Effect of the Nitrification Inhibitor 3,4-Dimethylpyrazole Phosphate on the Deep Placement of Nitrogen Fertilizers for Soybean Cultivation

Soshi Hatano,Sayuri Tanabata,Yoichi Fujita,Kuni Sueyoshi,Takashi Sato,Norikuni Ohtake,Takuji Ohyama,Akihiro Saito,Yoshifumi Nagumo,Kyoko Higuchi,Yoshihiko Takahashi

doi:10.1155/2019/9724214

Abstract

The deep placement of urea fertilizer (DMU) containing 1% (W/W) of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on soybean growth and seed yield was as effective as those of the coated urea (CU) and lime nitrogen (LN) in a field research. The average seed yields were high in LN (464 g·m−2) and DMU (461 g·m−2) and relatively low in CU (405 g·m−2), U (396 g·m−2), and Cont (373 g·m−2) treatments. The accumulations of dry matter and nitrogen in soybean shoots were higher in the plants with deep placement of CU, LN, and DMU than U and Cont. The daily nitrogen fixation activity and daily nitrogen absorption rate were calculated based on the relative ureide method. Both nitrogen fixation activity and nitrogen absorption rate were higher in DMU, CU, and LN compared with control treatment, suggesting that the deep placement of DMU did not repress nitrogen fixation. Soil incubation test was performed using the same field soil with DMU, U, LN, and urea with DMPP 1%, 2%, and 4%. DMU inhibits nitrification similar to the pattern of LN until 8 weeks. The increasing DMPP concentration did not markedly increase the nitrification inhibition. From these results, it was concluded that urea fertilizer with 1% DMPP is efficient for deep placement of N fertilizer for soybean cultivation due to its lower price compared with CU and LN.

Highlights

Soshi Hatano,1 Yoichi Fujita,2 Yoshifumi Nagumo,2 Norikuni Ohtake,1 Kuni Sueyoshi,1 Yoshihiko Takahashi,1 Takashi Sato,3 Sayuri Tanabata,4 Kyoko Higuchi,5 Akihiro Saito,5 and Takuji Ohyama 1,5
E deep placement of urea fertilizer (DMU) containing 1% (W/W) of the nitrification inhibitor 3,4-dimethylpyrazole phosphate (DMPP) on soybean growth and seed yield was as effective as those of the coated urea (CU) and lime nitrogen (LN) in a field research. e average seed yields were high in LN (464 g·m−2) and DMU (461 g·m−2) and relatively low in CU (405 g·m−2), U (396 g·m−2), and Cont (373 g·m−2) treatments. e accumulations of dry matter and nitrogen in soybean shoots were higher in the plants with deep placement of CU, LN, and DMU than U and Cont. e daily nitrogen fixation activity and daily nitrogen absorption rate were calculated based on the relative ureide method
Both nitrogen fixation activity and nitrogen absorption rate were higher in DMU, CU, and LN compared with control treatment, suggesting that the deep placement of DMU did not repress nitrogen fixation

Summary

Introduction

E increasing DMPP concentration did not markedly increase the nitrification inhibition From these results, it was concluded that urea fertilizer with 1% DMPP is efficient for deep placement of N fertilizer for soybean cultivation due to its lower price compared with CU and LN. To obtain a high yield of soybean, good nodulation and high and long-lasting nitrogen fixation activity are very important because the availability of soil N is limited in many regions. It is well known that a high concentration of mineral N represses nodule formation and nitrogen fixation activity, especially, nitrate, the most abundant inorganic nitrogen in upland fields, severely inhibits nodulation and nitrogen fixation activity of soybean plants [5,6,7]

Methods

Results

Discussion

Conclusion