Biological nitrogen fixation (BNF) is the process that provides organic ni-trogenous compounds to the plants by using molecular nitrogen in atmosphere. Higher plants are not capable to use molecular nitrogen in atmosphere as a nitrogen source to generate essential proteins. Therefore plants either should be fertilized by adequate nitrogenous fertilizers or the microorganisms which are capable to produce nitrogenase should provide nitrogen to the plants by BNF. From among a number of factors affecting BNF, soil moisture content and ambient temperatures are considerably effective on the fixation rate. Therefore the global warming would be dramatically defective on BNF, thus effects of soil moisture as well as soil and ambient temperatures on BNF should evaluate prior rising temperature. A pot experiment was carried out to determine the effects of soil water contents on BNF. Four different soil water contents (%25, %50, %75 and %100 of water holding capacity) were adjusted either every 3 days or just after plants indicate wilting point. Non-inoculated pots were added to experiment as a control. The re-sults revealed that BNF is affected by different level of soil water content. The mechanism of this effect would not be the direct effect of water, but the side ...
Nitrogen is one of the key components of plant production and the nitrogen requirement of the plant supplied either by mineral nitrogen applications or by biological nitrogen fixation. Although the atmosphere contain huge amount of N2, plants are not able to use that as a nitrogen source. Immediately usable forms of nitrogen are nitrate (NO3-) or ammonium (NH4+). The bonds between two nitrogen atoms are quite strong thus, reducing N2 gas to mineral nitrogen forms needs considerable high amount of energy. However, in biological life, microorganisms may convert N2 to mineral nitrogen sources in ambient temperature and pressure; therefore, biological nitrogen fixation is both environmental friendly and sustainable. Industrial nitrogen fixation and mineral fertilization leads both environmental pollution and economic impact. In this research, the effects of humic+fulvic acid (HFA) on nitrogen fixation were evaluated. For this purpose, a pot experiment in controlled environment was carried out. Peanut seeds were sawn in the hole prepared after dual application of HFA doses and rhizobium bacteria. Two times sampling was realized, one in the flowering and the other in harvest time. Results revealed that HFA application was effective on biologic nitrogen fixation; however, increasing HFA doses were adversely influenced determined parameters. Due ...
