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IRON DYNAMICS AND ITS RELATION TO SOIL REDOX POTENTIAL AND PLANT GROWTH IN ACID SULPHATE SOIL OF SOUTH KALIMANTAN, INDONESIA Wahida Annisa; Dedy Nursyamsi
Indonesian Journal of Agricultural Science Vol 17, No 1 (2016): April 2016
Publisher : Indonesian Agency for Agricultural Research and Development

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21082/ijas.v17n1.2016.p1-8

Abstract

Organic matter has a function to maintain reductive conditions and to chelate toxic elements in acid sulphate soils. The study aimed to assess the dynamics of ferrous iron (Fe2+) in acid sulphate soil and its correlation with soil redox potential (Eh) and plant growth. The experiment was arranged in two factorial randomized block design with three replications. The first factor was two types of organic matter: (1) control (without organic matter), (2) rice straw and (3) rush weed (Eleocharis dulcis). The second factor was time of decomposition of organic matter: I1 = 2 weeks, I2 = 4 weeks, I3 = 8 weeks, and I4 = 12 weeks (farmer practice). The results showed that concentration of ferrous iron in the soil ranged from 782 to 1308 mg kg-1 during the rice growing season. The highest constant rate of iron reduction (k F2+) was observed on application of rice straw and rush weed with decomposition time of 8 weeks with the k Fe2+ value of 0.016 and 0.011 per day, respectively, while the ferrous iron formation without organic matter had the k Fe2+ value of 0.077 per day. The ferric iron (Fe3+) reduction served as a function of soil Eh as indicated by the negative correlation of ferrous iron and Eh (r = -0.856*). Organic matter decreased exchangeable iron due to chelating reaction. Iron concentration in roots was negatively correlated with soil soluble iron (r = -0.62*). Application of rice straw decomposed for 8 weeks increased the height of rice plant up to 105.67 cm. The score of Fe2+ toxicity at 8 weeks after planting ranged from 2 to 3, so rice crop did not show iron toxicity symptoms. 
Populasi Bakteri Dan Jamur Pada Rizosfer Caisim (Brassica juncea L.) Yang Ditanam Di Tanah Dikontaminasi Insektisida Organoklorin Setelah Aplikasi Konsorsia Mikroba Dan Kompos Reginawanti Hindersah; Wawan Rachman; Betty Natalie Fitriatin; Dedy Nursyamsi
Agrologia Vol 3, No 2 (2014): Agrologia: Jurnal Ilmu Budidaya Tanaman
Publisher : Faculty of Agriculture, Pattimura University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.30598/a.v3i2.246

Abstract

Organochlorine insecticide was banned for agriculture but nowadays its residue was still found  in some agricultural soil. One of ways to lowering organochlorine residue in soil is by used of degrading-organochlorine microbial consortia accompanied with compost application. However, application of exogenous microbes might affect bacterial and fungal population in soil. The pot experiment has been set up to verify the influence of Pseudomonas mallei and Trichoderma sp. and compost on total bacteria and fungi on rhizosphere of Cai Sim (Brassica juncea L.) grown on Andisols which were contaminated with organochlorine insecticide of heptachlor, endosulfan, dieldrin and DDT. Experimental design was Factorial Randomized Block Design with three replicates. The first factor was microbial consortia of P.mallei and Trichoderma sp., and the second one was kind of compost. The result showed that effect of microbial consortia on total bacteria population was determined by kind of compost. Total bacterial population in rhizosphere of Cai Sim grown with cow manure compost and microbial consortia was more increased.  However, microbial consortia as well as any kind of compost did not influence total fungal population in Cai Sim rhizosphere. In this experiment, total bacterial and fungal population in rhizosphere reached 109 cfu g-1 and  104 cfu g-1 respectively, indicating that major microbial population in rhizosphere was  in the normal range.