The advent of nanotechnology has led to new achievements in the different fields of science and technology. The minified size of materials under this technology discloses certain novel or hitherto ignored features and properties of these materials. It is true that nanotechnology has helped enhance certain features of fertilizers as evidenced by a number of studies reporting their positive effects on different plants. However, it should be noted that most of these studies were performed under laboratory conditions and considered only short periods of plant life, in many cases only up to germination. This is while there are many reports showing the adverse consequences of using nano-materials. For example, nanoparticles of aluminum, iron, zinc, titanium, nickel, and silver or hydroxyapatite nanoparticles and carbon nanotubes have caused reduced growth in onions, vetch, rye, rice, beans, corn, cucumber, sorghum, and tomato plants. These inconsistent reports call for exhaustive investigations to determine the interactions between nano-materials and plants and their final fate in the plant and food chain before they can be used as fertilizers. Since plants stand at the beginning of the food chain, introduction and accumulation of nano-materials inside them might help transfer these materials to higher levels of the chain to end up in the human body. This paper studies the effects of high concentrations of nano-materials on plant growth in certain species, the associated damages, and the uptake and accumulation of nanoparticles in plant.

To investigate the response of corn to combined application of chemical fertilizers with rhizobacteria plant growth promoting, an experiment was conducted in 2017 at Research farm of Agricultural and Natural Resources Campus of Tehran University, Karaj, Iran, in a randomized complete block design with four replications. Four nutritional treatments including T1 (Control treatment without applying fertilizer), T2 (Just PGPRs), T3 (Use chemical fertilizers based on soil test) and T4 (T3 + PGPRs) were considered. According to the results, the highest total dry weight (3.9 kg/m2), crop growth rate (79.8 g.m-2.day-1), net assimilation rate (15.3 g.m-2.day-1) and grain yield (18.2 ton.ha-1) were observed in T4 treatment and T2 treatment produced the highest  leaf area index (5.3), leaf area duration (205.2) and specific leaf weight (78.5 g.m-2) . Also, the lowest value of all traits was observed in in T1 (control) treatment. The results showed that the presence of rhizobacteria plant growth promotioninduction in the corn nutrition program increased the growth and growth indices of the plant. Combined application of chemical fertilizers with rhizobacteria plant growth promoting resulted in the highest growth and final grain yield of corn.

To evaluate the relationships between soil inorganic phosphorus P (Pi) fractions, the soil P test and plant parameters such as plant P uptake, dry matter yield, tissue P concentration and relative yield, glasshouse experiments and chemical analyses were conducted on 13 calcareous soils from six agricultural and seven adjacent bushland (virgin soil) sites. Four rates of P (0, 15, 30, 60 mg/kg soil) were applied as reagent-grade KH2PO4 to the soils in a randomised complete block design with three replications. Perennial ryegrass (Lolium perenne cv. Roper) was grown and forage was harvested five times over a period of 210 days. Successive harvesting resulted in the depletion of plant available P as measured by NaHCO3-extractable P, which coincided with the decrease in the plant dry matter yield and P uptake. After five harvests, the order of reduction in Pi fractions induced by cropping without added P was Ca10-P>Al-P>Ca2-P>Ca8-P>occluded-P>Fe-P for the virgin soils and Ca2-P>Al-P>Ca10-P>Ca8-P>Fe-P>occluded-P for the agricultural soils. The order of abundance of Pi fractions for P treated-soils was non-occluded Al and Fe phosphate (Al-P+Fe-P)>secondary Ca-bound P (Ca2-P+Ca8-P)>acid-extractable P (Ca10- P)>occluded-P for both virgin and agricultural soils. Although a marked proportion of added P was transformed into less soluble Al and Fe phosphates, successive harvesting had depleted considerable percentages of these fractions. Highly significant (p<0.001) relationships were found for P uptake vs. Olsen-P, P uptake vs. Pi fractions (Ca2-P, Ca10-P, Al-P, Ca8-P, Fe-P) and Olsen-P vs. Pi fractions. NaHCO3-extractable P seems to be adequate for evaluating plant available P in calcareous soils. However, the closer relationship for the Fe-P fraction vs plant P uptake than for Olsen-P versus plant P uptake indicates that NaHCO3 may not provide the best estimate of plant available P for calcareous soils. Using stepwise regression analysis, it was found that the Ca2-P fraction was most predictive of P uptake (60%), total dry matter (68%), relative yield (74%) and Olsen-P (69%), followed by the Fe-P fraction.

In congruence with the idea of sustainable development, integrated soil fertility and plant nutrition management has received global attention. The challenges facing soil fertility and plant nutrition in Iran include low soil organic carbon and nutrient contents, imbalanced plant nutrition, low nutrient efficiency, ineffective soil fertility system, environmental stresses, non-efficient fertilizer application, and inadequate knowledge transfer to users. Under these conditions, recommending proper fertilizers will be a multi-faceted and complex task. The development of a framework that incorporates all the factors involved into a single management package is the prerequisite to the integrated soil fertility and plant nutrition management as a smart system for applying an optimal assortment of chemical, organic, and biological sources of nutrients well adapted to environmental and local conditions and aimed at optimized exploitation of inherent soil capacities in a cropping system while sparing negative effects on soil ecological services. The desired integrated management system must be capable of duly accounting for all the components including plant variety; chemical, organic, and biological fertilizers; cropping system; climatic and soil conditions; and socio-economic parameters. The present study introduces the following three steps to achieve an integrated management system: 1) participation of all the stakeholders in the design, prioritization, implementation, and monitoring processes; 2) integrated use of chemical, organic, and bio-fertilizers in terms of amounts, timing, and method of application well adapted to the nutritional requirements of the plant varieties grown in the established cropping system with due consideration of environmental stresses; and 3) dissemination of localized knowledge and know-how of the integrated management system with the help of local extensionists and volunteer farmers from a pilot farm for replication and achievement of the expected outcomes in other farming sites.

Phytoremediation of lead using plants in lead-contaminated soils is a new and safe environmental technology. By adding chelators and increasing plant extraction, the efficiency of this technology can be increased. In this regard, we evaluated the effect of adding EDTA chelates to lead-contaminated soils to investigate the amount of lead accumulation in a medicinal plant, Calendula officinalis. We designed a factorial experiment in the form of a completely randomized, with three replicates in pots and two factors including EDTA at two levels (0, 50 mg kg-1) and lead at four levels (0, 30, 90, and 270 mg kg-1). In this plant, the accumulation of lead was accompanied by an increase in the amount of lead in the soil due to the addition of EDTA to the soil. The results showed that EDTA significantly increased the lead translocation of lead from roots to the aerial part of the plant.Total Chl. and shoot dry weight decrease significantly in EDTA treatment than control specific at a high level of Pb in the soil. Also, the results showed that EDTA increased lead removal from soil to soil solution and increased lead translocation from roots to the aerial part of the plant of Calendula officinalis. In general, the results of this research showed that with the careful management and EDTA use in lead extraction, it has provided a cost-effective and safe environmentally strategy.

To investigate the effects of nutrition systems on the yield and some traits of Mentha piperita L., this experiment was carried out in the experimental field of Kerman Agricultural and Natural Resources Research Center, during 2008 to 2010. A combined analysis of variance was performed using Randomized Complete Block Design with three replications by MSTATC statistical software and means were compared by Duncan test. The treatments were consisting of different levels of N, P and K (conventional system), mixture of different levels of NPK and manure (integrated system), different levels of manure (organic system) and control. The results showed that, the effect of nutrition systems on biological yield, economic yield, dry matter percentage, leaf length, leaf width, and plant height were significant. The yield increased with increasing the amount of nitrogen, phosphorus, and potassium. The yield of Mentha piperita in the integrated system was higher than that of other systems. Maximum fresh weight yield (38313 kg/ha) and maximum economic yield (5634 kg/ha ) were obtained in the first year from integrated system (120kg N, 90kg P, and 120kg K+5 tons manure per hectar). With increasing age of the plant, the fresh weight yield decreased to 15% and 63% in the second and third years, respectively. In the present experiment, the highest yield was obtained with application of 120 kg nitrogen, 90 kg phosphorus, 120 kg potassium, and 5 tons manure per hectare. The use of this plant in a plot of land more than three years will not be cost-effective.

To investigate the effects of soil fertility methods on economic yield and essential oil compositions of Nigella sativa L., an experiment was conducted in a randomized complete block design with three replications. Experimental treatments included different levels of NPK chemical fertilizer, manure, NPK+ manure, and NPK+ manure+ inoculation of Azorizobium biofertilizer. Seed yield, aerial parts yield, and percentage, yield, and essential oil compounds were studied. The results showed that the highest seed yield (1270. 43 kg. ha-1) was obtained in the 40 kg. ha-1 N+ 32 kg. ha-1 P+ 40 kg. ha-1 K+ 30 ton. ha-1 manure treatment. The highest percentage (0. 25%) and essential oil yield (2. 8 kg. ha-1) was obtained in the 40 kg. ha-1 N+ 32 kg. ha-1 P+ 40 kg. ha-1 K+ 30 ton. ha-1 manure+ Azurizobium treatment. The highest thymoquinone percentage (14. 9%) was observed in the 30 ton. ha-1 manure treatment. Overall, the integrated and biological treatments had the most positive effects on seed yield and essential oil percentage of N. sativa. The use of suitable fertilizer sources not only increased the yield, essential oil percentage, and thymoquinone content in Nigella sativa, but also reduced the consequences of excessive use of chemical fertilizers. The use of integrated fertilization methods is an effective step to achieve the sustainable agriculture goals.