Effect of Plant Growth Promoting Rhizobacteria (PGPR) and Planting Pattern on Yield and Its Components of Rice (Oryza sativa L.) in Ilam Province, Iran
Abstract—Most parts of the world such as Iran are facing the excessive consumption of fertilizers, that are used to achieve high yield, but increase the cost of production of fertilizer and degradation of soil and water resources. This experiment was carried out to study the effect of PGPR and planting pattern on yield and yield components of rice (Oryza sativa L.) using split plot based on randomized complete block design with three replications in Ilam province, Iran. Bio-fertilizer including Azotobacter, Nitroxin and control treatment (without consumption) were designed as a main plot and planting pattern including 15 × 10, 15 × 15 and 15 × 20 and the number of plant in hill including 3, 4 and 5 plants in hill were considered as a sub-plots. The results showed that the effect of biofertilizers, planting pattern and the number of plants in hill were significant affect on yield and yield components. Interaction effect between bio-fertilizer and planting pattern had important difference on the number spikelet of panicle and harvest index. Interaction effect between bio-fertilizer and the number of plants in hill were significant affect on the number of spikelet per panicle. The maximum grain yield was obtained by inoculation with Nitroxin, planting pattern of 15 × 15 and 4 plants in hill with mean of 1110.6 g.m, 959.9 g.m and 928.4 g.m, respectively.
Effect of Azospirillum brasilense inoculation on growth dynamics and hydraulic conductivity of sorghum bicolor roots
Abstract Root growth was monitored in hydroponic systems under greenhouse conditions. Inoculation with Azospirillum brasilense increased the total number and length of adventitious roots of Sorghum bicolor by 33–40% over non‐inoculated controls. This resulted from a higher rate of growth, earlier root appearance and a greater elongation rate of individual sorghum roots. Inoculation also led to a 25–40% increase in hydraulic conductivity of the inoculated root system as compared to controls. In plants subjected to an osmotic stress by the addition of polyethylene glycol (PEG 6000) to the growth medium to produce an osmotic potential of ‐2.0 bar, inoculation significantly diminished most of the drastic adverse effects on root growth. It was concluded that beneficial effects of Azospirillum on the growth and yield of sorghum can be attributed largely to improved growth and function of the root system.
Determination of Optimal Ball-Burnishing Parameters for Plastic Injection Moulding Steel
The objective of this study is to determine the optimal plane ball-burnishing parameters for plastic injection moulding steel PDS5 on a machining centre by utilising the Taguchi’s orthogonal array method. The design and manufacture of a burnishing tool are described. Four burnishing parameters, namely the ball material, burnishing speed, burnishing force and feed, were selected as the experimental factors in Taguchi’s design of experiments to determine the optimal burnishing parameters which have the dominant influence on surface roughness. The optimal burnishing parameters were found after carrying out the experiments specified by Taguchi’s L18 orthogonal table, by the analysis of variation, and by a full factorial experiment. The optimal plane burnishing parameters for the plastic injection moulding steel PDS5 were a combination of a tungsten carbide ball, a burnishing speed of 200 mm/min, a burnishing force of 300 N and a feed of 40 μm. The surface roughness Ra of the specimen can be improved from about 1 μm to 0.07 μm by using the optimal burnishing parameters for plane burnishing.