Roles of Nitrogen Deep Placement on Grain Yield, Nitrogen Use Efficiency, and Antioxidant Enzyme Activities in Mechanical Pot-Seedling Transplanting Rice

Lin Li,Zhaowen Mo,Zaiman Wang,Shuli Wang,Umair Ashraf,Hua Tian,Zheng Zhang,Xiangru Tang,Meiyang Duan,Shenggang Pan

doi:10.3390/agronomy10091252

Abstract

Mechanical pot-seedling transplanting (PST) is an efficient transplanting method and deep nitrogen fertilization has the advantage of increasing nitrogen use efficiency. However, little information is available about the effect of PST when coupled with mechanized deep nitrogen (N) fertilization on grain yield, nitrogen use efficiency, and antioxidant enzyme activities in rice. A two-year field experiment was performed to evaluate the effect of PST coupled with deep N fertilization in both early seasons (March–July) of 2018 and 2019. All seedlings were transplanted by PST and three treatments were designed as follows. There was a mechanized deep placement of all fertilizer (MAF), broadcasting fertilizer (BF), no fertilizer (N0). MAF significantly increased grain yield by 52.7%. Total nitrogen accumulation (TNA) was enhanced by 27.7%, nitrogen partial factor productivity (NPFP) was enhanced by 51.4%. nitrogen recovery efficiency (NRE) by 123.7%, and nitrogen agronomic efficiency (NAE) was enhanced by 104.3%, compared with BF treatment. Moreover, MAF significantly improved peroxidase (POD), catalase (CAT), and notably reduced the malonic dialdehyde (MDA) content for both rice cultivars, compared to BF. Hence, the result shows that mechanical pot-seedling transplanting coupled with nitrogen deep placement is an efficient method with the increase of grain yield and nitrogen use efficiency in rice cultivation in South China.

Highlights

Rice (Oryza sativa L.) is one of the world’s major crops and it provides food for over three billion people [1,2]
The highest grain yield for mechanized deep placement of all fertilizer (MAF) treatment was found for the broadcasting fertilizer (BF) and N0 treatments in both years
Our results showed that Total Above-Ground Biomass (TAB) at the maturity stage (MS) stage remarkably correlated with Leaf Area Index (LAI) at the heading stage (HS) stage, and both of them were positively related to grain yield

Summary

Introduction

Rice (Oryza sativa L.) is one of the world’s major crops and it provides food for over three billion people [1,2]. China is the main country of rice production, with rice planting area and yield in the forefront of the world [2,3]. Increasing rice production is essential for population growth in China and the world [4,5]. Transplanted rice is the most traditional planting method. The traditional fertilization method is manually surface broadcast [6]. This method is not suitable for the stable improvement in Chinese agricultural systems because of some serious problems such

Objectives

Methods

Results

Discussion

Conclusion