This study was conducted under cold temperate climate condition in Khorasan during 2006-2008 growing season to determine the suitable preceding CROP, nitrogen and CROP RESIDUE management for wheat. A randomized complete block design in split-split plot arrangement with three replicates was used. Main plots were rotation with five different CROPs including wheat-wheat, potato-wheat, silage corn-wheat, c1over- wheat and sugar beet-wheat. Sub plots were N fertilizer rates in preceding CROP including no N (Control), 50% lower than optimum N rate, optimum N rate and 50% more than optimum rate. The sub-sub plots were preceding CROP RESIDUE return with two levels including no RESIDUE return (Control) and 50% return of CROP RESIDUE. Results showed that CROP rotation and N rate in preceding CROP influenced grain yield, biological yield, spike per m2, stem length and spike length in wheat. Interaction of CROP rotation and N rate on grain yield and yield components was significant. The highest yield obtained from potato-wheat rotation and the lowest grain yield observed in continuous wheat rotation for all N rates. There was no significant difference for 1000 kernel weight and kernel per spike of wheat in all treatments. Return of CROP RESIDUE had no significant effect on grain yield but was effective on biological yield, spike per m2 and harvest index.

CROP RESIDUE is a non-chemical method of weed control in agricultural sustainable systems. This research was conducted at the Alarogh site of Ardabil to evaluate the effect of integrated use of mulch and herbicide on weed emergence and growth in potato in 2007. Treatments were four levels herbicide including: (1) Paraquat [N,N'-dimethyl-4,4'-bipyridinium dichloride] herbicide as pre-planting, (2) metribuzin [4-amino-6-(1,1-dimethylethyl)-3-(methylthio)-1,2,4-triazin-5-one] herbicide as pre-emergence, (3) Paraquat as pre-planting plus metribuzin as pre-emergence and (4) without herbicide (control) as main plots, and four levels CROP mulch including: (1) wheat RESIDUE, (2) barley RESIDUE, (3) canola RESIDUE and (4) without mulch as subplots. Results showed that metribuzin application reduced weed density at the both stages (flowering and pre-harvesting) two times. CROP RESIDUE on the soil surface completely suppressed winter and early spring weed emergence and growth, but did not suppress on lately spring weed. In plots that was applied metribuzin herbicide plus CROP RESIDUE redroot (Amaranthus retroflexus) and lambsquarters (Chenopodium album) density was reduced to lower than 3 plant m-2, and purslane (Purtolace olerace) density declined to lower than 8 plant m-2. These results show that: 1) CROP RESIDUE can suppress winter weed growth specially to flowering stage of potato, 2) The effect of CROP RESIDUE on soil surface decline after 4 to 6 weeks and weeds which emerged after need control by either practice.

In order to evaluation of CROP RESIDUE and nitrogen fertilizer levels on micronutrient and macronutrients content in grain wheat, and also carbohydrate and dry matter, this study was conducted during 2012 - 2014 CROP years. Experimental design was split- plot within randomized complete block with three replication.the treatments included CROP RESIDUE levels: (CR1: 50% barley straw, CR2: 50% barley straw+vetch (green manure), CR3: green manure (Viciaspp), CR4: 100% wheat straw, CR5: rape RESIDUE, CR6: No CROP RESIDUE incorporation) as main plot and nitrogen fertilizer levels: (150, 270, 360 kg urea ha-1) as subplot. The result showed that CROP RESIDUE incorporation significantly affected the nitrogen, potassium, phosphorous, manganese, zinc, iron, copper and boron (p=0.01). So the maximum macro and micro nutrient contents and dry matter was related to T2: 50% barley straw+ vetch (green manure) incorporation. also increase nitrogen fertilizer levels, increased Iron (Fe), Zinc (Zn), and Manganese (Mn) contents in grain wheat, but Copper (Cu) concentration decreased. Interaction of CROP RESIDUE and N levels significantly affected the total dry matter of wheat, and 270 kg urea ha-1 in T2 treatments compared to 360 kg urea ha -1 in T6 dry matter was obtained 11.8 % higher.then CROP RESIDUE and nitrogen fertilizer management important for increase quality and quantity of wheat.

The use of nuclear techniques can be helpful in the selection and implementation of optimal agronomic practices as well as the provision of appropriate management strategies in soil and water conservation, achieving sustainable development goals. In this study, we investigated the effects of applying wheat and maize CROP RESIDUE at five rates, including 0, 25, 50, 75, and 100 %, on the dynamics of soil particulate organic matter (POM) and its origin at depths of 0-10 and 10-20 cm under conventional tillage and notillage systems were aimed. For this purpose, the natural abundance of carbon-13 (δ, 13C) technique was used. The results showed that increasing RESIDUE rates in the conventional tillage system increased the amount of δ, 13C at two soil depths of 0-10 and 10-20 cm. In the no-tillage system, increasing RESIDUE rates led to an increase of δ, 13C only for the depth of 0-10 cm, and no significant differences were observed among RESIDUE treatments at a depth of 10-20 cm. In addition, the comparison of δ, 13C values of soil and plant RESIDUEs of wheat and corn confirmed that the main source of soil particulate organic matter originated from the wheat RESIDUE, indicating the more substantial effect of wheat RESIDUEs on improving soil organic matter than maize.

Introduction: Soil is one of the renewable natural resources that take a long time to get renewed; its destruction or conservation depends on how land is used and managed. Soil quality refers to soil capacity in maintaining biological fertility, sustainability in plant production and yield. Maintaining soil quality is essential for sustainable food production and decomposition of organic wastes. Different agronomic managements have various effects on soil quality indicators. There are few published researches about the effect of various agronomic managements on soil quality indices in arid and semi-arid regions (such as Iran). Therefore, this study was conducted to investigate and compare the effects of three different agronomic management including CROP rotation-CROP RESIDUE removal, monoculture-CROP RESIDUE removal and monoculture-CROP RESIDUE retention systems on some physical indicators of soil quality. Materials and Methods: In this research, three farms with three CROP management systems including CROP rotation-CROP RESIDUE removal, monoculture-CROP RESIDUE removal and monoculture-CROP RESIDUE retention (10 ton per hectare) systems were investigated. In the monoculture-CROP RESIDUE removal treatment, wheat was continuously cultivated for 8 years. In the rotation-CROP RESIDUE removal system, wheat-mung bean were cultivated in rotation for 2 years. For the monoculture-CROP RESIDUE retention system, wheat was planted for 10 years, after which the post-harvest RESIDUEs were mixed with topsoil (0-15 cm). One hundred twenty soil samples (40 samples from each field) were prepared by systematic sampling from 0 to 15 cm depth. In order to investigate the effect of different agronomic management on soil physical quality, some indicators including soil organic matter, total porosity, bulk density, mean weight diameter of aggregates, aggregate stability, available water capacity, penetration resistance, saturated hydraulic conductivity, and slope of retention curve at inflection point (S-index) were measured. The experiment was conducted in a randomized complete block design with four replications. Also, the mean comparison was performed using Duncan's multiple range test. Results and Discussion: The results of analysis of variance showed that the type of CROP management had a significant effect (p<0. 01) on organic matter, total porosity, bulk density, mean weight diameter of aggregates, aggregate stability, available water capacity, penetration resistance, saturated hydraulic conductivity and Sindex. The results of mean comparison indicated that the monoculture-CROP RESIDUE removal system resulted in a significant increase in bulk density (1. 31 g cm-3) and soil penetration resistance (0. 4 MPa) than other systems, while the highest organic matter content (1. 038 %), porosity (55. 7%), mean weight diameter (1. 04 mm), aggregate stability index (28%), available water capacity (0. 15%), saturated hydraulic conductivity (46. 17 cm h-1) and S-index (0. 053) was observed in the monoculture-CROP RESIDUE retention system. The most measured values for soil quality indicators were more in monoculture-CROP residual retention system compared with the other treatments. The amount of S-index of soils under monoculture-CROP residual retention, CROP rotation-CROP RESIDUEs removal, and monoculture-CROP residual removal systems were 0. 053, 0. 032 and 0. 019, respectively. The high S-index value of soil under monoculture-CROP residual retention system can be attributed to its suitable amount of soil organic carbon and better soil structural quality. By contrast, in monoculture-CROP RESIDUE removal system, elimination of organic matter had undesirable effect on soil porosity, and aggregate stability. Furthermore, the S-index values of the soils under CROP rotation-CROP RESIDUEs removal, and monoculture-CROP residual removal systems are below the Dexter’ s soil quality index threshold (0. 035); therefore, the results indicated that the soils are degraded. Conclusion: The results of this study showed that CROP management plays an important role in changing soil physical quality indicators. Among the studied CROP managements, monoculture-CROP RESIDUE retention management system showed more positive effects on soil physical parameters than the others. Retention of CROP RESIDUEs on soil surface increases the soil organic matter which in turn has positive effects on soil properties such as aggregate stability, saturated hydraulic conductivity, available water content and slope of retention curve at the inflection point. On the other hand, the monoculture-CROP reside removal treatment, with less soil organic matter, had more undesirable effects on agronomic soils than other treatments. Based on the results, the effect of different agronomic management systems on improving soil physical quality indexes was in the following order: monoculture-CROP RESIDUE retention >CROP rotation-CROP RESIDUE removal > monoculture-CROP RESIDUE removal. According to the results, it can be concluded that soil organic matter is the central index of soil quality, which is intensely influenced by CROP management system. Therefore, in arid and semiarid areas such as Iran, monitoring of the long-time effect of agronomic management on status of soil organic matter and soil physical indices is urgent.

The objective of this study was to evaluate SIMDualKc CROP model and then simulating different scenarios of surface RESIDUE cover. This model estimates evapotranspiration with dual CROP coefficient approach. Therefore, that enables investigation of various mulch effects on evapotranspiration amount. Five management scenarios (organic mulch with densities of 0.2, 0.3, 0.4, 0.5 and 0.6) were simulated with SIMDualKc CROP model during the 2001 and 2002 growing seasons. SIMDualKc model calibration and validation was performed with the results of 2 years data obtained from wheat field experiments located in Aboreihan University College of Tehran University. Then, climate, soil, CROP and irrigation management data were inserted into model. The model estimated soil available water with model efficiency (EF) of 0.902 and calculating the following evaluation criteria: RMSE=1.34 mm, absolute error=0.955 mm and mean relative error=4.67 %.with lack of required data for calibration, using FAO-56 standard CROP and soil evaporative parameters resulted in reasonable accuracy.Various scenarios of CROP RESIDUE mulch simulation results showed that with increase of organic mulch density, the ratio of evaporation to evapotranspiration (E/ET) decreased and transpiration rate increased. While ratio of E/ET was 18% w/o CROP RESIDUE mulch, by applying organic mulch with density of 0.6 Kg/m2 decreased to 8%.

Background and objectives: The amount of macronutrients content is affected by various environmental factors such as severe water stress occurs after anthesis. Using of Azospirillum brasilense as a biofertilizer and CROP RESIDUEs for increasing soil organic matter are the two methods for reducing water stress in the farms. However, despite the favorite effects of Azospirillum brasilense and CROP RESIDUEs application for reducing negative effects of water stress, a few studies have been performed on regarding the effects of these factors on macronutrients uptake of barley in the warm and arid regions of Southern Iran. Therefore, the aim of this study was to investigate the effects of Azospirillum brasilense and wheat RESIDUEs applications on macronutrients uptake of barley.Materials and Methods: This research was conducted at the experimental farm of the Darab Agricultural College of Shiraz University. A split factorial experiment in a randomized complete block design with three replicates were carried out in 2017 - 2018 growing season. Treatments included: two levels of irrigation as the main plots [normal irrigation (IRN): irrigation based on the plant's water requirement up to the physiological maturity and the other factor was deficit irrigation (IRDI): irrigation based on the plant's water requirement up to the anthesis stage (cutting of irrigation after anthesis)]. Also, sub plots were two levels of CROP RESIDUEs [1. without RESIDUE, 2. returning 30% of wheat RESIDUEs to soil] and four fertilizer sources [N0, no nitrogen fertilizer (control); N100, 100 kg N ha-1 (as urea); Bio + N50, Biofertilizer (Azospirillum brasilense) + 50 kg N ha-1 (as urea) and Bio, Biofertilizer (Azospirillum brasilense)].Results: Interaction of RESIDUE × nitrogen (N) source on barley grain N content showed that the highest and the lowest grain N content (161.7 and 43 kg ha-1, respectively) were achieved in without RESIDUE and the Bio + N50 and in with RESIDUE and Bio treatments, respectively. Also, the straw N content was affected by the interaction of irrigation regime × RESIDUE × N source. The highest N content of straw was obtained in IRDI, with RESIDUE and N100 treatments (62.9 kg ha-1) and the lowest was achieved in IRDI, with RESIDUE and N0 treatments (5.7 kg ha-1). The highest grain and straw phosphorus (P) content (1.35 and 1.12 kg ha-1, respectively) was obtained by the Bio + N50 and N100 treatments, respectively. The irrigation regime × RESIDUE × N source interaction showed that the highest and the lowest grain potassium (K) content (12.6 and 4.0 kg ha-1, respectively) was belonged to IRDI, without RESIDUE and N100 treatments and IRDI, with RESIDUE and N0 treatments, respectively. Also, irrigation × N source interaction showed that the highest K content of straw (114.4 kg ha-1) was achieved in IRN and Bio + N50 treatments and the lowest K content of straw (33.3 kg ha-1) was observed in IRDI and Bio treatments.Conclusions: Based on the findings of this experiment, the Bio + N50 treatment is appropriate for achieving the maximum macronutrients content of barley in IRN conditions. Therefore, with respect to environmental and economic considerations and achieving high levels of barley macronutrients content, this fertilizer regime is recommended.

Addition of plant RESIDUEs is an effective strategy for increasing soil nutrients, improving their use efficiency, providing better conditions for root growth and sustainable CROP production. A field experiment was conducted to assess the effects of incorporation of varying rates of CROP RESIDUE on the soil organic carbon and nutrients status at 0-10, and 10-20 cm soil depth, in a wheat-corn rotation under conventional tillage system. The field experiment was performed as a factorial and in the form of completely randomized block design with four replications in the farm of agricultural and natural resources college of University of Tehran for two growing years. The treatments included incorporation of five levels of CROP RESIDUEs (100, 75, 50, 25 and 0%) which were added to the soil in two steps, following wheat and corn rotation. The results of this study indicated a significant effect of CROP RESIDUEs on the measured properties. Among the CROP RESIDUEs treatments, the 100% level showed the greatest increase of organic carbon (38. 4%), available phosphorus (34%) and potassium (47. 6%), as well as iron (27%), manganese (30. 3%), copper (39. 5%) and zinc (62%), as compared to 0% RESIDUE treatment. The 25% RESIDUE treatment showed the lowest value for the studied properties, compared to other RESIDUEs treatments. Available phosphorus, iron and zinc were significantly affected by depth and their values decreased with increasing depth from 0-10 to 10-20 cm.