Dr Delima pays courtesy to Dean Lilian Sison of the Graduate School.
Findings:
Biological Nitrogen (Bio-N bacteria) and mycorrhizal innoculum in combination with half or three-fourth of the recommended inorganic fertilizer is sufficient to supply the nutrient requirements of corn, hence can offer considerable benefits in terms of growth and yield. Bio-N and AMF are potential substitute to fertilizers and biocides.
However Bio-N or Mykovam as single inoculant is insufficient for crop growth.
High amount of N has a negative impact on the AMF resulting to low yield.
Bio-N, and combination with inorganic fertilizers with biofertilizers without herbicide were found to be profitable and pitential substitutes to the commercial inorganic fertilizers.
Recommendations:
Promote the utilization of environmentally sound inoculant fertilizers among farmers to reduce their fertilizer input and consequently help mitigate global warming.
Biofertilizers should be used in combination with optimun amount of inorganic fertilizers (50% to 75%) to maintain sustainability in crop growth and productivity.
Further study is recommended to establish guidelines in applying the findings of this research, namely:
- location-specific (within and outside Cagayan Valley)
- season-specific based on the sub-climate of the area.
- variety-specific (white, other corn varieties, and different cultivars of yellow corn)
- residual effect of the two biofertlizers
- application of low input systems such as organic farming on biofertlizers
Background
1. Corn (Zea mays), one of the three most important cereals in the world, beats its counterparts - rice in the tropical region and wheat in the temperate region - for the fact that it can grow on a wide range of latitude and altitude, practically growing along side either or both crops - or alone owing to its high adaptability to soil and climatic conditions, resistance to force majeure including drought, pests and diseases.
Talahib (Saccharum spontaneum), source of free living nitrogen-fixing bacteria (Azospirillum complex)
2. Corn is versatile in its usage: as forage, silage and roughage for livestock at any stage of the plant, human food in a hundred-and-one recipes from popcorn to corn-on-cob, tacos to corn chips, and as animal feeds which constitute 80 percent of most feed formulation for poultry, hogs and livestock; and with the fuel crisis on the rise, corn is the main source of biofuel - ethanol and oil - as substitute to conventional fossil fuel.
3. Corn cultivation ranges from small tenanted farms to corporate farms, with the latter employing the latest in technology and management, such as on large scale farming in southern United States, South America, and now Africa, expanding the world's corn belt, with increasing population and affluence; yet much of the small farms mainly in Asia and island countries remain marginal and subsistent.
4. Corn, the heavy feeder of Nitrogen it makes into protein and oil and countless other products, leaves the soil spent and unproductive through repeated cropping, thereby requiring fallowing (a time for the land to rest), more so replenishment through fertilization and rotation planting with legumes known for their N-fixing capacity.
5. Corn, the high yielder that for every kilo of Nitrogen applied produces ten to twenty times yield increase no other cereal could match, on the other hand induces heavy chemical fertilization on the part of the farmer to force yield levels to reach 7 to 10 tons per hectare (up to 15 tons); resulting in the long run acidity buildup and depletion of soil nutrients both major and minor elements.
6. Corn in the Philippines, second most important to rice, is planted to some 2.5 million hectares generally once a year, under poor agronomy and lack of policy direction, resulting in very low average yield (less than 1 MT/ha, lower that the world's average); yet the hybrid varieties can produce three to four times higher but occupies only 10 percent of cornfield. Because of low yield - and high cost - the country would rather import corn for its animal feeds requirement.
7. Corn, an upland crop is dependent on residual soil moisture after rice crop and occasional precipitation, otherwise flush irrigation is required to complete its productive cycle in about 90 days, including postharvest operations - detasselling, harvesting, shelling, drying and storage.
8. Corn usually gets its supply of Nitrogen and other elements from chemical fertilizers mainly Urea and complete fertilizer (12-12-12 or 10-10-10) which are very costly and not readily available, not to mention the harmful effect of chemicals to the soil and environment.
9. Corn - if it can be cultivated organically with the use of biological Nitrogen fertilizers (Bio-N) will tremendously reduce if not substitute chemical fertilizers, and help stabilize pH, improve tilth, and cut down pollution from the by-products of chemicals, and at the very source of manufacture.
10. Corn, being a member of the grass family (Graminae, now Poaceae) may benefit from microorganisms in the soil that aid in the conversion of N2 into NO3 called nitrification, like in the case of talahib (Saccharum spontaneum) which harbors a nitrogen fixing bacterium - a factor that explains its adaptability in almost desert condition.
11. Corn and the major food crops mostly non-leguminous to become as naturally Nitrogen-fixing, and therefor become self-sufficient has been the Utopia of science. Thus the continued search for nitrogen-fixing microorganisms, some like Mycorrhiza fungus in the roots of forest trees, Rhizobium in legumes, Nostoc and Anabaena (BGA) in lowland rice, among many other beneficial organisms which have been isolated, cultured and developed as inoculants for field use. d.
12. Corn research is overwhelming in kind and number, corn being one of the most researched and experimented crops, resulting in the production of hybrid varieties, and the BtCorn or Bacillus thuringienis-Corn, produced by splicing a gene part of the bacterium into the corn's DNA, the first commercial Genetically Modified Organism (GMO) now planted extensively in the US and other parts of the world including the Philippines.
13. Corn production currently faces serious problems: first, economic viability and sustainable productivity; second, dynamic adaptability to changing climatic conditions; and thirdly, shifting use from staple to animal feed, and now, a growing shift from food to biofuel and other industrial uses. Calorie value is lost tremendously when converted from grain to meat (conversion ratio: 1/5 in poultry, 1/8 in pork, 1/16 in beef); whereas conversion into biofuel results in net loss, instead of gain in energy.
14. Corn by-products range from thatched roofing to particle board, its flower silk is medically approved as diuretic tea, now marketed in sachets and dispensers, its cob ground into powder used in the formulation of face and baby powder, and being organic is safer to health and environment. Corn meal after extracting oil is supplies many culinary preparation, and the sludge sediment in alcogas fermentation is excellent organic matter and soil conditioner
15. Corn fertilization with biological Nitrogen (vesicular-arbuscular-mycorrhiza or VAMF, a fungus; and BIO-N composed of bacteria complex - Azospirillum spp) promises high hopes to reduce dependence on chemical fertilizer while maintaining high yield on long term advantage, and that it could be a key to combining agriculture and ecology as partners, instead of strange bedfellows.
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