جستجوی مقالات مرتبط با کلیدواژه "relative crowding coefficient" در نشریات گروه "اکولوژی"

In intercropping systems, inputs in a unit area have been reduced but use of available resources is optimized, leading to increased production and promotion of evaluation indices. In a study on maize and peanut intercropping, the highest index of land equivalent ratio (LER=1.04) was obtained in 100% corn + 100% peanut. In addition, barley and peas as well as garlic and chickpea intercropping, improved the LER and the other intercropping indices. Therefore, the main objective of this research was the estimation of the yield and intercropping indices of garlic (Allium sativum L.) and peas (Pisum sativum L.) in two regions of Sari and Gonbad Kavoos.

The present research was conducted at research farms of Gonbad Kavoos University and Sari region during 2013-2014. The experiment was arranged based on randomized complete block design with three replications. Treatments were nine levels including sole cropping of garlic and pea, beside replacement series of 25:75, 50:50 and 75%:25% pea: garlic as well as additive series of 25, 50, 75 and 100% pea +100% garlic. Plot size was 1.8 × 6m with six rows of cultivation. Plant densities in the control treatment were the same for both garlic and peas, with a 30 × 10 cm square and rectangular plant arrangement with six lines of six meters long and 360 plants per plot. In the incremental mix of 25% pea + 100% garlic, 50% pea + 100% garlic, 75% pea + 100% and 100% pea + 100% garlic 90, 180, 270 and 360 plants of peas were added to each plot of garlic, respectively.

The results showed that the highest garlic yield (9800 kg.ha-1) was obtained in pure cropping in Sari region, which increased 14% as compared to the Gonbad Kavoos region. The yield of pods (1060 kg.ha-1) and seed (348.3 kg.ha-1) decreased (up to 64 and 61%, respectively) in pure cropping of peas in the Gonbad Kavoos region. In additive series, LER and relative crowding coefficient in100% of garlic + 100% peas was 1.33 and 1.49 as well as 1.1 and 2.54 in Sari and Gonbad Kavoos, respectively. Actual yield loss (AYL=-0.15 and -0.20) were observed only in Sari and in additive series of 75% peas + 100% garlic and 100% of peas + 100% garlic, respectively. In contrast, the intercropping advantage (0.38) was observed in Sari where the 25% of peas intercropped with 75% of garlic, increasing up to 15% as compared to the Gonbad Kavoos region. Furthermore, partial competitive ratio (CRa) for pea and garlic was affected by different planting arrangements. The highest CR value for garlic (1.55) was recorded when 25% pea was added to 100% garlic. The higher root system and leaf area of pea helps to its advantage in intercropping system. The partial advantage of intercropping for garlic was affected by planting arrangement. The maximum partial advantage was obtained in replacement series of 755 garlic +25% pea.

In general, results of the present research clearly showed that intercropping of garlic and peas improved yield performance and intercropping evaluation indices. In additive series, a mixture of 100% pea + 100% garlic with relative crowding coefficient of 5.17 was the best combination of intercropping in terms of yield improvement in both regions. The presence of garlic in the mixture, particularly in the Gonbad Kavoos region, dramatically reduced the adverse effect of cold temperature on seed yield of peas and prevented the severe reduction of yield. Therefore, in each region where it is possible to cultivate these two plants, it is recommended that garlic considered as the main plant and peas with a density of 75% or more could add to the mixture.

Acknowledgements

We are grateful to the University of Gonbad Kavoos for its contribution to the implementation of the project as well as Sari Agricultural Science

In the production of medicinal plants, it is a global approach toward sustainable agricultural systems and use of agricultural practices such as intercropping, application of biofertilizer and mulch to enhance the quantitative and qualitative performance of medicinal plants. Thus, two experiments were conducted with factorial arrangement based on randomized complete block design (RCBD) with three replications at the Research Farm of University of Tabriz in 2015 and 2016. The first factor was included sole cropping of purslane, sole cropping of dragon’s head, additive intercropping of dragon’s head + purslane (20, 40, 60 +100 %), and the mulch application as second factor including wheat straw mulch and no mulch; two types of fertilization including application of 100% chemical fertilizer and 50% chemical + biological fertilizers as third factor. Results revealed that the highest values of oil content and unsaturated fatty acids were observed in D20 + P100 intercropped plants, while the highly saturated fatty acid of palmitic content was observed in sole cropped. Mulch application had the highest yield and growth traits. Also, quantity and quality of dragon’s head was not significantly affected by replacing biofertilizers with chemical fertilizer. In other words, it can be used 50% chemical + biological fertilizers. The highest land equivalent ratio and relative crowding coefficient were obtained from dragon’s head with purslane intercropping (D40 + P100), wheat straw mulch application, and combinative application of chemical and biological fertilizers in second year. It seems that intercropping system (D40 + P100) and application of biofertilizers and mulch can be suggested as an appropriate agricultural method to reduce the consumption of chemical inputs and increase yield of dragon’s head.

In order to evaluate of peppermint and faba bean intercropping, a field experiment was carried out as a randomized complete blocks design (RCBD) with eight treatment and three replication at the faculty of Agriculture, University of Maragheh during 2015 growing season. Treatments were included sole planting of peppermint and faba bean, 1 row peppermint 1 row faba bean, 1 row peppermint 2 rows faba bean, 2 rows peppermint 1 row faba bean, 2 rows peppermint 3 rows faba bean, 3 rows peppermint 2 rows faba bean, 1 row peppermint 3 rows bean and 3 rows peppermint 1 row bean. Intercropping different patterns were calculated by means of land equivalent ratio (LER), standard land equivalent ratio (LERS), area time equivalent ratio (ATER), area harvest equivalent ratio (AHER), land use efficiency (LUE), peppermint equivalent yield (EYP), relative crowding coefficient (RCC or K), aggressivity (A), competitive ratio (CR), actual yield loss (AYL), monetary advantage index (MAI), intercropping advantage (IA), system productivity index (SPI) and relative value total (RVT). Results showed that seed yield of faba bean per occupied unit area and per intercropped unit area were affected significantly by intercropping patterns. The highest seed yield of faba bean per occupied unit was obtained in the 2:3 and 1:3 treatments. In addition, the highest seed yield of faba bean per intercropped unit area observed in faba bean sole crop. The highest values of LER, LERS, ATER, AHER, LUE, EYP, IA, MAI and SPI obtained in 2:3, 3:2 and 1:3 intercropping patterns, indicating that the intercropping systems were the most profitable on basis of agronomical and economical. Generally, the A, CR and AYL values in peppermint were higher than bean, indicating that peppermint was more competitive and dominant than faba bean. Generalley, in basis of more agronomy and economic indices in 2:3 cropping pattern, this cropping pattern was superier than other treatments.

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.

Evaluating yield in intercropping systems is based on selecting compatible plants with appropriate characteristics to establish minimum competition and maximum cooperation, and the application of suitable agricultural practices (crop density and intercropping ratio). The use of plant species with different morphological characteristics in terms of nutrient uptake and utilization of growth environment, and the least competitive species in ecological and environmental factors in a fixed nest causes possibility of presence of two plants in the same ecological niche and better use of resources (Banik et al, 2006; Mushagalusa et al., 2008). Competitive ability of species in the intercropping is estimated using the relative interference parameters and determining the dominant species (Dhima et al., 2007). One of the indicators to evaluate intercropping is competitive ratio which is the competitive ability of the crop in the form of a better expression (Dhima et al., 2007). In general, the intercropping is one of the ways that increases the stability of agroecosystems.
In order to study the effects of density, weedy and various proportion of corn (704 Variety) and peanut (Goli Variety) intercropping an experiment was conducted in 2012 in the Agriculture Research Station (Chah Nimeh) of Zabol University. The experiment design was factorial in randomized complete block design with three replications. Experiment factors consisted of planting proportions in 4 levels (sole crop of corn, 50% corn % peanut, 100% corn 100% peanut and sole crop of peanut), weedy in 3 levels (non-weedy, once-weedy and twice-weedy) and the space between rows in 2 levels (40 and 50 centimeter). For appointment of dominant treatment, Relative Crowding Coefficient (RCC), Competitive Ratio (RC), Aggressivity and Land equivalent ratio (LER) were calculated. All treatments were planted in a row of peanut and a row of corn. In intercropping alternative treatments and increasing sowing ratio with bush density change (the distance change between two bushes on a row) and variable distance between two rows (40 and 50 cm) were carried out. In monoculture and alternative intercropping systems, the distance between bushes for both plants was identical, but alternative intercropping, a row of corn and a row peanut were planted and there were 30 plants of corn and 40 plants of peanut per unit area on each row. To intensify the intercropping, the distance between plants on the rows decreased and due to variable spacing between rows, number of plants per unit area increased and there were 60 corn plants and 80 peanuts plants per unit area on each row.
The highest yield for corn (3.18 t.ha-1) was obtained in a intercropping of 100% corn흍% peanut and peanut (9.43 t.ha-1) in 50% corn% intercropping of peanut respectively. This means that the proximity of the legumes and grasses can be more productive in terms of intercropping than mono cropping system. The reason could be due to biological nitrogen fixation and increases in light absorption by roots of peanuts. Results indicated that various factors had significant effects on valuated index. The highest and least LER was in 100% corn 100% peanut and 50% corn 50% peanut. The highest RCC was for peanut, treatment non-weedy at higher population (7.41) and least was in the corn, treatment once-weedy at lower population (0.4). Corn competitive ratio on peanut in all treatments was less than one, which indicated peanut had advantage over corn. Based on this scale treatment with less density and twice-weedy was more dominate. The Aggressivity index for corn in all the treatments were negative but increased. Therefore in the all indices peanut was the dominant species, this was referred to better use of resources and weed control.
The results showed that both morphology and structure of the components of a intercropping, in dominant and recessive forms are effective. Row spacing and weed control are factors affecting the competitiveness and profitability indicators in intercropping. Peanut was the dominant species and a top competitor in corn and peanut intercropping with higher Aggressivity index, relative interference and higher competition and to the effective use of environmental resources and weed control, which makes it the most serious rival for corn.

With the continuous growth of world population، degradation and ecological imbalance throughout the world، there is a need to increase agricultural production and environmental protection measures. In this respect، efforts to supply nutrients to the environment are at the head of the programs. One of the ways to approach this goal is the use of intercropping systems (Najafi & Mohammadi، 2005(. Suitable performance in intercropping systems may be achieved by selecting genotypes possessing traits consistent with and appropriate for establishing minimum and maximum synergy and competition employing proper agronomic practices such as density and planting pattern (Mutungamiri et al.، 2001). In this context، selected plants should be less competitive in terms of environmental impact. The purpose of this study was to investigate the effect of different planting patterns on the competition between the two species of Calendula and soybean and to evaluate the yield and quality of an intercropping system compared with a mono-cropping system.

In order to evaluate the competition between soybean and calendula، a field experiment was conducted based on randomized complete block design with 7 treatments and 3 replications in the research farm of the Faculty of Agriculture، the University of Tabriz in 2009. The treatments included pure stands for both species، 1:1، 2:2، 4:2، 4:4 and 6:4 for soybean and calendula number of rows per strip، respectively. Before planting، soybean seeds were inoculated with Bradyrhyzobium japonicum. Before harvesting، the number of pods per plant، seeds per plant، 1000- grain weight، grain yield، percentage of oil and protein of soybean grain were measured in 10 randomly selected plants. The number of flowers per plant، dry inflorescence weight and dry petal weight of Calendula were recorded. The harvest of flowers of calendula began on July 30 and harvesting was done every 15 days in six steps. It was continued to mid-October. Total dry petals and sepals of 6 withdrawals flower per plot were considered as inflorescence dry weight. The land equivalent ratio (LER)، actual yield loss (AYL)، relative crowding coefficient (RCC)، aggressivity (A) and competitive ratio (CR) were determined at the end of the growing season. For statistical analysis، analysis of variance (ANOVA) and Duncan’s multiple range test (DMRT) were performed using MSTAT-C.

The results showed that the effect of planting pattern on the number of pods per plant، seeds per plant، 1000-grain weight، grain yield of soybean، percentage of oil and protein contents of soybean was not significant. The effect of planting pattern on inflorescence dry weight and dry petal weight of calendula was significant. Row and strip intercropping 6:4 produced greater dry inflorescence weight and dry petal weight than calendula monoculture. The highest petal and inflorescence yield was achieved by 1:1 (87. 63، 30. 75) and 6:4 (41. 75، 22. 68) intercrops، respectively. The effect of planting pattern on the number of flowers per plant was significant at 1% level. The number of flowers per plant for row intercropping and strip intercropping of 1:1 and 6:4 were greater than calendula monoculture. The highest flowers per plant was achieved by 1:1 and 6:4 intercrops، respectively. The land equivalent ratio was greatest for 6:4 and 1:1 intercrops equal 1. 34 and 1. 13، respectively and the lowest land equivalent ratio was achieved by 2:2 intercrops. The actual yield loss value of all treatments were positive that indicated increased yield. In row intercropping and strip intercropping 4:4 and 2:2 competitive ratio of calendula (1. 13، 1. 25، 2. 06) was>0 and the competitive ratio of soybean (1. 07، 1. 2) was>1 that show that yield advantage was greater than mono-cropping system. The relative crowding coefficient (RCC) of calendula (0. 46، 0. 46، 0. 76) was greater than that of soybean that proves the competitive advantage of calendula against soybean. In strip intercropping، 6:4 and 4:2 aggressivity of soybean (0. 98، 1. 43) was>0، that indicates the relative yield of soybean is greater than calendula. The negative aggressivity of calendula (0. 93، 1. 19) in this treatment shows that the relative yield of calendula is less than soybean. In row intercropping and strip intercropping 4:4 and 2:2 competitive ratio of calendula (1. 13، 1. 25، 2. 06) was>0 and competitive ratio of soybean (1. 07، 1. 2) was >1 that shows that yield advantage was greater than mono-cropping system.

The experiment was conducted in order to evaluate of competitive and economic indices in canola and pea intercropping at different rates of nitrogen fertilizer at Shahrekord University research farm during 1390 - 1391. Intercropping and sole cropping treatments (100% canola; 66% canola + 33% pea، 50% canola + 50% pea; 33% canola + 66% pea; 100% pea) were evaluated as the first factor and nitrogen rates (100% need; 75% need and 50% need) as the second factor in a randomized complete block design with three replications. The calculated competitive indices were included land equivalent ratio (LER)، relative crowding coefficient (K)، aggressively (A)، the system production index (SPI)، actual yield loss (AYL)، competitive ratio (CR) and economy indices included monetary advantage index (MAI)، and the intercropping advantage (IA). Results showed that all the competitive and economic indices had the highest amount in 50 and 75% of nitrogen requirement. The amounts of AYLt and SPI and economic indices (MAI and IA) were positive for all intercropping ratios. Also، LERt and Kt for all intercropping ratio were greater than one، that indicating the superiority of intercropping over sole cropping any of the two plants. The positive values aggressively index and the greater than one values competitive ratio for canola، indicated canola was superior competitor in compared to pea. In conclusion، the evaluation of competitive and economic indices appropriately describes intercropping advantage of canola with pea in reduced nitrogen fertilizer conditions.

In order to study the competition ability of amaranth and mungbean in fodder intercropping system under different crop residue management، a field experiment was conducted at two seasons (first planting of wheat and then intercropping management) in Agricultural Faculty of Shahid Chamran University of Ahvaz during growing season of 2010-2011. The experimental design was split plot based on randomized complete block design with three replications. Three crop residue managements were in main plot and five planting ratios were in sub-plot. Eight indices of the competition abilities were measured. The results showed that the highest intercropping fodder yield (1347. 6 g. m-2) and LER (1. 27) were obtained in residue incorporated and 50% planting ratio of each crop. Residue burning increased variation of CR، reduced RLO and RCI and also، had the highest RYL. In higher planting ratio، the aggrissivity of amaranth was more than mung bean. In treatments with highest forage yield، amaranth and mungbean were dominant and non-dominant crops، respectively. In conclusion، amaranth was more influenced by residue management methods and planting ratios than mung bean and also، its competition ability had more variation in compared by mung bean.

The mathematical formulas for evaluation of intercropping advantage provides accurately assess of intercropping systems based on economic and competitive parameters. In order to study the economic and competitive indices on intercropping of soybean with sweet basil (Ocimum basilicum L.) and borage (Borago officianalis L.) an experiment was performed in a randomized complete block design with 9 treatments and 3 replications in 2011 at a field located 10 km of Shirvan (Northern Khorasan). Treatments were included different ratios of intercropping of soybean with sweet basil and borage (100:0، 75:25، 50:50، 25:75، and 0:100، soybean: sweet basil or borage). In this experiment، we used the indices of land equivalent ratio (LER)، relative crowding coefficient (K)، aggressivity (A)، competitive ratio (CR)، system productivity index (SPI)، actual yield loss (AYL)، area-time equivalent ratio (ATER) and competitive index (CI) and economic indices of monetary advantage (MAI) and intercropping advantage (IA). The results showed that intercropping had superiority compared to monoculture. In all ratios، aggressivity indices indicated that soybean was dominant compared to sweet basil and borage. The results suggested that there was a relationship between economic and competitive indices، so that economic advantageous was observed in treatments with LER and K higher than one. In general، treatments of 75% soybean: 25% sweet basil and 50% soybean: 50% borage were superior than other treatments. The indices indicated that intercropping soybean with sweet basil has a high efficiency when compared to intercropping soybean with borage.