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

Intercropping beside of increasing of yield than sole crops, enhance heterogeneity and biodiversity in agroecosystems. To evaluate yield and productivity indices of Guilan lanrace bean (Phaseolus vulgaris L.) and sunflower (Helianthus annuus L.) intercropping, a field experiment was conducted as randomized complete block design with three replications in 2014-15 growing season, at Somea-Sara, Iran. The planting ratios were 0:100, 25:75, 50:50, 75:25 and 100:0 (bean: sunflower) using replacement method. Intercropping had significant effect on pods per plant and seed yield of bean, and it had significant on plant height, head diameter, heads per plant, 100 seed weight, seeds per head and grain yield of sunflower. The land equivalent ratio (LER) were less than one in 75:25 and 50:50 (bean: sunflower) intercropping ratios, while it was equal to 1.15 in 25:75 bean-sunflower intercropping ratio, which indicates the intercropping cultivation of beans-sunflower had the highest efficiency by 15%. Sunflower in the planting ratios of 25:75 and 50:50 (bean: sunflower) had the highest relative crowding coefficient (RCC), therefore it was a dominant crop and bean had the least RCC and was a reccesive crop. The competitive ratio value (CR) of bean was less than one, which this means that bean was less competitive than sunflower in the intercropping system. It is concluded that sunflower and bean intercropping system have a substantial advantage compared to sole cropping systems and the intercroping ratios of 25:75 (bean-sunflower) was as superior planting ratio.

Backgrounds and Nowadays, intercropping is highlighted as a solution to optimize usage of inputs, to decline pesticides and to produce safe food in agriculture. The previous studies represent relative advantages of multiple cropping versus sole cropping. Since, garlic and pea are well-adapted plants to northern Iran climatic conditions and there were no comprehensive studies about their intercropping, the present study was aimed to evaluate and determine the best intercropping treatment between garlic and pea in terms of yield.
The research was conducted at research farm of Gonbad Kavoos University and Sari 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 and replacement series of 25:75, 50:50 and 75%:25% pea: garlic and additive series of 25, 50, 75 and 100% pea 흍% garlic.
The biological yield of garlic in Gonbad region (2357.21 g/m2) was 10 percent lower than Sari region. Means sulfur percentage in garlic bulb was recorded 0.81 and 0.94 for Gonbad Kavoos and Sari, respectively. The maximum bulb yield (1193.42 g/m2) was belonged to sole cropping of garlic in Sari conditions. Seed yield of pea was 399.3 and 736.17 kg/ha in Gonbad Kavoos and Sari, respectively. Results indicated that the maximum seed yield of pea was recorded in sole cropping and followed by additive series of 100% garlic 100% pea by 53.3 g/m2. In Sari region, the seed nitrogen and phosphorous content in was 4.85 and 0.29 %, respectively and was 3 and 11.5 % more than Gonbad. The maximum seed potassium (1.53%) was related to additive series of 25% pea 100% garlic in Sari conditions. The highest land equivalent ratio (1.76), relative crowding coefficient (7.4), aggressivity (0.79) and relative value total (1.53) was recorded when additive series of 75, 25, 100 and 75 % of pea 100% garlic intercropped in Sari climatic conditions, respectively.
was related to additive series of 25% pea 100% garlic in Sari conditions. The highest land equivalent ratio (1.76), relative crowding coefficient (7.4), aggressivity (0.79) and relative value total (1.53) was recorded when additive series of 75, 25, 100 and 75 % of pea 100% garlic intercropped in Sari climatic conditions, respectively.
Overall, results of different additive and replacement series of intercropping showed that the additive series intercropping of 75 and 100 % pea 100% garlic resulted the maximum quantitative and qualitative yield in both studied regions

In order to evaluate the benefits of maize, pinto bean and naked pumpkin triple cropping, an experiment was carried out as a randomized complete block design with three replications at Faculty of Agricultural Science, University of Guilan, Rasht, Iran in 2012. The treatments consisted of maize, pinto bean and naked pumpkin sole cropping (100, 75 and 50% of conventional densities), maize – pinto bean and maize – pumpkin double cropping (100-100%, 75-75% and 50-50%), and maize-pinto bean-pumpkin triple cropping (100-100-100%, 75-75-75% and 50-50-50%). The highest and lowest forage fresh weights were obtained in triple cropping system with high density and sole cropping systems with low density, respectively. In double cropping systems, the maize-pumpkin out-yielded the maize-pinto bean in terms of fresh weight. The relative crowding coefficient, competitive ratio and aggressivity of maize in double cropping of maize-pinto bean and naked pumpkin in double cropping of maize-naked pumpkin were dominant. In triple cropping systems, while maize and naked pumpkin were comparable, but both of the latter crops were dominant over pinto bean. Land Equivalent Ratio (LER) for double and triple cropping was greater than one, revealing the profitability of double and triple cropping systems on sole cropping. According to the LER, the cropping systems can be ranked as follows: triple cropping > double cropping maize/pinto bean > double cropping maize/pumpkin

Competitive relationships of watergrass (Echinochloa oryzoides) and barnyardgrass (Echinochloa crusgalli) with rice in different plant proportions of 0:4, 1:3, 2:2, 3:1, and 4:0, weed:rice in each hill were investigated in a field experiment. Weed biological and grain yield (both Echinochloa species) were higher than rice; however, the harvest index was higher for rice compared to weed species. Relative yields (based on number of tillers, biological yield, and grain yield), replacement series diagrams, rice aggressivity index, and relative crowding coefficient exhibited higher competitiveness for weed than rice. Rising in the ratio of each species at the planting proportion increased the biological, grain and relative yield and harvest index in both rice and weed. Furthermore, it caused an increase in rice aggressivity index. In all tested plant proportions, weeds were superior to rice regarding biological and grain yield, except for 1:3 weed:crop in which both species were similar for grain yield. Comparing two Echinochloa species, watergrass, had lower biological yield, but higher harvest index. Grain and relative yields, and relative crowding coefficient were not significantly different for two weed species; however watergrass led to more reduction in grain yield, harvest index, relative yield and aggressivity index of rice.

To evaluate yield and productivity indices of maize and sugar beet intercropping with different planting ratios, a field experiment was conducted in randomized complete block design with three replication at Hamedan province in Nahavand, in 2013. The planting ratios were 100:0, 75:25, 50:50, 25:75 and 0:100 (maiz: sugar beet) using replacement method. Results showed that intercropping had significant effect on yield and some yield component of both crops. The root-yield, sugar sterling, melas-sugar, content purity and sugar yield of sugar beet as well as shoot height, No. row. ear-1, kernel. Row-1, 1000 kernel weight and grain yield of maize were significantly affected by different planting ratios. Calculation of land equivalent ratio (LER) revealed that planting ratio of 25:75 (LER= 1.09) and 75:25 (maize:sugar beet) (LER= 1.08) had the highest efficiency by 9% and 8%, respectively. Calculation of area time equivalent ratio (ATER) revealed that planting ratio of 25:75 (maize:sugar beet) (ATER= 1.03) had the highes efficiency. Maize in the planting ratio of 75:25 had the highest relative crowding coefficient (ka= 7) as dominant crop and sugar beet had the highest RCC (KB= 3.88) in the ratio of 25:75 (maize:sugar beet) at the dominant crop.

In order to study the phenology and competition of potato and safflower intercropping system, present study carried out in 2009 in Ardebil. Afactorial experiment was conducted in Randomized Complete Block Design (RCBD) with seven treatments and three replications. First treated to cultivate potatoes in net density of six plants per square meter fixed was allocated. Three dimensional culture treated potato mixture (with a density of six plants per square meted) and safflower densities of 6, 12, 18 plants per square meter was allocated and the other three trat ment densities of pure cultures of safflower 6, 12, 18, plants formed. The analysisof variance in pheology stages of pure culture and mixed with potatoes sheweed that all treatment were significant differences. Similary, the smaller of these indexes suggest weak competition in safflower as compared to potatoes. Ameuts of relative yield total of potatoes and safflower in all treatments intercropping was smaller than the one.

To evaluate yield and productivity indices of chickpea and canola intercropping with different planting ratios، a field experiment was conducted in randomized complete block design with four replications at Agricultural Research Station of Mazandran province in Ghaem-Shahr، in 2010. The planting ratios were 0:100، 25:75، 50:50، 75:25 and 100:0 (chickpea: canola) using replacement method. Results showed that intercropping had significant effect on yield and some yield components of both crops. The number of branch and silique. plant-1، 1000-seed weight and grain yield of canola as well as shoot height، number of pod. plant-1 and kernel yield of chickpea were significantly affected by different planting ratios. Calculation of land equivalent ratio (LER) revealed that planting ratio of 50:50 (LER= 1. 26) and 25:75 (canola- chickpea) (LER= 1. 18) had the highest efficiency by 26% and 18%، respectively. Canola in the planting ratio of 50:50 had the highest relative crowding coefficient (KB= 2. 36) as dominant crop and chickpea had the least RCC (KC= 0. 72) in the ratio of 75:25 (canola- chickpea) as the in dominant crop. Results also indicated that the interference type was positive and complementary and the observed yield of canola and chickpea were not different from their expected yields in all planting ratios. It is concluded that increased number of branches and siliques. plant-1 in canola، in intercropping with chickpea، were the main reasons of yield benefit.

Efficient use of natural and biological cycles such as nitrogen fixation by legumes may stimulate yield of the non-legumes crops in an intercropped system. To evaluate spring barley and annual medic intercropping، an experiment was conducted in the research field of Tehran University in Karaj، Iran، in 2009-2010 growing season. Randomized complete block design (RCBD) with four replications and 14 treatments were used. Treatments included: B1:1M، B2:2M، B4:4M، B6:6M، B6:2M، B4:2M، B2:4M، B2:6M، B100%: 20%M، B100%: 40%M، B40%: 100%M، B20%: 100%M and two additional treatments of barley and annual medic sole crop were established. The highest dry matter yield for barely and annual medic was achieved from sole crop (2900 kg ha-1 for barely and 1773 kg ha-1 for annual medic، respectively). The highest forage water soluble carbohydrates (WSC = 15. 42%)، forage crude fiber (CF = 38. 40%)، silage neutral detergent fiber (NDs = 44. 72%)، silage pH (pH = 5. 31) belonged to sole crop of barley. Also، the highest silage acid detergent fiber (ADF = 26. 42%) and forage acid detergent fiber (ADF = 30. 88%) belonged to sole crop of annual medic. The highest seed yield for barely and annual medic was achieved from sole crop (1907 kg ha-1 for barely and 877 kg ha-1 for annual medic، respectively) and the maximum harvest index (HI) was for B2:6M for barley (34. 75%) and B2:2M for annual medic (28%). The highest land equivalent ratio for dry forage yield (LER = 1. 232) was obtained from H1:1M. The highest land equivalent ratio (LER = 1. 29)، monetary advantage index (MAI = 1329877. 5 toman) and relative crowding coefficient (RCC = 2. 79) for seed yield obtained for B6:2M mixture. Results suggested that the suitable mixture for dry matter yield was B1:1M. For achieving better silage and forage quality، higher ratio of annual medic in mixtures with barley is necessary. Results also suggested that the suitable mixture for seed yield was B6:2M.

Efficient use of natural and biological cycles such as nitrogen fixation by legumes may stimulate yield of non-legumes crops in an intercropped system. In order to evaluate spring barley (H) and annual alfalfa (M) intercropping, a study was conducted in the research field of University of Tehran (located in karaj) during 2009-2010 growing season. In this research, a randomized complete block design with 4 replications and 14 treatments were used. Treatments include: H1:1M, H2:2M, H4:4M, H6:6M, H6:2M, H4:2M, H2:4M, H2:6M, H100%:20%M, H100%:40%M, H40%:100%M, H20%:100%M and two additional treatments of barley and alfalfa sole intercropping were established. The highest cumulative dry forage yield was achieved from treatment H1:1M (2934 Kg/ha). The maximum forage crude protein (CPf=30.87%), dry matter digestibility (DMDf=76.57%) and silage crude protein (CPs=17.88%) was detected in sole culture of alfalfa. Also, the highest silage dry matter digestibility (DMDs=31.37%) and silage ash (18.73%) belong to H4:2M, H6:2M, respectively. The highest land equivalent ratio (LER=1.232), and relative crowding coefficient (RCC=2.60) was detected for H1:1M mixture. Our results suggested that the best mixture is H1:1M for quantity yield. For achieving better quality, more percentage of alfalfa in mixtures is necessary.