Weed management strategies for wheat in the irrigated Punjab: farmers knowledge, adoption and economics

Abstract

Weeds have been reported as a major limiting factor in efforts to further raise wheat productivity in the irrigated Punjab. With this in mind, the study was planned to assess the extent of weeds in farmers' fields, their present weed management strategies and economic aspects of weed control in the irrigated Punjab. The study was focussed on two distinct cropping systems; rice-wheat and cotton-wheat, of the Punjab. Phalaris minor was the most prominent weed in the rice-wheat cropping system. About four-fifths of the respondents viewed it as the major weed in wheat. Wild oats and broad leaf weeds were less of a problem. For the cotton zone, both phalaris minor and broadleaf weeds were the major problem. Generally, the incidence of weed infestations was greater in the rice zone than the cotton zone. In the rice zone, average wheat yields for farmers who had phalaris as a major weed problem, were 1.9 t/ha compared to 2.6 t/ha for those who had other weeds. This represents a yield loss of over 25 percent. As the phalaris minor problem was not so serious for the cotton zane, yield differences were not so great. In the rice zone, 21 percent of the respondents reported their weed problems were serious as compared to only 7 percent in the cotton zane. Farmers in the rice zone having only minor weed problems were getting average yields of 2.2 t/ha as compared to 1.8 t/ha with serious weed problems. For the cotton zone, the comparable yields were 2.6 t/ha (minor weeds) and 2.3 t/ha (serious). Hand weeding was the most common method of weed management in both zones. Fifty five percent of the farmers practiced hand weeding in the cotton zone, as compared to 34 percent in the rice zone. Thirty six percent of the rice-wheat farmers rotated their fields for weed control. Only 5 percent, in both zones, used herbicides to control weeds. In the rice zone, 74 percent of the farmers were aware of herbicides as compared to 60 percent tn the cotton lone. Generally, farmers who had knowledge of new varieties, who used extension and radio as major sources of information, and who had higher social status and education had more knowledge a bout herbicides compared to others. The results indicate that in the rice zone knowledge of herbicide can be influenced by two key sources of agricultural information, radio and extension. The results also confirmed that more influential members of the farming community serve as the means through which technological knowledge enters the farming community. Farmers not using herbicides were asked about why they do not do so. The majority of farmers in the rice zone said that herbicide application was too expensive. About a third had not adopted it because they felt that they did not have a severe weed infestation. In the cotton zone, one quarter replied that this method was too costly; 44 percent replied that weeds represented no problem in their fields; and 18 percent replied that herbicides had not been adopted in their areas, and were not available. Average losses of yield in the most weedy fields of farmers surveyed were 0.7 t/ha. At a field price of 1.54 Rs/Kg, these losses are equivalent to Rs. 1078/ha. The herbicide Arelon would cost about 350 Rs/ha. Adding the cost of application, (labour and a spray) of 125 Rs./ha and 40 percent to cover capital, risk and farmers' return gives a total cost of Rs. 665 /ha. In this way application of herbicide would be economical in weedy fields. This would be especially the case if herbicide use also meant fewer cultivations. The extent of yield loss that would make if just profitable to use herbicides (the breakeven yield loss) was calculated to be 430 kg/ha. In lightly-infested fields, yield losses due to weeds would be less than this, so herbicides would be uneconomical in this case. Results of a village case study indicate that rapid uptake of herbicides for weeds in wheat can occur in the irrigated Punjab. In this case, serious weed infestations and effective institutional arrangements led to the rapid adoption of herbicides. The institutional arrangements that were particularly effective were guidance from extension agent and the availability of spray pump in the village. Overall estimates of wheat yield losses due to weed sin the irrigated Punjab were calculated as part of this study. The weighted average yield loss per hectare was around 350 kgs/ha. Overall 1.6 million tons of wheat are lost each year because of weeds. This is a loss of grain of 2.4 biIlion rupees, after netting out costs of harvesting, threshing and transport of grain.