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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 46 (1996), S. 189-193 
    ISSN: 1573-0867
    Schlagwort(e): available P ; green manure ; P source ; P uptake ; residual effect ; rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To evaluate residual recoveries of fertilizer phosphorus (P) two field experiments were conducted in Quezon Province, Philippines during 1991 dry season, under irrigated condition. Average grain yield increase was 0.50–0.9 t/ha due to residual effects of inorganic fertilizer P, regardless of source. Residual effects of fertilizer P with Sesbania rostrata or alone increased grain yield by 0.3–1.0 t/ha over control. Significantly higher yields were obtained with S. rostrata fertilized with Morocco phospate Rock (MPR) and S. rostrata + MPR applied on rice than the control. Results revealed that there is a promising effect of residual P from the applied P sources in increasing rice grain yield. Total P uptake increased due to residual P from fertilizer P applied. Results suggest that increased P uptake increased dry matter and grain yield.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 46 (1996), S. 195-203 
    ISSN: 1573-0867
    Schlagwort(e): available phosphorus ; green manure ; phosphorus source ; phosphorus uptake ; relative effectiveness ; rice
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract To evaluate alternative fertilizer phosphorus (P) sources in lowland rice, two field experiments were conducted under irrigated conditions in Quezon Province, Philippines during 1990–1991 crop year. In another field experiment fertilizer P recycling through a green manure crop applied in the succeeding rice, was studied. Addition of fertilizer P increased grain yield by 1.5–2.0 t/ha (46%) in 1990 wet season (WS) and by 1.6–2.1 t/ha (56%) in 1991 dry season (DS). However, fertilizer P source and application level did not effect grain yield significantly. Results indicated that the less water-soluble and less expensive partially acidulated phosphate rock (PAPR), phosphate rock (PR) and less reactive PR were as effective as the more soluble but more expensive triple superphosphate (TSP). The relative effectiveness (RE) of local guano was significantly lower than that of other sources of fertilizer P. Fertilizer P applied to a pre-rice Sesbania rostrata green manure increased rice grain yield by 1.5–1.9 t/ha during 1991 DS. Further, S. rostrata fertilized with Morocco phosphate rock (MPR) gave significantly higher rice grain yield than did rice fertilized with MPR applied alone. In the P source experiments Olsen method and Pi correlated better with growth attributes than Bray 2 P. Phoshours uptake did not differ significantly among P sources and levels. Results suggest that P uptake was improved with green manuring. Correlation analyses revealed a close correlation between P uptake and dry matter yield and P uptake and grain yield.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Nutrient cycling in agroecosystems 26 (1990), S. 157-167 
    ISSN: 1573-0867
    Schlagwort(e): Ammonia volatilization ; green manure ; partially acidulated phosphate rock ; integrated nutrient management
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The use of N fertilizer in Asia has increased from 24 to 39% of the world's total consumption between 1973 and 1987/88. Approximately 60% of the N fertilizer consumed in Asia is used on rice (Oryza sativa L.). However, the N applied to rice, primarily as urea, is not effectively utilized by the crop. Ammonia volatilization is recognized as a major mechanism of N loss, causing ineffective N utilization. Basal incorporation of urea without standing water; deep placement of urea; and modification of urea with algicides, urea inhibitors or coatings are strategies to reduce ammonia loss. Loss of N by nitrification-denitrification may be a serious problem particularly when soil is dried between rice crops, then flooded for the subsequent rice crop. The use of organic N sources, such as green manure and organic manures, as partial substitutes of inorganic N fertilizer is receiving renewed research interest. The use of P fertilizers for rice is most necessary on Oxisols and Ultisols with high P-fixing capacity. Phosphate rock and partially acidulated phosphate rock are alternatives to soluble P sources used on these soils. Response to K is normally highest on light-textured soils. The limited available information suggests that in lowland rice-upland crop rotations, K fertilizers should be applied to the non-rice crop. Zinc deficiency can be overcome through (a) use of varieties more tolerant to zinc deficiency, (b) application of zinc sulfate, and (c) dipping seedling roots in a zinc oxide suspension. Increasing use of S-free fertilizers, intensive cropping, and use of high yielding rice varieties have led to S deficiency in many rice growing countries. Sulfur deficiency can be corrected by applying S-containing materials even with elemental S. Residual effects have also been reported even at a low rate of 20 kg S/ha. Thus, S does not need to be applied every season. To address the unresolved integrated nutrient management issues, both strategic and applied research are required on interacting soil-plant-water-nutrient-climate processes. Long-term sustainability is one of the parameters that must be considered in evaluating the desirability of alternative rice technologies.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Plant and soil 126 (1990), S. 227-235 
    ISSN: 1573-5036
    Schlagwort(e): Oryza sativa ; rice ; root length density ; soil impedance ; tillage ; water stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The influence of various tillage methods on two wetland rice soils in the Philippines is reported. The soils differed principally in clay content, 38% for the clay loam (clayey, mixed isohyperthermic Entic Hapludoll) while 56% for the clay (clayey, mixed noncalcareous, isohyperthermic Andaqueptic Haplaquoll). This had a marked effect on their response to tillage and varying water regime. The clay soil, under field conditions, showed little change in pore size distribution or soil water behaviour with different tillage methods. Crop (Rice, Oryza sativa L., var. IR20) yields were unaffected by tillage. In contrast, tillage effects were very marked in the clay loam soil, which consisted of a greenhouse and a field trial. In the greenhouse, which experienced severe dry periods, wet tillage not only increased the moisture retentivity but also the soil impedance at soil matric potential (ψ)〈−0.01 MPa. Seasonal average ψ was 〈−1 MPa. Root length density decreased by 39% with dry tillage and by 56% with wet tillage compared with zero tillage. Grain yield however, did not vary with soil treatment. In the field, which experienced moderate dry spells, ψ varied between −0.13 and −0.48 MPa. Root length density was significantly reduced at soil impedance 〉0.75 MPa. Wet tillage increased soil moisture storage which minimized the soil impedance during the dry cycle more effectively than did dry tillage. The crop performed best under wet tillage and least under zero tillage. Wet tillage in this soil was more effective under moderate than under severe water stress conditions.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Plant foods for human nutrition 40 (1990), S. 123-130 
    ISSN: 1573-9104
    Schlagwort(e): rice ; grain quality ; inorganic and organic N fertilizers ; protein and lysine content ; season effect ; IR64
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The effects of nitrogen fertilizer treatment and source (prilled urea, urea supergranule, fresh azolla, rice straw or sesbania or rice straw compost and their combinations) on grain quality were studied in the 1987 crops of variety IR64 at IRRI. Although fertilizer application improved grain yield, it improved protein content only in the case of urea supergranule, azolla and rice straw. Lysine contents of brown rice protein were similar in samples with no N fertilizer and those with the highest protein content in both seasons. Fertilizer treatment regardless of source tended to decrease weight and increase translucency of brown rice in both seasons. Effects on other grain properties were not consistent in both seasons. Season affected more grain properties than fertilizer treatment did, particularly translucency which was higher in the dry season than in the wet season.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1573-5036
    Schlagwort(e): green manure ; nitrogen fixation ; phosphorus ; potassium ; rice ; Sesbania rostrata ; stem nodules
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract The stem-nodulating tropical legume Sesbania rostrata is a promising green manure species for low input rice-farming systems in lowland areas. However, its success as biofertilizer depends on its biomass production and N2 fixation. Nutrient imbalances and soils low in available nutrients can considerably affect biofertilizer production. Use of mineral N, P, and K fertilizers in growing S. rostrata as biofertilizer for lowland rice was therefore evaluated in pot experiments, and in the fields in Central Luzon, Philippines. Two soils low in Olsen P (3–7.3 mg kg−1) and exchangeable K (0.05–0.08 meq 100g-1) were used. Increasing amounts of N (0, 10, 20, 30, and 40 mg kg-1), P (0, 50, and 100 mg kg-1), and K (0, 100, 200, and 300 mg kg-1) were applied to S. rostrata grown in the greenhouse, whereas small amounts of N, P, and K fertilizers (30, 15, and 33 kg ha-1, respectively) were applied in the field. Mineral N application depressed nodulation and N2 fixation in roots. It however, stimulated nodulation and N2 fixation in stems. Applying 30 kg N ha-1 as urea increased total N accumulation by S. rostrata and yield of the subsequent rice crop (IR64). Applied P and K both stimulated growth, nodulation, and N2 fixation of S. rostrata. Nitrogen accumulation in P- and K-fertilized S. rostrata was about 40% higher than that in nonfertilized green manure. Thus integration of mineral N, P, and K fertilizers in a green manure-based rice-farming system can considerably improve biofertilizer production and increase rice grain yield.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1573-5036
    Schlagwort(e): Aeschynomene afraspera ; green manure ; lowland rice ; 15N balance ; Sesbania rostrata
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract In the recent past considerable attention is paid to minimize dependence on purchased inputs such as inorganic nitrogen fertilizer. Green manure in the form of flood-tolerant, stem-nodulatingSesbania rostrata andAeschynomene afraspera is an alternative N source for rice, which may also increase N use efficiency. Therefore research was conducted to determine the fate of N applied to lowland rice (Oryza sativa L.) in the form ofSesbania rostrata andAeschynomene afraspera green manure and urea in two field experiments using15N labeled materials.15N in the soil and rice plant was determined, and15N balances established. Apparent N recoveries were determined by non-tracer method. 15N recoveries averaged 90 and 65% of N applied for green manure and urea treatments, respectively. High partial pressures of NH3 in the floodwater, and high pH probably resulted from urea application and favoured losses of N from the urea treatment. Results show that green manure N can supply a substantial proportion of the N requirements of lowland rice. Nitrogen released fromSesbania rostrata andAeschynomene afraspera green manure was in synchrony with the demand of the rice plant. The effect of combined application of green manure and urea on N losses from urea fertilizer were also investigated. Green manure reduced the N losses from15N labeled urea possibly due to a reduction in pH of the floodwater. Positive added N interactions (ANIs) were observed. At harvest, an average of 45 and 25% of N applied remained in the soil for green manure and urea, respectively.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1573-5036
    Schlagwort(e): leaf elongation rate ; leaf water potential ; maize ; nitrogen ; nutrient uptake ; phosphorus ; potassium ; rice ; soybean ; transpiration rate ; water stress
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A pot experiment was conducted in the greenhouse to determine and compare the responses of rice (Oryza sativa L. var, IR 36), maize (Zea mays L. var. DMR-2), and soybean (Glycine max [L.] Merr. var. Clark 63) to soil water stress. Leaf elongation, dawn leaf water potential, transpiration rate, and nutrient uptake in stressed rice declined earlier than in maize and soybean. Maize and soybean, compared with rice, maintained high dawn leaf water potential for a longer period of water stress before leaf water potential. Nutrient uptake under water stress conditions was influenced more by the capacity of the roots to absorb nutrients than by transpiration. Transport of nutrients to the shoots may occur even at reduced transpiration rate It is concluded that the ability of maize and soybean to grow better than rice under water stress conditions may be due to their ability to maintain turgor as a result of the slow decline in leaf water potential brought about by low, transpiration rate and continued uptake of nutrient, especially K, which must have allowed osmotic adjustment to occur.
    Materialart: Digitale Medien
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