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Volume 44 (2009)
- Issue 4 Pages 185-
- Issue 3 Pages 127-
- Issue 2 Pages 65-
- Issue 1 Pages 1-
Volume 44, Issue 3
Displaying 1-6 of 6 articles from this issue
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Original Papers
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Naomi ASAGI, Hideto UENO2009 Volume 44 Issue 3 Pages 127-136
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSThe effects of cover crop on rice growth, yield, and nitrogen in soil were investigated and compared with those of chemical fertilizer (CF) and no fertilizer (NF) application in the Shikoku region of Japan. White clover (WC) was incorporated into paddy soil (WCIN) or used as living mulch without tillage (WCLM). A field experiment was conducted in 2004 and 2006. The NH4-N level in the soil of WCIN was higher than that in NF at 1 day after transplanting (DAT). Rice height, number of tillers and leaf chlorophyll content (SPAD value) at 50, 97, and 114 DAT, the number of spikelets and yield per unit area at 114 DAT in WCIN were higher than those in NF. These findings indicate the positive effects of WC incorporation on soil nitrogen, rice yield, and nitrogen uptake. In WCLM, the NH4-N level in soil was lower than that in NF at 1 DAT. The yield per unit area in WCLM was lower than that in CF and WCIN. This may be due to the lower numbers of panicles and spikelets per unit area in WCLM. These suggest that effects of WC living mulch on nitrogen supply to rice, increase of the numbers of panicles and spikelets were lower than those of WC incorporation. In order to increase rice yield in cultivation with a cover crop, it is necessary to increase yield of cover crop and improve methods of fertilization suitable for each application with cover crop (incorporation, living mulch).View full abstractDownload PDF (972K) -
Rumiko KUROKAWA, Hisayoshi HAYASHI, Naoki SAKAI2009 Volume 44 Issue 3 Pages 137-144
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSThe effect of fertilized conditions on environmental loads of methane emissions and water quality in a paddy field and the yield of rice were comprehensively evaluated. The experimental plots were no-fertilizer plot (0), NPK plot (N, P2O5, K2O 7.5g/m2 each), NPKM plot (N, P2O5, K2O 7.5g/m2 each, rice straw manure 1000g/m2) and 2NPK plot (N 15.0g/m2, P2O5, K2O 7.5g/m2 each). Total nitrogen concentration (TN) in the flood water increased at basal application and top dressings but total phosphorus concentration (TP) increased at basal application only. The total methane emissions during the rice growing period and the weight of winnowed rough rice were ordered as follows : 0<NPK<NPKM<2NPK. There was a positive correlation indicating methane emissions increase with higher rice yield. Approximately 80% of the total methane emissions occurred after heading. Total methane emission, TN and TP were calculated per unit yield of winnowed rough rice, expressed as the proportion of the NPK plot, and recorded in a radar chart. This chart was very useful for comprehensively assessing the productivity and environmental loads. Manure input increased methane emissions but decreased TP. Double input of nitrogen increased methane emissions but didn't affect the environmental loads in the water. Therefore, the influences on environmental loads per unit yield widely differed with the kind and amount of fertilizer used.View full abstractDownload PDF (889K) -
Yoshitaka KAWAI, Kazunori ISHIKAWA, Hiroyuki FUJISAWA2009 Volume 44 Issue 3 Pages 145-151
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSThis study was undertaken to investigate the effects of girdling and strapping of lateral branches, combined with application of CPPU (N-(2-chloro-4-pyridyl)-N′-phenylurea) to the fruitlets, on fruit quality of two cultivars of Japanese persimmon (Diospyros kaki L., ‘Fuyu’ and ‘Jiro’). Girdling in May and July and strapping in May, June and July significantly increased fruit size and weight of ‘Fuyu’. Strapping in May, June and July increased fruit sugar content of ‘Fuyu’ and enhanced fruit quality more than girdling in ‘Fuyu’. Girdling in June significantly increased fruit size and weight of ‘Jiro’. Because girdling and strapping in May or June showed the best results in both cultivars, it is suggested that these treatments are suitable for persimmon during the first half of stage I of fruit development. The combination of girdling and CPPU significantly increased fruit size in ‘Fuyu’, and CPPU decreased fruit size in ‘Jiro’. CPPU decreased fruit color and sugar content in both cultivars.View full abstractDownload PDF (603K) -
Tetsuro KATAOKA, Hirofumi KUBOTA, Satoshi YONEKAWA2009 Volume 44 Issue 3 Pages 153-161
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSTwelve experimental sections of 4 rows×3m were established to examine the heterogeneity of a 72-a wheat field. Using 20 sample yield values from each experimental section, the heterogeneity of the field size was examined using the coefficient of variation through experimental section size and zoning size, which was a combination of several experimental sections. In addition, experimental section size and optimal number of samples in zoning were examined by randomly reducing the number of samples and by weighing the sample values. The results indicated that the space distribution of soil nitrate content and soil moisture content as well as the direction of movement of tractors affected the yield in this test agricultural field, indicating that these can be used as environmental factors in the concept of complex adaptive systems. This test agricultural field, sampling efficiency was improved by zoning the field into 4 sections, each of which had approximately the same environmental factors.View full abstractDownload PDF (785K) -
Mohammad Zarif SHARIFI, Shoji MATSUMURA, Tadashi HIRASAWA, Masakazu KO ...2009 Volume 44 Issue 3 Pages 163-172
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSApparent nitrogen mineralization rates and the availability of released nitrogen to komatsuna plants succeeding green manures (GMs) incorporated to soil were investigated using a pot experiment to develop a reasonable crop rotation system that decreases environmental loads by ensuring nutrient cycling. Four GM residues—hairy vetch (HV), sunflower (SF), crotalaria (CR), and upland rice (UR)—were mixed with soil, respectively, to produce 200kg N ha-1. Furthermore, a fertilizer (F) plot with the same N amount of chemical fertilizer applied and a control (C) plot with no amendment were set. Komatsuna plants were grown for 75 days under the treatments in a plastic green house. Plants were sampled five times to determine their dry weights and nitrogen contents. Dry weight yields of komatsuna were highest in F plot, with those of HV and SF plots following, although that of UR plot was less than that of C plot. The N content of komatsuna showed similar results. Absorbed N, as derived from the amendments, was greatest in F plot, followed by HV and SF plots, although the UR plot had less than control. Regarding apparent nitrogen mineralization rates which were calculated by subtraction method, significant differences were found between HV and CR, and HV and UR plots, and between SF and CR, and SF and UR plots, but not between HV and SF. Inorganic nitrogen in soil was higher in HV and SF plots than CR and UR plots. The residues of HV and SF demonstrated preferred characteristics as GMs for a nitrogen supplier to succeeding crops.View full abstractDownload PDF (400K)
Research Paper
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Masakazu KOMATSUZAKI, M. Faiz SYUAIB2009 Volume 44 Issue 3 Pages 173-179
Published: September 20, 2009
Released on J-STAGE: March 20, 2010
JOURNAL FREE ACCESSOrganic farming provides a lot of benefits in Indonesia, because it can improve soil quality, food quality and soil carbon sequestration. This research was designed to evaluate the ability of soil carbon storage by making comparisons between conventional and organic farming systems for rice production in West Java, Indonesia. The results from soil analysis indicated that organic farming had significantly higher soil carbon storage capacity than conventional farming. Organic farming can also cut some costs for farming, but it requires about twice as much labor. The sharecropping system of rice farming in Indonesia is highly exploitative of workers ; therefore, research should be conducted to develop a fairer organic farming system that can enhance both local and global sustainability.View full abstractDownload PDF (308K)
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