Effect of Light Qualities and Storage Periods on the Germination of Pennisetum Polystachion Seeds*)

Seeds of the yellowish inflorescence strain of Pennisetum polystachion, collected from the field in Indonesia, were kept in the dark for 30 days, then germinated in 12-h light and 24-h light under various light qualities, namely, white, black, blue, red and far-red. There was no effect of photo-period to seed germination. Percent of seed germination under white, red, far-red, blue and dark were 49, 43, 22, 11 and 2%, respectively. White and red light did not cause any difference to seed germination. Seeds kept in 12-h light alternating with 12-h dark and 24-h dark for 15 and 30 days were tested for germination. Results showed that light condition during seed storage did not effect seed germination. Long storage period resulted in more seed germination. During seed germination test, effect of light played a great role on increasing seed germination

The Performance of Upland Rice Established on Alang-alang Dominated Area After Various Techniques of Alang-alang Control

Pot experiment to investigate the performance of upland rice in a previously alang-alang dominated area was conducted under greenhouse condition at BIOTROP, Bogor, Indonesia from November 1986 to May 1989. The treatments were factorially combined, replicated 5 times and randomized completely. The first factor was alang-alang control consisting of 5 different techniques, i.e. (1) glyphosate applied at 2.2 kg a.e./ha; (2) imazapyr applied at 1.5 kg a.e./ha; (3) dalapon applied twice at 7.4 + 7.4 kg a.i./ha; (4) slashing followed by soil cultivation; (5) slashing of alang-alang only; while the second factor was nitrogen fertilizer at 4 different levels, i.e. (1) 0 kg N/ha, (2) 60 kg N/ha, (3) 120 kg N/ha given twice, 60 kg N/ha at planting time and 60 kg N/ha at 38 dap, (4) 180 kg N/ha given twice, 90 kg N/ha at planting and 90 kg N/ha at 38 dap. Plant height (cm), tiller number/pot, productive tiller (%), panicle length (cm), spikelets/panicle, empty spikelet (%), weight 1000 grains (g) and grain yield (ton/ha) were observed. Upland rice grown with zero tillage technique using glyphosate (2.2 kg a.i./ha) or dalapon (14.8 kg a.i./ha) performed as good as or even better than manual cultivation. Imazapyr at 1.5 kg a.e./ha was phytotoxic to rice planted 1 month after spraying. The application of N fertilizer lower than 60 kg N/ha was not sufficient, but more than 60 kg N/ha was too high; it stimulated the production of too many tillers, with high percentage of unproductive tillers and empty grains

The Performance of Soybean (C.v. Americana) Established by Zero Tillage Technique in Imperata Field Controlled by Herbicides

A field experiment was conducted to investigate the performance of soybean (c.v. Americana) when established with zero tillage technique on Imperata dominated area. Four different techniques of alang-alang control i.e. imazapyr (20 kg ai/ha), glyphosate (25 kg ai/ha), glufosinate (3.0 kg ai/ha) and manual cultivation were arranged factorially with time of plantings i.e. 1,2 and 3 months after treatments. The alang-alang damages varied with herbicides and times, imazapyr (20 kg ai/ha) showed slow appearance of damage at 3 months after application it was only 69%, while that of glufosinate was already down to 48% due to regrowth. No phytotoxicity was recorded, but the yield was low

EFFECT OF LIGHT QUALITIES AND STORAGE PERIODS ON THE GERMINATION OF PENNISETUM POLYSTACHION SEEDS*)

Seeds  of  the  yellowish  inflorescence  strain  of  Pennisetum polystachion,  collected  from  the  field  in Indonesia, were kept  in the dark  for 30 days,  then germinated  in 12-h  light and 24-h  light under various  light qualities, namely, white, black, blue, red and far-red. There was no effect of photo-period to seed germination. Percent of seed germination under white, red, far-red, blue and dark were 49, 43, 22, 11 and 2%, respectively. White and red light did not cause any difference to seed germination. Seeds kept in 12-h light alternating with 12-h dark and 24-h dark for 15 and 30 days were tested for germination. Results  showed  that  light  condition during  seed  storage did not  effect  seed germination.  Long storage period resulted in more seed germination. During seed germination test, effect of light played a great role on increasing seed germination

The Adsorption of Imazapyr by Three Soil Types in Indonesia

The adsorption of imazapyr in three Indonesian soil types was investigated with labelled 14C-imazapyr using Freundlich adsorption isotherm. The availability of adsorbed imazapyr to plants as affected by washing and liming was assayed using root elongation of rice seedlings. Red-Yellow Podsolic soil adsorbed imazapyr more than Andosol and sandy soil of Laladon. The adsorption was greater at lower pH. Washing seemed to reduce the concentration of imazapyr as shown by the increasing length of rice roots. On the other hand liming facilitated higher concentrations of imazapyr in the solution as shown by the reduction of rice root length. The practical implication is discussed

THE PERFORMANCE OF UPLAND RICE ESTABLISHED ON ALANG-ALANG DOMINATED AREA AFTER VARIOUS TECHNIQUES OF ALANG-ALANG CONTROL

Pot experiment to investigate the performance of upland rice in a previously alang-alang dominated area was conducted under greenhouse condition at BIOTROP, Bogor, Indonesia from November 1986 to May 1989. The treatments were  factorially  combined,  replicated  5  times  and  randomized  completely.  The  first  factor  was alang-alang  control  consisting  of  5 different  techniques,  i.e.  (1)  glyphosate  applied  at  2.2  kg  a.e./ha;  (2) imazapyr applied at 1.5 kg a.e./ha; (3) dalapon applied twice at 7.4 + 7.4 kg a.i./ha; (4) slashing followed by soil cultivation; (5) slashing of alang-alang only; while the second factor was nitrogen fertilizer at 4 different levels, i.e. (1) 0 kg N/ha, (2) 60 kg N/ha, (3) 120 kg N/ha given twice, 60 kg N/ha at planting time and 60 kg N/ha at 38 dap, (4) 180 kg N/ha given twice, 90 kg N/ha at planting and 90 kg N/ha at 38 dap. Plant height (cm), tiller number/pot, productive tiller (%), panicle length (cm), spikelets/panicle, empty spikelet (%), weight 1000 grains (g) and grain yield (ton/ha) were observed. Upland rice grown with zero tillage technique using glyphosate (2.2 kg a.i./ha) or dalapon (14.8 kg a.i./ha) performed as good as or even better than manual cultivation. Imazapyr at 1.5 kg a.e./ha was phytotoxic to rice planted 1 month after spraying. The application of N fertilizer lower than 60 kg N/ha was not sufficient, but more than 60 kg N/ha was too high; it stimulated the production of too many tillers, with high percentage of unproductive tillers and empty grains

A STUDY ON WEED CONTROL IN SOYBEAN

Two field experiments on weed control in soybeans were carried out at BIOTROP, Bogor, Indonesia from February to June, 1989. The critical period for weed control was found to be between 20 - 40 days after planting of soybean (c. v. Wilis) grown at a planting distance of 40 x 10 cm. It did not coincide with the fastest growth  in  terms of  trifoliate  leaf number. Further studies were suggested  to understand the physiological growth of soybean related to weed control. Pendimethalin at 660- 1320 g a.e./ha applied one day after sowing did not cause any phytotoxic effect to soybean and had good weed control performance

THE ADSORPTION OF IMAZAPYR BY THREE SOIL TYPES IN INDONESIA

The  adsorption  of  imazapyr  in  three  Indonesian  soil  types  was  investigated  with  labelled 14C-imazapyr  using  Freundlich  adsorption  isotherm.  The  availability  of  adsorbed  imazapyr  to  plants  as affected by washing and liming was assayed using root elongation of rice seedlings. Red-Yellow  Podsolic  soil  adsorbed  imazapyr  more  than  Andosol  and  sandy  soil  of  Laladon.  The adsorption was greater at lower pH. Washing seemed to reduce the concentration of imazapyr as shown by the increasing length of rice roots. On the other hand liming facilitated higher concentrations of imazapyr in the solution as shown by the reduction of rice root length. The practical implication is discussed

Persebaran Agens Hayati Neochetina Spp. (Coleoptera: Curculionidae) Di Jawa Barat Dan DKI Jakarta

The establishment of Neochetina spp. as biocontrol agent of waterhyacinth are related to the weevil's ability to disperse and to increase their population sizes. The objective of this research was to study the distribution and abundance of Neochetina spp. at several areas in West Java and DKI Jakarta. The field research was done in several freshwater ecosystem infested by waterhyacinth, including Cibinong and Lido lakes in Bogor, irigation canal in Karawang, Muara Angke Sanctuary in North Jakarta, and Citarum Hulu river in Purwakarta, during April to August 2004. Coordinate and elevation of the research sites where N. eichhorniae and N. bruchi found were reported, while their abundances were observed by direct hand-collection technique. The results of the research showed that N. eichhorniae was widely distributed and established in most sampling sites, except in Karawang, whereas N. bruchi was not found in any sampling sites. Our observations also indicated that N. eichhorniae was distributed passively so that the weevil couldn't colonize isolated habitats or locations

Kandungan, Resorpsi N dan P Serta Specifi C Leaf Area Daun Kakao (Theobroma Cacao L.) pada Cekaman Kekeringan

Plant nutrient absorptions depend on their environment and plants' stage of development. Beside from soil, nutrient absorption also proceed through resorption in leaves. The resorption efficiency varies based on types of habitat. Drought stress also influences the efficiency of nutrient resorption, growth rate, and plant development. The purpose of this research was to study the change of nitrogen (N) and phosphorus (P) content and leaf resorption value of N and P, and specific leaf area of 6-years old cacao grown under drought stress. Research was carried out in a cacao plantation with 7-years old Gliricidia sepium Jacq. as shading trees. The results showed that drought stress with Troughfall Displacement Experiment (TDE) system did not affect the content and resorption level of N and P of cacao leaves. However, N resorption of cacao leaves tended to increase while P resorption decreased. Cacao plants experienced drought stress have the ability to resorp leaf N for 46.64-50.63%, leaf P for 47.98-58.40%, whereas, the control plants had the leaf N resorption of 45.05-52.97%, and leaf P resorption of 36.64-44.10%. Drought stress for 13 months on 6-years old cacao did not affect specifi c leaf area