ABSTRACT
The effect of different herbicides applied at different timings viz. 30, 45 and 60 days after sowing (DAS) of wheat crop was studied for controlling weeds. Herbicidal treatments were Assert (Imazamethabenz-methyl) 0.30, isoproturon 1.12 kg alone and buctril-M (bromoxynil+MCPA) 0.72 kg+topik (clodinofop) 0.37 kg, logran (trisulfuron) 0.64 kg+topik (clodinofop) 0.37 kg, 2,4-D (2,4-D ester) 1.20 kg+topik (clodinofop) 0.37 kg and puma super (phenoxyprop-ethyle) 0.75 kg+2,4-D (2,4-D ester) 1.20 kg a.i. ha-1. A weedy check was also included for comparison. The analysis of the data revealed significant differences among the times of application for biological yield and grain yield. Similarly significant differences were recorded for herbicidal treatments in traits like spikelets spike-1, 1000 grains weight (g), biological yield (kg ha-1) and grain yield (kg ha-1). The interaction of the times of application and herbicides was significant for spikelets spike-1 and for grain yield. Maximum number of spikelets spike-1 and heavier 1000 grains weight was observed in plots treated with buctril-M+topik mixture, while minimum in weedy check plots. Biological and grain yield (kg ha-1) were higher in plots treated with buctril-M+topik and logran extra+topik while lower biological and grain yield were in weedy check plots. Buctril-M+topik proved to be the most economical herbicides giving maximum return of Rs. 24631 ha-1, if applied 45 DAS in wheat.
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DOI: 10.3923/ajps.2003.310.313
URL: https://scialert.net/abstract/?doi=ajps.2003.310.313
INTRODUCTION
Wheat is the most important food crop of the world. The largest cropped area is devoted to wheat and the quantity produced is more than that of any other crop. In Pakistan, 37% of the cropped area is devoted to wheat, annually. The best quality wheat is produced in areas having a cold winter and comparatively warm spring or summer with moderate rainfall.
Although the environmental conditions are favourable and the high yielding varieties are available in the country yet we cannot achieve its potential yield. So many factors are responsible for low yield. Among these factors, infestation of weeds is a serious issue and requires immediate attention. The infested situations need the development of package of weed management technology, helpful to avoid wheat production losses Pakistan. The control of weeds is a basic requirement and major component of management in most production systems (Young et al., 1994; Norris, 1982; Triple, 1976).
Out of the factors contributing to low yield, presence of weeds in wheat fields is considered to be one of the most limiting factor. Weeds cause considerable yield loss amounting to 29.03% (Qureshi, 1982). Several reports address the importance of weed control at proper time in wheat. Rossarola et al. (1993) reported that application of herbicides resulted in increased grain yield at 2nd node stage.
In view of the importance of the problem from the national point of view, the research work was conducted to study the impact of different herbicides on different weeds and to know the response of crop to such herbicides in terms of tolerance, yield and yield components.
MATERIALS AND METHODS
The research work was conducted at Malkandher Farm, NWFP Agricultural University, Peshawar during the rabi season 2000-01. The experiment was laid out as split plot in RCB design with three replications. In each replication, there were three main plots. Each main plot consisted of seven sub-plots having five meter length. The number of rows in each sub-plot was five, spaced at 30 cm. The time of herbicidal application were kept in main plots while the herbicidal treatments were assigned to the sub-plots. The seed was sown @ 120 kg ha-1 with the help of hand hoe. The detail of the treatments was as under:
● | Times of herbicidal application (main plots) |
● | Thirty days after sowing (30 DAS) |
● | Forty five days after sowing (45 DAS) |
● | Sixty days after sowing (60 DAS) |
B. Herbicidal treatments (sub-plots) | |
All the herbicides were applied post-emergence and data were recorded on the following parameters, to determine the effect of aforesaid treatments.
Relative density (%), number of spikelets spike-1, 1000 grains weight (g), biological yield (kg ha-1), grain yield (kg ha-1) and economics of weed control.
The data collected were subjected to statistical analysis, using MSTATC computer software and means were separated by using Fishers protected LSD test (Steel and Torrie, 1980).
RESULTS AND DISCUSSION
Relative density (%): Six weeks after herbicidal application, relative density of weed species was computed (Table 1). Statistical analysis of the data revealed that weed species were significantly affected by herbicidal treatments and their interactions. Highest relative density 22.91 and 21.16% were recorded for Cyperus rotundus and other weeds, respectively. While the lowest relative density (4.40%) was recorded for Euphorbia helioscopia followed by Convolvulus arvensis and Ammi vis-naga (6.06%) each. The highest relative density (28.41%) of Cyperus rotundus and other weeds (grasses, broadleaved and sedges) indicates that Cyperus rotundus is a perennial and other weeds were not successfully controlled with the herbicidal treatments. While the broadleaved, Euphorbia helioscopia, Convolvulus arvensis and Ammi vis-naga were controlled successfully. The data indicated that broadleaved weeds were controlled by broad spectrum herbicides. Herbicides and weed species interaction was also significantly different. Maximum density (28.41%) of Cyperus rotundus was recorded in buctril-M+topik mixture treated plots followed by 27.80% relative density of the same species in logran+topik treated plots as compared with 19.59% relative density in weedy check plots. The lowest relative density (1.21%) of Convolvulus arvensis was recorded in plots receiving buctril-M+topik mixture followed by isoproturon alone and buctril-M+topik mixture with relative densities of 2.41 and 2.62% of Ammi vis-naga and Euphorbia helioscopia, respectively. In weedy check plots the relative densities of these species were 7.32 and 6.26%, respectively.
Number of spikelets spike-1: Statistical analysis of the data revealed that times of application had non-significant effect on number of spikelets per spike while different herbicidal treatments and their interactions with times of herbicidal application had significant effect on number of spikelets spike-1 (Table 2). Plots treated with buctril-M+topik had the highest number of spikelets spike-1 (17.92), while weedy check plots had the least spikelets spike-1 (13.21). In interaction of herbicides x application times, the highest number of spikelets spike-1 (18.33) were found in buctril-M+topik treated plots, treated 30 DAS. It was however, statistically at par with the application of the same herbicide at 45 DAS (19.20) or 60 DAS (17.23), while lowest spikelets were found in the weedy check plots at 60 DAS and it was statistically at par with isoproturon at 30 DAS, due to phytotoxicity (Table 2). These results are in conformity with the findings of Khan et al. (1999). They reported that spikelets spike-1 were affected with the use of herbicides.
1000-grains weight (g): Different herbicidal treatments significantly affected 1000 grains weight (Table 3). While the times of herbicidal application and interaction of times x herbicidal treatments did not affect the 1000 grains weight significantly. Highest 1000 grains weight (39.83 g) was recorded in buctril-M+topik treated plots followed by logran extra+topik, 2,4-D+topik and puma super treated plots with 38.36, 37.34 and 37.79 g. Lowest 1000 grains weight of 34.65 and 35.80 g were recorded in isoproturon treated and weedy check plots. In case of times of application, heaviest 1000 grains weight was recorded when herbicides were applied at 45 DAS while lightest 1000 grains weight was given by 30 DAS herbicidal application. In mutual interaction of herbicidesxtimes of application, the heaviest 1000 grains weight was recorded when buctril-M+topik was applied at 45 DAS followed by the same treatment applied at 30 DAS with 1000 grains weight of 40.67 and 40.23 g, respectively. Due to phytotoxicity, isoproturon produced the lightest 1000 grains weight of 33.87 g when applied 30 DAS followed by weedy check at 60 DAS with 1000 grains weight of 35.03 g. Similar results were also reported by Baldha et al. (1988). They reported that isoproturon showed phytotoxicity after 30 DAS. Increasing 1000 grains weight with the use of herbicides are the similar results reported by Marinkovic et al. (1997).
Table 1: | Relative density of weeds as affected by herbicidal application |
Table 2: | Spikelets spike-1 as affected by herbicidal applications at different times |
LSD value at 5% level for herbicides = 0.7090 LSD value at 5% level for interaction = 1.228 |
Table 3: | 1000 grains weight (g) as affected by herbicidal application at different times |
LSD value at 5% level for herbicides = 1.212 Means not followed by same letters are significantly different by using LSD test at 5% level of probability. |
Biological yield (kg ha-1): Analysis of the data showed that times of application and different herbicidal treatments significantly affected biological yield (Table 4). Herbicidal application, at 45 DAS produced highest biological yield of 8352 kg ha-1 followed by 60 DAS application, which produced 7845 kg ha-1.
Table 4: | Biological yield (kg ha-1) of wheat as affected by herbicidal application at different times |
LSD value at 5% level for application times = 588.4 LSD value at 5% level for herbicides = 747.2 |
Table 5: | Grain yield (kg ha-1) as affected by herbicidal application at different times |
LSD value at 5% level for application times = 268.4 LSD value at 5% level for herbicides = 231.5 LSD value at 5% level for interaction = 400.9 Means not followed by same letters are significantly different by using LSD test at 5% level of probability. |
The lowest biological yield (7428 kg ha-1) was recorded when herbicides were applied at 30 DAS. Maximum biological yield of 9370 kg ha-1 was observed in buctril-M+topik treated plots.
Fig. 1: | Net income from different herbicides treated plots |
Significantly lowest biological yield of 6333 kg ha-1 was recorded in weedy check plots. Herbicides x times of application interaction was statistically non-significant however, buctril-M+topik when applied at 45 DAS, gave the maximum biological yield of 9800 kg ha-1. The minimum biological yield (4666 kg ha-1) was recorded in isoproturon treated plots at 30 DAS. Similar findings were also reported by Samar et al. (1993) and Porwal and Gupta (1987). They reported that different herbicides applied at 35 DAS reduced weed dry matter and increased grain and straw yield over control.
Grain yield (kg ha-1): Statistical analysis of the data indicated that times of herbicidal application, different herbicidal treatments and their interactions had significant effect on the grain yield (Table 5). Herbicidal application at 45 DAS produced the highest grain yield (2426 kg ha-1) followed by 30 DAS with grain yield of (2194 kg ha-1). Lowest grain yield was recorded when herbicides were applied at 60 DAS. However, statistically it was similar to 30 DAS application. Highest grain yield (3420 kg ha-1) was recorded in buctril-M+topik treated plots followed by logran+topik and puma super+2,4-D with grain yield of 2558 and 2493 kg ha-1. Lowest grain yield of 1377 and 1435 kg ha-1 was recorded in isoproturon and weedy check plots, respectively. For interaction, maximum yield of 3896 kg ha-1 was recorded in treatments subjected to buctril-M+topik applied 45 DAS followed by the same herbicides when applied 30 DAS (3481 kg ha-1). Minimum grain yield of 1007 and 12318 kg ha-1 was recorded in isoproturon and weedy check plots, respectively. Among the times of application, maximum grain yield (2426 kg ha-1) was recorded when herbicides were applied 45 DAS followed by 30 DAS giving 2194 kg ha-1. While minimum grain yield (1951 kg ha-1) was observed at 60 DAS application. Similar results were reported by Holm et al. (2000). Who reported that herbicides applied at later times reduced wheat yield. The results are in agreement with the work reported by Montazeri (1994). Who reported that herbicide treatments increased the grain yield significantly.
Economics of weed control: Different herbicides were applied at three different times in wheat and it was concluded that maximum net profit of Rs. 24631 ha-1 was obtained from Buctril-M+topik treated plots when applied 45 days after sowing in wheat (Fig. 1).
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