POPULATION RESPONSE COMPOUNDS Nitrifying
Bacteria legume residues
Uum Umiyati
Weed Science Lecturer in the Faculty of Agriculture, Padjadjaran University
ABSTRACT
The purpose of this study is to determine the effect of compounds residues generated by Vigna radiata cultivars Sriti and Mucuna pruriens on nitrification bacterial population.
The design used was factorial randomized block design with four replications, treatments used are two different soil types (Inseptisol (a1) and Vertisol (a2); Two Kinds of Produce legume residues (t), and two types of weed management (g).
Results showed that Vigna radiata L. cultivars Sriti and Mucuna pruriens affect nitrifying bacterial populations, thus affecting the availability of nitrogen in the soil causes the N available N is not available to weeds that are living together. Causes of organic nitrogen content on weeds less than the organic nitrogen content in Vigna radiata
L. cultivars Sriti and the content of Mucuna pruriens increases. Total population of nitrifying bacteria is influenced by soil type, causing the number of nitrifying bacterial populations between species and Inseptisol vertisol different.
Key Word : Vigna radiata , Mucuna pruriens, Allelopathyc, nitrosomonas and nitrobacter, N organic content.
INTRODUCTION
Background
In broad outline of world agriculture, the plant consists of weeds (Weeds) and plants (crops) are always co-exist but in a different position, namely the one desired and the other is not desired. Life with the plants will always lead to a relationship called the associations because each plant will utilize the genetic potential to dominate its
environment in order to grow better. Associates in plants can lead to positive effects such as mutualism, ie, if plants are to each other live together and mutually beneficial. On another occasion plant associations can also result in negative effects, ie, known by the term competition and residues.
The phenomenon of residues includes all types of chemical interactions between plants, microorganisms, or between plants and microorganisms (Einhellig, 1995). According to Rice (1984) and this interaction include inhibition pemacuan directly or indirectly, a compound formed by an organism (plants, animals or microbes) on the growth and development of other organisms. chemical compounds that play a role in the mechanism called alelokimia. alelochemical effect is selective, in influence the types of other organisms (Western, 1996).
produced by Vigna radiata is a C-glycosyl flavonoid flavonoid. Rank these compounds can inhibit the activity of nitrogen, which resulted in population and activity of bacteria nitrosomonas nitrifying bacteria is low and therefore the land would be lack of nitrogen
Other situations can cause inhibition of flavonoid microorganisms associated with nitrogen-producing plants, by inhibiting the formation of NH 4 + that will be used other
plants for germination and growth. Research conducted by Rice (1984), suggests phenolik content can inhibit the oxidation of NH 4 + to NO 3-. But the opinion delivered
by Bremner and McCarty (1993), phenolik in soil can enhance the instability moved NH 4+ caused inhibition of bacterial activity nitrosomonas.
Research conducted by Nilsson et Al., (1993) in that the extract of Empetrum
greenhouse hermaphoditum seen reducing mycorhizal infection in pine seedlings. Intake nitrogen by Pinus sylvetris germination decrease with increasing E hermaproditum
extracts and in extreme environmental conditions.
Compounds alelokimia generated by Mucuna including flavonoids, galic acid and L-Dopa. Compounds L-Dopa have in seeds of Mucuna has been used as a cure for Parkinson's disease, whereas the flavonoids as well as isoflavonoid produced by Vigna radiata L can suppress growth of bacteria in the soil ( Eilitta et al., 2002).
The addition of organic material concentration can increase microbial activity, which will spend all of the nutrients in the soil. Effects of toxic residues could not be separated from the effects of soil microbial activity. (Inderjit and Foy, 1999). Therefore, research must be done to determine determine the effect of compounds residues
generated by Vigna radiata cultivars Sriti and Mucuna pruriens on nitrification bacterial population.
MATERIALS AND METHODS RESEARCH
Time and Place Research
This research is a field experiment in order to determine the effect of plant residues contributing to the population of bacteria and nitrobakter nitrosomonas. The field experiment was conducted in Cirebon regency, Central Java Brebes of the Month February - October 2008. The experiment included two orders of Inseptisol and Vertisol soil, each environment is arranged according to randomized block design (RBD) factorial with treatments of two legume species (t), and weed management (g) consists of two treatment was repeated four times.
Material and Experimental Equipment
Seeds of Vigna radiata L. cultivars Sriti and Mucuna pruriens (surly), and other. Observations made in the field and tested in the laboratory of land, including: Calculation of bacterial populations and nitrobakter nitrosomonas using selective media from Ford. Unit to calculate the amount of soil bacterial populations are CFU (Colony Forming Units) observed at the age of 56 days after planting, the soil was taken at around rhizosfer roots of plants and weeds. The content of N-organic, Mucuna and weeds, the observation was made during planting 42 DAT for Vigna radiata L. cultivars Sriti and 56 DAT for
RESULTS AND DISCUSSION
Nitrosomonas and Nitrobakter bacteria population on the Order Land Inseptisol and Vertisol
Vigna radiata L. cultivars Sriti and Mucuna is a plant that has the ability to chemically interact with the production of secondary metabolites issued environment through root exudates, which can directly affect the growth of other plants and can indirectly affect soil properties, nutrient status and soil microbial activity or population (Orcutt, 2000).
Soil organisms can be grouped into microflora (bacteria, fungi, actinomycetes and algae) and soil fauna. Bacteria are the most dominant organism with a population of 10 8 -10 10 per gram of soil. Airasi and soil with good drainage is a good environment for microorganisms to perform the necessary gas exchange for his life, as well as land preparation and drainage repair airasi soil (Inderjit and Dakshini 1994).
The more surface area a soil particle, the greater the role of these particles in regulating chemical and biological soil properties, namely its ability to bind water and nutrients, as well as the density of soil organisms Accordingly, the presence of microorganisms in the soil clay fractions more than the other fractions , so in Table 1, see the amount of bacterial populations nitrosomonas and nitrobacter on Vertisol land more than land Inseptisol.
Nitrosomonas and nitrobacter bacterial population in the area planted Vigna radiata
L. cultivars Sriti (t 1) less than the total bacterial population and nitrobakter nitrosomonas on land that is planted Mucuna pruriens (t 2). That situation shows that the larger Vigna
radiata L inhibite against weeds and the availability of nitrogen for other plants (Blum 1998).
.Tabel 1. The population of bacteria Nitrosomonas and Nitrobacter on the Order Land Vertisol and Inseptisol
No. Treatment Ordo Vertisol Order Vertisol Ordo Inseptisol Order Inseptisol Nitrobacter
Source: Soil Microbiology Laboratory, Padjadjaran University, 2008 t1 = Vigna radiata L cultivari Sriti; t2 = Mucuna pruriens ; g1 = bergulma; g2 = no weeds
O 2 for ammonia oxidation activity. (Dixon, 1983). Plant Mucuna alelochemical which produce L-DOPA (L-3, 4 - Dihydroxyphenyl alanine) that can inhibit bacterial populations nitrosomonas which causes oxidation of NH 4+ to NO 3- becomes obstructed. With the type of clay soil and slightly acid pH near neutral and high cation exchange capacity increase generated alelochemical activity, causing inhibition of the population of microorganisms involved in nitrification process either in soil type and Inseptisol Vertisol thus affecting N available to other plants become unavailable (Robert
and Vitousek, 1981).
N CONTENT DIFFERENCES DUE TO ORGANIC CROPS RESIDUES DIFFERENCES IN SOIL TYPE
Nitrogen is the element that most limits plant growth. Also needed in large quantities compared with other nutrients, nitrogen is very important role in increasing plant growth. This nitrogen important position in biochemical processes of plants as an essential element in the formation of cells, preparation of proteins, cytoplasm, nucleic acids, chlorophyll and other cell components.
Differences in soil type will give a different effect on nutrient content, pH, and activities of microorganisms, so that crop response to nutrient will vary and affect the percentage of nutrients in plants.
According to Dixon and Whiller (1983). The contribution of environment to differences in plant population affected by the variation sources and the use of nitrogen by plants and the variation of pH. Condition of pH affects the activity of soil microorganisms. Land which has a neutral pH supports the growth of microorganisms with the good.
However, at pH less than 5, 5 inhibited growth of microorganisms. The range of soil pH are used in this experiment were 6.5 for ground Inseptisol and 6, 8 for Vertisol soil so that the organic nitrogen content between Vigna radiata L and Mucuna on both land shows the difference.
The differences in the use of nitrogen causes nitrogen content differences in body tissue or Vigna radiata L and Mucuna. Dixon (1983), the available nitrogen source can not be exploited by cucumber plants due to competition between the chemical Mucuna or
Vigna radiata L with weeds, so Vigna radiata L or Mucuna issued alelochemical through root exudates such as flavonoids, glycocyl C, L-Dopa to the soil caused a decrease in pH or rooting rhizosfer Vigna radiata L or Mucuna, resulted inhited other plant root growth and also causes stunted nitrifying bacterial populations in the region so that the supply of nitrogen for your plants non rhizosfer low that of other nitrogen stored in body tissue is low.
of nutrients, especially nitrogen obstacle, causing weeds in organic nitrogen content is low.
Table 2. Shows the organic-N content of Vigna radiata L and Mucuna remain high both on land Vertisol and Inseptisol compared with the weed. This indicates that both legume has a high ability to compete with weeds (competitive ability) in relation to the use element nitrogen.
Table 2. Content of Organic Nitrogen in legume and Group Two Weeds in the Order Land and Inseptisol Vertisol
No. Treatment Order Vertisol Order Inseptisol Crop / Weed
Classification Organic-N content (grams) Crop / Weed Classification Organic-N content (grams) 1 1 t 1 g 1 Green Peas 3, 85 Green Peas 5, 56
Riddles 0, 88 Riddles 0, 94
Grass 0, 98 t Grass 2, 31
Leaf Width 0, 11 Leaf Width 0, 32
2 t 1 g 2 Green Peas 6, 96 Green Peas 7, 48
Riddles 3, 59 Riddles 1, 74
Grass 1, 62 Grass 3, 28
Leaf Width 0, 76 Leaf Width 0, 82
3 t 2 g 1 Mucuna 5, 50 Mucuna 14, 37
Riddles 2, 25 Riddles 0, 54
Grass 1, 82 Grass 7, 92
Leaf Width 0, 17 Leaf Width 1, 54
4 t 2 g 2 Mucuna 5, 23 Mucuna 9, 48
Riddles 0, 67 Riddles 0, 72
Grass 2, 09 Grass 8, 61
Leaf Width 1, 29 Leaf Width 1, 17
Source: Soil Fertility Laboratory, Padjadjaran University, 2008..t1 = Vigna radiata L; t2 = Mucuna; g1= weed; g2 = no weeds
diversity of existing populations on the ecosystem both above ground and below the surface of the ground surface.
Chemical interaction with the issuing alelopat through root exudates Vigna radiata L or
Mucuna to the area resulted in disruption of the oxidation process rhizosfer NH 4 + to NO 3 -. NH 4 + bound by carboxylic acids issued Vigna radiata L and Mucuna so it can not move out of the area rhizosfer Vigna radiata L and Mucun plant roots , so that elements that are available outside rhizosfer nitrogen in the form of NO 2 - which is very volatile, therefore it can not be exploited by the roots of weeds.
Capability is supported by the ability to produce alelochemical that can affect the life of existing microorganisms in the soil, mainly bacteria and nitrosomonas nitrobakter useful in the event of nitrification (Blum and Shafer, 1988). With the inhibition of nitrification by metabolites produced by these two legume crops, causing nitrogen can be absorbed by the weeds and stored in the network is low. The nitrogen is captured and stored in a network of more legume, this is because the soil nitrogen is not available (immobile) for weeds alelochemical generated by the presence of the two legumes.
According to Orcutt (2000), in diverse ecosystems (Vigna radiata L, Mucuna and weeds) the effect can easily be identified alelokimia ie when some soil chemical control of plant species (such as observation of Table 1) and dominate the ecosystem. The table shows that the Vigna radiata L or Mucuna has a more organic N content of weeds, it indicates that the Vigna radiata L and Mucuna is a legume, which has alelochemical activity.
CONCLUSION
The presence of crop residues will affect the life of existing microorganisms in the soil, mainly bacteria and nitrosomonas and nitrobacter useful in the event of nitrification and thus affects the nutrient cycle and nutrient cycles that exist in an ecosystem which in turn affects both the diversity of the population below the ground surface or above ground level and found on land is overgrown with vegetation climax.
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