جستجوی مقالات مرتبط با کلیدواژه "کارایی جذب" در نشریات گروه "کشاورزی"

One of the strategies of using low-soluble P farctions in the soil is selection and cultivation of plants and varieties with high P uptake efficiency. According to the necessity of P uptake efficiency and effective mechanisms in commercial varieties of sugarcane knowledge, a pot experiment was carried out in greenhouse condition in Hakim Farabi Agro-Industry CO.. The treatments were P fertilizer (including: blank (P0), 125 (P50) and 250 (P100) kg ha-1 as triple superphosphate) and varieties of sugarcane (including: CP57-614, CP69-1062 and CP48-103) in three sampling times (including: 45, 90 and 130 days after planting) with three replications in factorial based on completely randomized design. In this study, P uptake, root length, specific root length, root to shoot ratio and P influx were evaluated at each sampling time. In low available P condition, the CP48 and the CP57 varieties able to uptake more P and then considered as efficient P varieties. However, CP69 has less ability to uptake of P in this condition. In this condition, CP48 variety, P uptake was increased by 13% and 45% compared to CP57 and CP69 varieties respectively. However, CP57 showed enhancement of P uptake up to 29% compared to CP69 variety. Phosphorus influx decreased in CP57 and CP69 varieties by 53% and 67% respectively with aging of sugarcane that the greatest decrease of influx was observed in CP69 variety. In the CP48 variety, P influx increased up to 66%, which can be an effective factor in more P uptake. Therefore, these differences in the ability of P uptake in sugarcane varieties and mechanisms affecting P uptake can improve the management of P fertilizer consumption especially in ratoon.

During the 1950s and 1960s, the green revolution led to a dramatic increase in global food and fodder production to eliminate hunger and boost food security. This production enhancement was accompanied by an intensified agricultural and chemical input consumption and increased cultivated area and mechanization. Although yield per unit area has improved in most crops, concerns about food security for the world's rising population are still significant. Guaranteeing food security in the future will necessitate a shift in management approaches to boost output, agroecosystem sustainability, and stability and reduce the environmental harm caused by agriculture. The first step to achieving sustainability and ecological intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems in each region. Hence, the complete evaluation and analysis of agroecological features according to their type in each region is necessary for establishing an optimal management technique. After analyzing the present state of each region's shared ecosystems, the optimal strategy for boosting production stability must be devised and implemented.

The goal of this study was to undertake a detailed investigation of the agroecological state of the sugar beet ecosystems on a local scale. For this purpose, data were collected on the area under cultivation, yield, and input consumption (including nitrogen and phosphorus fertilizers and chemical pesticides) from 2001 to 2016. Data was acquired from the Ministry of Agriculture and other related organizations and direct interviews with the farmers. In addition, data on climatic parameters (including daily minimum and maximum temperatures, precipitation, and sunny hours) were collected from the Torbat-e Heydariyeh meteorological station. This study researched the most important agroecological indicators of sugar beet farming systems in the Torbat-e Heydarieh region. Study indicators include variations in sugar beet cultivation area and yield, Potential yield via the methods FAO and FAO modified, beet yield gap, Regional Yield Factor trend, Changes in the intensification, yield stability, nitrogen uptake, and nitrogen utilization, and nitrogen use efficiency.

According to this study results, sugar beet production increased by 59 percent between 2001 and 2016. During the research years, sugar beet ecosystems saw a drop in the cultivation area. Potential yield calculations using both FAO and modified FAO methodologies revealed that potential yield was nearly consistent over the research period in the region.The sugar beet yield gap averaged 35 ton.ha-1 over the research period. According to the findings, the percentage of sugar beet yield gap ranged from 53 to 69 %, with an average of 63 %. The extent of the yield gap decreased over the research period. The study of the regional yield factor (RYF) revealed that improving the management system resulted in higher actual yield and thus a smaller yield gap in sugar beet ecosystems. In sugar beet cultivation systems, the results revealed that by increasing intensification, the stability decreased. In sugar beet cultivation systems, there was a reduction in yield stability. Given that nitrogen consumption efficiency is one of the most important factors influencing the degree of stability in agricultural systems, the findings revealed that the rate of nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE), and nitrogen use efficiency (NUE) all decreased during the studied years in the region.

According to the findings, the major cause of the increase in nitrogen consumption, growing intensification, and decreasing stability in the analyzed systems appears to be a deficiency of nitrogen use efficiency and its downward trend. As a result, planning and altering management methods focusing on enhancing Nitrogen use efficiency may be proposed as the first step toward boosting sustainability in the Torbat-e Heydarieh sugar beet agroecosystems.

The issue of maximizing crop yields through excessive consumption of chemical inputs and high costs in the production of these products has led agricultural experts and analysts find a suitable way to integrate technology and conserve natural resources in order to create a favorable environment for the optimal use of available resources, reduce environmental problems and increase yields per unit area and provide greater profitability in agriculture (Ratek et al., 2004). On the other hand, Iran's location in arid and semi-arid climates has caused the soil of most areas to be poor in organic matter and this is one of the problems that can be effective in reducing performance and increasing production costs (Chegni et al., 2014). So it seems maintaining of sufficient amount of plant residues in the soils is an effective way to overcome the soil quality threats. This research was carried out with the aim of investigating the effects of different cropping systems management and wheat residues on grain yield and efficiency indices of nitrogen and phosphor in autumnal rapeseed. The experiment was conducted as strip split plot based on randomized complete block designs in three replications in 2015-2016 in two locations (Sarableh and Roumeshgan) in southern west of Iran. The first factor was cropping systems in three levels as low input (one disk + 25% of plant nutrient requirement as fertilizer + two stages manual weed control), Mid input (one plowing + one disk+ 50% of plant nutrient requirement as fertilizer+one stage manually and one stage using herbicide to weeds control) and full input (two plowing +two disk + 100% of plant nutrient requirement as fertilizer+ two stages herbicide to weeds control). The second factor was wheat residues managements in four levels of 0 as control, 2, 4 and 6 t.ha-1. The required fertilizer was calculated based on the results of soil analysis so that 100 kg of superphosphate and 200 kg of urea in Romeshgan and 150 kg of superphosphate and 300 kg of urea in Sarablah were required. To control weeds in the low input system, two stages of mechanical weeding in 7 and 45 days after planting, in the medium input system, one stage of chemical control (terflan) at the same time as planting and one stage of mechanical weeding in 45 days after planting, and in the full input system, two stages of spraying simultaneously with planting (Terflan) and 45 days after planting (Lontrol + Supergalant) were performed. Finally, after calculating grain and biological yield, uptake efficiency, utilization efficiency and nutrient use efficiency were determined.After testing the uniformity of variance using Bartlett test, the combined analysis of data was performed by SAS 9.1 software.Results and DiscussionThe results showed that in low input management with increasing wheat residues, the phosphor and nitrogen use efficiency was decreased so that in the treatments of four and six tons of residues per hectare compared to non-residues, respectively, nitrogen productivity of 15 and 22 percent and phosphor productivity of 15 and 20 percent were significantly decreased. With the move of crop system management towards high input management, the positive effect of low residue levels on nutrient use efficiency was determined so that in high input management, the highest efficiency of nitrogen and phosphorus consumption was obtained with 12.3 kg of grain per kg of nitrogen and 30.3 kg of grain per kg of phosphorus from treatments of four tons of wheat residues, respectively. The results also indicated that in all treatments, the effect of nitrogen and phosphorus uptake efficiency was higher than their utilization efficiency on the use efficiency of each of these nutrients. Therefore, the management of crop systems based on increasing the uptake efficiency of each nutrient in rapeseed cultivation can play a decisive role in increasing yield.In general, the results showed that with increasing the entrance of inputs and crop system management the uptake and use efficiency of nitrogen and phosphorus increased, but nutrient utilization efficiency was maximized in medium input management. It was also found that with increasing the application of wheat residues to the soil, the efficiency of uptake and use of nitrogen and phosphorus nutrients indicated a decreasing trend.

Element efficiency is one of the most important characteristics of different plant cultivars for managing nutrition and fertilizer application in plants. This study was carried out to investigate the efficiency of silicon in different maize cultivars in a calcareous soil under greenhouse conditions. Treatments included five maize cultivars (single crosses 400 (ksc400), 410 (ksc410), 704 (ksc704), 705 (ksc705), 706 (ksc706)) and two silicon levels (0 and 100 mg silicon in 1 kg soil from potassium silicate source), which was performed in a factorial arrangement based on a completely randomized design. After eight weeks of vegetative period, plants harvested and factors such as shoot and root dry weight, leaf area, root volume and surface area and plant silicon uptake were measured. Efficiency element indices including adsorption and consumption efficiency of silicon and silicon efficiency of different cultivars were calculated. Among cultivars, ksc706 with 14.54 g yield, root weight of 6.7 g, leaf area of 173700 mm2 and root area of 185185 mm2 had the best results in terms of morphological characteristics and ksc410 cultivar with yield of 10.03 g, root weight of 5.25 g, leaf area of ​​2147900 mm2 and root area of ​​136284 mm2 showed the lowest desirable characteristics, compared to the control treatment. Yield increase of cultivars compared to the control treatment were: ksc400 (20.7%), ksc706 (17.8%), ksc410 (9.2%), ksc704 (8.9%) and ksc705 (4.8%). The highest silicon uptake efficiency was in ksc706 cultivar (85.7%) and the lowest in ksc704 (58.9%), and the highest silicon consumption efficiency was in ksc705 (12.52%) and the lowest in ksc400 (5.44%). With regard of increasing the area of root system in the treatment containing silicon compared to the control, and the effects of silicon on the uptake and transfer of more nutrients from the soil to the shoots, an increase in plant yield is evident. Accordingly, it is suggested to consider the development of planting the effective element plants with the aim of managing input consumption, soil fertility and sustainable agricultural goals.

There is a little information regarding the chromosomal regions conferring seed zinc accumulation in barley. With the aim of QTL mapping of Zn concentration and content, 121 barley genotypes (including local landraces, released cultivars, gene bank germplasm) were screened under field conditions. The trial was conducted in square latice in 2015-2017 cropping seasons at dryland agricultural research institute (DARI) in Maragheh. To construct genetic linkage map, 149 SSR markers were applied. Based on ANOVA, there was a great genotypic variation for seed Zn concentration and content among the genotypes, which approves the excessive diversity of genotypes. Five QTLs located on 2H, 3H, 4H and 5H were associated with seed Zn concentration, and could explain 81% of total phenotypic variation. Marker BMAG0720 had the highest (25%) phenotypic variation. This marker could also explain 23% of total variation for seed Zn content. Moreover, 5 genomic regions on 2H, 3H and and 4H were associated with seed Zn content. In conclusion, the identification of these major QTLs would provide an important starting point for marker assisted selection (MAS) that may contribute to the improvement of barley productivity and nutritional quality.

In order to study the effect of sowing date and different amounts of nitrogen and phosphorus fertilizers on the grain yield, mucilage production, nitrogen and phosphorus uptake, utilization and use efficiency in Lallemantia royleana Benth., a factorial experiment was conducted in a randomized complete block design with three replications in medicinal plants research center  of Shahed University. The treatments included two levels of sowing date (autumn planting in the second week of November (2013) and spring planting in the second week of March (2014)) and three levels of nitrogen and phosphorus (control (without fertilizer), 50%: Npure 23 kg ha-1 + P2O5 50.6 kg ha-1 and 100%: Npure 46 kg ha-1 + P2O5 101.2 kg ha-1). The results showed that the interaction between sowing date and fertilizer application was significant on grain yield, mucilage production, and nitrogen and phosphorus uptake, utilization and use efficiency. At 50% fertilizer in both sowing dates, the amount of grain yield and mucilage production was obtained 377.15 kg ha-1 and 23.45%, respectively. The highest nitrogen utilization and use (respectively, 33.86 and 5 kg kg-1 at 50% fertilizer) and uptake efficiency (0.13 kg kg-1 at 100% fertilizer) were obtained in autumn planting. The highest phosphorus uptake and utilization efficiency (respectively, 0.06 and 11 kg kg1) was observed at 50% fertilizer in spring planting. The results showed the importance of nitrogen in Lallemantia royleana production in both sowing dates.

  Intercropping defined as growing two or more crops simultaneously in the same field, considering for its more sustainability and higher yields compared to sole-cropping. More developed and distributed root systems besides efficient architecture may enhance uptake and efficiency of nutrients. Application of organic fertilizers, on the other hand reduces environmental pollution and lead to longer nutrients recycling in agricultural systems. Considering these issues, this study aimed to evaluate nutrient efficiency of dragonhead - soybean intercropping nourished with organic manure and chemical fertilizer. A RCBD factorial experiment with three replications was conducted at Shahrekord University research farm in 2016. Five sowing patterns include: Sole-cropping of soybean (S), sole cropping of dragonhead (D) and three intercropping ratios of them (S:D 2:1, 1:1, and 1:2) as first factor were evaluated at two fertilization sources (chemical fertilizer and broiler litter) as second factor. Dragonhead and soybean were harvested at flowering and maturity stages, respectively. Concentration of nitrogen, phosphorus, potassium, copper, iron, zinc and manganese were determined for each plot. Finally, uptake of nutrients was calculated by multiplying the concentration by yield. The relative crop yield and relative nutrients yield in intercropping were calculated. The analysis of variance for the obtained data was done by statistical analysis system (SAS V.9) software. The mean comparison was done using the least significant difference (LSD) test at the 5% probability level. The result showed that the maximum uptake of nitrogen (10.59 g.m-2) and phosphorus (1.79 g.m-2) were obtained in sole cropped soybean and dragonhead treated with organic manure, did not show significant difference with intercropped ratio of soybean: dragonhead (1:1). The highest uptake of potassium (14 g.m-2), iron (0.253 g.m-2), zinc (0.065 g.m-2) and manganese (0.080 g.m-2) were achieved in sole cropped dragonhead treated with organic manure too. While for copper the highest ones (0.0135 g.m-2) were obtained in sole cropped dragonhead under organic manure, showing no significant difference with soybean: dragonhead (1:2) ratio under organic manure. The highest relative yield of nitrogen (1.04), phosphorus (1.09) and iron (1.03) was obtained in soybean: dragonhead (1:1) under organic manure. The greatest relative yield of potassium (1.07), copper (1.32) and manganese (1.03) was observed in soybean: dragonhead (1:2) under organic manure.
In this study, organic manure showed significant gains in terms of nutrient uptake compared to chemical fertilizer. In addition to, uptake efficiency of nutrient was higher compared with sole cropping. Intercropped patterns especially for organic manure application enhances nutrient efficiency. So, enhancement of uptake efficiency reduces the need for fertilizers in farm, in addition to lower environmental hazards contributes to increasing economic efficiency

Water and nutrient deficiency often limit the growth and productivity of crop in agricultural systems (Cao et al., 2007). It has been reported that the effects of nutrient supply and water regimes may interact significantly on plant growth (Hu and Schmidhalter, 2005). A simple assessment of the effect of each input may not show a complex interaction with the other inputs. Therefore, it is necessary to understand the interactive effects of soil water and nutrients on plant growth in the arid environments. Hence, the objectives of this study were to: (1) determine the interactive effects of ETc, nitrogen and phosphorus on yield and N-P efficiency indicators in maize crop and (2) evaluate the importance of uptake efficiency versus utilization efficiency of nitrogen and phosphorus on NUE and PUE.
This study was carried out at the research farm of Ferdowsi University of Mashhad, Iran, located 10 km east of Mashhad at 36.16° North latitude, 59.36° East longitude, and height of 985 m above sea level, in two growing years of 2014 and 2015. The experiment was conducted as split plot based on a randomized complete block design with three replications. The main plot consisted three levels of 80 (ETc80), 100 (ETc100) and 120 (ETc120) of plant evapotranspiration, and sub plot included a factorial combination of three N levels (0, 200 and 400 kg ha-1) and three P levels (0, 100 and 200 kg ha-1). Combined analysis of variance was performed by SAS 9.4 software, and means of different treatments were compared by Tukey test at the probability level of 5%.
Maize grain yield increased significantly as a result of increase in all inputs. However, effect of nitrogen on grain yield was more than others. Application of 200 and 400 kg ha-1 N caused 24% and 38% increases in maize yield, respectively. The interaction effect of ETc and N for grain yield was significant, and the highest and the lowest yield of maize with the values of 9486.8 and 5836.4 kg ha-1 was obtained with ETc100N400 and ETc80N0, respectively. When applied water increased up to ETc100, all levels of nitrogen increased yield but water use higher than this level decreased grain yield in N400. It appears that under these conditions, leaching increases, which ultimately led to the reduction of yield. According to these findings, irrigation more than ETc100 decreased N uptake in this treatment.
The trends of NUE and PUE in response to treatments were similar to that of grain yield. It has been reported that changes in each of the P use efficiency components are significantly dependent on plant yield (Fageria et al., 2014). The interaction of nitrogen and phosphorus showed that in N0, the effect of different levels of phosphorous on grain yield was not significant, while phosphorus application at levels N200 and N400 significantly increased maize grain yield. These findings suggest that the interaction of nitrogen and phosphorus on grain yield and nutrient uptake is synergistic. The results of path analysis indicated that in most of the treatments, the role of N and P uptake efficiency was superior to that of their utilization efficiency on the NUE and PUE.
The results showed that maize grain yield improved with increasing the inputs. The magnitude of the effects of all inputs on yield was in the order of N > ETc > P. The interaction effect of ETc and N showed that ETc100N200 was the optimum treatment to improve the yield and nitrogen efficiency simultaneously. The interaction of N and P on the yield and nutrient uptake was positive and synergistic. Overall, this study emphasized the importance of the interactive relationships between water and nutrients for achieving both the highest grain yield and nutrient use efficiency.

IntroductionIntercropping is one of the most effective approaches for developing sustainable agriculture which causes control of soil erosion, decreasing usage of agrochemicals, increasing biodiversity, yield in area unit, quantity and quality of the product and it finally makes stability in agronomical ecosystems. Many researchers consider the multiple cropping as the most important factor for increasing the diversity of cultures in agricultural ecosystems. Increasing crop diversity through intercropping can be effective to improve the ecological functions and ecosystem services.
The aim of this study was to determine the best pattern of wheat and canola intercropping based on yield and nutrition use efficiency.
Materials and MethodsIn order to study the effects of intercropping on yield and nitrogen and phosphorus use efficiency, a field experiment was conducted as randomized complete block design (RCBD) at Agricultural Research Station, Ferdowsi University of Mashhad, Iran, during 2012-2013 growing season. Experimental treatments were included planting patterns of wheat (Alvand and Falat cultivars) and canola (Ocapy and Zarfam cultivars) intercropping with ratios of 1:1, 2:2, 3:3 and sole cropping of them with three replications. The size of each plot was 6 m2 and distance between plots and blocks were 0.5 and 1 m, respectively. Planting of wheat and canola cultivars were done with densities of 320 and 80 plant per m2, respectively, at the same time.
Nitrogen content of plant was determined by microkejeldal machine and wet digestion method. Phosphorus content was measured by spectrophotometer machine and Olsen method. Land equivalent ratio (LER) was used to evaluate the advantage of the intercropping. Analysis of variance was done with SAS ver 9.1 software and means were compared with Duncan’s test at the 5% level of probability.
Results and DiscussionThe results showed that the highest economical yield was obtained from sole cropping of Alvand (4199.77 kg ha1). Treatment of Alvand-Ocapy intercropping (3:3) had the highest economical yield within different patterns of intercropping. The highest and lowest biological yield of wheat were revealed from sole cropping of Alvand and Falat-Zarfam intercropping (2:2), respectively. The sole cropping of Ocapy and Falat-Zarfam intercropping (2:2) had the highest (4034.54 kg ha-1) and lowest (1691.98 kg ha1) economical yield of canola. The highest and lowest amounts of canola biological yield were obtained from sole cropping of Ocapy and Falat-Zarfam intercropping (2:2), respectively. Land equivalent ratio (LER) in all different patterns of intercropping was more than one which shows advantage of the intercropping. The highest LER was obtained from Alvand-Ocapy intercropping (3:3). The highest nitrogen and phosphorus physiological efficiency were observed in sole cropping of Falat cultivar (wheat) and in the case of canola was obtained from Falat-Zarfam intercropping (2:2). The sole cropping of Alvand and Alvand-Ocapy intercropping (3:3) had the highest use efficiency of nitrogen and phosphorus, respectively. The highest amount of nitrogen and phosphorus uptake was obtained from Alvand- Ocapy intercropping (3:3) and sole cropping of Ocapy (respectively, for wheat and canole).
ConclusionsThe results of this study indicated that treatment of Alvand- Ocapy intercrroping (3:3) had the highest economical yield, land equivalent ratio and also the highest amount of nitrogen and phosphorus uptake. This planting pattern can be suggested to obtain proper yield of wheat and canola as well as appropriate amount of nitrogen and phosphorus uptake.

Nitrogen is needed in plants to form chlorophyll as well as to increase crop protein and plant yield. Application of too much nitrogen-containing fertilizers, however, is not economical. It has the additional disadvantage that it ultimately ends up in groundwater resources. Potato production in light soils usually requires a high consumption of nitrogen and frequent irrigation. At the beginning of the growing season, potatoes need a lot of nitrogen. High consumption of it at the end of the growing season, however, will cause increased foliage instead of larger tubers. Studies with high levels of nitrogen input aimed at comparing fertilizer regimes have also shown differences in nitrogen use efficiency (NUE). In recent years, the use of nanotechnology has been considered. With respect to the food recommended in most cultures, and limited research on the efficacy of nanofertilizers on crops, the present study is meant to evaluate the effectiveness of two types of nitrogen nanofertilizers, sulfur-coated urea and urea fertilizer, on potato crops.
The effect of nitrogen fertilizers on nitrogen efficiency in potato cultivation were investigated by performing a factorial experiment based on a completely randomized design with four fertilizer treatments. These included applications of Nano-Nitrogen Chelate (NNC), Sulphur Coated Nano-Nitrogen Chelate (SNNC), Sulphur Coated Urea (SCU) and Urea (U) in the greenhouse over two years. Each treatment, including 46 kg-N/ha, 92 kg-N/ha, and 138 kg-N/ha, with three replications were compared. The study parameters included nitrogen efficiency indices, leaf nitrogen percentage, yield and tuber nitrate. Also calculated for each treatment were the N-efficiency parameters of Agronomic-Nitrogen Use Efficiency (A-NUE), Economic-Nitrogen Use Efficiency (E-NUE), Nitrogen Uptake Percentage (NUP), Agronomic-Physiologic Nitrogen Use Efficiency (A-PNUE) and Economic-Physiologic Nitrogen Use Efficiency (E-PNUE)
The results showed that the maximum nitrate concentration of 240 mg kg-1 in tubers was obtained using 138 kg-N ha-1 supplied from urea. The lowest nitrate concentrations came from the nanofertilizer and SCU treatments. In total fertilizer treatments with increased N application, the amount of A-NUE, E-NUE and NUP decreased in both years. The SNNC in the first year and SCU in the second year had the highest E-NUE and ANE of the fertilizer sources. Comparison of means indicated that the highest tuber nitrate in the first year (215.63 mg kg-1) and in the second year (239.7 mg kg-1) was the outcome of the 138 kg-N ha-1 U treatment. Also, the results showed that in the first year, the highest E-NUE was the product of the first nitrogen level of SCU while the lowest levels were produced by the third nitrogen level of urea. It may therefore be concluded that nanofertilizers and SCU are more efficient in cultivations with nitrogen requirements. The changes in the E-PNUE index are similar to those in the E-NUE index. In other words, the values of E-PNUE and E-NUE decrease with increasing fertilizer applications while that of the E-PNUE increases with increasing nitrogen. The potato experiments of Darwish et al. (2006) and Halitligil etal. (2002), showed that E-NUE and E-PNUE were reduced with increasing nitrogen levels of urea treatment. The A-NUE and A-PNUE did not affect yield equally. Also, the role of fertilizers with equal nitrogen in yield increase did not have the same function; nanotechnologies have a synergistic effect on plant response to nitrogen use.
Since a higher yield with the least adverse environmental effects is paramount in the third millennium, it is essential to use suitable fertilizers. The application of nanotechnology to agriculture in recent years has attracted much attention. In this study, reduced nitrate leaching and increased potato yield with an emphasis on reduced soil and water pollution were investigated in experiments with treatments that consisted of three nitrogen levels of NNC, SNNC, SCU, and U. The results showed that the 138kg-N/ha SNNC and 138kg-N/ha NNC produced the highest tuber yield. The lowest yield was obtained from the application of 138kg-N/ha U fertilizer. Comparing N-efficiency parameters showed that the highest E-NUE value was obtained with the first nitrogen level of SCU and lowest was the outcome of the third nitrogen level of Urea. Moreover, comparison of different levels of nitrogen indicated that low nitrogen levels in slow-release fertilizers performed better than the high levels of U fertilizer, which indicates an economic advantage as well. Since this experiment was conducted under greenhouse conditions, repeating this research in field conditions and with other crops is recommended.

Conventional operations in fields، soil and water management are not efficient and loss of and damage to the environment are considerable (Lal، 2000). Crop diversity and understanding the complex interactions between environmental and socioeconomic factors are approaches to make better use of limited resources (Tengberg et al.، 1998). The most diverse ecosystems have a higher production under environment stress conditions compared with ecosystems with low diversity due to the better efficiency in the use of water، radiation and nutrients (Hulugalle & al، 1986; Walker & Ogindo، 2003).

In order to investigate the effects of crop diversity and nutrient source on resource use efficiency، a split plot experiment was conducted based on complete randomized blocks with 3 replications at the Agricultural Research Station، the Ferdowsi University of Mashhad، Iran، during 2006 and 2007. The treatments included manure and chemical fertilizers as the main plots and intercropping of 3 soybean varieties (Williams، Sahar and Gorgan3)، intercropping of 3 Millet species (common millet، foxtail millet and pearl millet)، intercropping of millet، soybean and sesame (Sesamum indicum) and intercropping of millet، sesame، fenugreek (Trigonella foenum-graecum) and ajowan (Trachyspermum ammi) as sub plots.

The results indicated that in the first year، intercropping of 3 Millet species and intercropping of millet، soybean and sesame showed the highest water use efficiency (WUE) based on biological yield. In the second year، intercropping of 3 millet species showed the highest WUE based on biological yield. The highest concentrations of nitrogen، phosphorous and potassium in crop tissues were observed in intercropping of 3 soybean varieties and intercropping of millet، soybean and sesame. In the first year، intercropping of 3 soybean varieties showed the highest nutrient use efficiency (NUE). In the second year، intercropping of 3 soybean varieties، intercropping of millet، soybean and sesame and intercropping of millet، sesame، fenugreek and ajowan showed the highest NUE. In the two years، intercropping of millet، soybean and sesame and intercropping of millet، sesame، fenugreek and ajowan showed the highest nitrogen and phosphorus absorption efficiency (NAE). Intercropping of millet، soybean and sesame showed the highest potassium uptake efficiency. In this study، nutrient resource did not have a significant effect on water and nutrient use efficiency. The research results have indicated that often nitrogen amount and use efficiency in legume and non legume intercropping were higher than monocultures. This indicates the synergist effect in the intercroppings (Vandermeer، 1989; Szumigalski & Van Acker، 2006). In general، the different benefits of diversity and better use of available inputs are obtained by increasing the diversity of crops and proper selection of plants cultivated in intercropping systems and crop rotations in monoculture systems

Most of medicinal plants are able to grow in low P supply as well. In order to study the ability of some medicinal plant species، a greenhouse experiment was conducted with Salvia virgata، Achillea millefolium and Ziziphora clinopodioides Lam in a low P soil. The experiment was undertaken with three levels of P (0، 15، 150 mg kg-1)، two harvests and three replications as a randomized complete block design. In the second harvest and low P treatment، all species showed a high relative shoot dry matter (above 80%) which indicated a high P use efficiency of them. The range of shoot P concentration in low P treatment at the first harvest was between 0. 23% and 0. 29%. In this case، no significant difference was observed among different P treatments. In addition، the shoot P content of plants was almost high. As a result، all three plant species were P uptake efficient plants. The P influx in Ziziphora clinopodioides Lam was more than two other plant species. The results of the root- shoot ratio of plants at low P supplied was indicated that high P uptake efficiency of Salvia virgata was mostly due to its extensive root system، whilst، for Ziziphora clinopodioides Lam it was mostly due to its high P influx.

In order to evaluate efficiency of nitrogen fertilizers consumption in a sugar beet monogerm hybrid variety of Zarghan, a field experiment was conducted in a loamy soil during 2007 in the research farm of Sugar Beet Seed Institute located in Karaj. Five levels of nitrogen fertilizers including 0 (check), 120, 160, 200 and 240 Kg/ha of net nitrogen from urea fertilizer (46 percent of pure nitrogen) and three levels of phosphor including 0 (check), 50 and 100 Kg of P2O5 per hectare from the triple super phosphate were arranged in a factorial experiment (5×3) in a randomized complete block design with four replications. The results showed that the effect of nitrogen application was significant for nitrogen uptake of both top and root parts of sugar beet, and also for nitrogen uptake efficiency of whole crop. However, nitrogen uptake of sugar beet was not affected by phosphor fertilizer and by the interaction of nitrogen × phosphor application. The highest nitrogen uptake by whole crop in this experiment was equal to 447 Kg ha-1 from the treatment of 240 Kg ha-1 nitrogen application. In the check treatment, nitrogen uptake by whole crop was 250 Kg ha-1. In Zarghan sugar beet variety, for one t ha-1 beet root production about 4 Kg nitrogen was used and from the total nitrogen uptake by whole crop, 44% was allocated in the top part and 56% in the storage root of sugar beet. There was no significant difference between the treatments for nitrogen uptake efficiency, whereas nitrogen utilization efficiency for sugar yield in the treatment of N0P0 was 35% greater than that in the treatment of 240 Kg ha-1 nitrogen application. On average, nitrogen utilization efficiency was equal to 40 Kg sugar for each Kg of N uptake by the crop. Thus, for the production of sugar beet close to actual yield potential it is necessary to consider 5 Kg of N for each t of beet root. Consequently, in order to prevent the environmental pollution, improve nitrogen efficiency, and taking into account the best quality and quantity of sugar beet yield, nitrogen application must be recommended based on the soil analysis and expected root yield and quality of sugar beet.

Application of bio-fertilizers in Sustainable Agriculture perform important role at increasing of crop production and improving of soil fertility. Hence, a field experiment was performed during 2009 growing season at Agricultural Research Center of Hamedan, to study the effect of nitrogen fertilizer rates, i.e., 0, 90, 135 and 180 kg N ha-1; as CF1 to CF4, respectively, and bio-fertilizers sources i.e., without bio-fertilizer, Nitrazhin inoculation and Nitroxin inoculation; as BF1 to BF3, respectively, on yield and nitrogen use efficiency of corn. So, a factorial experiment was carried out based on randomized complete block design (RCBD) with three replications. Traits of number of grain rows/ear, grain/row, grain/ear, 1000-seed weight, grain yield, nitrogen uptake efficiency (NUPE), Agronomic nitrogen efficiency (ANE) and N-harvest index (NHI) were evaluated. Results showed that nitrogen rates had significant effects on all traits. Also, the effect of bio-fertilizer treatment on grain rows/ear, grain/row, grain/ear, grain yield, biological yield, NUPE and ANE was significant. The interaction of N rates × bio-fertilizers sources had significant effect on number of grain rows/ear, grain/ear, grain yield, biological yield and nitrogen uptake efficiency (NUPE). Maximum grain yield (956 g m-2) was achieved at CF4 × BF2 treatment. Also, the lowest grain yield (475 g m-2) belonged to CF1 × BF1 treatment. In general, with application of bio-fertilizers, there was no significant difference between CF3 and CF4 treatments for grain yield. So, it can be concluded that bio-fertilizer application with CF3 treatment, can reduce the N fertilizer up to 25% and increased yield of corn. So, it seems that, this treatment could be beneficial for corn production.