ISSN 2284-7995, ISSN Online 2285-3952
 

Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4
Written by Tarek FOUDA, Abd-Elrahman ELRAYES, Abd-Elhameed ELHANAFY, Mohamed GHONAME

The expansion of aquaculture ponds necessitates the development of aeration and the addition of oxygen. Rubber tubes are a new way of aerating by generating micro bubbles on the water surface. Experiments were conducted to investigate and determine the effects of air flow rate, tube wall thickness, depth from the surface and design shape on saturation time, the oxygen mass transfer coefficient and standard aeration efficiency. To identify each indicator, testing were carried out in accordance with ASCE 2007 guidelines from the American Society of Civil Engineers. The findings demonstrated a connection between oxygen mass transfer coefficient and operational parameters were as follows: inverse relationship with air flow rate, inverse relationship with depth from water surface, positive relationship with tube wall thickness and increases with circular shape design more than longitudinal. The maximum value of standard aeration efficiency was 2.66 kg.O2/kW.h under operational parameters of 0.1 m3.h-1 for air flow rate, 0.70 m for depth from the water surface, 7 mm for tube wall thickness and circular design shape. The minimum value of saturation time was 8 minutes under operational parameters of 0.1 m3.h-1 for air flow rate, 0.70 m for depth from the water surface, 7 mm for tube wall thickness and circular design shape.

[Read full article] [Citation]

FOUDA T., ELRAYES A.E., ELHANAFY A.E., GHONAME M. 2022, USING RUBBER TUBES TO GENERATE MICRO BUBBLES FOR AERATION SYSTEM IN SEMI-INTENSIVE FISH FARMING . Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4, PRINT ISSN 2284-7995, 239-250.

Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4
Written by Gabriela MACRA, Florin SALA

The study evaluated the variation in the efficiency of nitrogen use from mineral fertilizers, associated with foliar fertilization in wheat, based on biological yield. Two specific indicators (Agronomic Efficiency - AE, Partial Factor Productivity - PFP) were calculated to quantify the efficiency of nitrogen use. The study was organized within the Didactic and Experimental Resort, BUASVM Timisoara. The 'Alex' wheat cultivar was cultivated, under the conditions of a chernozem type soil, medium fertility, and non-irrigated culture system. The 2020 – 2021 agricultural year was taken into account. Biological yield (BY, g m-2) was evaluated at physiological maturity (BBCH code 9, Senescence). Polynomial models of the 2nd degree described the variation of BY in relation to nitrogen (N) on each level of foliar fertilization (Super Fifty – SF), in differentiated conditions of statistical certainty (p<0.05 for the SF2 variant). There was an increasing variation in the AE and PFP values associated with foliar fertilization (SF), up to the level of SF2 and SF3 variants (2 – 3 L ha-1), followed by a decreasing trend. The regression analysis led to obtaining an equation-type mathematical model that described the BY variation in relation to N and SF, as a direct and interaction effect, under statistical safety conditions (p<0.001, R2=0.957). Based on the values of the obtained equation coefficients, the optimal doses were calculated (xopt=137.05 kg ha-1N active substance, yopt=2.92 L ha-1 SF, concentration 1.168 %).

[Read full article] [Citation]

MACRA G., SALA F. 2022, VARIATION OF NITROGEN USE EFFICIENCY FROM MINERAL FERTILIZER ASSOCIATED WITH SOME FOLIAR TREATMENT . Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4, PRINT ISSN 2284-7995, 379-386.

Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4
Written by Cristina TOȚA, Maria BALA, Florin SALA

The present study analyzed the influence of some bioactive substances on vegetative propagation based on stem cuttings of Crassula ovata (Miller) Druce (jade tree). Stem cuttings were taken from the source plants for vegetation propagation. The cuttings were 5 cm long, 0.6 cm in diameter and had two pairs of leaves, with a high degree of uniformity. Three biostimulant products were used, Raiza, Rhyzo and Sangral, along with a control variant (Ct). A peat substrate, Klasmann TS3, was used for rooting. The cuttings treated with the biostimulating products and those from the control variant were placed on the rooting substrate on June 16, 2022. The number of roots (RN) and the length of roots (RL) were evaluated at three times during the study period; June 30 (t1), July 7 (t2) and July 14 (t3). The variation of RN and RL in relation to time (days) during the study period was described by polynomial equations of the 2nd degree, under statistical safety conditions (p<0.01). According to PCA, PC1 explained 60.665% of variance, and PC2 explained 26.216% of variance. Associated with the Sangral product were RN-t2 and RN-t3 parameters, and associated with the Raiza and Rhyzo products were RN-t1 parameters and especially root length, RL-t1, RL-t2 and RL-t3. Under the aspect of the increase in the formation of the number of roots, based on the recorded values, it was found that the Sangral product generated a stronger rooting (RN-t2-I = 4.92; RN-t3-I = 3.25), and with regard to the length of the roots (RL), the Rhyzo product generated the largest increases (RL-t2-I = 1.03 cm, respectively RN-t3-I = 1.49 cm).

[Read full article] [Citation]

TOTA C., BALA M., SALA F. 2022, VEGETATIVE PROPAGATION IN JADE TREE USING ROOTING BIOSTIMULATORS OF STEM CUTTINGS. Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4, PRINT ISSN 2284-7995, 743-750.

Published in Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4
Written by George MOISE

Waste are a big problem in the economci and not only affecting environment quality. For this reason, it is compulsory to find solutions to reconvert these waste to avoid pollution. This paper presents the management and utilization of waste from the 11 wood industry factories in the city of Reghin, Mureș county, Romania and also a few case studies in agriculture where solutions were found to increase production and maintain environment quality. Wood waste is a category that can be used to obtain energy by burning or composting sawdust that can be used as fuel, sawdust that can be used for wood boilers, for pal panels or for paper pulp, or in animal husbandry as litter for animals. The purpose of the study was the study of waste management within these companies, where we found that a simple production results in several categories of waste such as: glass, plastic, paper, chemicals, oils, glues, paints, combustion ash, slag and the largest amount of wood waste. To increase production and reduce manufacturing costs, we recommend reintroducing this wood waste back into the production cycle, harnessing it in the form of thermal energy.

[Read full article] [Citation]

MOISE G. 2022, WASTE MANAGEMENT - STUDY CASES . Scientific Papers. Series "Management, Economic Engineering in Agriculture and rural development", Vol. 22 ISSUE 4, PRINT ISSN 2284-7995, 433-442.

Page 19 of 19

The publisher is not responsible for the opinions published in the Volume. They represent the authors’ point of view.

© 2019 To be cited: Scientific Papers. Series “Management, Economic Engineering in Agriculture and Rural Development“.

Powered by INTELIDEV

Management Journal