Journal of Agricultural Science and Sustainable Production
Year:2016 | Volume:26 | Issue:2|Papers Count:14

Yield and yield components of sweet corn and eggplant under different proportions of replacement intercropping, examined in randomized complete blocks design with 5 treatments and 3 replications in 2014. The treatments were included 75% sweet corn: 25% eggplant, 50% sweet corn: 50% eggplant, 25% sweet corn: 75% eggplant and sole cropping of each plant. The results showed that conserve grain yield, ear yield, fresh and dry matter yield of sweet corn and eggplant yield was higher than intercropped treatments. In addition, yield of each plant decreased with increasing of proportion of other plant in intercrop. The highest ratio of grain to ear, harvest index, and grain weight, ear weight in plant, fresh and dry weight of plant was related to 50: 50 sweet corn: eggplant ratio. Sweet corn was dominant in intercropping based on Aggressive Ratio. Investigating of Relative Crowding Coefficient ratio showed the advantage of 25% sweet corn + 75% eggplant and 50% sweet corn + 50% eggplant ratios compared to sole cropping. Based on Land Equivalent Ratio, the ratios of 25% sweet corn + 75% eggplant and 50% sweet corn + 50% eggplant increased land use efficiency by 5% and 6% more than crops in pure stand, respectively.

Both planting pattern (with changes in canopy structure) and soil water availability (which affects growth and development) exert a strong effect on crop-weed competitiveness. Therefore, the effect of different planting patterns on the wheat yield and weed biomasses under different irrigation conditions were evaluated. The experimental design was a split plot with three replications, with irrigation treatments as the main plot, and planting pattern as the sub plot. Main plots included three irrigation regimes: normal irrigation, deficit irrigation (irrigation after planting and in start of flowering) and rainfed. Subplots were four planting patterns (three rows of wheat on the ridge, three rows of wheat inside the furrow, one row on the ridge and one row inside the furrow). The results showed that wheat grain yield significantly affected by both irrigation treatments and planting pattern. In irrigated condition, using the pattern of three rows on the ridges resulted in higher wheat grain yield (3437.8 kg.ha-1), while in the deficit irrigation and rainfed condition, the pattern of “one row inside furrow” had greater grain yield, whereas the average grain yields were 2574.3 and 1868.2 kg.ha-1, respectively. Results also showed that, weed biomasses were the lowest in one row inside furrow pattern in all irrigation treatments. However, lowest weed biomasses on the ridges obtained in the “one row inside furrow pattern” at irrigation and rainfed condition and in the “three rows on the ridges pattern” at deficit irrigation. Average over all irrigation treatments, the “one row inside the furrow pattern” decreased weed biomass by 67.4, 14.9 and 60% compared with three rows inside the furrow, three rows one the ridge and one row on the ridge patterns, respectively.

The aim of the present study was to investigate the effects of sewage sludge (SS) application individually and with chemical fertilizer and application time on the micronutrient concentration in soil and lettuce (Lactuca sativa L.) in the field. The experiment was arranged in split plots based on complete randomized block design with two factors and three replications. The main plot included 6 fertilizer treatments consisting of control, chemical fertilizer (pottasium solfate, triple phosphate super of 75 and urea 200 kg/ ha) 20 and 40 ton.ha-1 of sewage sludge individually and with 50% chemical fertilizer. The sub-plots were considered as one year, two-year and three-year application of fertilizer. Experimental results showed that the treatment significantly affected the available Zn and Cu of soil and concentration of Fe, Zn, Cu and Mn in lettuce root and Zn and Cu in shoots. The results also showed that concentration of the microelement in soil and root and shoot of lettuce were affected significantly by annual application of fertilizers. Interaction of the two factors showed significant effect on available Zn content of soil, Zn and Mn concentration of root and Fe and Cu of shoot. The highest increase in content of soil and lettuce micronutrient belonged to the application of 40 ton. ha-1 sewage sludge individually and enriched with 50% chemical fertilizer.

In order to study the competitive effects and interference of above and below-ground of wild oat on grain yield and yield components of two cultivars of spring barely a greenhouse experiment as factorial based on complete randomized design with three replications was carried out in Tabriz University. The interference treatments included full interference, shoot interference, root interference and no interference as a control. Plant density factor included 2 and 4 plants of barely and wild oat per pot and third factor as two barely varieties (Jonob and Kavir). The result indicated that above-ground interference of wild oat had no significance difference with control treatment in number of tiller, number of seeds per primary spike, number of seeds per secondary spike, one thousand grain weight, biological yield per plant, grain yield per plant and harvest index of barely, but below-ground interference of wild oat and full interference showed significance difference with control. In all measured traits Jonob cultivar in 2:2 (Jonob: wild oat) density and Kavir cultivar in 4:4 density (Kavir: wild oat) had highest and lowest rate, respectively. Jonob cultivar had higher competitive ability than Kavir. Grain yield of barley in above, below and full interference decreased 8.13, 42.39 and 43 percent, respectively. Wild oat exerted the most competitive effects through the roots on the barely and reduced its growth and yield.

Heavy metals are the most important pollutants in the environment. One approach to reduce the accumulation of heavy metals in plants is usage of different growing substrates. In order to investigate of heavy metals effect on growth and yield components of pinto bean (cv. Sadri), a greenhouse experiment was conducted as a factorial based on completely randomized design with three replications in Yasouj university, in 2013. The first factor included of five levels of heavy metals (control without heavy metals, Cd (NO3)2, Pb (NO3)2, Ni (NO3)2 and CuSO4) and the second factor included of four levels of different growing substrates (compost, vermicompost, Populus sawdust and non-application of organic compounds). The results showed that the addition of vermicompost respectively increased plant height and root length in conditions of without heavy metals 53, 88%, nickel nitrate 61, 35%, lead nitrate 63, 17% and copper sulfate 25, 85% compared to non-application of organic compounds. Vermicompost application also increased 87% the number of pods per plant and seed per pod in cadmium nitrate stress. On the other side, use of vermicompost, compost and Populus sawdust could not limit the adverse effects of heavy metals on seed weight per plant. Vermicompost increased hundred grain weights (11%) and protein content of bean (9%) compared to non-organic material conditions. In general, the results of this study showed that application of vermicompost on soil contaminated with heavy metals, to some extent, can improve undesirable effects of heavy metals stress.

The soil nitrogen content with impact on weed seed dormancy breaking can change their seedling emergence pattern. A trial was carried out in 2014 to predict seedling emergence of Xanthium strumarium, Chenopodium album, Echinocloa cruss-galli, Amaranthus retroflexus and Convolvulus arvensis, and to evaluate the impact of soil nitrogen content (Control with 0.07% nitrogen, adding 50 and 100 kg N.ha-1) on seedling emergence pattern in Moldavian balm. The experimental design was randomized complete block design. Weed seedlings were counted and removed on a weekly basis throughout the season. The data were converted to percent of cumulative emergence and percentage of cumulative emergence values was compared with thermal time using Gompertz modified functions. The all species showed different emergence patterns and thermal time required for the onset of emergence. The results also showed that the emergence patterns of Chenopodium and Convolvulus not affected by nitrogen treatments. However, soil nitrogen content significantly changed emergence patterns of A. retroflexus, E. cruss-galli and X. strumarium. According to our model, A. retroflexus, E. cruss-galli and X. strumarium emergence, respectively, started at 237, 96 and 63 TT with 50 kg additional nitrogen.ha-1, while the respective value in control were 340, 117 and 135, respectively. Due to influence of soil nitrogen on emergence pattern of A. retroflexus, E. cruss-galli and X. strumarium, soil nitrogen content should be considered as an important parameter in the modeling of these weed seedling emergence.

In three years rotation systems each field divided to two parts and 1st part cultivated with onion and potato and second part kept fallow. In 2nd year onion cultivated on potato and vice versa and fallow plots went under potato planting. In the 3rd year, onion cultivated on onion and potato planted on potato and onion. So fallow-onion, fallow-potato, onion-onion, potato-onion, onion-potato and potato-potato rotation systems were studied. Results showed that potato-onion rotation increased significantly bulb yield by producing jumbo bulbs. Tuber yield in fallow-potato was high because of more coarse seed tubers. In onion-potato system, tubers were tiny and big tubers were less but jumbo. Second year fallow-potato seed and little tubers were more so their sizes become tiny. But in potato-potato fewer yields obtained because of three sizes less number and size. Potato increased soil organic carbon (OC) percentage. Following onion decreased OC and another potato increased OC again sharply. OC changes in fallow year plots showed minimum change but in second year planting potato increased OC more than onion. Fallow-potato-potato system increased OC from second year end, but potato-onion-potato system showed decrease after increase and onion-onion-onion increase OC constantly.

In order to evaluate the effect of water deficit stress on growth, yield and fruit quality of two Iranian cantaloupe, the experiment was set out in a split plot design with three replicates in research filed of University of Zanjan. Treatments consisted arrangement of three Irrigation levels (starting irrigation at 100, 66 and 33 ETc) and two accessions of Iranian cantaloupe (Tile-Zard and Tile-Sabz). Results showed that irrigation had a significant effect on leaf area, fruits number per plant, plant length, Leaf dry matter, flesh firmness, total soluble solids (TSS) content, fruit weight and yield ratio. The water stress significantly increased TSS, leaf dry matter and reduced leaf area, fruits number per plant, plant length, flesh firmness, fruit weight and yield. The lowest values of yield (13357 kg.ha-1), fruit weight (1504.2 g), and the highest total soluble solids (TSS) (12.75 Percent) was obtained in the sever water stress (start point of 33 ETc). Cantaloupe accessions showed significant differences in studied traits. The highest values of yield (46171 kg.ha-1) and fruit weight (3656.7 g) was obtained under 100 ETc irrigation in "Tile-Zard". Also the highest TSS was obtained in Tile-Sabz under 33 ETc irrigation. According to the results, Tile-Sabz and Tile-Zard had 63.6% and 59.7% yield loss respectively, under 33 ETc irrigation compared normal irrigation, that both accessions are sensitive to water deficit stress.

In sustainable agriculture, efficient use of the nutrients residues of fertilizers had superior importance to production of green manure. In order to utilize the organic and chemical fertilizer residue in black cumin (Nigella sativa L.) crop to green manure production of pea (Pisum sativum), the experiment was conducted at Shahrekord University during 2012-2013. Treatments included application of cattle manure (CM), urea (U), three ratios CM:U full dose application (2:1; 1:1;1:2), three ratios CM:U split application (2:1; 1:1;1:2), and unfertilized control to in previous crop (black cumin) in 2012. Pea seeds planted in 2013, and provided no additional manure or fertilizer. The results indicated that the residue of cattle manure and cattle manure: chemical fertilizer (2:1) produced the greatest of pea dry matter (3734 and 3526 kg.ha-1, respectively) at flowering stage. The greatest nitrogen concentration (51.1 and 50.3 g.kg-1 at before flowering and flowering stage, respectively), nitrogen uptake (176.2 kg.ha-1 at flowering stage) and N/P (13.3 at flowering stage) were obtained in the residue of split integrated fertilizer (2:1), however the maximum of phosphorus uptake (16.1 kg.ha-1 at flowering stage) observed in cattle manure residue. The lowest C/N (13.14 at before flowering stage) obtained in the residue of split integrated fertilizer (2:1). In general it can be concluded that the use of the applied fertilizers residue of previous crop, in addition to preventing the loss of nutrients is effective technique to improve the production and quality of green manure.

Savory (Satureja hortensis L.) is one of the important medicinal plants, which is used in pharmaceutical and perfume industry. In a pot experiment, effects of Azospirillum irakense (A) and Pseudomonas putida (P) and nitrogen levels (no nitrogen (N0), N1: 80 mg/kg, and N2: 160 mg/kg) were investigated on elemental composition, essential oil and thymol content of savory. The results showed that both bacteria had a significant and positive effect on essential oil percentage. In the presence of A. irakense (A+), essential oil was 0.832% and increased by 44% compared to the absence of this bacterium (A-). Also, in the presence of P. putida (P+), essential oil increased 26% by weight compared to the absence of this bacterium (P-). Application of nitrogen fertilizer, also enhanced the essentiol oil percentage, but it was significantly decreased in N2 level. Both bacterial strains and nitrogen fertilizer increased the thymol content, but the increase was not significant. A. irakense increased the shoot nitrogen concentration up to 8.37%. P. putida and A. irakense increased shoot and root K concentration by 10.24% and 15.86%, respectively. A.irakense deacreased shoot P and Ca concentration and P.putida increased shoot and root P concentrations by 17.73% and 30.32%, respectively.

suitable location for organic apple production is the important factors involved in site selection including elevation, slope of land, access to water, land units, the average annual temperature and average rain fall and access to markets, each with more variables were separated and proportional to their importance in site selection were ranked and weighted. Then, with GIS, digital layers of each of these factors were prepared and integrated with the digital layer of apple orchards and the final map of suitable orchards for organic apple production was prepared. Results showed that in the studied area, from 26, 000 ha of apple orchards, about 25.5 and 707 ha were grouped as most suitable and suitable, respectively. The main features of the suitable area are desired topography (elevation more than 1,300 m) and slopes (8-20%), type of land (with sediment and deep soil) and favorable average daily temperature (5-10oC) as well as access to the river and the market. However, much of apple orchards in Urmia (over 17,000 ha) were determined not suitable for organic apple production, because of the lower altitude less than 1300 meters, low quality water for irrigation, and higher average daily temperatures or poor access to the roads and markets. It can be recommended that the only suitable and most suitable orchards as determined in this study should be involved in programming for sustainable production of organic apple.

The effect of foliar application of zinc sulphate and salicylic acid on forage yield and some qualitative and physiological characteristics of sorghum bicolor Var. Speedfeed, under water deficit conditions, was studied as split-plot experiment based on randomized complete block design with three replications at University of Urmia Research Farm in 2013. Water deficit stress as main plot consisted of three levels (irrigation at the 90%, 70% and 50% of soil field capacity) and foliar applications as sub plot with five levels including: no foliar application (control), foliar application of salicylic acid (0.5 and 1mM) and zinc sulphate (300 and 3000 mg.l-1) Which were applied in the 5 to 6 leaf stage. The highest digestibility (64.76 %) was obtained from the foliar application of zinc sulphate 3000 mg.l-1 at all levels of water deficit. Maximum crude protein and ash contents (13.35% and 8.32%) were achieved with foliar application of zinc sulphate 3000 mg.l-1 in control and moderate water deficit. Severe water deficit decreased hay yield by 21.11% in comparison with control. Both foliar application of zinc sulphate 3000 mg/l and salicylic acid 0.5 mM with average of 1571.53 g.m-2 produced the highest hay yield. Therefore, these treatments that led to significant improvements in the hay yield quality and quantity are recommended as the best treatments of this research for farmers.

Biochar has received great attention by many researchers recently due to its potential to improve soil fertility and immobilize contaminants and is proper as a way of carbon sequestration and therefore a possible carbon sink. In this work, a series of biochar were produced from wheat straw by slow pyrolysis at different temperatures (300, 400, 500, 600 and 700oC) and their physicochemical properties were analyzed. Biochar yield, ash content, the amount of nutrients and other physicochemical properties in the all treatment of the raw material for the effect of temperature on the wheat straw biochar and to determine the best temperature pyrolysis temperature for converting wheat straw to biochar with agricultural usage. As temperature increased incrementally from 300 to 700oC, biochar yield, total N content and organic carbon (OC) decreased while pH, EC, ash content and OC stability increased. The generated biochars production caused yields 28.34-58.32 % of feed mass, stable OC % 65.32-92.14 and pH 7.4-10.9. The maximal transformation of feed OC into biochar recalcitrant OC occurred at 500oC. There were reductions in the amount of functional groups as pyrolysis temperature increased for wheat straw biochar. However, total acidity of the functional groups increased with pyrolysis temperature increased for wheat straw biochar. To produce agricultural-use wheat straw biochar, 300oC should be is suggested in pyrolysis process and for carbon sequestration biochar 500oC is recommended.

The effects of planting date on seed yield and its components of maize hybrids evaluated in factorial experiment based on complete randomized block design with four replications during two growing seasons in Moghan Research Station. Treatments consisted of two planting dates (1 May and 25 June) and five maize hybrids, namely SC704 and SC720 from a late maturing group, TWC600 and SC647 from mid maturing group and SC301 from early maturing group. Results showed that 1 May planting date at two growing seasons had higher yield and its components of maize. SC704 had high grain yield at 1 May planting date. Therefore, this planting date could be recommended for Moghan region. A significant correlation indicated a strong positive relationship between grain yield and number of grains per ear.