fertilizer use

Fertilizer Use Boon or Bane
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Fertilizer is an important component of dry land technology. For example, 20 pounds per acre (22 kilograms per hectare) of nitrogen are recommended where rainfall is less than 13 inches (330 millimeters), ranging up to 60 pounds per acre (67 kilograms per hectare) where more rain is available; those figures refer to the production of wheat, but they are applicable to other dry land-farming areas. Where average annual precipitation is less than 12 inches (300 millimeters), the use of nitrogen is limited to years where moisture outlook is exceptionally favorable. Nitrogen fertilizer can be applied either in fall or spring. Band placement or broadcast techniques are utilized. Good results are obtained from broadcast spring application of nitrate fertilizer, and fall application of ammonia has also been successful. Local climates and rainfall patterns also determine choice of fertilizer and time of application.

For India, there is an urgent need to narrow the wide ratio between nitrogen (N) and phosphorus (P) and potassium (K) consumption by stepping up P and K usage, which suffered markedly during much of the 1990s. By doing so, food security will be safeguarded and agricultural practices will be more sustainable. India would need about 25
Million tonnes (M t) of NPK in addition to 10 M t of organic and biofertilizer sources to produce about 246 M t of foodgrain required by 2010.

India’s introduction to fertilizer-responsive, high-yielding varieties (HYV) of rice and wheat during the 1960s made it possible to produce 15 to 20 tonnes of plant biomass (dry matter) per hectare per year. This productivity could be initially maintained with N fertilizer alone as the soil could provide much of the other nutrients needed by the crop. However, within a few years, the soil reserves of many nutrients were
Gradually exhausted and high yields were no longer possible by applying N alone. Therefore, a growing emergence of plant nutrient deficiencies occurred in areas of increasing crop intensity. During 1998-99, consumption of N, P2O5 and K2O in India was 11.3, 4.1 and 1.33 M t, respectively at 90 kg/ha. A sustained, imbalanced use of nutrients is reflected by the N: P2O5: K2O ratio which widened from 5.9:2.4:1 in 1991-92 to 8.5:3.1:1 in 1998-99. If the nutrient consumption pattern in 1998-99equaled the desired 4:2:1 ratio, the 11.32 M t of N would be matched with 5.66 million P2O5 tones (38 percent more than actual) and 2.83 million K2O tones (over twice actual K2O consumption). The challenge for government and industry alike is to meet or exceed this consumption level.
Long-term Experiments Emphasize Balanced Fertilizer Use
Findings from long-term fertilizer experiments have clearly shown how the high productivity of an N-driven system is short-lived and counter-productive. Continuous use of N alone can never produce sustained, high yields without addition of adequate P, K and other deficient plant nutrients. This can be verified by
the relatively higher P and K fertilizer use efficiencies and relatively lower N use efficiency in India during the 1980s and 1990sas compared to the 1970s.
The Dynamic Nature of Balanced Fertilization
A wealth of information on the dynamic nature of balanced fertilization in intensive cropping systems has become available from several long-term fertilizer experiments in which HYVs are grown. Results
Consistently show:
1) Intensive cropping with only N input is a short-lived phenomenon;
2) Omission of a plant nutrient (be it macro or micro) leads to its progressive deficiency as a result of
Heavy removals;
3) Sites initially well supplied with natural soil P, K or sulfur (S) become deficient when continuously cropped using N alone or S-free fertilizers;
4) Fertilizer rates considered as optimum still resulted in nutrient depletion at high productivity levels and, if continued, become sub-optimal rates.
More than anything else, experiments solidly demonstrated that a field producing 1,300 kg grain/ha from two crops grown without fertilizer could produce 7,420 kg grain (5.7 times more) under optimum plant nutrient application (data not shown). Responses to fertilizers in these experiments were always
in the order of NPK>NP>N. Continuous use of N alone produced the greatest yield decline at a majority of sites. Responses to N declined with the passage of time, while responses to P and K improved due to increased soil P and K deficiency.
Balanced Fertilization Includes Nutrients Other than NPK
Balanced fertilizer use today in India implies much more than NPK application. Almost 50 percent of over 200,000 soil samples analyzed have tested low (deficient) in zinc (Zn).Soil S deficiencies once considered to be confined to coarse-textured soils under oil seeds are now estimated to occur in a wide variety of soils in nearly 130 districts, and yield increases from application of S under field conditions have been recorded in over 40 crops. Likewise, in specific areas, the application of magnesium (Mg) and boron (B) has become necessary for high yields, greater plant nutrient use efficiency, and enhanced profits. These nutrient combinations represent the many facets of balanced fertilizer use. Therefore, feeding crops for high yields in India is no longer a simple NPK story. This in no way minimizes the importance of NPK (fertilizer pillars), but emphasizes that the efficiency of NPK and returns from their application can be maximized only when due attention is paid to other plant nutrient deficiencies.
In conclusion, Indian agriculture is now in an era of multiple plant nutrient deficiencies. At least five nutrients (N, P, K, S, and Zn) are now of widespread practical importance from an application point of
View. It would not be surprising if progressive farmers in several areas must apply four to six nutrients to sustain high yields of premium crops. Policies and strategies need to be developed to fully recognize the changing needs and dynamics of balanced fertilization. Towards this end, policy-makers, researchers, extension personnel, fertilizer industry, dealers, and farmers all have to contribute.

For feeding the enormously increasing world population it is necessary that cultivable fields are used optimally and so far we have not fallen short of the demands because of the scientific developments in the field of agriculture and the one discovery which has changed the face of agriculture around the world is the discovery of chemical fertilizers. It was the use of fertilizers only which gave positive results for the labour of cultivators in fields, helped them to remain in the same profession and fed the whole world despite shrinking graph of cultivable land. Green Revolution and other such activities would not have made history if the agrarians would not have learnt the benefits of fertilizers. So there is no need to make a hue and cry over the drawbacks of fertilizers. In fact it is not the use of fertilizers which is spoiling nature but excessive human greed which is over exploiting the biggest boon of agriculture with its excessive use.



Against:
The future for fertilizers
Future trends in fertilizer technology may be predicted by extrapolating from current developments. Mixtures and materials with high percentages of plant nutrients will dominate the field. Better ways of providing nitrogen, the most expensive of the three major nutrients, will be forthcoming, including increased use of anhydrous ammonia, ammonium nitrate, and urea. Non leachable nitrogen, for example, can be obtained through the urea–formaldehyde (ureaform) reaction, and ammonium metaphosphate offers a concentrated liquid product. Micronutrients, or trace elements, specific to particular geographical areas will come into increasing use, as will custom mixing and bulk selling of mixtures containing several nutrients based on reliable soil and plant data.
“Complete environment” seeding in which seed, fertilizer, and water are incorporated in a biodegradable (decomposable in the soil) tape may come into use; with the tape planted, no further fertilizer or water will be needed until growth is well established. Such techniques using biodegradable tapes have already been developed on a small scale for use by home gardeners. Finally, larger and more precise fertilizing machines will be developed and adopted.
Soil and water pollutants that may adversely affect agricultural operations include sediment, plant nutrients, inorganic salts and minerals, organic wastes, infectious agents, industrial and agricultural chemicals, and heat. Sediment is a resource out of place whose dual effect is to deplete the land from which it came and impair the quality of the water it enters. Aside from filling stream channels, irrigation canals, farm ponds, and irrigation reservoirs, sedimentation increases cost of water clarification. Suspended sediment impairs the dissolved-oxygen balance in water. The recreational value of farm ponds is diminished by sediment, while soil depleted farmland is reduced in value. Nutrients of plants become resources out of place when they appear in groundwater and surface water; in fact, they become serious pollutants. Unwanted aquatic plants are nourished by plant nutrients derived from agricultural runoff, feedlots and barnyards, municipal and rural sewage, and industrial wastes. Aquatic plants clog irrigation and drainage structures, thus increasing maintenance cost and reducing capacity. Nitrates and nitrites in groundwater, which can poison human beings and livestock, result from both agricultural and industrial operations. Inorganic salts and minerals that impair the quality of soil and water are derived from natural deposits, acid mine drainage, industrial processes, and drainage flow from irrigated areas. Salt accumulation on irrigated soils causes the most damage and loss in this category. A high proportion of sodium in irrigation water supply affects plant life adversely (Salinity). More than just a trace of boron is highly toxic; therefore, water used in municipal and industrial processes involving borax may not be usable for agriculture. All these are also supplied from Fertilizer use in abundant.
No need to say that the old method of agriculture was sustainable which lasted for centuries without having any adverse effect either on the climate, soil, water, humans or anywhere else. Definitely we do not need anymore chemical fertilizers in fields but effective use of natural resources along with natural fertilizers which will not have any adverse effect on anything and will boost the yield of agricultural products. We need to go near nature again for the solution of our problems and we will have to understand that nature was, nature is, and nature will always remain our best friend till we are not stopping unethical exploitation of ‘dear nature’.