| Popis: |
Nitrogen, phosphorus and potassium are three major nutrients, whose availability often become limiting factor to plant growth and crop yield. We have published in our previous reports that a new fertilization method with deep placement of slow release N fertilizers, such as coated urea and lime nitrogen (calcium cyanamide) supplied at 20cm depth from soil surface promoted soybean growth and seed yield. In the present experiment, the effects of deep placement below plants of 100kgN ha-1 of N fertilizers, coated urea (CU) and lime nitrogen (LN) in addition to 100kgP2O5 ha-1 of fused phosphorus (P) and 100kgK2O ha-1 of potassium silicate (K) fertilizers, on growth and seed yield of soybean (Glycine max [L] Merr.) plants were examined by comparing with those from control plots in rotated paddy field of Nagaoka. The fertilizers were applied for both the nodulated soybean (cv. Enrei) and the non-nodulated isogenic line (En1282). Different fertilizer combinations were used which includes CU, CU+P, CU+K, CU+P+K, LN, LN+P, LN+K and LN+P+K. The deep placement of the fertilizers, especially LN+P+K, markedly increased the growth of Enrei plants compared to other treatments. The seed yield and visual quality of harvested seeds also showed that LN+P+K enhanced the yield as well as quality of seeds compared to the other treatments. Thus, it is suggested that N fertilization management, like deep placement of slow release N fertilizers in addition to P and K fertilizer, is important for maximum yield and enhancement of seed quality of soybean. As regard to wrinkle seeds, percentage of side wrinkle was higher in CU+K treatment compared with other treatment. The percentage of turtle wrinkle was positively correlated with pealed seeds (R2=0.707), broken coat (R2=0.399) and side wrinkle (R2=0.294), and negatively correlated with the percentage of good seed (R2=0.587).窒素(N)、リン(P)、カリウム(K)は、肥料三大要素であり、しばしば、その供給量が植物生育と作物収量の制限因子になる。これまで、地表下20cmの位置に緩効性窒素肥料(被覆尿素と石灰窒素)を深層施肥する新しい施肥法が、ダイズの生育及び子実収量を増加させることを報告してきた。本研究では、長岡の水田転換畑(新潟県農業総合研究所)において、100kgN ha-1の被覆尿素(CU)または石灰窒素(LN)の深層施肥に加え、熔リン(100kgP2O5 ha-1)または、ケイ酸カリウム(100kgK2O ha-1)を深層施肥することによるダイズの生育と子実収量に対する影響を調べた。根粒着生ダイズ品種エンレイとその非着生変異株En1282を畦に交互に栽培した。処理区は、CU、CU+P、CU+K、CU+P+K、LN、LN+P、LN+K、LN+P+Kと対照区を設けた。エンレイではLN+P+K区で生育がもっともよく、最大の子実収量が得られた。また、子実の外観的な品質についてもLN+P+K区で高品質であった。これらの結果から、緩効性窒素肥料の深層施肥に加えて、PとKの深層施肥を行うことにより、最大収量が得られる可能性が示唆された。しわ粒については、CU+K区でちりめんしわの比率が高かった。亀甲しわの割合は、皮切(R2=0.707)、剥皮(R2=0.399)およびちりめんしわ(R2=0.294)と正の相関がみられたが、整粒(R2=0.587)とは、負の相関が認められた。 |
