ال ناز ابراهیمیان

The continuation of agricultural operations, based on conventional ploughing along with removal or burning of plant residues, can lead to soil degradation and erosion. Taking into account the increase in environmental pollution, the exploitation of new technologies in the direction of sustainable agriculture should be taken seriously. Along with conservation tillage, maintaining or adding plant residues, especially wheat mulch, on the soil surface can also be emphasized. Increased yield, stimulated soil microbial activity, improved soil structure and reduced water erosion are among the beneficial consequences of wheat residues on the soil.Determining the effects of crop residue and tillage systems on productivity is essential for sustainable land management. Therefore, the current experiment was carried out with the aim of investigating the effect of different tillage systems and wheat residue levels on growth indicators, yield and yield components of wheat.

In order to study the effect of tillage systems and residue management on yield and yield components of wheat, a field study was conducted as a split block experiment in a randomized complete block design with three replications. Experiment was implemented at experimental site of Ferdowsi University of Mashhad, Iran in 2013 growing season to evaluate the impact of tillage systems and wheat residue application on growth parameters, yield and yield components of wheat. For this purpose, four different tillage systems (disk, mouldboard plough + disk, sweep plough + disk and chisel plough + disk) as were employed vertical factor in combination with five different crop residue applications (0, 25, 50, 75 and 100% wheat residue) as horizontal factor. Number of ear per plant, seed number per ear and plant, 1000 seed weight, grain and biological yields of wheat were determined. Experimental data were analysed considering the analysis of variance using SAS 9.3. In order to determine the statistical differences between treatments, the least significant difference (LSD) was performed at level of P ≤ 0.05.

According to the results, the highest leaf area index and crop growth rate of wheat were observed in 167 and 151 days after sowing. These times were equal to beginning of seed filling. Chisel plough + disk tillage system increased leaf area index and crop growth rate by 14 and 21%, respectively compared with mouldboard plough + disk tillage system. In addition, the lowest and the highest ear number per plant and seed yield were observed when disk and chisel plough + disk tillage systems were applied, respectively. In general, the chisel system creates relatively deep furrows in the soil, but unlike the mouldboard plough, it does not cause overturning. As a result, at the same time as a decrease in the loss of moisture and nutrients, slight changes in the soil structure are caused.The results showed that by increasing wheat residues up to 75%, the leaf area index and plant growth rate considerably increased. For example, at the level of 75%, these traits were registered up to 35 and 60%, respectively, more than the control treatment. Moreover, ear number per plant and seed yield was significantly increased with increasing crop residue application. In a general statement, providing as much organic matter and nutrients as possible is considered one of the main benefits of applying wheat residues on the soil surface. Hence, an increase in the leaf area index, growth rate, and seed yield of wheat following the application of straw residues may be due to the gradual decay of plant residues during the growing season and subsequently the availability of nutrients required for plant growth. 

Application of wheat residue along with reduced tillage (based on disk and chisel plough) as an ecological approach can be recommended in arid and semi-arid regions of Iran to increase wheat yield and promote sustainable production.

Under limited moisture conditions, various row planting arrangements have been utilized to provide additional moisture for plant growth and development. Planting patterns had significant effects on the availability of water in time to better match crop development.Soil fertility is one of the most important factors in agricultural operations. Also, soil fertility greatly contributes to yield differences for the same agronomic practices. It is well-known from numerous fertilizer experiments that mallow yield is strongly dependent on the supply of organic matter and mineral nutrients. Cow manure and municipal waste compost in controlling different types of debris and the reduction in fertilizer consumption in agricultural products and mineral absorption elements improve low consumption by plants. Mallow (Malva sylvestris) (Malvaceae) is a medicinal plant that it was used for its emollient and laxative properties and is a popular medicine. Mallow broadly used for various inflammatory conditions (Wichtl, 2004). Phytochemical studies of this plant revealed the presence of numerous polysaccharides, anthocyanins, coumarins, tannins, flavones, flavonols, anthocyanidins, leucoanthocyanidines, mucilagen and essential oil (Unver et al., 2009). Therefore, the objectives of the current study are to evaluate the effects of planting pattern and fertilizer treatments on growth, flower and seed yield of mallow as a medicinal plant.

A field experiment was conducted as a split-plot based on a complete randomized block design with three replications at Faculty of Agriculture, Ferdowsi University of Mashhad during two growing seasons of 2012-2013 and 2013-2014. Fertilizer sources of cow manure (40 t.ha-1), municipal waste compost (20 t.ha-1), chemical fertilizer and control (without fertilizer), three planting patterns included 70 cm apart single side row, 90 cm apart single side row and two side rows and two harvests were the main, sub and subfactors, respectively. After land preparation, organic fertilizers were added to the soil. Based on nutrient contents in organic fertilizers, N, P and K for chemical fertilizers were determined by 114, 18 and 220 kg.ha-1. P (as triple superphosphate) and K (potassium sulfate) were applied just before sowing. Urea (N fertilizer) was applied as a top dressing in three stages such as sowing, thinning and flowering stages when the crop was irrigated.Plant height, the fresh yield of flower, the dry yield of flower, biological yield, seed yield and mucilage content of mallow were measured. To analyze the variance of the experimental data and drawing of diagrams, MSTAT-C and Excel software was used. All the averages were compared according to Duncan’s multiple range test (p≤0.05).

The results showed that the simple and interaction effects were significant on most studied traits. The highest dry yield of the flower was observed in the interaction of manure+ two side rows (4071.17 kg.ha-1) and the lowest was for control+90 cm apart single row (1095.85 kg.ha-1). The maximum and the minimum dry yield of the flower were observed in manure in the second harvest (4596.06 kg.ha-1) and for control in the first harvest (941.69 kg.ha-1) treatment, respectively. The highest biological yield and seed yield were obtained in two side rows (4731.01 and 813.60 kg.ha-1) and the lowest was for 90 cm apart single row (with 3880.96 and 635.74 kg.ha-1), respectively. Manure affected mucilage percent significantly, (12.06%) and the lowest was for chemical fertilizer (9.32%).

Manure increased nutrient uptake by plants, improving plant hormone-like activity, increase soil water holding capacity, and generally improve the growth and yield of medicinal plant. It can be concluded that two side rows and cow manure could be considered as a suitable treatment for improving quantity and quality yield of this medicinal plant.

In order to study the effects of tillage systems and wheat residue levels on soil physical, chemical and biological characteristics a randomized complete block design arranged in split block with three replications was set in research farm of Ferdowsi University of Mashhad in 2013-2014 growing season. Four different tillage systems (disk, mouldboard plough disk, sweep plough disk and chisel plough disk) as vertical factor were employed in combination with five different crop residue applications (0, 25, 50, 75 and 100 percent wheat residue) as horizontal factor. Due to soil sampling in April (2013), November (2013) and June (2014), data were analysed as split block in time. According to the results, the lowest total nitrogen (0.094%), available phosphorus (12.50 mg/kg) and organic carbon (0.52%) were observed when mouldboard plough was applied, while the highest values were obtained using chisel plough followed by disk. Irrespective of sampling time, total nitrogen, available phosphorus and potassium as well as organic carbon significantly increased with increasing wheat residue application. Furthermore, crop residue application caused significant reduction in soil pH (up to 0.45 unit) and improved microbial biomass and activity (by 20.6%).

To evaluate nitrogen uptake, nitrogen uptake efficiency, nitrogen use efficiency and nitrogen harvest index of wheat (Triticum aestivum L.) affected by different tillage systems and wheat residue application, an experiment was conducted as a split block experiment in a randomized complete block design with three replications at Ferdowsi University of Mashhad, Iran, during 2013-2014 growing season. Four different tillage systems (disk, mouldboard plough disk, sweep plough disk and chisel plough disk) were considered as vertical factor and five different crop residue applications (0, 25, 50, 75 and 100% wheat residue) as horizontal factor. The results showed that lowest (2.58%) and highest (2.77%) seed nitrogen percentage were obtained from disk and chisel plough disk, respectively. Also, the highest nitrogen uptake and use efficiency (60.67% and 17.25 g seed/g soil) were obtained from chisel plough disk treatment. The results indicated that seed nitrogen percentage, nitrogen uptake and use efficiency significantly increased with increasing the levels of wheat residue, so that application of 75% wheat residue increased nitrogen uptake to 62.2% compared with control treatment. Regarding to the results of this study, it seems that application of wheat residue along with reduced tillage as an ecological approach can be recommended in arid and semi-arid regions of Iran to increase nitrogen uptake and use efficiency.

In order to investigate the effects of different irrigation levels and biological fertilizers on quantitative and qualitative yield of ajowan (Carum copticum L.), a field experiment was conducted at a farm located in West Azerbaijan province - city Nagadeh, Iran during growing season of 2012-2013. The experiment was arranged as split plot based on Randomized Complete Block Design in three replications. The main plots were allocated to irrigation levels (Irrigation after 50 mm (control), 100 mm (moderate water stresses) and 150 mm (severe water stresses) evaporation from class A pan) and sub-plots were allotted to biological fertilizers (Mycorrhiza, the combination of Azotobacter and Barvar Phosphate-2, Mycorrhiza + Azotobacter + Barvar Phosphate-2 and control). Results showed that by increasing irrigation times from 50 to 150 mm evaporation, plant height, number of umbel per plant, 1000 seed weight, biological yield, seed yield and concentration and content of essential oil in ajowan were significantly decreased. Among the biological fertilizers, combined usage of biofertilizers (Mycorrhiza + Azotobacter + Barvar Phosphate-2) showed greater increment in studied traits than individual consumption. In each irrigation levels (Irrigation after 50, 100 and 150 mm evaporation), the highest seed yield (783 kg/ha) was obtained from combined usage of biofertilizers and the lowest seed yield (400 kg/ha) belonged to control treatment, respectively.

Soil or water salinity is one of the major problems of agriculture in the arid and semiarid regions of the world، especially in Iran. Beside the Salinity، reasonable canola production depends on nutrient supply so that increase in quantitative and qualitative yield is highly correlated with nutrients availability، especially nitrogen and Zinc. In order to investigate the effects of the nitrogen، zinc fertilizer and irrigation salinity on yield quality characteristic and nutrient uptake of canola (Brassica napus L. cv. Okapi)، a field experiment was conducted in Agriculture Research Centre of East Azarbaijan، Iran in 2009-2010. The experiment was arranged by using a completely randomized block design based on factorial fashion with three replications. The experimental treatments included the nitrogen levels (0، 50 and 100 kg. ha-1)، different zinc levels (0، 5 and 10 kg. ha-1) and irrigation salinity levels (8 and 16 dS. m-1). Based on results، nitrogen and zinc application had a significant effect of increasing plant height، number of pod per plant and grain yield of canola. However، mentioned traits of canola were decreased as result to increasing irrigation salinity levels (from 8 to 16 dS. m-1). Irrigation salinity at rate of 16 dS. m-1 had a significant effect on increasing glucosinolate percentage in seed. In addition، effect of irrigation salinity levels on decreasing the N، P، Ka and Ca uptake and increasing the Na and Cl accumulation in seed canola were significant. In sum، it seems that nutrient supply، especially nitrogen، can be considered as effective solution to diminish negative effects of salinity.

Effects of chemical and organic fertilizers combinations on yield, yield components, seed oil and protein percentage of two canola cultivars were studied. The experiment was carried out as factorial based on a randomized complete block design with three replications in Agricultural and Natural Resources Research Center of Azerbaijan-e-Sharqi province of Iran in 2010. The first factor comprised seven levels of organic and chemical fertilizers and their combinations including: non cattle manure and non urea (control), 100% cattle manure (organic), 80% cattle manure and 20% urea (combined), 60% cattle manure and 40% urea (combined), 40% cattle manure and 60% urea (combined), 20% cattle manure and 80% urea (combined) and 100% urea (chemical) and the second factor was two canola cultivars (Okapi and Modena). The results showed that the highest yield, yield components, oil and protein percentages were obtained from a combination treatment, application of 20% cattle manure along with 80% urea (96 kg/ha), that was differed significantly from other chemical treatments for seed yield and number of seeds per pod. Therefore, application of this treatment could be recommended because it leading to a higher yield with lower chemical fertilizer application. Besides, variety okapi was superior to Modena based on the measured characteristics.