Leaf litter decomposition of Piper aduncum, Gliricidia sepium and Imperata cylindrica in the humid lowlands of Papua New Guinea
TL;DR: Piper leaf litter is a significant and easily decomposable source of K which is an important nutrient for sweet potato and the decomposition and nutrient release patterns had significant effects on the soil.
Abstract: No information is available on the decomposition and nutrient release pattern of Piper aduncum and Imperata cylindrica despite their importance in shifting cultivation systems of Papua New Guinea and other tropical regions. We conducted a litter bag study (24 weeks) on a Typic Eutropepts in the humid lowlands to assess the rate of decomposition of Piper aduncum, Imperata cylindrica and Gliricidia sepium leaves under sweet potato (Ipomoea batatas). Decomposition rates of piper leaf litter were fastest followed closely by gliricidia, and both lost 50% of the leaf biomass within 10 weeks. Imperata leaf litter decomposed much slower and half-life values exceeded the period of observation. The decomposition patterns were best explained by the lignin plus polyphenol over N ratio which was lowest for piper (4.3) and highest for imperata (24.7). Gliricidia leaf litter released 79 kg N ha(-1), whereas 18 kg N ha(-1) was immobilised in the imperata litter. The mineralization of P was similar for the three species, but piper litter released large amounts of K. The decomposition and nutrient release patterns had significant effects on the soil. The soil contained significantly more water in the previous imperata plots at 13 weeks due to the relative slow decomposition of the leaves. Soil N levels were significantly reduced in the previous imperata plots due to immobilisation of N. Levels of exchangeable K were significantly increased in the previous piper plots due to the large addition of K. It can be concluded that piper leaf litter is a significant and easily decomposable source of K which is an important nutrient for sweet potato. Gliricidia leaf litter contained much N, whereas imperata leaf litter releases relatively little nutrients and keeps the soil more moist. Gliricidia fallow is more attractive than an imperata fallow for it improves the soil fertility and produces fuelwood as additional saleable products.
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TL;DR: Amorphous silica was synthesized from cogon grass (Imperata cylindrica) by combustion at 650°C as mentioned in this paper, where the parameters of the combustion were determined by fitting thermogravimetric analysis (TGA) data to the Flynn-Wall-Ozawa model.
20 citations
TL;DR: Leucaena leucocephala contributed more nutrients, especially nitrogen, than other litter components, and mass loss was significantly correlated with calcium, which reflected the quantity and quality of nitrogen in the soil.
Abstract: Nutrient contents and rate of litter decomposition were investigated in Leucaena leucocephala plantation in the University of Agriculture, Abeokuta, Ogun State, Nigeria. Litter bag technique was used to study the pattern and rate of litter decomposition and nutrient release of Leucaena leucocephala . Fifty grams of oven-dried leaf litter of the species was weighed into 0.2 mm mesh litter bag, 35 cm × 25 cm in size, these bags were closed at all ends. Eighteen litter bags were used for the studies. The litter bags were numbered and placed on the field (above ground) on 26th April 2005. Three bags were retrieved randomly from the field at 20-day intervals for 120 days. The nutrient concentration in L. leucocephala followed the trend N > P > Mg > Ca > K > Na for leaf litter and seed components. Nutrient concentration in twigs and pods ranked N > Mg > P > Ca > K > Na. Among all the litter components, leaf litter contributed more nutrients, especially nitrogen, than other litter components. High potassium concentration during the dry season was due to lack of rainfall to leach out the element. Lower magnesium content in leaf litter was due to chlorophyll decay. High N-flux reflected the quantity and quality of nitrogen in the soil. Mass loss was significantly correlated with calcium (P West African Journal of Applied Ecology Vol. 13 2008: pp. 96-103
19 citations
TL;DR: In this article, the effect of integrated use of lime, inorganic, and organic manures on soil health and sweet potato performance was studied in a field experiment in Al Alfisols.
Abstract: Field experiments were conducted in Alfisols to study the effect of integrated use of lime, inorganic, and organic manures on soil health and sweet potato performance. Integrated use of nitrogen, phosphorus, and potassium and farmyard manure recorded a significantly higher tuber yield (18.7 Mg ha−1) followed by lime + farmyard manure + neem cake + green manure (17.7 Mg ha−1). Incorporation of organics and 100% nitrogen, phosphorus, and potassium showed a yield response of 23%, 2%, and 10% in respect of farmyard manure, neem cake, and green manure over nitrogen, phosphorus, and potassium. A yield response of 12%, 10%, and 13% was observed due to incorporation of lime along with ½ nitrogen, phosphorus, and potassium and organics (farmyard manure, neem cake, and green manure) over that of unlimed plots. Conjunctive use of organic manures along with balanced fertilizers and lime not only produces higher crop yields but also enhanced the efficiency of added nutrients and sustains the soil fertility.
18 citations
TL;DR: In this paper, the authors discuss and describe the oxygen consumption during aerobic mineralization of organic products (cells and excretion products) from five unialgal cultures: Cryptomonas sp., Microcystis aeruginosa, Anabaena spiroides, Thalassiosira sp. and Aulacoseira granulata.
Abstract: This study aimed to discuss and describe the oxygen consumption during aerobic mineralization of organic products (cells and excretion products) from five unialgal cultures: Cryptomonas sp., Microcystis aeruginosa, Anabaena spiroides, Thalassiosira sp. and Aulacoseira granulata. These species were isolated from Barra Bonita reservoir (22o 29 S and 48o 34 W) and cultivated in the laboratory. From each culture, two decomposition chambers were prepared; each chamber contained about 130 mg.L-1 of carbon from water samples of the reservoir. The chambers were aerated and incubated in the dark at 20.0 oC. The concentration of dissolved oxygen, pH values and electrical conductivity of the solutions were determined during a period of 10 days. The results indicated increases in oxygen consumption for all the solutions studied and also for electrical conductivity. The pH values presented a decreasing tendency throughout the experiment. Oxygen consumption varied from 43 (Aulacoseira granulata chamber) to 345 mg O2 g-1 C (Anabaena spiroides chamber). Decrease in pH values was probably due to increase in CO2 concentration from microbial respiration. Increase in electrical conductivity might be due to the liberation of ions during decomposition. The results demonstrate the potentiality of the studied genera in influencing oxygen availability followed by a die-off event. It also indicates the possibility of changing of the electrical conductivity and pH values in the water column due the aerobic algae mineralization.
14 citations
TL;DR: In this paper, the short-term effect of legume litter addition on N supply and the longterm effect on soil organic matter (SOM) formation and soil C/N decrease was evaluated in a 2-year mesocosm experiment.
Abstract: Several long-term studies on tropical soils have shown that legume residue incorporation increases soil nitrogen (N) sequestration more than that of carbon (C), resulting in a fall in the C/N ratio. This study was designed to assess the short-term effect of legume litter addition on N supply and the long-term effect on soil organic matter (SOM) formation and soil C/N decrease. The long-term effect was evaluated in a 2-year mesocosm experiment with high and frequent organic inputs from two types of legume litter with different C/N ratios, using stable isotope techniques. The short-term effect of litter was analysed using four different litters in 3-month laboratory incubations. A model of litter decomposition was used to describe C and N kinetics in the laboratory experiment and to verify whether the long-term effect of litter may be predicted from short-term incubations. The results of the mesocosm experiment confirmed that legume inputs increased soil organic N (mean +21%) more than organic C (mean +15%) (P = 0.05). Although no differences between litters were observed for C dynamics, N sequestration (14% and 28%) and the final soil C/N (12.0 and 10.8) varied with litter C/N (34.4 and 16.1, respectively). The laboratory experiment and model outputs confirmed these findings and indicated that the higher N sequestration was due to a change in the parameters describing humification of C and N coming from litter. This change depended on litter quality and was greater for litters with low C/N—C humification 0.66 g C g–1 C and N humification 0.76 g N g–1 N for litter C/N 16.1. Carbon and N sequestration were greater in the laboratory experiment, due to a higher mineralisation of the new SOM derived from litter in the mesocosm experiment—32% and 15% for the mesocosm and the laboratory experiments, respectively. Our results indicated that the decrease in soil C/N and the rapid mineralisation of new SOM should be considered in models of litter decomposition to respond correctly to the long- and the short-term effects of legume litter inputs in tropical soils.
14 citations
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TL;DR: Two general analytical approaches to the examination of decomposition data are reviewed and single and double exponential models best describe the loss of mass over time with an element of biological realism.
Abstract: The study of plant litter decomposition in terrestrial ecosystems commonly employs litter bags to compare the loss of mass among species, among sites, and under various experimental manipulations, or to investigate the process itself. Analysis of the resulting data is quite variable among investigators, and at times inappropriate. Two general analytical approaches to the examination of decomposition data are reviewed. Analysis of variance is useful if the intent is to compare treatment means, but does not directly test hypotheses regarding decomposition rates. If the intent is to determine rate constants, than fitting mathematical models to data is the more appropriate analysis. Single and double exponential models best describe the loss of mass over time with an element of biological realism. See full-text article at JSTOR
937 citations
Book•
01 Nov 1996
TL;DR: Pathways and processes in decomposition foraging, feeding and feedback manipulation of plant litter quality synchrony and soil organic matter - theory into practice?
Abstract: Pathways and processes in decomposition foraging, feeding and feedback manipulation of plant litter quality synchrony and soil organic matter - theory into practice? building soil organic matter modelling - providing the framework.
933 citations
786 citations
"Leaf litter decomposition of Piper ..." refers methods in this paper
...Lignin was determined by the procedure of Van Soest and Wine (1968), and polyphenol by that of Dalzell and Kerven (1998), using purifiedLeucaena pallidacondensed tannin as standard....
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TL;DR: In this article, the chemical composition and N release patterns of legumes being used in tropical agroecosystems were determined in a laboratory experiment and three patterns of net N mineralization emerged during the 8-weeks.
Abstract: Leguminous plant materials used as mulches, green manures and cover crops are generally assumed to provide a readily-available source of N to crops. However, little is known about the chemical composition and N release patterns of the variety of legumes being used in tropical agroecosystems. N release patterns from the leaflets of 10 troplcal legumes and rice straw were determined in a laboratory experiment. Ground leaf material was allowed to decompose in an acid soil (pH 4.5) for 8 weeks and the soil was analyzed periodically for extractable NH4+-N and NO3∼, -N. N release in the soil plus plant material were compared to that of the soil without plant material added and related to the N, lignin and polyphenolic concentrations of the leaflets. Three patterns of net N mineralization emerged during the 8-weeks. One pattern exhibited by the control soil, rice straw and leaves of two of the leguminous plants was a low, positive net mineralization. Another pattern showed much higher rates of mineralization than the control soil and the third pattern showed initial net immobilization followed by low but positive net mineralization rates. The amount of N mineralized during the 8 weeks as compared to the control soil ranged from +46 to −20% of the N added in plant material. Net mineralization was not correlated to % N or % lignin in the leaf material but was found to be negatively correlated to the polyphenolic concentration, r = −0.63, or the polyphenolic-to-N ratio, r = −0.75. Mineralization in excess of the control soil was found only for materials with a polyphenolic-to-N ratio
724 citations
TL;DR: In this article, the decomposition and nutrient release patterns of three woody agroforestry plant species (Acioa barteri, Gliricidia sepium and Leucaena leucocephala), maize (Zea mays) stover and rice (Oryza sativa) straw, were investigated under field conditions in the humid tropics, using litterbags of three mesh sizes (0.5, 2 and 7 mm) which allowed differential access of soil fauna.
Abstract: Decomposition and nutrient release patterns of prunings of three woody agroforestry plant species (Acioa barteri, Gliricidia sepium and Leucaena leucocephala), maize (Zea mays) stover and rice (Oryza sativa) straw, were investigated under field conditions in the humid tropics, using litterbags of three mesh sizes (0.5, 2 and 7 mm) which allowed differential access of soil fauna. The decomposition rate constants ranged from 0.01 to 0.26 week−1, decreasing in the following order; Gliricidia prunings >Leucaena prunings > rice straw > maize stover >Acioa prunings. Negative correlations were observed between decomposition rate constants and C:N ratio (P < 0.004), percent lignin (P < 0.014) and polyphenol content (P < 0.053) of plant residues. A positive correlation was observed between decomposition rate constant and mesh-size of litterbag (P < 0.057). These results indicate that both the chemical composition of plant residues and nature of the decomposer played an important role in plant residue decomposition.
Nutrient release differed with quality of plant residues and litterbag mesh-size. Total N, P, Ca and Mg contents of plant residues decreased with time for Gliricidia and Leucaena prunings, maize stover, and rice straw, and increased with time for Acioa prunings. There was some indication of N immobilization in maize stover and rice straw; P immobilization in Leucaena prunings and rice straw; and Ca immobilization in maize stover, rice straw and Gliricidia and Leucaena prunings. Acioa prunings immobilized N, P, Ca and Mg. All plant residues released K rapidly. Nutrient release increased with increasing mesh-size of litterbags, suggesting that soil faunal activities enhanced nutrient mobilization.
577 citations
"Leaf litter decomposition of Piper ..." refers background in this paper
...The rapid initial loss of K, particularly from the piper leaf litter, is commonly found in litter bag studies (Budelman, 1988; Palm and Sanchez, 1990; Tian et al., 1992a)....
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...…number of studies have been conducted under laboratory conditions (Handayanto et al., 1997; Lupwayi and Haque, 1998; Palm and Sanchez, 1991; Tian et al., 1992b) or under field conditions with no crop after the fallow (Budelman, 1988; Handayanto et al., 1994; Mwiinga et al., 1994; Oglesby…...
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