Abstract: The effect of different weed control measures was studied in wheat crop. The experiment was laid out in simple RCB design, replicated four times. It was comprised of seven treatments i.e. Irelon 50 SC @ 1.12, Puma S 75 EW @ 0.85, Buctril M 40 EC @ 0.72, Buctril M +Topik 15 WP @ 0.72 and 0.75, 2,4-D (powder) @ 1.20 kg a.i ha-1, Hand weeding after 35 days of sowing and a weedy check was kept for the comparisons. Data recorded were weeds count m-2, plant height (cm), grains spike-1,1000 grains weight (g), biological yield (kg ha-1) and grain yield (kg ha-1).The lowest (16.10) weeds m-2 was count in Puma S treated plots as compared to the highest (69.72) recorded in the weedy check plots. Buctril M and 2,4-D were comparable with Puma S. Buctril M + Topik mixture increased grains spik-1and 1000 grains weight significantly in wheat. Significant increase was also occurred in biological and grain yield (kg ha-1) with the application of Buctril M + Topik application. It gave maximum of 9236.35 and 2986.43 kg ha-1 biological and grain yields, respectively. Puma S, 2,4-D, Irelon and hand weeding also increased biological and grain yields significantly.
INTRODUCTION
Wheat is the most important staple food crop worldwide. Majority of the world's population depends on wheat food. Wheat is adapted to a variety of soil and climatic conditions. Wheat plays an important role in the Pakistan's economy. During the last few years a better progress has been made in increasing the per unit area yield of wheat in the country. If we compare the yield of wheat per unit area of Pakistan with the per unit area yield of wheat of the advanced countries, we are still far behind. Many reasons for low yield of wheat are known, however the most important but less noticeable reason for low yield of wheat is the infestation of different weeds flora. Pakistan suffers 17.25% losses in wheat crop due to weeds (Pervaiz and Quazi, 1992). The losses on annual basis in wheat amount to more than 28 billion at the national level and 2 billion in NWFP (Hassan and Marwat, 2001).
To check the weeds below economic injury level, various methods of weed management are involved. Weeds can be controlled by manual, cultural and chemical methods. Zahir and Gupta (1981) reported that about 50% of the farmers in wheat growing area of India, used a combination of manual and chemical weeds control methods. The best method of weed control is the one which combines all these activities and could be effective and easy to adopt and finally helpful in increasing crop yield. It has been reported that chemical weed control method is also effective in combination with cultural methods of weed control. Shabir (1990) found that hand weeding gave the maximum increase in the yield of wheat. Khan et al. (1999) concluded that Logran, Tolkan and Buctril-M provided the maximum weed control in wheat crop. Isoproturon, Tribunil and Nitrogen gave best weed control and increased grain yield and other yield components of wheat (Borghain et al., 1985). Buctril-M sprayed for weed controlled in wheat crop decreased broad leaf weeds significantly and increased yield and yield components of wheat (Shah et al., 1989; Khan et al., 2001). Therefore, the present study was aimed to find out the efficiency of different weed control measures for controlling weeds in wheat crop for increasing wheat yield per unit area.
MATERIALS AND METHODS
The research study was launched at the Malakandher Research Farm, NWFP Agricultural University, Peshawar during the rabi season 1999-2000. Wheat variety sown was Bakhtawar-96 with the help of pora. Row to row distance was kept 30 cm apart. The seed was used at the rate of 120 kg ha-1. All the required inputs were applied properly. The simple RCB design was applied. There were 7 treatments, replicated four times with at plot size of 5x1.5m2.
The different treatments were as follow:
All the herbicides were sprayed as post emergence and hand weeding was carried out after 35 days of sowing. Data were recorded on the parameters like, weeds count m-2 after herbicidal spray, plant height (cm), grains spike-1, 1000 grains weight (g), biological yield (kg ha-1) and grain yield (kg ha-1). The accurate and standard procedures and methods were used for recording and calculating the data of various parameters. The data were finally subjected to statistical analysis applying LSD (Least Significant Difference) test (Steel and Torrie, 1980).
RESULTS AND DISCUSSION
Weeds count m-2: Statistical analysis of the data (Table 1) revealed that weeds count m-2 were significantly (P≤0.05) affected by different weed control measures. Mean values of the data showed that highest (69.72) weeds m-2 were counted in the weedy check plots followed by hand weeding (30.98) weeds m-2. While lowest (16.10) weeds m-2 were observed in plots treated with Puma Super 75 EW, comparable with Buctril M 40EC treated plots of 19.17 weeds m-2. 2,4-D also was comparable statistically with Puma Super 75 EW and Buctril M, in which 21.90 weeds m-2were counted. The weeds species found were Avena fatua, Phalaris minor, poa annua, Rumex crispus Euphorbia halioscopia and Ammi visnaga. These results are in conformity with the findings of Khan et al. (2001). They reported that grass and broad leaf killers controlled maximum weeds. Ahmed et al. (1993) also observed that Buctril M 40 EC controlled the broadleaf weeds efficiently.
Plant height (cm): Statistically the effect of different weed management measures were significant for plant height (cm) of wheat crop (Table 1). Tallest plants of 84.15 and 83.95 cm were observed in weedy check plots and plots treated with Irelon 50 SC. The remaining treatments were statistically at par with each other. The tallest plants in the weedy check plots could be due to the competitive activities between the crop and weeds and tallest plant in plots treated with Irelon should be due to the efficient weed control to ease the growth of wheat crop. These findings are however, at variance from Ahmad et al. (1993), who reported non-significant effect of herbicides on plant height.
Grains spike-1: Different weed control measures had statistically significant effect on grains spike-1 (Table 1). The mean values showed that maximum 19.17 and 17.67 grains spike-1 were observed in plots sprayed with Buctril+Topik and Puma. Treatments like Irelon,2,4-D and Buctril alone were statistically at par with each other. On the other hand the minimum of 9.23 grains spike-1 were counted in the weedy check plots followed by plots where hand weeding was carried out. The maximum number of grains spike-1 may be due to the herbicidal effect on the weeds, which provided competition free environment for the crop to utilize the resources to give the maximum grains spike-1. These results are in agreement with those of the findings of Khan et al. (1999).
1000 grains weight (g): Herbicidal treatments and hand weeding significantly affected 1000 grain weight (g) (Table 1). The heaviest 1000 grains weight of 44.75 gm was observed in plots received with Buctril M + Topik. While the lightest of 24.35 and 25.83 g 1000 grain weight was produced by the weedy check followed by hand weeded plots which were statistically at par with each other. Puma super produced (39.88 g) 1000 grain weight, statistically comparable with Buctril M + Topik mixture. The heaviest 1000 grains weight of Buctril M + Topik is due to the efficient control of broad leaf and grassy weeds, which provided an ample opportunity for the crop to utilize the available resources to increase 1000 grain weight. Similar findings were reported by Marinkovic et al. (1997).
Biological yield (kg ha-1): Statistical analysis of the data regarding biological yield (kg ha-1) (Table 1) indicated that significant differences were found among the weed control measures in wheat crop. The maximum biological yield of 9236.35 kg ha-1 was observed in Buctril M 40 EC + Topik 15 WP treated plots. While the minimum (4751.30 kg ha-1) biological yield was found in the weedy check plots, followed by 2,4-D. The biological yield of Buctril M 40 EC alone and Puma super 75 EW were statistically at par with each other. Hand weeded plots and Irelon 50 SC, biological yields kg ha-1 were also statistically at par with each other.
| Table 1: | Weeds count m-2, plant height (cm), grains spike-1, 1000 grain weight (g), biological yield and grain yield (kg ha-1) |
The highest biological yield kg ha-1 is attributed to the better weed control by the broad leaf and grassy herbicides combination which efficiently controlled the weeds of wheat crop and thus the crop was able to utilize the resources available efficiently. These findings are in conformity with those of Samar et al. (1993) and Bhagat and Jain (1985). They reported that biological yield was significantly increased with the application of herbicides for weed control in wheat crop.
Grain yield (kg ha-1): Statistical analysis of the data showed that weed control measures had significant effect on the grain yield of wheat (Table 1). The highest grain yield kg ha-1 (2986.43) was observed in plots treated with the mixture of Buctril and Topik. While the lowest grain yield of 1461.60 kg ha-1 was found in the weedy check plots. All the remaining weed control measures gave statistically higher grain yields than the weedy check plots. The highest grain yield in the plots received with Buctril M + Topik mixture is attributed to the effect of these broad leaf and grassy weedicides, which controlled both the broad leaf and grassy herbicides and thus the crop was made able to utilize the land resources and inputs to give maximum grain yield. Similar results were reported by Mantazeri (1994). Tanveer et al. (1999) have reported a significant increase in wheat grain yield with application of different herbicides.