Effects of Weed Interference and Starter Fertilizer on Subsequent Seed Germination and Vigour of Soybean (Glycine max [L.] Merr.)

G.R. Mohammadi,F. Amiri 韓國雜草學會 2012 Weed&Turfgrass Science Vol.32 No.1

The study was conducted to investigate the effect of weed interference and starter fertilizer on subsequent soybean seed quality at the Agricultural Research Farm and Laboratory of Razi University, Kermanshah, Iran, Two factorial experiment was laid-outon a randomized complete block design with four replications, First factor was starter fertilizer levels (0 and 25 kg ha-1) applied in the forms of monoammonium phosphate, the second factor was different weed interference periods consisted of five initial weed-free periods (in which, plots were kept free of weeds for 0, 15, 30, 45 and 60 days after crop emergence (DAE) and then weeds were allowed to grow until harvest) and five initial weed-infested periods (in which, weeds were allowed to grow for 0, 15, 30, 45 and 60DAE, after which the plots were kept free of weeds until harvest). Full season weedy condition reduced 100-seed weight, seed germination percentage and seedling dry weight by 25.9, 13.3 and 22.5%, respectively and increased mean germination time and seed electrical conductivity by 55.8 and 24.3%, respectively as compared with full season weed-free control. However, the traits under study were not significantly influenced when field was kept free of weeds for at least 45 DAE (R1) or weedy condition was continued for less than 30 DAE (V8). There was a significant and negative correlation between weed biomass and seed weight (r = -0.93), so that when weed free condition was less than 45 DAE or weed infested period was continued for at least 30 DAE, soybean plants produced wrinkled and underdeveloped seeds with lower weights and qualities. Moreover, soybean seed quality reduction due to weed interference was more evident when starter fertilizer was applied and weeds interfered with soybean from the beginning of the growing season. Information from the present study is beneficial in soybean seed production systems and where farmers use the harvested seeds for the following planting.

Effects of Weed Interference and Starter Fertilizer on Subsequent Seed Germination and Vigour of Soybean (Glycine max [L.] Merr.)

Mohammadi, G.R.,Amiri, F. The Korean Society of Weed ScienceThe Turfgrass So 2012 Weed&Turfgrass Science Vol.32 No.1

The study was conducted to investigate the effect of weed interference and starter fertilizer on subsequent soybean seed quality at the Agricultural Research Farm and Laboratory of Razi University, Kermanshah, Iran. Two factorial experiment was laid-outon a randomized complete block design with four replications. First factor was starter fertilizer levels (0 and 25 kg $ha^{-1}$) applied in the forms of monoammonium phosphate, the second factor was different weed interference periods consisted of five initial weed-free periods (in which, plots were kept free of weeds for 0, 15, 30, 45 and 60 days after crop emergence (DAE) and then weeds were allowed to grow until harvest) and five initial weed-infested periods (in which, weeds were allowed to grow for 0, 15, 30, 45 and 60DAE, after which the plots were kept free of weeds until harvest). Full season weedy condition reduced 100-seed weight, seed germination percentage and seedling dry weight by 25.9, 13.3 and 22.5%, respectively and increased mean germination time and seed electrical conductivity by 55.8 and 24.3%, respectively as compared with full season weed-free control. However, the traits under study were not significantly influenced when field was kept free of weeds for at least 45 DAE (R1) or weedy condition was continued for less than 30 DAE (V8). There was a significant and negative correlation between weed biomass and seed weight (r = -0.93), so that when weed free condition was less than 45 DAE or weed infested period was continued for at least 30 DAE, soybean plants produced wrinkled and underdeveloped seeds with lower weights and qualities. Moreover, soybean seed quality reduction due to weed interference was more evident when starter fertilizer was applied and weeds interfered with soybean from the beginning of the growing season. Information from the present study is beneficial in soybean seed production systems and where farmers use the harvested seeds for the following planting.

The Effects of Legumes as Living Mulches on Weed Control and Plant Traits of Corn (Zea mays L.)

G. R. MOHAMMADI 韓國雜草學會 2009 Weed&Turfgrass Science Vol.29 No.3

In order to investigate the effects of interseeding leguminous species as living mulches on weed control and plant traits of corn, a field study was carried out at the Agricultural Research Farm, Razi University, Kermanshah, Iran. The experimental design was a randomized complete block with four replications. The treatments consisted of six leguminous species (Persian clover, Trifolium resupinatum L.; white clover, T. repens L.; berseem clover, T. alexandrinum L.;hairy vetch, Vicia villosa L.; alfalfa Medicago sativa L. and black alfalfa, M. lupulina L.) and two controls (weeded and un-weeded for all of the growing season). The results indicated that the interseeded living mulches significantly improved the corn plant traits and reduced the weed dry weight produced as compared with full season weedy condition. All of the corn plant traits were substantially lower for full season weedy condition compared to the other treatments. This condition reduced corn yield 48.2% compared to weed free control. Among the interseeded treatments, the highest corn plant traits and the lowest weed dry weight were obtained from the plots interseeded with hairy vetch. Corn yield was increased 79% and weed dry weight was reduced 80.5% when the plots interseeded with hairy vetch as compared with full season weedy condition. Overall, this study confirmed the beneficial effect of the leguminous species as living mulches to efficient weed control and consequently the improvement of corn plant traits. This method would potentially reduce herbicide application and benefit a sustainable weed management program.

Critical Period of Weed Control in Maize

G. R. MOHAMMADI 韓國雜草學會 2008 Weed&Turfgrass Science Vol.28 No.4

Evaluation of Sorghum (Sorghum bicolor (L.) Moench) Ability to Control Weeds in Corn (Zea mays L.)

G. R. MOHAMMADI,D. KAHRIZI,N. RASHIDI 韓國雜草學會 2009 Weed&Turfgrass Science Vol.29 No.2

In order to evaluate the weed control ability of sorghum in corn, a field study was carried out in 2006 at the Agricultural Research Farm of Razi University, Kermanshah, Iran. Sorghum plant materials were applied in three ways : (1) incorporated into the soil (at 2,000, 4,000 and 6,000 kg ha-1) mulched on the soil surface (at 2,000 and 4,000 kg ha-1) or sprayed as sorgaab (water extract of mature sorghum plants) one, two, three or four times during the growing season. Two controls(full-season weedy and weed-free condition) were also included. Full season weed-free condition increased height, the number of ears per plant, the number of seeds per ear, 100 seed weight and yield of corn by 67.9, 35.8, 66.1, 23.3 and 47.8%, respectively, as compared with weedy condition for all of the growing season. Among the sorghum treatments, the highest corn plant traits and the lowest weed dry weight and density were occurred when sorghum herbage was incorporated into the soil at 6,000 kg ha-1 or used as a mulch at 4,000 kg-1. However, corn yield and weed dry weight and density were not significantly influenced by one sorgaab spray, when compared with full season weedy condition. In general, this study revealed that sorghum plant materials applied in different forms can suppress weeds in corn field.