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PERTUMBUHAN DAN PERKEMBANGAN MIKROORGANISME TANAH PADA MEDIA AGAR EKSTRAK TANAH YANG DIPENGARUHI HERBISIDA GLYFOSAT
Get PDFSoil microorganisms have significant role in plant nutrient cycles availability. Repeated glyphosate application and unwise use this herbicide may give an impact in soil microorganism population and create a shift in community structure in soil microcosm. The objectives of this study were to (1) analyze the effects of different glyphosate application rates on soil mcroorganism population and community structure. The research have done in two series i.e. in limed soil extract and unlimed soil extract media. Five treatments and 3 replications arranged in Completely Randomized Design were used in this experiment. The treatments assay were doses of glyphosat application i.e : without glyphosat, 2 ml, 4 ml, 6 ml and 8 ml of glyphosate. Duncan’s New Multiple Range Test were used to compare the results obtained in this experiment. Total population obtained in 2 ml application of glyphosate in soil extract agar medium are 5.6x108 g-1 of soil or decreasing 50%. If doses of glyphosate increase to 8 ml the total of population diminished 75%. The glyphosate application have only influence to fungi population but not to the total population in limed soil extract agar. The diameter of bacteria and fungi colony observed in unlimed or limed soil extract agar media decrease by rising of doses glyphosate application and have the same as the population pattern.
Key words : Glyphosate, soil microorganism, Ultiso
PERUBAHAN HARA DAN MIKROORGANISME PADA ULTISOL AKIBAT KASCING YANG BERBEDA
Get PDFThis research was conducted in Soil Drying Room at Faculty of Agriculture Andalas University. Analysed in Soil Biology, Soil Chemic and Plant test and Disease Laboratories from August 2006 to February 2007. Aim of this research is to know the effect of substrate of vermicompost on population of soil microorganism on Ultisol. This experiment were designed on Complete Randomized Block Design in three treatment and three replicate. The treatment were different substrate of vermicompost, consisted of : without vermicompost, 10 ton/ha vermicompost with rice strow substrate and, 10 ton/ha vermicompost with dust wood. The result was showed, that vermicompost with rice strow could increase the growth rate of microorganism 320,14 % of fungi and 123,3 % bacteri. Used that this vermicompost can also increase soil nutritions (0,22 %, variable P 0,7 %; K-dd 0,04 me/100 g, Ca-dd 0,13 me/100 g and Mg-dd 0,08 me/100.
Key word : vermicompos
EFFECT OF L-TRP ON PERFORMANCE OF IAA PRODUCING RHIZOBACTERIA ON GROWTH OF SWEETPOTATO (IPOMOEA BATATAS L.)
Get PDFPenelitian tentang penambahan L-Triptophan (TRP) pada rhizobakteri penghasil IAA terhadap tanaman ubi jalar yang merupakan percobaan pot bertujuan untuk melihat pengaruh dari L-TRP dan inokulasi isolat rhizobakteri pada pertumbuhan dan hasil ubi jalar, populasi bakteri dan jamur tanah serta kandungan nutrien pada tanah pasir bekas galian tambang timah di Malaysia. Penelitian ini merupakan percobaan pot yang disusun secara Acak lengkap (RAL) yang menggunakan tiga isolat rhizobakteri penghasil IAA yang juga berasal dari perakaran ubi jalar. Dari penelitian ini didapati bahwa isolat rhizobakteri SPR 66 mampu meningkatkan berat kering bahagian atas, kandungan klorofil dan jumlah luas daun, sedangkan isolat SPR 100 mempengaruhi berat kering dan volume akar, pembentukan ubi, kandungan nutrien tanaman dan nutrien tanah. Pemberian L-TRP kepada semua isolat terpilih cendrung meningkatkan pembesaran dan hasil tanaman ubi jalar. Peningkatan ini berkaitan dengan peningkatan keadaan kimia dan aktivitas mikroorganisme di dalam tanah
PELUANG PENGEMBANGAN JAGUNG PADA GAWANG KELAPA DALAM UPAYA PENINGKATAN PRODUKSI JAGUNG DI SUMATERA BARAT
Get PDFThe national maize necessity directly increase in the last few years. On the years 1996-2000 periods rate of maize import was about 52,08 % per year. The amount of national maize need for feeding increased approximately 52,4% of food derived from maize to increase the national maize production by expansions of maize hybrid and composite. However their development on the former still slowly. The production increasing from 1996 to 2001 0,17% on year and maize productivity about 2,67 t/ha. In the west sumatera by exspansion maize planting area and utilization of land area more efficient, and include land area either coconut plant. West sumatera province had coconut plantation would total area 91,920 ha. And spreahed in some regensi and city. The result of the experiment and assessment in west sumatera BPTP. In land area inter coconut plant plant can be growth maize C5,C7 and C9 hybrids and yield average about 5,0 – 6,7 t/ha in 50 kota dan Padang Pariaman regency with r/c ratio 1,9 – 2,5. From the result of research and assessment of west sumatera BPTP. Application of land area inter coconut plant had opportunity to increase maize production in West Sumatera.
Keywords: Extensifikasi,Expansions of maize hybrid, composit
MOVEMENT OF CHLORIDE INTO A WELL-DRAINED SOIL
Get PDFChemical leaching from soil surface will cause groundwater pollution. Researches showed spatial correlation of the leaching chemicals. Based on the fact, a filed research was conducted at Maury silt loam soil (fine, mesic, mixed, Typic Paleudalf) to evaluate spatial variations of anion movement, in tis case was Cl, into and below rooting zone. Source of chloride, SrCl2.6H2O, was evenly distributed on soil surface within a 18 x 18 m2 plot in University of Kentucky Experimental Station, Lexington, Kentucky USA. Soil was sampled for 4 times (after receiving 166, 310, 586, 1085 mm rainfall), in every 10 cm depth for 54 points within the plot. The result showed that Cl- movement did not show spatial model from soil surface into 100 cm profile in every sampling date. Therefore, based on analysis of variance, Cl- concentration was significantly different from one depth to another within one sampling time. Cl- concentration found on the depth of 100 cm was 75, 58, 27, and 15% for sampling time I, II, III, and IV, consecutively.
Key Words: groundwater pollution, anion leaching, agricultural chemicals, spatial structur
DEGRADASI LAHAN AKIBAT BERBAGAI JENIS PENGGUNAAN LAHAN DI KABUPATEN DHARMASRAYA
Get PDFIntensive deforestration for the purpose of agricultural field and transmigration area has happened lately in Dharmasraya Regency, West Sumatra. Land use change from forest into dry land farming, mixed trees and oil palm plantation, as well as rubber plantation has caused different level of soil fertility as a consequence of ecology changes of the areas. The objectives of this research were to identify the change of soil organic matter content, plant nutrition level, as well as bulk density of the soils at each land use.
This research was conducted in Sungai Rumbai, Dharmasraya Regency in 2007. Soil samples were taken from 5 land use, those were dryland farming, mixed trees, oil palm plantation, rubber plantation, and natural forest. The soil samples, then, were analysed for the soil organic matter content (%), N-, P-, and K-content, as well as bulk density (BV) in soil laboratory, Agricultural Faculty, Andalas University Padang.
The result showed that land use change from forest ecosystem into other ecosystems had decreased soil fertility level. This was reflected by the decreasing soil organic matter content, increasing soil bulk density. Nutrient status of the soil also decreased, especially potassium (K) level. Compared to the forest ecosystem, soil organic matter decreased by 13, 26, 33, and 36% respectively for dry land farming, mixed trees and oil palm plantation, as well as rubber plantation. Soil bulk density of the land use which was still close to soil under forest ecosystem (0.83 gcm-3) was found in rubber plantation (1.00 gcm-3), then followed by mixed trees (1.11 gcm-3). Potassium level of the land uses which were close to forest ecosystem (0.44 me/100g) was in rubber plantation (0,33 me/100 g), as well as in oil palm plantation(0,34 me/100 g). Based on the results above, it can be concluded that rubber and oil palm plantation was types of land use having better soil ecology compared to the other land use.
Kata Kunci: Degradasi Lahan, Ekosistem Hutan, Penggunaan Laha
TINGKAT KERACUNAN BESI DALAM BENTUK FERRO DAN FERRI SERTA PERTUMBUHAN TANAMAN PADI (Oryza sativa.L) PADA MEDIA PASIR
Get PDFThe Recent ricefield on marginal land such as Ultisol and Oxisol has low productivity due to Fe-toxicity for rice plant (Oryza sativa.L). Flooded ricefield has reduced Ferri (Fe3+) form into Ferro (Fe2+) from which is easy to dissolve and can be toxic for plant growth. This research was aimed to determine Fe concentration that causes toxic for rice growth on sand medium either under flooded or unflooded condition. Iron was applied in form of FeSO4 at 10 levels (0, 2, 4, 8, 16, 32, 64, 128, 256, 512 ppm). Based on laboratory analyses and visual symptoms, it was found that Fe toxicity was started at Fe concentration 128 ppm. Form of Fe which is toxic to this rice plant was ferro (Fe2+) because this form is active in plant metabolism. Fe concentration at 128 ppm both conditions had shown reddish brown spot on the whole plant, therefore growth and development of plants either above or below soil surface was limited or stressed.
Keywords: recent ricefield, Fe toxicity, Ferro and Ferri, brownish sympto
PERANAN KOLOID Al DAN Fe AKTIF DALAM PROSES RETENSI FOSFAT PADA ANDISOLS DARI SUMATERA BARAT
Get PDFThe presence of active Al and Fe compounds in large amount in Andisols has caused strong P-retention on these mineral structure or it is bound on OH functional group or positively charged H. The objective of this research was to provide fundamental information to manage and conserve Andisols as used to be vegetable production centre in West Sumatra. The results showed that volcanic soil from Pasaman Mountain had higher retention capacity than that of Marapi Mountain. Therefore, it was needed more P for optimum plant growth. The most dominant soil properties affected pattern and amount of P retention was due to type of clay mineral found in volcanic soils. The dominant clay mineral on Andisols in West Sumatra was alofan and ferryhydrite (non-crystalline clay mineral) which are active component of Al and Fe colloids.
Key Words: Volcanic ash soil, P retention, Alofa