Mojtaba Khazaie; Alireza Taab
Abstract
A field experiment was carried out to investigate the effect of Persian clover (Trifolium resupinatum L.) as an undersown cover crop on weed control in winter oilseed rape. The experiment was conducted in a randomized complete block design with four replications in Nahavand region (km: 35) of Iran during ...
Read More
A field experiment was carried out to investigate the effect of Persian clover (Trifolium resupinatum L.) as an undersown cover crop on weed control in winter oilseed rape. The experiment was conducted in a randomized complete block design with four replications in Nahavand region (km: 35) of Iran during 2017-2018. The treatments were included oilseed rape with four levels of Persian clover density (25, 50, 75 and 100 percentages of the optimum sowing rate) and two levels of weed management (weedy and weed-free). The results showed that the undresown Persian clover has a significant effect on reducing the density and aboveground dry weight of the weeds compared to the control. Oilseed rape + 25, 50, 75 and 100 percentages of Persian clover sowing rate, respectively, caused 63, 66, 80 and 91 percent reduction in weed density. The same treatments also caused 35, 51, 58 and 75 percent reduction in weed aboveground dry weight, respectively. Oilseed rape yield undersown with Persian clover was lower than oilseed rape in weed free treatment. However, oilseed rape yield in oilseed rape +75 and 100 percentages of Persian clover sowing rate was higher than oilseed rape weed infested treatment. The percentages of oil seed content in oilseed rape in all treatments undersown with Persian clover was equal to oilseed rape weed free treatment and higher than oilseed rape weed infested treatment. The land equivalent ratio in oilseed rape +75 and 100 percentages of Persian clover sowing rate was 0.92 and 1.09, respectively.
mojtaba khazaie; mohammad hassan hadizadeh; ehsan zaidali
Abstract
In order to determine the critical period of weed control (CPWC) in Corn (Zea mays L.), an experiment was carried out in a randomized complete blocks design with 14 treatments and three replications during 2013 growing season in the Nahavand climatic conditions. Two series of the treatments including ...
Read More
In order to determine the critical period of weed control (CPWC) in Corn (Zea mays L.), an experiment was carried out in a randomized complete blocks design with 14 treatments and three replications during 2013 growing season in the Nahavand climatic conditions. Two series of the treatments including weed-free and weed-infested were applied in the regular time distances of 10, 20, 30, 40, 50 and 60 days after Corn emergence. Two check treatments including full and no control of weed during the whole season were also included. The nonlinear models kind of Logistic and Gompertz were applied to determine the start and end of critical period of weed control respectively. Major weed species were field bindweed (Convolvulus arvensis L.), red root pigweed(Amaranthus retroflexus L.), pigweed(Amaranthus blitoides L.) and lambsquarters(Chenopodium album L.) with greater biomass and size. The results showed that periods of weed- free and weed- infested differently affected the dry weight and number of weeds in all treatments. The critical periods of weed control in Corn by accepting a 5% acceptable yield loss, it is necessary to control weeds in a period between 14-47 days after planting or 117- 566 growth degree day(4-12 leaf stage) and by accepting a 10% acceptable yield loss it is necessary to control weeds in a period between 23-36 days after planting or 220- 419 growth degree day(6-10 leaf stage).
mojtaba khazaie
Abstract
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 ...
Read More
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.