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: Conservative agriculture with minimal adverse effects on the environment has been the subject of great interest recently as a means of promoting sustainable CROP production and food security (Nkala et al., 2011). The approach is practiced in large-scale commercial agriculture. Conservative agriculture also encourages the optimal utilization of resources such as soil and water and helps the sustainability of products in the agroecosystem (Stavi et al., 2016). Nonetheless, due to the diversity of conservation farming operations around the world, it is critical to prioritize different tillage methods according to cultivation conditions and climatic conditions (Miller et al., 2012). The main objective of this study was i) to assess the efficacy of different conservative soil tillage (minimum and/or zero tillage) in combination with CROP RESIDUE and fertilizer MANAGEMENT in achieving maximum CROP production; and ii) to assess the effects of MANAGEMENT practices on agroecosystem performance using agronomic and environmental data and scoring function descriptions.Materials and methods: To achieve the goals, a field experiment was carried out involving 7 treatments with varying combinations of different tillage methods, CROP RESIDUEs and fertilizer MANAGEMENT on a field of maize which was planted after the cultivation of a wheat CROP. At the end of the growing season, the chemical and physical soil properties as well as the total yield of corn were measured. The physical and chemical parameters measured in the soil included electrical conductivity, field capacity, available water, porosity, pH, soil organic carbon, total CROP biomass and maize yield. Agroecosystem performance was assessed using a computer program entitled the AgroEcosystem Performance Assessment Tool (AEPAT). It utilizes performance-based index methodology to derive a relative ranking of agroecosystem performance among MANAGEMENT practices for functions and indicators included in the procedure. Data measured by the software AEPAT are rated from 0-100 to calculate two agroecosystem functions including conservation agriculture and food production.Results and discussion: The results showed that “stalk chopper+disc+100 kg N-fertilizer+ditcher” treatment resulted in the maximum amounts for field capacity (25.63%), available water (15.63%), porosity (49.2%) and organic carbon (0.73%). The highest total biomass (87.3 th-1) and ear yield (23.8 tha-1) was also obtained using this treatment. In contrast, the lowest amounts for these parameters were obtained with the “stubble burning + disc + ditcher” treatment. This was due to the stubble burning which increased the soil electrical conductivity and reduced the physical and chemical soil quality. On the other hand, leaving the on-farm RESIDUE in place plays an important role in regulating electrical conductivity and soil salinity. It can be concluded that the type of agriculture practiced affects the soil physicochemical properties to a high extent. Leaving CROP RESIDUE in the field may increase the soil biological activity resulting in soil porosity and aggregation. The analysis on sustainability of agricultural practices showed that “stalk chopper+disc+100 kg N-fertilizer+ditcher” treatment had the highest score for agroecosystem performance (61.21) in terms of both optimum yield and sustainability. The lowest score of 7.63 was obtained with “stubble burning+disc+ditcher” treatment.Conclusion: In conclusion, it was demonstrated that conservative tillage in combination with CROP RESIDUE not only led to a higher maize yield but also improved the soil quality. Nonetheless, for conservative tillage to be effective adequate N-fertilizer, as a starter to provide needed CROP growth nutrients, must be applied. In addition, the efficiency of the indexing score is critical in discriminating between different agricultural practices within and across agroecosystem functions. The agricultural practices had a direct effect on agroecosystem performance and the soil physicochemical properties can be used as an index to assess agroecosystem function and performance.

Introduction: Conservation agriculture is an appropriate strategy for maintaining and improving agricultural resources which increases CROP production and stability and also provides environmental protection. This attitude contributes to the conservation of natural resources (soil, water, and air) and it is one of the most effective ways to overcome the drought crisis, water MANAGEMENT and compensation of soil organic matter in arid and semi-arid regions. Practicing the conservation agricultural systems, which requires an effective usage of previous CROP RESIDUEs and reduced tillage methods, is an irrefutable necessity for arid regions like South Khorasan with low soil organic matter. The addition of CROP RESIDUEs to the soil in conservation agricultural systems, however, might immobilize nitrogen as an important nutritional element affecting plant growth. The transition from traditional to conservation agricultural systems, nevertheless, would affect different constituents of agroecosystems including weeds dynamics and growth, which would eventually affect the CROP production in these systems. Given that South Khorasan farmers still use traditional methods of cultivation and they do not return the previous CROP RESIDUEs to the soil in their farming systems, the aim of this study was to investigate the effect of CROP RESIDUE MANAGEMENT and nitrogen on dynamics and growth of weeds of cotton farm. Materials and Methods: In order to investigate the effect of CROP RESIDUE MANAGEMENT and nitrogen on the growth and dynamics of weeds of cotton farm, an experiment was carried out as split factorial design based on RCBD with three replications at the research field of Faculty of Agriculture, University of Birjand in 2013. In this experiment, the main plot was two tillage methods, including conventional tillage (moldboard plowing) and reduced tillage (disking) and the subplot consisted of a factorial combination of two nitrogen levels (50 and 150 kg ha-1) and five barley RESIDUE levels (0, 77, 154, 231 and 308 g m-2) which have been randomly distributed as a factorial in subplots. Weed samplings were performed at four stages including 30, 60, 90 days after planting and also at harvest time and after each sampling, weed density, dry matter and leaf area were measured. Results and Discussion: Results showed that plow type, residual amount levels and nitrogen fertilizer rate had significant effects on measured traits of weed species including density and dry matter of weeds as well as their leaf area. Increasing the RESIDUE amount significantly reduced weeds growth traits. The greatest density, dry matter and leaf area of weeds were observed with disk plow, while mouldboard plowing significantly reduced these traits. A lower disturbance of soil in conservation agricultural systems, which is the case with our study where disking was applied, often results in most weed seeds to accumulate on the upper soil layers and eventually might ends up with a higher weed density. The greater rate of nitrogen resulted in higher density, dry matter and leaf area of weeds. The stimulatory influence of nitrogen on weed emergence has been previously substantiated. Moreover, the interaction effects of studied factors were significant on weeds growth traits. The interaction effects of plow type by RESIDUE amount showed that the lowest weed densities were observed with mouldboard plow under all RESIDUE amount and the using greatest RESIDUE amount (308 g m-2) resulted in the lowest weed density under both tillage regimes. The control treatment (no RESIDUE) interestingly showed a lower amount of weed density compared with RESIDUE amounts of 77 and 154 g m-2. Weed control by CROP RESIDUEs is probably due to different factors like prevention of light penetration to the soil surface, exuding allelopathic substances, influencing soil nitrate content and moderating soil temperatures and improving CROP growth. Our study, however, showed that lower amounts of RESIDUEs on the soil surface cannot provide enough inhibitory effects to suppress weeds and might even stimulate weed emergence through maintaining more moisture under the RESIDUE layer at hot air of early summer. Conclusions: The results of this study revealed that although employment of conservation tillage systems is a suitable method to achieve sustainable agriculture, more extensive research studies are needed on the effects of these systems on weed density and their competition with CROP plants. Thus, cover CROPs and conservation tillage systems can be used as a promising solution for the development of sustainable agriculture and protecting the health of ecosystems. Due to widespread cultivations of wheat and barley in our country, it seems that incorporating the cereal CROP RESIDUEs into the soil might inhibit weeds growth in CROPping systems. Our study also showed that nitrogen MANAGEMENT is very important strategy in regard to weeds growth in these systems.

Background and Objectives: Nowadays, due to the increase in the population and the change in people's dietary patterns, the consumption of vegetable oils is increasing. Among the oil plants, Castor (Ricinus communis L.) due to drought, relative resistance to salinity as well as fast and easy growth can be a good choice for producing high oil percentage and according to the effect of optimal plant nutrition in achieving proper yield, this research was conducted in order to evaluate the effect of the type of plant RESIDUEs and integrated fertilizer MANAGEMENT on yield and yield components of castor.Materials and methods: An experiment was carried out in the form of one-time split plots in the form of a basic design of randomized complete blocks in 3 replications in the CROP year 2021-2022 in Andimshek city, located in the north of Khuzestan. Experimental treatments include the use of plant RESIDUEs (without RESIDUEs (control), rapeseed RESIDUEs, wheat RESIDUEs and corn RESIDUEs) as the main plot and the type of fertilizer MANAGEMENT that includes (completely chemical ((60)K (75)P (90)N), Organic (mixture of compost and vermicompost + Fertilizer 2 + supernitroplus + humic acid), Combined 1 (chemical base fertilizer + fertilizer 2 + supernitroplus + humic acid) and Consolidated 2 (compost and vermicompost mixture base fertilizer + Fertilizer 2 + supernitroplus + humic acid + urea vinegar) as a secondary plot in consideration. were taken. The studied traits included plant height, inflorescence height, number of capsules per plant, number of seeds per plant, thousand seed weight, seed yield, biological yield, harvest index and oil percentage.Results: The results showed that the use of plant RESIDUEs (corn, wheat and canola) and organic and integrated fertilizer 2 resulted in the highest number of seeds per plant, harvest index and oil percentage. So, with the use of organic fertilizer and wheat and corn RESIDUEs, the highest harvest index was obtained. With the positive effect of combined fertilizer 2 on the percentage of oil, it can be stated that combined fertilizer 2 and corn RESIDUEs have led to an increase in the quality of the castor plant. So that the grain yield had the highest correlation with the weight of 1000 seeds. Removal of plant RESIDUEs caused a significant decrease in oil percentage (reduction in quality). But on the other hand, the application of plant RESIDUEs had the least effect on yield and yield components. Conclusion: In general, the use of only chemical fertilizers led to an increase in yield and yield components of castor plant. In the event that organic fertilizer and corn RESIDUEs led to a decrease in yield and yield components. In this study, chemical fertilizer treatment is the most successful in yield and yield components, and organic fertilizer and corn and wheat RESIDUEs are the most successful in castor seed quality.

To study the effect of CROP rotation and wheat RESIDUEs MANAGEMENT on grain yield, some agronomic characteristics of maize, and some properties of soil in second CROPping system, an experiment was carried out in Experimental Research Farm of Orzoiyeh in Kerman Province for four CROPping seasons (2000-2003). A split plot arrangement in a randomized complete block design was used with four replications.Wheat RESIDUE MANAGEMENT at four levels (retention RESIDUE, burning and retention of RESIDUE every other year, removing RESIDUE, burned RESIDUE) were assigned to main plots, and CROP rotation with three levels (1- wheat- cotton, wheat- corn, 2- wheatsoybean, wheat- corn, 3- wheat- corn, wheat- corn) were randomized in sub-plots. Results showed that yield and yield components, kernel protein content, organic carbon, available phosphorus, and bulk density in soil were not affected by wheat RESIDUE MANAGEMENT, but available potassium in soil was affected significantly. Grain yield in RESIDUE retention treatment was 1150 kg ha-1 higher than burning RESIDUE. Organic carbon in retention and burning RESIDUE treatments were %0.65 and %0.59, respectively.Burning wheat RESIDUE increased available Potassium (204.95 mg/kg) in soil when compared with RESIDUE retention (180.04 mg/kg) and removing RESIDUE (178.48 mg/kg) treatments. Yield and yield components were not affected by CROP rotation, but cotton in rotation had the highest potassium, phosphorus and organic carbon in soil. Based on these results and considering low organic carbon in soil and high temperature in summer in Orzoiyeh region, retention of wheat RESIDUE and rotation of cotton and maize after harvesting wheat are recommended. It is also suggested that the effect of wheat RESIDUE and CROP rotation on grain yield and soil properties should be studied for a period of at least ten years.

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.

In order to study the effect of CROP rotation and CROP RESIDUE managament (CRM) on yield and yield components of mung bean, a field experiment was condueted in 2005 in Mashhad. The experiment was laid out in a split plot design with 3 replications. The main plot treatments were previous CROPs (i.e. wheat and canola) and sub plot treatments were CRM (i.e. incorporation, elimination and burning the previous CROP RESIDUE). Results showed that effect of wheat on mung bean yield was better than canola. Wheat with incorporation of RESIDUE and canola with burning of RESIDUE treatments had a highest and lowest mung bean grain yield, respectively. Also, wheat with elimination of RESIDUE and canola with elimination of RESIDUE had the highest and lowest mung bean grain protein percentage, respectively. Among yield components, grain and pod number had the highest and grain 1000 weight had the lowest changes between the treatments. Wheat mung bean rotation and incorporation of RESIDUE was a better CROPping MANAGEMENT than other treatments.

To study the effect of conventional vs conservational tillage practices though MANAGEMENT of plant RESIDUE on wheat physiological properties, a field experiment was conducted in 2013-2014 at Mashhad Agriculture and Natural Resources Research center of Razavi Khorasan province. The study was arranged in a split plot design based upon randomized complete block arrangements of three replications. The main plots were composed of tillage systems of: 1) conventional tillage, 2) reduced tillage and 3) no tillage; subplots consisted of MANAGEMENT of remaining RESIDUE of: 1) 0%, 2) 30% and 3) 60% RESIDUE. The results indicated that tillage systems significantly affected Mycorrhizal colonization (spore), soil temperature, water-holding capacity of the soil, porosity. The highest Mycorrhizal colonization (spore)(72. 88), Water-holding capacity of the soil (21. 59%), porosity (62. 09%), were obtained from no-till method. RESIDUE MANAGEMENT significantly and differently affected on Mycorrhizal colonization (spore), soil temperature, water-holding capacity of the soil, resistance to penetration, as well as porosity. The highest grain yields were obtained from no-till (6912. 2 kg/ha) and 60% RESIDUE treatment (6980. 8 kg/ha). It is concluded that conservation tillage with more RESIDUE left above ground could improve wheat yield along with some of the related soil physicochemical properties.

To evaluate the effect of nitrogen and water withholding in vegetative growth stage of corn on efficacy of nicosulfuron and 2,4-D+ MCPA an experiment was conducted as a factorial arrangement in a randomized complete block design with three replications at Tarbiat Modares University in 2017. The first factor contained four treatments including application of nicosulfuron, 2,4-D+ MCPA, weed free and weed infested as control. The second factor consisted of normal irrigation and water withholding from 4 to 8 leaf stage. Third factor contained either urea application or no fertilizer application. Normal irrigation and nitrogen fertilizer application significantly increased nicosulfuron and 2,4-D+ MCPA efficacy in weed control and total weed dry weight decreased to 341 and 361 g.m-2 respectively compared 1370 g.m-2 as weed infested. Nicosulfuron and 2,4-D+ MCPA reduced weed total dry weight significantly under irrigation withholding. Grain yield increased with application of nitrogen and nicosulfuron. Grain yield was higher with application of 2,4-D+ MCPA than nicosulfuron without nitrogen application under irrigation withholding. Application of nicosulfuron with nitrogen application provided satisfactory weed control and increased grain yield.