Preface

Nitrogen is an essential major element in all organisms and a component of proteins, amino acids, nucleic acids, and many indispensable metabolites. Nitrogen is the most important nutrient element for agriculture because the availability of nitrogen from the soil is generally not enough to support the yield and quality of crops.

In addition, the nitrogen stored in soil decreases with repeated cultivation because the harvested parts of the crop are taken out from the fields. To maintain soil fertility, crop rotation and application of organic matters have been practiced. After chemical nitrogen fertilizers have been produced by the industrial nitrogen fixation, farmers can use these fertilizers for agriculture. As a result, the productivity of crops increased several folds during the 20th century to feed the increasing world population. However, excess or inappropriate use of nitrogen fertilizers causes environmental problems such as nitrate leaching and contamination in groundwater and rivers and nitrous oxide (N2O) emissions.

This book discusses nitrogen in agriculture, including its usage in crops, the dynamics of soil nitrogen in agricultural fields, and the ecology of and use of nitrogen fertilizers in agriculture to improve nitrogen-use efficiency and reduce ecological problems for sustainable agriculture.

There are four sections in this book: Section 1: "Ecology and Environmental Aspects of Nitrogen in Agriculture," Section 2: "Nitrogen Fertilizers and Nitrogen Management in Agriculture," Section 3: "N Utilization and Metabolism in Crops," and Section 4: "Plant-Microbe Interactions."

The first section includes Chapter 1, "Mitigation of Climate Change by Nitrogen Managements in Agriculture", by Kazuyuki Inubushi and Miwa Yashima; and Chapter 2, "Influence of Heavy Metals on the Nitrogen Metabolism in Plants", by Vitor Nascimento, Glauco Nogueira, Gabriel Monteiro, Waldemar Júnior, Joze Melissa Nunes de Freitas, and Cândido Neto.

The second section includes Chapter 3, "Nitrogen Management in Conservation Agriculture", by Anthony Imoudu Oyeogbe; Chapter 4, "Agronomic Response of Camelina to Nitrogen and Seeding Rate on the Northern Great Plains", by Thandiwe Nleya, Dwarika Bhattarai, and Phillip Alberti; and Chapter 5, "Cover Crop Residue Management for Effective Use of Mineralized Nitrogen in Greenhouse Tomato Production", by Rafael A. Muchanga and Hajime Araki.

The third section includes Chapter 6, "Nitrogen Fixation in Soybean Nodules Affects Seed Protein and Oil Contents: The Suggested Mechanism from the Coordinated Changes of Seed Chemical Compositions and Phosphoenolpyruvate Carboxylase Activity Caused by Different Types of Nitrogen Fertilizer", by Toshio Sugimoto, Naoki Yamamoto, and Takehiro Masumura; Chapter 7, "Modeling of Nitrogen Use Efficiency in Lettuce Culture (*Lactuca sativa*): Isotopic Nitrogen (15 N) and AquaCrop" by Mawhoub Amirouche, Dalila Smadhi, and Lakhdar Zella; Chapter 8, "Nitrogen in Flowers", by Soraya Ruamrungsri, Kanokwan Panjama, Takuji

Ohyama, and Chaiartid Inkham; and Chapter 9, "Nitrogen Storage in Crops: Case Study of Zeins in Maize", by Marija Duvnjak, Kristina Kljak, and Darko Grbeša.

The final section includes Chapter 10, "Conservation of Edible Ectomycorrhizal Mushrooms: Understanding of the ECM Fungi Mediated Carbon and Nitrogen Movement within Forest Ecosystems", by Lu-Min Vaario and Norihisa Matsushita; Chapter 11, "Promotion of Nitrogen Assimilation by Plant Growth-Promoting Rhizobacteria", by Gabriel Monteiro, Glauco Nogueira, Cândido Neto, Vitor Nascimento, and Joze Freitas; and Chapter 12 "Mycorrhizal Fungi and Sustainable Agriculture", by Soibam Helena Devi, Ingudam Bhupenchandra, Soibam Sinyorita, S.K. Chongtham, and E. Lamalakshmi Devi.

We are grateful to all authors who contributed excellent chapters to this book. In addition, we thank external reviewers for their helpful feedback. Finally, we greatly appreciate Author Service Manger Mr. Josip Knapić at IntechOpen for all his kind support.

#### **Takuji Ohyama**

Faculty of Applied Biosciences, Department of Agricultural Chemistry, Tokyo University of Agriculture, Tokyo, Japan

#### **Kazuyuki Inubushi**

**1**

Section 1

Ecology and Environmental

Aspects of Nitrogen in

Agriculture

Graduate School of Horticulture, Faculty of Horticulture, Chiba University, Chiba, Japan

## Section 1
