@misc{oai:niigata-u.repo.nii.ac.jp:00004771,
 author = {Tewari, Kaushal},
 month = {Mar},
 note = {Average soybean seed yield in Japan is less than 2t ha-1, although the seed yield is sometimes much higher up to 6t ha-1 in a well managed field under good climatic conditions. Therefore, the present study was carried out in view to obtain better seed yield by employing the deep placement of different feritilizers such as coated urea, lime nitrogen and urea as well as by using different inoculation methods. For this purpose, ten days old seedling with Bradyrhizobium japonicum inoculated paper pot (IPP), with non-inoculated paper pot (NIPP) and those grown in vermiculite bed without paper pot (DT) were transplanted to sandy dune field of Niigata, rotated paddy field of Nagaoka and first cropping reclaimed field of Yamakita. In additon to a basal dressing application of 16 kgN ha-1 in a surface layer (Control), deep placement of 100 kgN ha-1 of urea (Urea), 100days type coated urea (CU-100) and lime nitrogen (CaCN2) treatments were applied at the depth of 20cm. From the results obtained it was observed that among the same N fertilizer treatments, the seed yield with IPP and DT tended to exceed those with NIPP in each respective fields; Nagaoka, Niigata and Yamakita. Among IPP method, significant higher seed yield was obtained with the deep placement of CaCN2 and CU-100 compared to Urea and Control treatments in all the experimental fields. The effect was more pronounced in the first cropping reclaimed field of Yamakita, in which CaCN2 gave 5 times higher the seed dry wight per plant than that of Control. Among the three fields, the best yield was obtained in the Nagaoka field. Being rotated paddy field, Nagaoka field was fertile and with the addition of inoculum and feritizers as CU-100 and CaCN2, seed yield of about 6 t ha-1, which is considered good seed yield, was obtained. Despite the Ymakita field being infertile with no rhizobial population, deep placement of CU-100 or CaCN2 in combination with inoculation enabled increase of yield by almost four times as much as that of Control without inoculation. The %Ndfa (N derived from atmospheric N2) estimated by the simple relative ureide method as well as 15N dilution method was also higher in the plants with CU-100 and CaCN2 compared to Urea and Control treatments, suggesting that the deep placement of these slow release fertilizers promoted the nitrogen fixation activity. Also Ndff (N derived from fertilizer) as well as N recovery rate was found to be highest with CaCN2 followed by CU-100, which suggested that these fertilizers were efficiently utilized by plant without depression of N2 fixation., In the next experiment, the effect of placement (broadcasting and deep placement) of urea and coated urea fertilizers were analyzed for yield and quality of soybean seeds and it was found that the seed yield was higher in the deep placement treatment of coated urea (7.3 t ha-1) than in the broadcasting treatment of coated urea (6.09 t ha-1), although slow release fertilizer CU-100 was used in both treatments, signifying the importance of deep placement broadcasting of fertilizer Again in the next experiment, we aimed to see the accurate amount and depth for the deep placement of slow release fertilizer for maximum promotion of soybean growth. So we performed the field experiment with lime nitrogen at various depths as 10cm, 15cm and 20cm and at different rates as 50kg, 100kg and 200kg per hectare in the field. The plant growth, Ndfa as well as seed yield was found to be highest with lime nitrogen at depth 20cm and with amount 100kgN ha-1, which suggested these treatments as most beneficial for promoting soybean seed yield without depression of N2 fixation. IN brief, the findings can be summarized as follow: 1. Inoculated paper pot seedling as well as deep placement of slow release fertilizers (coated urea and lime nitrogen) promoted the seed yield in comparison to conventional fertilization (Control) in all our experiments. 2. Slow release fertilizers, coated urea and lime nitrogen gave the highest seed yield in all experimental fields. Therefore, lime nitrogen, which is cheaper than Coated urea, has a good future scope for promoting the soybean yield due to economic viability. 3. The results obtained from 15N dilution method and relative method suggested that deep placement of slow release N fertilizers efficiently supply N until maturity without depressing the nitrogen fixation activity (%Ndfa). 4.The importance of deep placement over broadcasting of fertilizers was observed in our experiment. 5. The visual grain quality of seeds was notably affected by treatments, in terms of diseased seeds, although there was slight reduction in side and turtle wrinkle with lome nitrogen treatment. However, in terms of good quality seeds, there was notable increase by slow fertilizers. 6. The importance of N fertilization management for maximum soybean production is further strenghened by our results showing 20cm depth and 100kgN ha-1 as the most beneficial treatments for soybean growth., ダイズ子実収量は、土壌気象条件が好適で良く管理された圃場では、6 t ha-1に達する異もあるが、日本のダイズ子実収量は、2t ha-1を下回っている。本研究では、被覆尿素、石灰窒素、尿素などの窒素肥料の深層施肥技術および、根粒菌の接種方法の改良により、子実収量を増加することを目的とした。根粒菌摂取については、バーミキュライトを充填したペーパーポットでダイズ苗を栽培し、播種と同時にダイズ根粒菌(Bradyｒhizobium japonicum)を接種する根粒菌接種ペーパーポット栽培(Inoculated Paper Pot: IPP)を行った。対照として、根粒菌接種ペーパーポット栽培区(Non-Inoculated Paper Pot: NIPP)と、ペーパーポットを用いずに、バーミキュライト苗床で育苗した直接移植区(Direct Transplantation: DT)の2区を設けた。播種10日目の初生葉展開時の苗を、新潟大学の砂丘地圃場、長岡の農業総合研究所の水田転換畑、長岡市桂町山北地区の大規模新規造成圃場に移植した。移植前に、耕耘と同時に表土約10cmに出タイプの被覆尿素(CU-100)、石灰窒素(CaCN2)を地表下20cmに深層施肥する区を設けた。また、深層施肥を行わない対照区を設けた。どの圃場においても、根粒菌接種区では、根粒菌接種ペーパーポット区がもっとも高い収量を示し、直接移植区がそれに続き、根粒菌非接種ペーパーポット区がもっとも低収量であった。根粒菌接種ペーパーポット栽培では、石灰窒素または被覆尿素の深層施肥区、深層施肥を行わなかった対照区よりも高収量が得られた。特に表土に土着根粒菌が検出されない山北地区の客土新規造成圃場では、根粒菌接種と石灰窒素の深層施肥効果が大きく根粒菌非接種対照区の5倍の子実収量が得られた。三圃場試験のなかでは、比較的肥沃な水田転換畑の長岡の収量がもっとも高く、根粒菌接種と、被覆尿素または石灰窒素を組み合わせた区では、約6t ha-1の収量が得られた。山北圃場は、肥沃度の低い山土残土をもちいた造成した1年目の圃場であり、ダイズ根粒菌も表土に棲息していないため、対照区の生育収量が著しく劣り、根粒菌ペーパーポット接種と、被覆尿素や石灰窒素の深層施肥が、5倍もの増収をしめした。導管液の窒素成分を分析して算出する単純相対ウレイド法と15N標識肥料を用いる15N希釈法を用いて、窒素固定由来の窒素量を推定した。尿素深層施肥区と対照区に比べて、被覆尿層深層区、石灰窒素深層区では、窒素固定由来窒素量がむしろ高かった。通常、窒素施肥は、窒素固定を阻害すりが、緩効性窒素肥料の深層施肥は窒素固定活性を促進することが確認された。同時に、窒素肥料利用率も、石灰窒素深層施肥が最も高く、被覆尿素がそれに次いだ。, 尿素と被覆尿素を肥料に用い、全層施肥と深層施肥してえダイズを栽培し、子実収量と品質を調査した。結果は、被覆尿素の深層施肥区で最大収量(7.3t ha-1)が得られ、被覆尿素の全層施肥(6.09t ha-1)を上回ったことから、深層施肥の効果が確認された。これまでの実験でもっとも効果的であった石灰窒素の施肥位置(深さ 10cm, 15cmまたは20cm)と施肥量(50kg, 100kg and 200kg ha-1)を代えて詳細に調べた。植物の生育、収量、窒素固定由来窒素量ともに20cmに100kg ha-1を施肥する区が最高値を示した。浅井施肥や、200kg施肥では、窒素固定の阻害が見られ、収量もあまり高まらなかった。まとめ　1.土壌タイプの異なる三ケ所の圃場において、根粒菌接種ペーパーポット移植と緩効性窒素肥料(被覆尿素または石灰窒素)の深層施肥の組み合わせにより、一貫して栽培に比べて子実増収効果が認められた。2.どの圃場試験でも、石灰窒素深層施肥区が被覆尿素と同等またはより高い収量を示した。従って、実用面からは、被覆尿素より安価な石灰窒素が、経済的であると考えられる。3.15N稀釈法および相対ウレイド法による解析の結果、緩効性窒素肥料の深層施肥は、子実成熟期まで効率的に肥料窒素を供給すると共に、株当たりの窒素固定活性を阻害しないことが示された。4.増収効果には深層施肥が必須であることを確認し田。5.外観品質を調査した所、亀甲しわ粒とちりめんしわ粒の発生割合が、石灰窒素の深層施肥で低下し、整粒割合が増加した。6.石灰窒素の施肥位置、施肥量を変えて調べた結果、20cmに100kgN ha-1を施肥する区が最適であった。, 新大院博（農）甲第67号, 新大院博（農）甲第67号},
 title = {STUDIES ON NEW FERTILIZATION AND INOCULATION TECHNIQUES FOR PROMOTION OF GROWTH, SEED YIELD AND QUALITY OF SOYBEAN(Glycine max (L.)Merr.)PLANTS},
 year = {2006}
}