R325 - Effect of Different Rate of Azotobacter ... - Agrisciences.com

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Table 1. Chemical Composition of Onion (100g fresh product) Determination Unit Water and cellulose 86.10% Calcium 0.34 mg Potassium 0.17 mg Sodium 0.016 mg Phosphorus 0.045 mg Chlorine 0.021 mg Sulfate 0.07 mg Proteins 1.60% Fat 0.50% Hydrates of Carbon 11.60% It also contains a large amount of vitamin A, and a satisfactory quantity of both vitamin B and C. Their energy value is 0.45 calories per gram (TISCORNIA, R. 1974). The onion requires a temperate warm climate for its development, but the ideal condition is cool temperatures in the initial phase of development and warm toward maturity. Good temperatures are considered to be from 12° to 24°C (CÁCERES E. 1982). Thusly it is considered that the best growth of the cultivation is obtained with temperatures around 16° to 18°C, also, in temperate climates they need temperatures above 20°C to form bulbs (MESSIAEN, C. 1979). The cultivation is affected strongly by day length and length of photo-period. Some varieties grown in temperate areas don't develop bulbs completely in tropical areas, or even in subtropical areas; they are very developed vegetatively but need days with 15 hours of sun light for bulb development (MORTENSEN, E. 1967). The most desirable soils are calcareous, sandy, loose and aerated; in tight soils small, non-commercial bulbs are developed; onions don't tolerate soil already low in organic matter or purin (TAMARO, D. 1977). Checking results of the application of fertilizer nitrogen (75 kg/ha) shows a statistically superiority to control treatment (00 kg/ha), in that yields of 45,708 kg/ha and 30,312 kg/ha of onions were achieved in Red Arequipeña onions (SILVA, A. 1982). Likewise, using the same variety as control, a yield of 7,271 kg/ha was obtained, bulb diameter averaged 6.66 cm, and a high statistical significance (95 and 99%) existed among characteristic of diameter of bulb vs. yield (RED, C. 1977). For nitrogen incorporation into the soil, one of the most important microorganisms is the aerobic bacteria Azotobacter, discovered by the Dutch microbiologist Beijerinck, which are characterized as heterotrophic. (BONNER, J, 1973), (BURGES, J.) In the mature state, the bacteria are an oval shape, which may be for accumulation of big globules of fat. Most have a more or less rigid membrane that represents 20-25% of the dry matter of the microorganism; some of the membranes seem to be formed mainly by lipoproteins, in others by mucoproteins. Free living organisms prefer rizospheres of well-aerated soils; they feed on organic compounds synthesized by autotrophic organisms and healthy plants (BURGES, A. 1971), (BURDON, K. 1971). These bacteria use and oxidize organic matter: they spend energy in part liberated in the process of substratum oxidation in the processes of nitrogen reduction (BONNER, J. 1973); they take nitrogen directly from the air which combines inside the cellular plasma which is liberated in the form of nitrates (BURDON K. 1971). Neither starch nor the other polysaccharides are used. It grows well in the presence of nitrogen generating substances like nitrates, ammonium salts or urea, but if these substances are abundant, they don't fix atmospheric nitrogen (JAMES. W. 1967). 2
Azotobacter also enriches the soil with another necessary element, phosphorus. Whereas the polysaccharides of the bacteria seem to play the most important roll in the formation of the structure of the soil, especially in degrumos formation: the most appropriate pH for the development of the bacteria is 7 to 8, the lower limit is 6. There are a few bacteria that exist in lower pH such as the genus Beijerinckia that produce acids in the cultivations, tolerating pH as low as 3.5, these forms are “acid resistant" (BURDON, K. 1971), (MILLAR, C. 1964), (BURGES, A. 1971). These bacteria are found in the soil and after isolation they multiply in laboratory by two means of growth, one solid and another liquid. The growing of the bacteria is carried out by making grooves in each of the petri dishes, after having developed for 48 hrs on the solid material they multiply in a culture liquid. Then they are sterilized in an autoclave at 15 lb. of pressure and 120 O C for 15 minutes, then allowed to incubate at 30 O C for 96 hours after which respective observations are carried out for the purpose of verifying the characteristics indigenous of the bacteria (CHAINS, A. 1985). Inoculations with Azotobacter improve plant growth in the fields from 50 and 70% with 20% increases in yield achieved (BLACK C. 1975). Using Azotobacter spp. potato yield has been increased by 33.3% and 38.3%. This increase takes place when the bacteria at rates of 30 cf are combined with a low rate (50 kg/ha) and nil (00 kg/ha) of nitrogen respectively. When combining with a medium rate (100 kg/ha) and high rate (150 kg/ha) of nitrogen, the increase in yield is only 3.8% (CASTRO A. 1979). In an experiment carried out with the Red variety Arequipeña where nitrogen levels and inoculation of Azotobacter spp. were considered, there was no statistical significance supporting the use of both factors. The same result is obtained for the interaction of Nitrogen and Azotobacter; however, the combination (A 1 N 1 ) low rates of nitrogen (50 kg/ha) and an inoculation of Azotobacter to the onion plants (250 g/ha) provided the highest yield at 8,313.33 kg per hectare. At the same time, when comparing the inoculated treatment and the unfertilized control, the inoculant is superior at 1,187 kg per hectare to the control, which demonstrates the importance of the Azotobacter spp. (CADENILLAS, A. 1982). Agrispon, is a biostimulant for use in agricultural and horticultural production: it is easily handled, stored and applied. It is not toxic to plants, animals or people. The mode of action of this product in the plant is: it stimulates the development of foliage, the development of roots, flowering and fruiting, increases the fixation of nitrogen in the soil for bacteria, it reduces the consumption of nitrogen use, it increases tolerance to lack of water under adverse conditions (AGRICULTURAL IMPORTS, 1983). Table 2. Composition of Agrispon Determinations Units Cytokinins 10 ppm Giberilins 1 ppm Gibberellins are initially synthesized in very young leaves and later translocate into the region of the initial collar, where they are absolutely necessary for its operation (BEAULIEU, R. 1973). Gibberellins applied in small quantities to the soil or rosettes on the leaves and shafts of certain plants produces an increase in height. In grains such as wheat, and corn, they also cause an increase in length of the leaves. In some cases they also increase the fresh weight and dry weight. However it doesn't produce any effect on the growth of the roots (BEN, J. 1964). From the chemist's point of view, cytokinins are related to nucleic acids with precursor substances that act to stimulate cell division in vegetative growth areas. No information exist about its transport, or its physiologic role in plants, or on the production points areas, because of this, it is not possible to classify these substances as phytohormones (BEAULIEU, R. 1973). 3
Page 1 and 2: Effect of Different Rates of Azotob
Page 3: CHAPTER I INTRODUCTION Vegetables a
Page 7 and 8: Table 3. Meteorological Data of Sep
Page 9 and 10: Figure 1. Outline of distribution o
Page 11 and 12: 9. Evaluations: 9.1. Before the Cro
Page 13 and 14: small increment, it is decidedly po
Page 15 and 16: 27000 Figure 4. Azotobacer Interact
Page 17 and 18: The coefficients of Correlation in
Page 19 and 20: 6. From the economic point of view,
Page 21: CAPITULO VIII APENDICE Table No. 14

R325 - Effect of Different Rate of Azotobacter ... - Agrisciences.com

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