But this depends on the availability of the scientific information and the timely guidance on all aspects of agriculture to the farming community. Prior to mid July 2001, when upper Sindh received first monsoon rains, Sindh has been in the grip of drought-like situation. The situation was created because of the low or rains restricted to few sporadic showers over the last three years and the continuous water shortage in the irrigation canals. The economic implications of prolonged dry spell and irrigation water shortage proved detrimental to many sectors particularly agriculture, forestry and the wildlife. But at the same time this very phenomenon also allowed significant disruption in the life cycle of insect pests which proved a blessing in disguise for the farming community. The most important phenomenon was almost 99 per cent reduction in the population of yellow rice stem borer (S.incertulas) almost in the entire rice zone on the right bank canal area of the Sukkur Barrage. To control this major insect pest of rice, pesticides worth million of rupees are consumed every year in the country. Similarly, as per Federal Plant Protection source, despite widespread monsoon rain and favourable climatic conditions the population of desert locust remained at the lowest ebb this year requiring no control measures, thus saving million of rupees of the exchequer. Regarding the stem borer it would be proper to mention that after killing rice plants, larvae hibernate in the rice stubbles. According to a study undertaken at the rice Research Institute Dokri in Larkana district, the emergence of moth stem borer starts from the second fortnight of March and attains its first pick emergence in the second fortnight of April.
This year when the emergence of moth started in March, the rice zone was virtually under the drought-like situation and without any vegetation resulted in the natural death of emerging moths.
Accordingly, the rice crop during Kharif 2001 remained almost free from the rice stem borer problem and so the rice stubbles after paddy harvest. Due to the late transplantation of rice during the Kharif 2001, it is quite likely that almost 80 to 90 per cent area in the rice zone may not be available for wheat sowing during the month of November which is the recommended sowing period of wheat in upper Sindh. The review of the literature has indicated that sowing of wheat after the month of November onwards results in the reduction of yield by 35kg per hectare for each successive delay of one day. Unfortunately because of late harvesting of paddy this year the farmers will not get adequate time for land preparation involving 2 to 3 ploughing. In view of this fact it is, therefore, imperative that the sowing of wheat with zero tillage technique is done by the growers of rice growing districts of upper Sindh viz: Larkana, Shikarpur and Jacobabad so that significant yield reduction following late sowing of wheat could be avoided.
As a matter of fact zero tillage is an important component of agriculture. It is a technique of growing crops without prior land preparation. The technique has been found useful especially for growing wheat crop in the rice field after the paddy harvest. However, growing wheat after paddy harvest using zero tillage technology is not a new one. It was initiated in Punjab during 1996-97. Reportedly the area under zero tillage has increased from 50 acres in 1996-97 to 72168 acres in 2000-2001 in Punjab alone. In rice growing belt of upper Sindh some progressive growers are also using this technology for the last two years and obtaining more yield than the traditional method. However, these growers were found complaining about the excessive weed problem in the field where zero tillage technology was adopted for wheat sowing. According to a grower, one spray of weedicide is essential for good harvest.
However, one demerit with zero tillage technology in sowing wheat after paddy harvest is that because of zero or minimum tillage almost 90 per cent of the hibernating larval/pupae population of rice stem borer remain unexposed in the rice stubbles which in turn enhances borer attack on the following rice crop.
Suggestion: Since the cost of zero tillage drill machine is presently beyond the reach of the financially constrained paddy growers it is suggested that appropriate subsidy on this machine should be announced by the government like that of the tubewell installation.