COTTON being the major cash crop contributes 60-70 per cent in foreign exchange earnings. In the last 53 years, Pakistan has been able to establish a single largest industry which is textile, based on cotton.

Its production has shown excellent growth rate during 1980-90. The highest cotton production of 12.8 million bales was achieved in 1991, soon after which declining trend has been observed. The CLCV virus infestation has been the main cause of decline beyond 1991. In spite of this problem, farmers with good husbandry and proper management have been able to avoid the total crop failure thus harvesting satisfactory yield. Proper fertilizer application has played an important role in management practices.

Like other crops, cotton requires 16 important nutrient elements for its proper growth. These elements can be classified into three categories. Primary nutrient elements are carbon, hydrogen, oxygen, nitrogen, phosphorous and potassium. Secondary nutrient elements consist of calcium, magnesium and sulphur. Micro nutrients are called zinc, boron, iron, copper, manganese, molybdenum and chlorine. Of these, carbon is taken from the air; hydrogen and oxygen from water and the remaining 13 elements are provided by the soil. Most of our soils have enough supplies of these but intensive cropping and removal of crop residue from the farm have resulted in the reduced supply of the nutrients to plant. To make up the losses and deficiencies and to maintain these at satisfactory level for profitable farming, fertilizers are used. Its use has witnessed a steady increase over the last four decades. Despite this increase, its fertilizer usage is still low as compared to the other Asian countries (Table-1). We do not need to follow the suite irrationally but its use has to be optimum and balanced for increasing the crop production to feed the ever-growing population of the country.

Nitrogen is the most important nutrient element for plant growth and is widely deficient in our soils. The climatic conditions in our country do not allow organic matter to accumulate and thus the level of nitrogen remains low in most of the cropped areas of Pakistan. Hence the usage of nitrogen fertilizers is required for good crop production and cotton is no exceptions. Most of our soils have organic matter less than 1 per cent. It is difficult to raise the organic matter level beyond 4.5 per cent due to the arid climatic conditions. However, organic matter can be raised up to around 1.2 per cent with some endeavours. For sustaining good crop yield, the general principal calls for the replenishment of the nutrients equivalent to what is removed by the plants. The promotional efforts and follow-up by the private sector companies and government have developed awareness in farmers about the nitrogen fertilizers and most of the farmers are using adequate amount of it in cotton despite their limited resources.

Cotton plant requires nitrogen throughout the growing season but the magnitude varies with the age of plant. The Central Cotton Research Institute Multan, after extensive search has recommended that 28 per cent of the requirements for cotton plant, observed during the first 60 days of growth. The maximum absorption takes place during the first 60-90 days when boll formation is at its peak. Thus its application must be completed within speculated period and a cut-off date of August 15 is recommended for application. This can be applied in the area sown around May 15 but a sizable area under cotton is sown after this date and nitrogen application has to be extended beyond August 15 depending upon the date of sowing. It will be difficult to complete the recommended doses before August 15. Hence insistence on this cut-off date is not appropriate and this message has a potential of misinterpretations, which, will lead to hidden hunger of the crop. This is the time when nitrogen requirement is at its peak and is consumed for boll development. Any negligence at this crucial period is bound to affect cotton yield.

The productive and cost-effective method for crop management is soil testing. These services are available with the main fertilizer companies along with the other public and private sector soil testing laboratories.

The availability of secondary nutrients (calcium, magnesium and sulphur) is adequate in our soils. However, sulphur deficiencies are reported in some areas. Gypsum is a cheap and good source of sulphur supply. Application of 50-100 kg/acre of gypsum is a cheap and good source of sulphur supply. Application of 50-100 kg/acre of gypsum can take care of any sulphur deficiency.

Among the micro nutrients (zinc, boron, iron, copper, manganese, molybdenum and chlorine), zinc deficiency is widely recognized and boron response to cotton has been reported. Thus application of boron and zinc will have positive impact on crop yield.

The addition of crop residue especially the rotation of cotton sticks is a good practice for improving organic matter content and recycling of nutrients in the soil. Such practices do not only improve soil physical condition but also make up the nutrient loss to some extent. Therefore, it is suggested their efforts must be directed towards improving organic matter content of the soil through addition of crop residue, green-manuring or farm yard manure. Proper and balanced fertilizer application practice must be exercised to meet the nutrient requirement of the cotton crop for increasing per unit yield. Use of phosphatic fertilizer needs to be enhanced. Application of such all fertilizers must be based on soil test results so that optimum results of fertilizer application can be attained and there is no wastage of farmer’s limited resources. The soil fertility must be maintained for sustainable crop production level to meet the growing requirements of the country.

After the textile industry, fertilizer is another industry wherein Pakistan has succeeded in attaining self-sufficiency. There are many plants in public and private sector, which are producing sufficient quantities of different fertilizers. In some cases export of fertilizers has also been attained (Table-2).