The Potential of Legume Tree Prunings as Organic Matters for Improving Phosphorus Availability in an Acid Soil

A study that was aimed to elucidate roles of Gliricidia sepium and Tithonia diversifolia prunings and their extracted humic and fulvic acids on improving phosphorus availability and decreasing aluminum concentration in an Ultisol was conducted in a glasshouse. Thirteen treatments consisting of two prunings, six rates of pruning application (5, 7.5, 10, 20, 40 and 80 t/ha) and one control (no added prunings) were arranged in a randomized block design with four replicates. Each mixture of prunings and soil was placed in a pot containing 8 kg of soil and maize of Srikandi cultivar was grown on it for 45 days. At harvest, soil pH, P content and aluminium concentration were measured. Results of the glasshouse experiment showed that application of Gliricidia and Tithonia prunings significantly increased soil pH, reduced Alo concentration, increased Alp content, increased P availability, and increased P taken up by maize grown for 45 days. The optimum rate of both Gliricidia and Tithonia pruning should be 40 t/ha. However, at the same rate, optimum production gained by Tithonia would be higher than that of Gliricidia

Effects of Application of Groundnut Biomass Compost on Uptake of Phosphorus by Maize Grown on an Ultisol of South Sulawesi

Low crop production is acid dryland area of South Sulawesi is due to low availability of P in the soils. One of alternatives that can be performed to overcome the problems of acid soils having high level of exchangeable Al, is through the addition of organic material. In the upland areas in South Sulawesi, crop rice, maize and groundnut crop residues are readily available, but the crop residues are generally only used as animal feed or even burned. This study was aimed to elucidate the effects of groundnut compost on P uptake by maize in Ultisol of Moncongloe, South Sulawesi. Eight kilograms of air dried soil was mixed with compost according to the following treatments; 0, 10, 15, 20, 25, 30, 35 and 40 t compost/ha. All pots received 200 kg/ha KCl and 300 kg Urea/ha as basal fertilizers. Two maize seeds were planted in each pot and thinned to one plant per pot after one week. At harvest maize shoot dry weight and maize root dry weight, length of maize cop, cob weight, cob diameter, weight grains per cob, P uptake by maize, P content in maize grain, soil available P were measured. Results of the study showed that groundnut compost has the ability to improve the availability of P in the soil and increase P uptake by maize grown on an Ultisol of South Sulawesi. Application of 25 t groundnut compost/ha was the optimal rate that can be used to increase P availability in an Ultisol of South Sulawesi

The Potential of Phosphate Solubilizing Bacteria Isolated From Sugarcane Wastes for Solubilizing Phosphate

Most of P in agricultural soils is in unavailable forms for plant growth. Phosphate solubilizing bacteria can increase soil P availability. This study was aimed to isolate phosphate solubilizing bacteria from sugarcane waste compost and to test ability of the isolated bacterial to dissolve phosphate. The bacteria were isolated from three types of sugarcane waste, i.e. filter cake compost, bagasse compost, and a mixture of filter cake + bagasse + trash biomass compost. The potential colony was further purified by the Pikovskaya method on selective media. Eight isolates of phosphate solubilizing bacteria were obtained from all wasted studied. Amongst them, T-K5 and T-K6 isolates were superior in dissolving P from Ca3(PO4)2 in the media studied. The two isolates were able to solubilize P with solubilizing index of 1.75 and 1.67 for T-K5 and T-K6, respectively. Quantitatively, T-K6 isolate showed the highest P solubilization (0.74 mg / L), followed by T-K5 isolate (0.56 mg / L), while the lowest P solubilization (0.41 mg / L) was observed for T-K4 isolate. The increase of soluble P was not always followed by the decrease in pH

Humic and Fulvic Acids of Gliricidia and Tithonia Composts for Aluminium Detoxification in an Ultisol

A laboratory experiment was conducted to elucidate roles of Gliricidia sepium and Tithonia diversifolia composts and their extracted humic and fulvic acids on aluminum concentration in an Ultisol. Those composts and humic and fulvic acids extracted from them mixed with soil were arranged in a complete randomized design with three replicates, and incubated for 90 days. Al concentration and pH of the soil were measured at 0, 3, 10, 20, 30, 45, 60, 75 and 90 days after incubation. Results of the study showed that the highest decrease in exchangeable Al concentration (90.5%) was observed for Tithonia fulvic acid treatment during 90 days, followed by Tithonia compost (88.4%), Gliricidia fulvic acid (82.3%), Gliricida compost (82.2%), Tithonia humic acid (75.66%), and Gliricidia humic acid (73.46%) treatments, whereas control only decreased exchangeable Al concentration by 0.9%. The rate of change in exchangeable Al concentration was fast for the first 45 days, but it then slowed down for the second 45 days (45-90 days). This was particularly observed with organic acid treatments, whereas compost treatment still showed a subsequent decrease. Patterns of Al chelate and pH were very similar to that of exchangeable Al. It was thus concluded that roles of humic and fulvic acids in reducing exchangeable Al was only short term, whereas compost played roles in the long term

Decomposition and nutrient release of leguminous plants in coffee agroforestry systems.

Leguminous plants used as green manure are an important nutrient source for coffee plantations, especially for soils with low nutrient levels. Field experiments were conducted in the Zona da Mata of Minas Gerais State, Brazil to evaluate the decomposition and nutrient release rates of four leguminous species used as green manures (Arachis pintoi, Calopogonium mucunoides, Stizolobium aterrimum and Stylosanthes guianensis) in a coffee agroforestry system under two different climate conditions. The initial N contents in plant residues varied from 25.7 to 37.0 g kg-1 and P from 2.4 to 3.0 g kg-1. The lignin/N, lignin/polyphenol and(lignin+polyphenol)/N ratios were low in all residues studied. Mass loss rates were highest in the first 15 days, when 25 % of the residues were decomposed. From 15 to 30 days, the decomposition rate decreased on both farms. On the farm in Pedra Dourada (PD), the decomposition constant k increased in the order C. mucunoides < S. aterrimum < S. guianensis < A. pintoi. On the farm in Araponga (ARA), there was no difference in the decomposition rate among leguminous plants. The N release rates varied from 0.0036 to 0.0096 d-1. Around 32 % of the total N content in the plant material was released in the first 15 days. In ARA, the N concentration in the S. aterrimum residues was always significantly higher than in the other residues. At the end of 360 days, the N released was 78 % in ARA and 89 % in PD of the initial content. Phosphorus was the most rapidly released nutrient (k values from 0.0165 to 0.0394 d-1). Residue decomposition and nutrient release did not correlate with initial residue chemistry and biochemistry, but differences in climatic conditions between the two study sites modified the decomposition rate constants

MANFAAT BIOMASA TUMBUHAN LOKAL UNTUK MENINGKATKAN KETERSEDIAAN NITROGEN TANAH DI LAHAN KERING MALANG SELATAN

A research that was aimed to study the possible use of Mucuna pruriens, Psophocarpus tetragonolubus, Phaseolus lunatus, Dolichos lablab biomass as sources of local organic matters to improve soil fertility, and growth of maize on a Typic Tropaquent of South Malang. Six treatments, i.e. Mucuna pruriens, Psophocarpus tetragonolubus, Phaseolus lunatus, Dolichos lablab, Urea, and Control (no added legume biomass and fertilizers), were arranged in a Randomized Block Design with three replicates. Results of the study showed that the highest increase of soil N was due to addition of Phaeseolus, followed by Dolichos, Mucuna, and Psophocarpus. Application of Dolichos, Phaseolus, Psophocarpus and Mucuna could substitute 66%, 36%, 30% and 28% of N supplied by urea, respectively. The percentage of N urea recovered by maize was only 23,60%, while Dolichos and Phaseolus treatments resulted in 29,60% and 24,80% N recover

Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.

The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by the altitude and position of the area relative to the sun

PELEPASAN NITROGEN DARI PANGKASAN POHON LEGUM PADA SISTEM BUDIDAYA PAGAR

Decomposition and nitrogen mineralization of prunings from five species of legume hedgerow trees (Calliandra calothyrsus, Peltophorum dasyrrachis, Leucaena leucocephala, Gliricidia sepium, and Flemingia congesta) in relation to the pruning quality and methods of pruning application were studied in a laboratory and in the field. N mineralization of the prunings was tested upon application to the soil in a laboratory under controlled leaching and non-leeching conditions over the period of 14 weeks. The absolute decomposition rates of the prunings was measured using litterbags placed randomly on the soil surface or incorporated in the soil in the field over the period of 8 weeks. The results showed that the contribution of decomposing pruning materials to the soil was not only associated with their quality and with the leaching conditions, but also with the method of application of the prunings in the field. The decomposition and N release rate constants of the prunings declined in the order of Gliricidia> Leucaena > Flemingia > Calliandra > Peltophorum for all experiments carried out. The effect of quality of N release from legume prunings was modified by leaching conditions. Where there was no leaching, the protein-binding capacity of polyphenols in the prunings can play an important role in controlling the rate of N release. Under leaching conditions, the combined (lignin + polyphenol)/N ratio became an important quality factor in affecting the N release. The amounts of N released from the prunings placed on the soil surface were much smaller than those released from the incorporated pruning