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Volume 42 (2007)
- Issue 4 Pages 189-
- Issue 3 Pages 173-
- Issue 2 Pages 69-
- Issue 1 Pages 4-
Volume 42, Issue 1
Displaying 1-6 of 6 articles from this issue
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Tatsuo SATO, Kyoko MATSUURA, Rika TAKAYANAGI, Yutaka YONEYAMA2007 Volume 42 Issue 1 Pages 4-10
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSThe adaptability of a formula for estimating the amount of nitrogen absorbed (absorbed nitrogen (g/m2/14 days)=increased leaves (no./m2/14 days)×0.0441+2.189) in autumn cucumber, cultivated using drip tubes, was tested as a fertilization index. The amount of nitrogen applied was reduced to 31.9g/m2, which constituted a saving of 24% over conventional fertilization methods, without reducing the yield.
The adaptability of this formula was tested, using five training methods, with different leaf appearance patterns. Although the yields differed, the amount of nitrogen fertilizer differed only slightly, in the range from 27.6 to 29.2g/m2, which amounts to 63 to 51% of the 46.2g/m2 used in conventional fertilization
In conclusion, this formula for estimating the amount of nitrogen absorbed can be applied to save fertilizer in the cultivation of autumn cucumber, grown using drip tubes.View full abstractDownload PDF (763K) -
Yinghui MU, Masakazu KOMATSUZAKI, Shoji MORIIZUMI, Song GU, Masaaki AR ...2007 Volume 42 Issue 1 Pages 11-20
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSWe investigated the changes in soil physical properties, such as soil cone index (SCI), soil bulk density (SBD) and soil water content (SWC) in upland rice (Oryza sativa L.) production following rye (Secale cereale L.), hairy vetch (Vicia villosa Roth) and fallow (no cover crop) under different tillage systems (plowing, rotary and minimum tillage) with 4 replications. Field experiments were conducted at the Experimental Farm of Ibaraki University on a Humic Allophane soil (Haplic Andsolos) from Aug. 2002 to Dec. 2004. The main results obtained from these 2 years of field research were as follows:
1) The tillage system significantly affected soil water content, with minimum tillage having the greatest effect. Cover crop types also showed significant effects on soil water content, especially for minimum tillage with rye treatment.
2) The tillage system also had a significant effect on soil bulk density, with minimum tillage having the greatest compare with other tillage treatment. Cover crop types, however, showed little effect on soil bulk density.
3) The tillage system also affected soil hard-ness significantly during the dry paddy rice growing season. SCI was the highest for no. -till treatment, and the lowest for plow tillage treatment. With all the tillage systems, cover crop types also showed significant effects on reducing SCI. SCI showed the lowest value for rye and the highest for fallow.
4) These results suggest that cover cropping has some potential for reducing soil hardness without tillage treatment; consequently, cover crops may be effective tools to optimize soil hard-ness in minimum tillage systems.View full abstractDownload PDF (1672K) -
Ryuichi SAGO, Hisashi KOBAYASHI2007 Volume 42 Issue 1 Pages 21-28
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSA common definition of organic agriculture is farming without synthetic pesticides or chemical fertilizers. It has been pointed out that it is extremely difficult to apply sufficient nutrients by organic practices alone. The objective of this research is to assess the differences of the following soil fertility components between organic and conventional farming practices: total soil carbon (C), total soil nitrogen (N) and inorganic nitrogen (NH4-N, NO3-N), exchangeable potassium (K), available phosphorus (P), available magnesium (Mg), available calcium (Ca), manganese (Mn), copper (Cu), and zinc (Zn). In 2004, soil was collected from 19 paddy fields on working organic and conventional farms in the Kanto district.
We found no significant differences in the total soil carbon (C), the total soil nitrogen (N), and C/N ratio among the farming systems. Available soil N (NH4-N and NO3-N) declined significantly as total soil N rose with the use of organic practices. Ca and Mg rose with the use of organic practices, but K, P, Cu, Mn and Zn did not exhibit differences in farming systems in any of the analyzed fields. Inorganic N in conventional farming soil and Ca and Mg in organic farming soil reached a level that could be an environmental risk if soils are not managed carefully. In the future, we should control the amount of fertility component by soil analysis data.View full abstractDownload PDF (917K) -
Analysis by the Geographical Information SystemTakeshi SHIKANAI, Takayuki MINAMI, Senlin GUAN, Masami UENO2007 Volume 42 Issue 1 Pages 29-36
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSAlthough sugarcane agricultural production corporations have been established as the leaders of regional farmers to avoid cultivation abandonment, the sugarcane yield of these agricultural production corporations is low and the leased fields managed by these corporations are scattered. Because of the scattered leased fields, the workers of these corporations have to move from field to field for work and thus farm work becomes inefficient. Thus, it is considered that inefficient work results in a rather low yield of sugarcane for these corporations as compared to the average yield in Okinawa. This study aims to ascertain the correlation between the dispersion of farmlands and productivity by investigating the relation between the unit crop yields and some factors of the evaluation of the geographic condition of the dispersion obtained by the GIS. We proposed three factors of the evaluation of the geographical condition; that is, the area of the farmland, distance of the corporation office, and area of the surrounding farmlands. The area of the surrounding farmlands shows a positive correlation with the unit yields, while the distance of the corporation office shows an inverse correlation with the unit yields. The result shows that the dispersion of the accumulated fields could have some impact on the unit sugarcane yield of the agricultural production corporations.View full abstractDownload PDF (1818K) -
Ryuichi SAGO, Chihiro SUGIMORI, Hisashi KOBYASHI2007 Volume 42 Issue 1 Pages 37-45
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSThe Japanese pear grows abundantly in southern and western parts of Ibaraki Prefecture. In particular, the production of ‘Ko-sui’ pear is the highest in Japan.
Yields and growth rates of trees have decreased, and the amount and number of fertilizer applications have increased over the years. We investigated the plan for fertilizer application and the soil fertility of ten pear orchards in southern Ibaraki Prefecture.
The average of ‘Ko-sui’ pear tree was 28 years old, and the average of ‘Ho-sui’ pear tree was 26.5 years old in investigated orchards. The amount of fertilizer applied exceeded the recommendations in Ibaraki. Most farmers consider the soil modification function of organic fertilizer, but they do not consider its nutrient function. As a result, they apply organic fertilizer in addition to chemical fertilizer.
The pear yields were unrelated to the amount of fertilizer applied. Soil fertility also exceeded the standard of soil nutrients for pear orchards. Furthermore, the available phosphoric acid and exchangeable potassium in the soil was related to the amount of phosphoric acid and potassium applied with organic fertilizer, but inorganic nitrogen in soil was not related to the amount of nitrogen applied. This indicates that the available phosphoric acid and the exchangeable potassium were held in the soil, but the inorganic nitrogen runs off with soil water.
In order to protect the environment, nutrient recommendations in Ibaraki must indicate the presumable method of the available nutrient on organic fertilizer. We should regulate the amount of organic fertilizer applied based on the nutrient recommendation.View full abstractDownload PDF (963K) -
Thawansak PHAOSANG, Opal SUWUNNAMEK2007 Volume 42 Issue 1 Pages 46-50
Published: March 15, 2007
Released on J-STAGE: February 09, 2010
JOURNAL FREE ACCESSThough major organic products in Thailand are rice, grains, fruits and vegetables, organic sweet corn has been demanded commercially in the market. This paper introduced the first empirical study on the production and marketing of organic sweet corn “ATS-5” developed by “KU Fresh” of Kasetsart University, in collaboration with the food processing company, Malee Samphran Public Company Limited. The results of trials indicated that downy mildew, corn stem borer, and corn earworm were controlled, harvest period was significantly shorten, harvested corn size was as same as the conventional, and percentage of husk weight was significantly reduced as well. Price per kilogram at the farm gate was 2.50 times higher than that of the conventional. In addition, sensory test by the company showed higher average scores of organic “ATS-5” on 5 sensory characteristics compared with the chemical. Direct transportation from farm to the customer was recommended to keep the sweetness.View full abstractDownload PDF (530K)
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