For some reasons, increasing poplar spacing in traditional poplar farming is not accepted by farmers.Scientific investigations has shown that for increasing wood quality, selection of optimum spacing, appropriate harvesting time, and cultivation of agricultural crops between tree rows, specially at early years would increase productivity and poplar cultivation area. Therefore, in this studypopulus nigra betulifolia seedlings were planted as randomized complete block design with three replicates and four mixed poplar and alfalfa treatments with tree spacing including 3X4, 3X6.66, 3X8, and 3X10 m also 2 control treatments namely sole (pure) alfalfa and pure trees (3X4m). Plot size was 1200 square meters. We investigated some important attributes during the years 1998-2008. Irrigation operation was done during the growing seasons.Ten distinctive growth attributes in conjunction with poplar and alfalfa were recorded on the treatments at different stages and suitable times during the study period. The data were analyzed using univariate and multivariate statistical methods. The study is aimed at evaluating the performance of poplar production intercrops with alfalfa. Results showed that the most amount of tree height growth belonged to mixed treatments including 3X4, 3X8 and 3X6.66 m with 159, 158 and 142 cm, respectively. Regarding the wood volume growth per hectare, the most amounts belonged to the same treatments with 18.4, 11.1 and 10.99 cubic meters, respectively. Also the most amount of dry weight production of alfalfa belonged to sole alfalfa, 3X10 and 3X8 m treatments with 7507, 4788 and 4265 kg per hectare, respectively. All of attribute amounts showing differences among treatments were significantly different at 5% level of probability. There was no significant difference among the spacing after 11 intercropping years for branch diameter and annual tree growth diameter. Meanwhile, for some attributes there were significant differences among years and interaction between treatments and years. As a final result, the suitable planting spacing of tree in Poplar/alfalfa intercropping system is 3X6.6 m according to the site conditions.

Poplar species are usually cultivated for their wood production in most areas of Iran. They are traditionally planted with low spacing which does not render thick trees.Moreover, for different reasons, increasing poplar spacing is not accepted by people and the farmers before accepting a new system, pay high importance for earning continuous income. Thus, additional income besides wood products is a vital factor to increase the public acceptance for poplar intercropping system. Therefore, intercropping poplar and fodder with increased spacing in order to increase under Randomized Complete Block Design in 1998 with three replicates, using seedlings of P. nigra betulifolia, four spacing treatments (3x4, 3x6.66, 3x8 and 3x10m.), intercropped alfalfa and two monocultured control treatments of poplar and alfalfa.The trial continued to 2003. Each plot area was 1200 m2. Ten different growth parameters the poplar and alfalfa species were measured. The data were analyzed, using the univariate and the multivariate statistical methods.The results showed that the effect of treatments on poplar and alfalfa parameters were the greatest poplar height and volume amounts belonged to the spacing treatments of 3x4, 3x8 and 3x6.66 m which were 1541, 141, 136 cm and 31.7, 20 and 19m3, respectively. The greatest production of alfalfa belonged to control, 3x10 and 3x8 m. spacing treatments which were 7507, 4788 and 4265 Kgha-l biomass dry weight. The effects of the treatments on branch diameter and annual stem diameter growth rate were not significant, whereas the effects of time and interaction between time and treatments on some growth parameters were significant.

In order to evaluate of grain yield of groundnut under intercropping with corn under the application of phosphorus chemical and bio-fertilizers, this experiment is performed as factorial arrangement based on randomized complete block design with three replications in Rasht, Iran in 2017 and 2018 cropping seasons. Five level of phosphorus fertilizer (PF) as triple super phosphate (TSP) including 1. Zero (as control), 2. 50 kg/ha TSP, 3. 100 kg/ha TSP, 4. 50 kg/ha TSP + 200 g/ha Barvar2 phosphate bio-fertilizer (BPB), and 5. 100 kg/ha TSP + 200 g/ha BPB, and five intercropping pattern (IP) including 1. maize sole cropping, 2. groundnut sole cropping, 3. intercropped groundnut-maize with the ratio of 1: 1, 2: 1, and 1: 2 rows, comprise the experimental treatments. According to the results from this experiment, the interaction effect between phosphorus fertilizer × intercropping system has been significant for all measured characteristics. Maximum grain yield of maize and groundnut are observed in the application of 100 kg/ha phosphorus fertilizer plus 200 g Barvar2 phosphat bio-fertilizer under sole crop. The combined usage of chemical and biological phosphorus fertilizer increase grain yield of maize and groundnut under sole crop. The highest land equivalent ratio (LER) equal 1. 88 can be seen under control treatment and maize-groundnut intercropped system with the ratio of 1: 1 rows. Intercropping system improve yield attributes of groundnut such as pod numbers per plant and grain number per pod, pod length, and diameter. Based on the results of this experiment, maize-groundnut intercropped system are advantageous for crop production per unit area. In addition, the concentration of nitrogen and phosphorus content in groundnut grain rise in response to the integrated application of chemical phosphorus and Barvar2 phosphat bio-fertilizer under maize-groundnut intercropped system. Maizegroundnut intercropped system with the ratio of 1: 1 rows and the application of 100 kg/ha phosphorus fertilizer plus 200 g Barvar2 phosphat bio-fertilizer are superior to other treatments. Hence, Barvar2 phosphat bio-fertilizer superiority could be recommendable to enhance profitability and crop production at maize-groundnut intercropping system under region climatic condition.

Nondestrutive evaluation of wood quality of fast growing standing trees such as poplar has an important role in optimal management of wood production with desired quality and properties. Tha aim of this research was the use of stress wave technique for nondestructive evaluation of poplar standing trees (Populous deltoids) and to study the effect of intercropping (with wheat) and spacing on wood quality. For this purpose, stress wave velocities were measured in radial and longitudinal directions of poplar trees in four intercropping treatments with different spacing of 3×4 m, 3×6.66 m, 3×8 m, 3×10 m and treatment of net poplar with spacing 3×4 m. The velocities of stress wave in radial and longitudinal directions of poplar trees were determined using stress wave equipment. The results showed that at same spacing (3×4m), the radial and longitudinal velocities of stress wave in net treatment are significantly higher than those of intercropping treatment. The results also showed that increasing spacing in intercropping treatments will increase the stress wave velocities in both directions significantly. A poor regression relationship was obtained between stress wave velocities in radial and longitudinal directions.

In recent years, use of brakish water in agriculture, through either mixing fresh and saline water prior to irrigation or through an alternate use of saline and fresh water has become the focus of attention. The aim followed in this study was to investigate the effect of different levels of saline and non-saline water and as well the way of their being mixed on the sunflower and sorghum crops and also on the control and adjustment of salts within soil profile. To follow the aim, an experiment was performed within a randomized complete block design of six treatments and three replications for either of sorghum and sunflower crops (36 blocks in total) in the experiment al fields of Zabol University within 2012-2013. Treatments included control (100 % freshwater), treated with two-third salty, one-half salty, one-third salty, 90% salty, and finally 100% salty water. The investigated cropping indices were comprised of dry weight of stem, leaf and aerial organs of the plant, plant height, and leaf area index. The results indicated that, for both crops, one third salt treatment had the second most acceptable performance in terms of agronomy measures and also the abundance of salt in the soils profile, as after control. However the difference between one-third and both one-half and two-third treatments for most attributes as for sunflower was not statistically (p£0.05) significant. Also, for sorghum the average dry weight and leaf area index in one-third treatment was not significantly different from control. Moreover, one-third treatment for either plant has the second lowest EC in layers 0-20 and 20-40 cm (about 2.5 dS/m) and 0-60 cm (less than 2 dS/m), after control. According to the results, it seems that the proposed method of salt and fresh water mixing in any way, highly decreases salt stress on plant, and diminishes salt accumulation in the soil profile.

To determine the most appropriate method of weed management in conventional row and ultra narrow row spacings of cotton, a factorial experiment was based on a randomized complete block design with three replications was conducted in Sabzevar in 2015-2016. Factors under study were plant spacings in two levels, conventional (70 cm row spacing) and ultra-narrow row (20 cm row spacing) and weed management in six levels: without controlling of weeds (control), application of herbicide at recommended dose of Ethalfluralin (Treflan 48% EC) at 1160 g/ai ha), application of herbicide at 50% recommended dose + hand weeding at 45 days after emergence (DAE), application of herbicide at 50% recommended dose + two times hand weeding at 30 and 60 DAE, three times hand weeding at 30, 45 and 60 DAE, and full weed free condition. The results showed that traits like weed density, by 33. 71 percent, lateral branches by 14. 77 percent, number of bolls per plant by 16. 88 percent, and boll weight by 12. 30 percent were lower in narrow row spacing, while seed cotton yield by 39. 85 percent and fiber yield by 23. 71 percent higher, as compared to, conventional row spacing. In the conventional cultivation system, if 50% of the herbicide dose is reduced, it needs two hands weeding at 30 and 60 DAE,while in ultra-narrow row spacing condition, with a 50% reduction in the recommended herbicide dose, one hand weeding at 45 DAE is needed to achieve suitable seed cotton yield. As a whole, the results showed that, under ultra-narrow row spacing, with a 50% reduction in herbicide dose and reduced weed control times (only one hand weeding at 45 DAE) it can be obtained seed cotton yield similar to other control treatments.

Efficacy of tillage and herbicide factors was studied in fallow during 2007-2008 in Islam abad in a Russian knapweed infested field. The experiment was done as split plot with two factors: tillage (two levels: with and without tillage) in main plot and herbicide (seven levels: 2, 4-D+MCPA, Triclopyre, glyphosate, 2, 4-D+MCPA+Triclopyre, 2, 4-D+MCPA, glyphosate, Triclopyre+glyphosate, and Bromicide) allocated to subplots. 30 days after spraying, biomass production in knapweed in control plots (without herbicide) for tillage and no tillage treatments was 381 and 693 g/m2, respectively. All herbicide treatments caused significant decrease in knapweed biomass.There was no significant difference amount herbicides treatment. Based on knapweed evaluation in wheat after fallow, 2, 4-D+MCPA, glyphosate, with 90% knapweed control) was the best treatment for this weed control. However, glyphosate, 2, 4-D+MCPA+Triclopyre, did not have significant difference with this treatment. All herbicide treatments caused significant increase in wheat seed yield.