Overview Of Organic Fertilizer Use In Rice In The Philippines PDF

OVERVIEW OF ORGANIC FERTILIZER USE IN RICE IN THE PHILIPPINES By Wilfredo C. Cosico (2010) Dr. Patrick C. De Leon Associate Professor UP Diliman Extension Program in Pampanga  ABSTRACT The use of organic fertilizers o...

OVERVIEW OF ORGANIC FERTILIZER USE IN RICE IN THE PHILIPPINES By Wilfredo C. Cosico (2010) Dr. Patrick C. De Leon Associate Professor UP Diliman Extension Program in Pampanga  ABSTRACT The use of organic fertilizers on agricultural crops is not a new practice but it has no yet gained wide acceptance, especially among rice farmers. The major reasons for this are (1) the lack of information and (2) misconceptions about what organic materials can or cannot do to the soil and the crop.  ABSTRACT Many farmers tend to expect too much from organic materials and tend to be biased against anything “chemical” as inorganic fertilizers. Organic and inorganic fertilizers have their own merits and drawbacks and the user should decide to make use of what is best in both materials.  ABSTRACT The use of organic materials as fertilizers for rice must be thoroughly studied since the physical, chemical, and microbial characteristics of paddy soil are uniquely different from those of upland soil. Thus, the response of the rice plant to the application of organic materials is very different from that of upland crops.  ABSTRACT There are now various organic materials and techniques of application to which rice responds well. Rice farmers must be made aware of such technologies.  INTRODUCTION Organic materials have been used as fertilizers since time man began to domesticate crops, not by choice, but because they are the ones available. Ancient people observed that dead bodies increased the growth of crops in the battlefields. The ancient Athenians used water with manure to fertilize their vineyards.  INTRODUCTION As agriculture moved to modern times, greater use of mineral fertilizers began, particularly after the German scientist Justus von Liebig (1803-1873), through systematic experimentation, showed the fertilizing value of some minerals. Fertilizer factories sprouted in Europe and America and, along with the Green Revolution, sparked the intensive use of inorganic or chemical fertilizers.  INTRODUCTION Most chemical fertilizers, Type of Ave. Dealer’s Price particularly those sourced from Chemical (Php/sack) in the nitrogen (N), are oil-based and Fertilizer Philippines in Sept. 2017 they tend to follow the vagaries (psa.gov.ph, Oct. 13, 2017) of oil supply and prices. Urea 897 Therefore, the renewed interest Complete 1,087 on organic materials as Ammosul 560 fertilizers is not only due to what some claim to be bad effects of Ammophos 898 chemical fertilizers on the soil and on crops but also to the search for alternative sources of nutrients in the face of escalating prices of chemical fertilizers.  INTRODUCTION What then is the real score about organic fertilizers? Do they really do what they are claimed to do? Are chemical fertilizers really that bad? Some of the claimed benefits from organic fertilizers are true and valid, but some may be based on mere speculation and tend to be exaggerated. Particularly for rice, which grows in a more complex soil environment, the issues related to the use of organic fertilizers become more complex. Since research on organic fertilizers has not kept pace with that on inorganic fertilizers, much less is known about the use organic fertilizers for rice.  INTRODUCTION Many preachers of organic farming equate organic to “natural” and see the word as the opposite of “chemical,” ignoring the fact that organic and chemical fertilizers are both made up of chemical elements. Some even becloud the issues further when they begin to invoke the classical argument that anything chemical is bad. The debate is needless for it may not really be a matter of one being better than the other but of the two being complementary to each other.  ORGANIC VS. CHEMICAL FERTILIZERS Organic materials are derived from plants and animals and thus have a high content of carbon. Chemical fertilizers, on the other hand, are synthesized from minerals or non-living matter. The major distinction stops there.  ORGANIC VS. CHEMICAL FERTILIZERS Both materials serve as a source of nutrients for plants. They differ, however, (1) in form, (2) the amount of N contained, and (3) the rate by which nutrients are released to the plant. The plant root does not discriminate or know the ancestry of the nutrient it is taking up. No matter what the source is, the plant will assimilate the nutrient into the same compounds and structures (Dr. Susanne Bugel, University of Copenhagen)  ORGANIC VS. CHEMICAL FERTILIZERS No evidence exists that the judicious use of mineral fertilizers is injurious to soils or tends to produce crops which are unsatisfactory as feed for animals or food for man. Evidence exists showing clearly that the use of mineral fertilizers on depleted soils promotes the growth of crops which have superior nutritive values (Dr. Emil Truong, as cited by Manchester, 1962).  ORGANIC VS. CHEMICAL FERTILIZERS The positive effects of chemical fertilizers on crop quality are better known and supported by evidence, particularly that of potassium (K). K determines fruit quality of bananas and pineapples, sugar yield of sugarcane, and burning quality of tobacco leaves. Quality of crop is more a function of the nutrient rather than its source.  ORGANIC VS. CHEMICAL FERTILIZERS One of the most common misconceptions about organic farming is the positioning of chemical fertilizers alongside pesticides. Pesticides, by their very nature and purpose, are meant to kill, whereas fertilizers, chemical or organic, are meant to feed living plants and thus support life.  ORGANIC VS. CHEMICAL FERTILIZERS Another misconception is that organic fertilizers improve the texture of the soil and that chemical fertilizers cause soil compaction. Soil texture is the proportion of sand, silt, and clay particles in the soil mass, which makes it sandy loam, clay loam, or clay. It takes thousands of years for the geologic process of weathering to form soils of a particular texture. A few or even tons of organic fertilizers will not do it.  ORGANIC VS. CHEMICAL FERTILIZERS What organic fertilizers do is granulate the soil and improve the structure. With improved structure, the soil becomes more loose, better aerated, and easier to cultivate. This, the chemical fertilizers will not do.  ORGANIC VS. CHEMICAL FERTILIZERS The one chemical that can cause soil compaction is sodium chloride (NaCl), which causes destruction of soil aggregates and dispersion of particles. But NaCl is not even a component of chemical fertilizers.  ORGANIC VS. CHEMICAL FERTILIZERS Organic fertilizers increase soil aggregation, lower bulk density (compaction), and increase porosity, pH, and cat ion exchange capacity. Organic fertilizers also help neutralize aluminum, which is the predominant toxic metal in acid soils.  ORGANIC VS. CHEMICAL FERTILIZERS The deterioration of soil quality in the Philippines is attributed more to other factors than to the use of chemical fertilizers. Erosion, for one, contributes 48%. Others include insufficient replacement of the nutrients removed by the crops and mismanagement.  ORGANIC VS. CHEMICAL FERTILIZERS Some advocates of organic farming repeatedly accuse chemical fertilizer users as being instrumental in the deterioration of soil quality, acidifying and poisoning the soil with toxins and heavy metals, and contributing to global warming through the destruction of the ozone layer.  ORGANIC VS. CHEMICAL FERTILIZERS It is true that N fertilizers cause soil acidity from the following reaction:  ORGANIC VS. CHEMICAL FERTILIZERS However, the NH4+ whose oxidation by soil bacteria to produce H+ ions can also come from organic materials. The only difference is that, since N tends to be applied to soils in higher dosage of chemical fertilizers, the development of acidity is faster. However, soil acidity can be remedied by, among other means, liming.  ORGANIC VS. CHEMICAL FERTILIZERS The use of chemical fertilizers is also blamed for the pollution of surface waters with nitrates and phosphates, causing algal bloom and fish kill. However, the same nitrates and phosphates can also come from organic materials. This implies that the problem is curable and can be mitigated by judicious application of fertilizers.  ORGANIC VS. CHEMICAL FERTILIZERS Heavy metals such as mercury, lead, cadmium, chromium, and zinc are nearly always traced to chemical fertilizers, but only traces of these harmful minerals are in fertilizers whose raw materials are from earth minerals. Nitrogen fertilizers, which are produced from hydrogen and atmospheric nitrogen are practically free from these metals.  ORGANIC VS. CHEMICAL FERTILIZERS Nitrogen fertilizers are used in highest amounts in agriculture. It is in the sludge from industries and from urban garbage where metal pollutants are mostly found.  ORGANIC VS. CHEMICAL FERTILIZERS Both organic and inorganic fertilizers share in their contribution to global warming. In rice soil, in particular, both materials, under anaerobic conditions of the rice field, produce carbon dioxide, methane, and other greenhouse gases.  ORGANIC VS. CHEMICAL FERTILIZERS Hence, it is probably a good move to rest from fault finding in determining which fertilizer is more responsible for the damage to the environment and to start developing and implementing scientific-based strategies for more judicious use of all fertilizer materials to ensure sustainable farm productivity and a cleaner and safer environment.  REACTIONS OF ORGANIC FERTILIZERS IN RICE SOIL The lowland rice field is prepared by saturating it with water, puddling, and submergence. Puddling destroys the soil structure and, together with submergence, creates a thin oxidized layer on the surface and an anaerobic layer below.  REACTIONS OF ORGANIC FERTILIZERS IN RICE SOIL Under dry land conditions, organic materials undergo aerobic decomposition, the major gaseous product of which is CO2. The organic fertilizers are incorporated into the soil in advance of planting (2-3 weeks) to allow for more mineralization or release of nutrients.  REACTIONS OF ORGANIC FERTILIZERS IN RICE SOIL On the other hand, in the wetlands, anaerobic soil decomposition of organic materials releases CH4, mercaptans, hydrogen sulfide, various organic acids including fatty acids, which are toxic to rice. The other significant effect of submergence is the automatic adjustment of pH, with acidic and alkaline soils approaching neutrality or pH values between 6 and 7, which increase the availability of nutrients like phosphorous, molybdenum, and silicon.  REACTIONS OF ORGANIC FERTILIZERS IN RICE SOIL If organic materials, especially those with a high carbon to nitrogen ratio (C/N) – such as rice straw with a C/N of 50 – are incorporated into the soil close to transplanting time, seedlings may die due to toxins produced by anaerobic decay of the organic matter.  REACTIONS OF ORGANIC FERTILIZERS IN RICE SOIL Or even if they survive, they may suffer from temporary N starvation. Organic matter decomposes more slowly under anaerobic than under aerobic condition. Thus, incorporation of organic matter with high C/N must be done well in advance of planting.  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE In 2006, De Guzman gave an But for the rice crop, more idea of the extent of organic than 50% of rice farmers used fertilizer use in rice in the only chemical fertilizers. Philippines. Of 200 farmers surveyed in Laguna, Cavite, Bulacan, and Benguet, 42% used chemical fertilizers only and 54% used a combination of chemical and organic fertilizers on various crops.  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE Rice Straw Rice straw is one of the most abundant crop residues in the farm. A moderate grain yield of 3 t/ha would give a straw yield of about 4.5 t/ha. This would contain as much as 27 kg N, 6 kg P, 75 kg K, 18 kg Ca, 6 kg Mg, 6 kg S, 510 kg Si, and 1,800 kg C. Thus, if straw is plowed back into the soil, it recycles about ¼ of the recommended amount of N fertilizer for rice, 1/5 of the P, all of the K, and a substantial amount of Si and of C, which are the food of soil organisms.  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE Green Manure High-N-containing plants such as azolla and sesbania have been extensively studied, for many years, to serve as organic fertilizers for rice. Their value lies in their having high N content (about 4%), rapid decomposition, and high biomass yield (Cosico, 1985).  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE Animal Manure Animal manure may be used in rice fields but only after being composted with rice straw. Chicken manure has the highest N and P contents and the highest Ca if it comes from layers.  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE Biofertlizers Biofertilizers are organic fertilizers containing microorganisms or growth- promoting substances that enhance nutrient absorption by the plants. Some examples are Bio-N, Bio- fix, Bio-green, and Vital N.  TECHNOLOGIES FOR APPLYING ORGANIC FERTILIZERS IN RICE Compost and Composting Traditional composting of rice straw involves piling it in some corner of the field and letting nature take its course, which normally takes about three months. When some manure is mixed into the pile of straw, watered, and turned, decomposition is shortened to about two months.  CONCLUSIONS Certain misconceptions about At present, scientific evidence the use of organic and shows the big potential of inorganic fertilizers in rice certain organic fertilizer fields must be cleared up to technologies for rice. appreciate the potential Support from various benefits from organic fertilizers stakeholders in the agricultural and to chart clearer directions sector is needed for the in their use. dissemination and adoption of Many types of organic these technologies. fertilizers, production technologies, and application methods in rice fields still need further validation.