جستجوی مقالات مرتبط با کلیدواژه « Intercropping » در نشریات گروه « گیاهپزشکی »

In order to evaluate the effect of different methods in control of weeds in pumpkin fields, an experiment was conducted based on randomized completely block design with four replications in 2019. Treatments consisted of weed free, complete weeding, mulch (clear and dark plastic), intercropping with quinoa, once weeding and three herbicides: Trifluralin (7.5 liters of commercial material per hectare) before planting and after crop growth, indaziflam (100 ml commercial material per hectare), pendimethalin (6 liters commercial material per hectare). Indaziflam and pendimethalin chemical treatments were applied after emergence on July. Results showed that the dark plastic mulch caused the maximum dry matter (141.4 g/m2) and fresh (289.8 g/m2) weight of pumpkin leaf and the maximum dry matter (78.5 g/m2) and fresh (641.6 g/m2) weight of pumpkin shoot in comparison of other treatments. In addition, dry matter of weeds got decrease up to 90 percent just through by type of dark plastic from mulch treatment and 97 percent by clear one. Furthermore, it caused 49 and 129 percent increasing respectively in fresh and dry matter weight of pumpkin. On condition of chemical control, using Trifluralin herbicide before of planting caused the fruit diameter (13.4 cm), fruit area (46 cm) and seed (35.5 g) dry matter of pumpkin so improved the yield in comparison other chemical treatments. Finally, using different mulching treatment got yield increased up to maximum, proper control of weeds and decreased the environmental pollution through decreasing of chemical materials.

Bean (Phaseolus vulgaris L.) is so sensitive to intercompetition especially with weed species. Weed management is an essential factor for the success of an agricultural production system. The use of high competitiveness figures is one of these approaches. Another way to manage properly is just to reduce herbicide dose using through the mixed herbicides in crops. By intercropping, filling the empty space prevents weed development in the area. Mixing or simultaneous cultivation of two or more species in one plot of land is one of the oldest agricultural systems in the world. Planting density is another important factor in determining plant yield. Planting density not only determines competition for light and nutrients, but also controls the distribution and allocation of dry matter between plant organs. The studies showed that by increasing bean planting density from 20 to 30 and 40 plants m2, yield increased by 15.4% and 24.7%, respectively, and the weed biomass also increased by a density of 20 to 40 by 30 percent. The use of high competitive cultivars and increasing planting density are the main strategies to increase the competitive ability of beans against weeds. This study was carried out to investigate the methods of pure and mixed cultivation of bean cultivars with different densities for their effect on reduction of bentazone herbicide dose, weed control and crop yield.

In order to investigate the effect of planting density and reducing herbicide doses on weeds biomass and crop yield in pure and mixed cultivation of red bean cultivars, a field experiment was carried out at Agronomy Research Field of Ferdowsi University of Mashhad during 2013 - 2014. A factorial experiment (with three factors) was conducted in a completely randomized block design with 4 replications. Experimental treatments including bean planting densities in three levels consisting of optimum density (Goli 40 and Akhtar 50 /m2), 20 and 40 % higher than the optimum density of both Akhtar and Goli cultivars, and Bentazone herbicide concentrations (0, 50 and 100 %) based on the recommended dose (2.5 liters per hectare), and separate and mixed cultivation of Akhtar (standing) and Goli (ascending) cultivars were performed in rows (1:1). Weed biomass was evaluated every two weeks after spraying by 100*25 cm2 cadaver from two middle rows. At the end of the growing season, a 1*1 m2 staff was used to determine the performance. Data were analyzed by SAS 9.1 software and averages were compared with the LSD test at 5% probability level and the graphs were analyzed using SigmaPlot 12.0 software.

The results showed that for the weed biomass, the mixed cultivation of Akhtar and Goli cultivars was more than pure cultivation due to its success in suppressing high competitive weeds through rapid space cover, which can be attributed to this feature. It was used to reduce the herbicide dose. Also, the highest and lowest grain yield (respectively 463 and 132 g/m2) were found for the pure cultivation of Akhtar cultivar at concentration of 100 and 0 % herbicide, respectively. However, in flowering and mixed cultivars, the highest grain yield was observed at 372.2 and 341.3 g/m2, at 50% herbicide concentration, which was also observed in biological yield. Results of interaction effect showed that the highest biological yield in intercropping (1166 g/m2) was observed for 50% herbicide concentration and 40% planting density. It can be, therefore, concluded that reduced doses of herbicides can only be used if the crop has high competitive ability and planting density is increased, which can reduce the competitive ability of weeds. The use of high competitive crops and increased density of crops have the greatest potential in suppressing weeds and reducing herbicide dosage. The previous studies also showed that limiting bean growth leads to a decrease in leaf area index and bean growth rate, which in turn reduces its competitiveness against weeds.

The use of high-strength cultivars in mixed cultivation due to their overlap, space conquest, and ability to compete with weeds along with increased plant density has a high potential for weed suppression and can be used in other ways to reduce herbicide dose. The results of this experiment showed that there was no significant difference between biological yield at 50% and 100% herbicide concentrations in the mixed cultivation and the highest biological yield was observed in the mixed cultivation.

Background and Objectives:

 The melon aphid, Aphis gossypii Glover, is one of the most important pests of tomato in Iran. This aphid causes severe damage on tomato crop in northern Iran. 

Materials and Methods:

 Present study was conducted in an experimental field, 0.3 h, in Behshahr region in Mazandaran province based on a randomized completely block design. In this study, the effectiveness of intercropping tomato (T) with clover (C) in the three combinations: (1) one row of tomato with two rows of clover (1T:2C), (2) two rows of tomato with two rows of clover (2T:2C), and (3) three rows of tomato with two rows of clover (3T:2C) along with sole tomato were assessed on the densities of melon aphid, Aphis gossypii Glover, diversity of its natural enemies and yield of both crops in 2016 and 2017.

 Results:

 The density of nymphs and adults of A. gossypii were significantly higher in sole tomato compared with intercrops. Among intercrops, the lowest density of nymphs and adults of A. gossypii were observed in 1T:2C intercrop. In present study, 13 predator species were collected and identified on aphid-infested plants of tomato in the experimental field. Among the predators, Coccinella septempunctata L., Chrysoperla carnea (Stephens) and Episyrphus balteatus DeGeer had more abundance in the two studied years.  The Shannon diversity index (H´) and the Pielou’s evenness index (J´) for composition of predator species were significantly higher in intercrops compared with sole tomato crop. Moreover, more nymphs and adults of A. gossypii were parasitized in all intercrops compared with sole tomato crop in 2016 and 2017. The highest value of land equivalent ratio was found in 1T: 2C (LER = 1.28 in 2016 and 1.30 in 2017) among intercrops in the two cropping seasons.   

Discussion:

 All the three intercropping patterns of tomato with clover including 1T:2C, 2T:2C and 3T:2C, especially 1T:2C could be recommended in management programs of the melon aphid in tomato fields.

Coriander, Coriandrum sativum L. abbreviated here as Co, belongs to Apiaceae which is an aromatic herbaceous annual plant. In this study, intercropping coriander with strawberry, Fragaria ananassa Duchesne abbreviated as S, in the two patterns 2S: 2Co and 5S: 2Co (row ratios) were assessed for controlling the two-spotted spider mite, Tetranychus urticae Koch, compared to strawberry. The results indicated that intercropping coriander and strawberry reduced the density of T. urticae eggs compared with strawberry monocropping. Furthermore, the densities of mobile forms of T. urticae were significantly lower in intercropping systems, especially 2S: 2Co compared with strawberry monocropping. Moreover, the land equivalent ratio (LER), which is used to assess the yield benefit in intercropping systems, was greater than 1 in intercrops, especially 2S: 2Co (1.413 in 2017 and 1.430 in 2018). These results indicated that intercropping strawberry with coriander could be beneficial in integrated management of T. urticae by reducing two-spotted spider mite densities and increasing the crop yields.

Safflower fly, Acanthiophilus helianthi Rossi (Diptera: Tephritidae), is one of the important pests of safflower in the world. The intercropping pattern can be one of the suitable and safe methods to control the pest. Therefore, the influenceof different intercropping patterns of chickpea and safflower (sole cropping of safflower, replacement series consisted of 4:4, 2:2, 1:1, 3:1, 1:3, and additive series consisted of 20 and 40% chickpea in two situations: between and around of safflower rows) on the population density and infestation rate of this pest was studied in a randomized complete block design at the research field of Kurdistan University. Results showed that different intercropping patterns affected the population density of the pest significantly. The population density of the pest in all intercropping patterns of chickpea and safflower except 20% I pattern was lower than the sole cropping of safflower. 1:3 and 3:1 intercropping patterns resulted in the lowest average population density of the pest among other cropping patterns (18.33 ± 0.6 and 220 ± 3, respectively). Studying the infestation rate of the pest also showed thatthe mean density percentages of the infested capitula per plant were significantly different among the cropping patterns, and 1:3 and 3:1 intercropping patterns had the lowest mean densities of the infestation rate (6.1 ± 1.1 and 8.3 ± 0.5%, respectively). According to the results, 1:3 and 3:1 intercropping patterns showed a high potential for using in the integrated management of safflower fly among the other studied patterns.

Increasing the production of products with greater diversity through mixed cultivation can be effective in improving ecosystem services and functions. One of the most important functions of the mixed crop system is the reduction in the population of pests and, consequently, the increase of crop yields. This research is aimed at effects of the intercropping system of soybean and corn on abundance of insect pests, pollinators and natural enemies, an experiment was conducted at the Agricultural Research field of Lorestan University, Iran. The experiment was carried out in the randomized complete block design on five treatments with four replications. The experimental treatments were sole soybean 100:0, sole corn 0:100 and 50:50, 75:25 and 25:75 soybean: corn combinations, respectively. Different sampling methods such as pit fall trap, sieve, yellow and blue sticky cards, striking, sweep netting and local counting were applied to collect insects. Sampling was taken five times at interval of 14 days. Total of 7,395 insects were collected during the sampling period belonging to 10 orders and 39 families. Results showed that the population of the collected insect including pests, pollinators and natural enemies were significantly influenced by the intercropping system. The maximum number of natural enemies and the minimum number of pests were also observed in the 50:50 soybean: corn treatment. The maximum number of pollinating insects was found in 75:25 soybean: corn treatment. However, the highest rate of pests and subsequently the lowest pollinating and natural enemy insects were found in the sole corn treatment. On the other hand, a negative relationship between natural enemies and pests as well as soybean yield and pest insects was obtained. The population of some pest families influenced by the system showed an increase in abundance of insects in intercropping system compared to that of the control treatment (i.e., sole cropping). Results showed that, some mixed treatments of soybean: corn proved to have more efficient biological control and more yielding than their sole cultures.

Weed management is an important agronomic practice. It would be takes 40% of time of small holder farmers, if carried out by hand. Farmers have being interested in more comprehensive programs for weed management that reduce weed populations over time and the use of reduced herbicide doses in order to diminish their production costs. Integrated weed management takes advantages of various methods to suppress weeds in a more common and environmental natural way. Today, it is understood that chemical herbicides are not free of problem. So researchers are working on integrated weed management, which brings all possible methods to control weeds. The use of reduced herbicide doses will cost a fraction of full dose and make them even more affordable to poor farmers who have a limited amount of resources. Researches indicate that there is good potential to reduce the number of herbicide applications and utilize lower herbicide doses within competitive cropping systems. Crop competitiveness advantage is a great potential for weed suppression that provides reducing herbicide dose to avoid its environmental and economic suffers. Therefore, a field experiment was conducted to evaluate the effect of reduced dose of imazethapyr on weed control when two bean cultivars grown in pure stand and intercropping together.
The field experiment was conducted as split plot based on randomized complete block design at the Research Farm of University of Tehran located in Karaj during 2013–2014. Main plots were five doses of imazethapyr (0, 25, 50, 75 and 100 percent of the recommended dose) and sub-plots comprised pure stands and intercropping of two bean cultivars include: Akhtar (the growth habit is upright) and Goli (the growth habit is creeping). Also there is a plot as weed free (control). When the plants were at the third trifoliate stage, determined doses of imazethapyr were sprayed. Weed dry weight and bean yield were analyzed by nonlinear regression. In order to obtain the response curves to the doses of imazethapyr, data were fitted by SigmaPlot software (version 11) according to the standard dose-response equation:Where W is the dependent variable, ED50 is equivalent to a dose of herbicide that reduces weed dry matter by 50 percent and b is the curve slope where the trend is linear. The yield data were fitted using a three-parameter logistic equation:where a is maximum yield, x0 represents a dose of herbicide in which the yield reaches 50 percent and b is the slope of the curve.
The community of weeds in the field mostly consisted of three species; Amaranthus retroflexus, Chenopodium album and Solanum nigrum that all are summer annual weeds. The dose-response model well described the effect of doses of herbicide on weed dry weight. Results indicated that weed species response to herbicide doses differently in bean cultivars and their intercropping. Among dominant weeds, A. retroflexus was determined high sensitive to increasing doses. Bean cultivars were solely different in competition with weeds, as creeping cultivar i.e. Goli with more competitive ability (like: fast early growth and area coverage) was more successful in weed suppression. Herbicide application at reduced dose could also be efficient when we used 75 percent of the recommended dose because led to a yield more than 4000 kg/ha in pure stand of Goli. Pure stand of Akhtar and intercropping showed yields of 3617 and 3641 kg/ha, respectively at 75 percent of the recommended dose. Relative yield total (RYT) for doses of 75 and 100 percent of the recommended dose and weed free control were 0.95, 0.87 and 1.03, respectively.
The results of experiment showed that weed sensitivity to herbicide doses vary differently by species. So that, A. retroflexus dry weight was more affected than C. album and S. nigrum in response to reduced doses of imazethapyr. The application of 25 percent of the recommended dose of this herbicide reduced A. retroflexus dry weight more than 50 percent. It seems that if the dominant weed in a field was the A. retroflexus, the farmer could greatly reduce dose of imazethapyr. However, usually weed community of fields are consisted of several species, therefore, to use reduced herbicide doses, sensitivity of all species should be considered. Also, using bean cultivars that potentially have high competitive ability, it could be a good supplement in combination with reduced doses of herbicide. In this experiment, Goli cultivar presented more potential to combine with reduced doses of imazethapyr.

In recent years Jasmine whitefly Aleuroclava jasmini(Takahashi,1932), has caused severe damage to the citrus orchards of Khuzestan province. In order to evaluate the effect of intercropping on population of Jasmine whitefly, a field trial (T1) with six treatments include four treatments intercropping of Broad beans (Vicia faba L.), Common bean (Phaseolus vulgaris L.), White clover (Trifolium repens L.) and Cucumber (Cucumis sativus L.), and two treatments control of without weeds (C1) and with weeds (C2) in an orchard of Valencia oranges in a completely randomized design with five replications was carried out from September 2013 until July 2014. Each plot consisted of 20 trees that five trees per plot (five repetitions) were selected and 12 leaf samples were taken randomly from each tree. The results showed that in six times sampling in spring, among intercropping treatments, the whitefly's egg and nymph population had significant differences in the levels of 0.05 and 0.01, respectively. The minimum egg population was in the treatments of C1=13.88±0/12( statistical group b), cucumbers 17.82±0/06( statistical group ab), and Broad beans 19.14±0/06( statistical group ab) which had significant differences with other treatments. The minimum nymph population was in the treatments of C1=6.5±0/07(statistical group d), Broad beans 9.21±0/08( statistical group c), and cucumber 10.13±0/07(statistical group bc) which had significant differences with other treatments.