[en] A two seasons field experiment was conducted to study the carry over effect of previous crop on the succeeding crop yield and plan nutrient (N and P) availability. The experiment consisted of eight treatments were arranged in a randomized block design with six resplications. Cropping sequence was studied that was soybean followed by corn and a continuous corn system. The effect of added P to the previous crops on the succeeding crops yield was also observed. Labelled fertilizer were used in the experiment to measure dinitrogen fixation of two soybean varieties and the amount of available nutrient in the soil by using isotopic dilution technique. The result obtained showed that corn yield was significantly influenced by cropping sequence, but available nutrient was not. Corn grown after soybean produced about 22 percent more grain than those of the continuous corn system. The phosphorus applied to the first season crops increased significantly the succeeding corn yield. The highest amount of accumulation in soybean was 81 kg N/h, around 40 percent of the amount was obtained through fixation. (authors). 19 refs.; 8 tabs

[en] An experiment has been conducted to determine the N2-fixing ability of Azolla pinnata using the 15-N method. Data from this experiment showed that N-dff (N-derived from fertilizer) of Azolla pinnata is lower compared to N-dff pf the standard plant Salvinia sp. for all the harvest done. This is an important issue and is the base for the calculation of the N2-fixing ability of a plant using the 15-N method. Other data from this experiment also showed that the highest N2-fixing ability of Azolla pinnata is between 18-21 days after Azolla has been planted. Based on the data from this experiment, the N2-fixing ability of Azolla pinnata per Ha per days is 1.24 kg N. (authors). 5 refs, 2 figs, 4 tabs

No abstract available

[en] Seven high yielding rice varieties used in the experiment are IR5, IR8, IR20, IR22, Pelita 1/1, Pelita 1/2, and Dewi Ratih. The experiment is carried out in the glass house and using ³²P-labelled superphosphate. Specific activity of the labelled fertilizer used is 0,25 mCi/gr P₂O₅. Results obtained from this work show that Pelita 1/2 and IR5 take up a higher phosphorus nutrient than the other varieties, but IR5 gives the lowest percentage of phosphorus in plant derived from fertilizer. The average of plant phosphorus derived from fertilizer is about 35 to 45%, depending on the varieties. The application of phosphorus fertilizer increases soil phosphorus uptake and soil phosphorus content in plant. The decrease of the increments of soil phosphorus content in plants starts at the application rate of 60 kg P₂O₅/ha and reaches its maximum at the rate of 90 kg P₂O₅/ha. (author)

[en] The principles of isotope technique, covering formulations for determining the nitrogen concentration in roots, isotope dilution technique for determining the nitrogen coming from soil and that from fertilizer in plants, as well as formulations for determining the percentage of the fertilizer applied to soil which can be absorbed by plants, are described. The isotope technique for efficient application of fertilizer, especially nitrogen and phosphor for macro nutrient, and zinc (Z) for micro nutrient has been applied. Research on the behaviour and the fate of fertilizer in soil is still to be carried out by using a more sensitive instrument and complicated sampling techniques. (RUW). 7 refs

[en] The relation of higher rates of nitrogen application on phosphorus absorption and requirement in the pelita 1/1 rice cultivar was studied by pot experiment in the green house. Nitrogen was applied as urea at rates of 0, 45, 90, 135, and 180 kg N/ha. Phosphorus requirement was supplied as P³²-labelled super-phosphate at levels of 0, 30, 60, 90, and 120 kg P₂O₅/ha. The specific activity of the labelled fertilizer used was 0.20mCi/g P₂O₅. Results obtained from this experiment showed that without supply of phosphorus, the application of nitrogen fertilizer up to the very high dose of 400 kg urea/ha did not improve plant growth. Better growth of rice plant was obtained by increasing nitrogen application, when higher rates of phosphorus were also supplied. Higher rates of nitrogen application up to 135 kg N/ha followed by high rates of phosphorus supply of 90-120 kg P₂O₅/ha, increased the utilization of phosphorus fertilizer, but medium supply of 60 kg P₂O₅/ha with nitrogen application higher than 90 kg/ha lowered the percentage of utilization of the phosphorus fertilizer. The application of higher levels of nitrogen increased the amount of phosphorus taken up by the plants, but application higher than 135 kg N/ha lowered the total uptake of phosphorus nutrient, eventhough high level of phosphorus was supplied. The decrease of phosphorus uptake was the result of the decrease of the uptake of fertilizer-phosphorus as well as soil-phosphorus. (author)

[en] A field experiment was carried out during the dry season of 1972 at Muara Experimental Station of the CRIA at Bogor. The objective of the experiment was to further study the optimum time of nitrogen application and its effect on yield components as well as the yield and on the distribution of absorbed fertilizer N in Pelita I/1 rice variety. N 15 labelled urea fertilizer was used in the experiment. TSP at a rate of 60 kg P₂O₅/ha and muriate potash at a rate of 30 kg K₂O/ ha were used as basal dressing. Nitrogen fertilizer applied at a rate of 100 kg N/ha had affected the yield of grain, straw as well as the plant. The highest yield was derived from a two split doses of (25-75) kg N/ha, applied at transplanting and either at primordia or at mid point in time between 21 days after transplanting and primordia respectively. Yield components might also be affected by urea application, however no significant effect was found on the number of grain per panicle. In line with the yield potential, the N total of rough grain was the highest when urea was applied in two split doses of 25 kg N/ha at transplanting and 75 kg N/ha either at mid point or at primordia. The percentage of fertilizer N utilized by Pelita I/1 rice variety was in the range of about 32,058,0%. (author)

[en] Carbaryl is one of the insecticides used in large quantities in Indonesia. It is effective against soybean and peanut plant insects. The residues in the plants are determined by Colorimetry at the residues level up to 5 ppm and by thin layer chromatography at level up to 0,1 ppm. Both methods use coupling reaction between hydrolysis product of Carbaryl and diazo reagent to produce colour. (author)

[en] An experiment for studying the placement of phosphorus fertilizer was carried out in the glass house by using ³²P-labelled superphosphate. The specific activity of the labelled fertilizer used was 0,25 mCi/g P₂O₅. Three placement methods were studied: (1) Hill placement: Fertilizer was burried at a distance of 5cm from the plants at the depth of 5 cm, (2) Surface placement: Fertilizer was spread on the surface, and (3) Soil mixed application: Fertilizer was mixed with the soil at the depth of 5 cm. Superphosphate was applied at the rates of 0, 30, 60, 90, and 120 kg P₂₅/ha. Results obtained from the experiment showed that the dry matter production was significantly affected by the methods of placement of phosphorus fertilizer. Soil mixed placement gave the lowest yield of dry plant material. It differed significantly from the two other methods of placement. However, there was no significant difference between hill and surface placement. The placement of phosphorus fertilizer significantly affected the total uptake of phosphorus nutrient, uptake fertilizer phosphorus, and the percentage of fertilizer utilization. Surface placement gave the highest utilization of fertilizer when supplied at rates higher than 60 kg P₂O₅/ha. At low rate applications, hill placement was the best, but, at rates higher than 60 kg P₂O₅/ha the percentage of fertilizer utilization decreased. Soil mixed application was the least efficient fertilizer utilization. (author)

[en] Five methods of nitrogen fertilizer application were tested on tidal swamp soils at Upang Delta South Sumatera, namely a single dose of 100kg N/ha, two split-dosesof of (50+50)kg N/ha, (25+75)kg N/ha, (75+25)kg (75+25)kg N/ha, and a four-split doses of (25+25+25+25)kg N/ha. IR32 rice variety and ¹⁵N-labelled urea with 1.0 and 4.0% atom excess ¹⁵N were used in the experiment. The rate of efficiency of N utilization by plant was in the range of 26 to 44 percent. The highest efficiency was derived from the four-split doses with yield of grain amounted 4018kg/ha. The lowest efficiency was found with the single dose application of 100kg N/ha with a yield of 3705kg/ha. The highest yield was obtained from the two-split doses (50+50)kg N/ha with a slightly less efficiency (40 percent). No significant differences between the two methods of application were found, neither in the efficiency nor in the yield. (author)