants. Similarly, the tallest (41.42 cm) plant was recorded from Dalota variety. In addition, the highest number of primary branches (6.83) and secondary branches (16.42) per plant were recorded from Dalota variety, while the lowest number of primary branch (5.5) and secondary branches (8) were scored from Ejere and Teji varieties, respectively. Highest grain yield (2415.4 kg ha-1) was obtained from plots sown on September 14th whereas Dalota variety produced highest grain yield (2051.25 kg ha-1). Hence, Dalota variety and September 14th sowing date emerged as best among all tested treatments and can be recommended for chickpea production in the study area and similar agro-ecologies. Conclusive recommendation could be obtained if the study is repeated at more locations and seasons in the future.

Chemo-Mechanical Grinding for K9 Optical Glass

K9 optical glass was widely used in national defense and civilian fields. In this paper, chemo-mechanical grinding (CMG) was applied to process the K9 optical glass. Selecting CeO2, MgO and Fe2O3as CMG abrasives, the corresponding CMG tools were purposely developed for the check experiment. High surface and subsurface qualities on the K9 optical glass specimen were obtained as the polished results by the CeO2-CMG tools. Surface roughness and material removal rate were used to evaluate the grinding performance. The low-abrasive ratio of CeO2-CMG tool was proved as the optimal one, by which the surface roughness Ra reached 0.586nm, and the surface morphology appeared smooth and flat. The angle polishing was applied to detect the subsurface quality and the subsurface cracks were not observed.

TCA Principe and Application of the Double Circular Arc Tooth Spiral Bevel Gear

Tooth contact analysis (TCA) is an effective tool for meshing analysis of the double circular arc profile spiral bevel gear (DCAPSBG), and it is the basis of loading tooth contact analysis and finite element analysis. The TCA application is developed by Visual Basic and MATLAB mixed programming method, this paper compared the results of the TCA application analysis with the results of contact area check experiment on one pair of gears with given parameters. The TCA application had been verified by real experiment, this provided an effective approach for the design of DCAPSBG.

Study and Experimental Analysis of Oval Bevel Gear Transmission

Oval bevel gear is introduced as a new gear transmission type of intersecting axes, in which high-order, denaturing and eccentric one are included. Based on the theory of spatial engagement, spatial spherical coordinate system of the noncircular bevel gearing was developed and a generalized tooth profile equation of noncircular bevel gears was also proposed. The gear profile can be enveloped for the generating movement between conical cutter and oval bevel gear according to the envelope principle of conjugate profiles. Then a new and general parametric design method for oval bevel gear was founded. The classification and gear variability condition of oval bevel gear were discussed. Meanwhile, its pitch curve, addendum and dedendum curve were studied, and the corresponding equations were deduced. A roll check experiment is performed on the prototype workpiece. Then the influences of motor speed and load on transmission ratio were analyzed. Finally, the design method, profile generation method and manufacture method of oval bevel gear were certified as correct by comparing experimental curve of transmission ratio with theoretical one.

Chemical and integrated control of the long-tailed mealybug, Pseudococcus longispinus (Targioni-Tozzetti) (Hemiptera: Coccidae) in the Riverland of South Australia

Chemical control of the mealybug Pseudococcus longispinus (Targioni-Tozzetti) was most effective if sprays were applied when the mealybugs were in the dispersive crawler stage and when the host plant afforded the least shelter. A two-spray program with sprays applied in August and late November effectively controlled a dense infestation of the mealybug on citrus. Red scale (Aonidiella aurantii (Maskell)), the major insect pest of citrus, was also effectively controlled. An overall pest management program has been developed for citrus in which all insect pests are controlled by combination of natural enemies and insecticides as required. Outbreaks of the mealybug, and other secondary pests, are controlled by sprays of aminocarb or methomyl. These two insecticides prevented the population resurgence of mealybugs in the subsequent generation which occurred when maldison was used. Bioassays showed that aminocarb and methomyl were toxic for less than a week to the mealybug and to parasites and predators, whereas maldison and methidathion were toxic to the parasites and predators for about a month. Parasite pupae inside the host mealybug survived sprays of maldison and aminocarb. It is suggested that natural enemies emerging after spraying, from resistant or protected stages, survive sprays of aminocarb and methomyl but not sprays of more persistent insecticides like maldison; and that these survivors continue to suppress populations of their hosts. Hence aminocarb and methomyl are probably specific in their action against the mealybug and the other secondary pests of citrus because of their short persistence.An insecticide check experiment failed to demonstrate that natural enemies significantly reduce populations of the mealybug. Possible reasons for the failure are discussed.

A New Method for Computing Axisymmetric Buckling of Spherical Caps

A modification of Newton’s method is applied to the solution of the nonlinear differential equations for clamped, shallow spherical caps under uniform pressure. The linear form of Newton’s method or quasi-linearization breaks down at limit points of the differential equations. A simplified “quadratic form” is derived in the paper and shown to be satisfactory for continuing the solution past the limit point and into the postbuckling region. Results for the buckling pressures defined by the limit points agree with published results for perfect caps. New results are presented for imperfect caps that check experiment.