Agricultural Improvement through Fertilizer
By Dr. Syed Manzoor Alam NIA, Tandojam
Dec 20 - 26, 1999
The inorganic manuers are of three kinds viz., nitrogen (N), phosphatic (P) and potassic (K). Amongst the nitrogenous fertilizer, the most commonly applied are urea, sodium nitrate, Ammonium sulphate, calcium nitrate and calcium cyanamid. Deficiency of nitrogen retards growth of plants resulting in low productivity. The nitrogenous manures if used in optimum quantities stimulate above ground parts of the plants and increase protein content of crops. Phosphatic manures (SSP, T.S.P, DAP etc) encourage development of grain, induce early ripening, root development and winter hardiness. The potassic fertilizers (MPO, SOP) stimulate production of carbohydrates (starch and sugar) and are naturally highly conducive to crop like sugar beet and potatoes impart resistance to plant diseases and help in protein production.
The use of chemical fertilizers in Pakistan was inappreciable in early sixties to promote their use. The government relied on agricultural extension services and information media and also subsidized the use of fertilizer with the result that in early seventies demand for fertilizers at subsidized rates exceeded the supply. That there is a rapidly rising trend in fertilizer production in the recent years. Chemical fertilizer is a modern wonder, which has played the most important role in meeting the food requirements of rapidly multiplying mouths caused by an unprecedented population explosion. Fertilizer use in the past has grown considerably and is the most important single factor with maximum contribution to increased agricultural production in the world. Further increases in agricultural production particularly in the developed countries and also some developing countries are becoming more and more difficult. A healthier growth in fertilizer use in future will have to be maintained particularly in countries like Pakistan with high population which is further growing at the rate which is one of the highest in the world. In order to obtain better results from fertilizer, the farmers must also use other recommended management practices such as, use of certified seed at the recommended rate per acre, planting crops in rows with recommended row to row and plant to plant distance to achieve optimum plant population, planting crop at suitable time after proper preparation of seed bed, proper leveling of fields and then providing uniform and required level of irrigations, adequate and timely plant protection measures and control of weeds, use of organic manures to the maximum possible extent.
Agriculture sector plays a very important role in the development of the economy of the country. It contributes about 25 per cent to the gross domestic product (GDP), provides employment in the rural areas, fetches foreign exchange through the export of rice, cotton and supply raw materials to our domestic industry, like textile, tobacco, sugar, rice mills, vegetable oil industry etc. Agriculture field recorded a significant growth of 6.7 per cent during 1995-96 as compared to 5.9 per cent in 1994-95 i.e. 9 per cent growth in major crops and 4.9 per cent in minor crops. In early days of 1950, chemical fertilizers as sources of plant nutrients were introduced in the country. Since then, there had been phenomenal increase in fertilizer consumption, which contributed substantially in enhancing crop yield. During 1996-97, agriculture showed a poor growth of 0.7 per cent. The low growth in agriculture was mainly attributed to failure of cotton crop and decline in production in wheat. This also reduced a 4.1 per cent decline in fertilizer consumption and particularly phosphate utilization declined drastically by 15.2 per cent worsening N:P use ratio to 4.7:1, resulting in an adverse impact on crop productivity. There is an urgent need to improve the ratio between N,P particularly from the present to the desired level of at least 3:1, if not 2:1 in both the seasons. The most important constraints to crop growth are those caused by inefficient and imbalance use of plant nutrients. Fertilizers constitute the most important scientific breakthrough in feeding the growing populations in Pakistan. Historically, growth in agriculture is always associated with healthy growth in fertilizer use. The trend was reversed in 1997-98 when 5.2 per cent growth in agriculture was associated with 8.0 per cent increase in fertilizer use.
The Food and Agriculture Organization at Rome has estimated that contribution of fertilizer in increasing crop productivity is about 50 per cent. Studies in Pakistan showed that contribution of fertilizers through crop production ranges between 30 to 50 per cent under a given soil climatic conditions. It is reported that production and consumption have almost twice since 1981-82 and reached 4.16 and 5.50 million tons, respectively in 1995-96. The consumption during 1996-97 was 5,162 thousand tons. However, the per hectare use rate was 114 nutrient kg and N:P ratio was 4:3:1 during 1995/96. This ratio was deteriorated in 1996-97, when fertilizer use dropped to 106 kg/ha and ratio worsened to 4.7:1.
Domestic production: The overall domestic production of fertilizers during 1996 was about 4,203 thousand tons, but in 1997 was 3,921 thousand tons. The domestic production meets about 75 per cent of total fertilizer consumption demand. During 1996, fertilizer imports amounted to 1709 thousand tons. Three products were imported and infected into the marketing system. The quantities imported during 1996 mainly comprised of urea 620, DAP 909, TSP 84, NPK (10:20:20) 35, SOP 37, and MOP 32 thousand tons. During 1997, a total quantity of 971 thousand tons was supplied through purchased from foreign countries. The consumption of all nutrients (N+P2O5+K2O) reached a level of 2635 thousand tons compared with 2317 thousand tons during 1995 marked by a growth of 13.8 per cent.