Root Contact between Maize and Alfalfa Facilitates Nitrogen Transfer and Uptake Using Techniques of Foliar 15N-Labeling

Zeqiang Shao,Jinjing Zhang,Xinyu Wang,Hailing Yu,Qiang Gao,Yin Wang,Jamal Nasar,Hualiang Zhang,Yingzhi Gao

doi:10.3390/agronomy10030360

Abstract

Belowground nitrogen (N) transfer from legumes to non-legumes provides an important N source for crop yield and N utilization. However, whether root contact facilitates N transfer and the extent to which N transfer contributes to crop productivity and N utilization have not been clarified. In our study, two-year rain shelter experiments were conducted to quantify the effect of root contact on N transfer in a maize/alfalfa intercropping system. N transfer occurred mainly one direction from alfalfa to maize during the growth period. Following the N0 treatment, the amount of N transfer from alfalfa to maize was 204.56 mg pot−1 with no root barrier and 165.13 mg pot−1 with a nylon net barrier, accounting for 4.72% and 4.48% of the total N accumulated in maize, respectively. Following the N1 treatment, the amount of N transfer from alfalfa to maize was 197.70 mg pot−1 with no root barrier and 139.04 mg pot−1 with a nylon net barrier, accounting for 3.64% and 2.36% of the total N accumulated in the maize, respectively. Furthermore, the amount of N transfer without no root barrier was 1.24–1.42 times higher than that with a nylon net barrier regardless of the level of N addition. Our results highlight the importance and the relevance of root contact for the enhancement of N transfer in a maize/alfalfa intercropping system.

Highlights

IntroductionThe north-eastern area of China is characterized as a semi-arid and temperate climatic region
The north-eastern area of China is characterized as a semi-arid and temperate climatic region.The farming and pastoral area in this region represents an important grain commodity and animal husbandry base and covers 3.83 × 105 km2
The total N uptake of both the maize and the alfalfa was significantly affected by N level, root separation method, and planting year, as well as their interactions (Table 2)

Summary

Introduction

The north-eastern area of China is characterized as a semi-arid and temperate climatic region. The farming and pastoral area in this region represents an important grain commodity and animal husbandry base and covers 3.83 × 105 km. The farming and pastoral area in this region represents an important grain commodity and animal husbandry base and covers 3.83 × 105 km2 This area plays a key role in the development of Chinese agriculture and animal husbandry. A long period of intensive agricultural production has led to serious problems, including soil degradation, chemical pollution, and the loss of biodiversity in the agricultural soil [1,2]. Low vegetation cover and wind erosion have deteriorated the ecosystem in this region. It is crucial to adjust the planting structure and reduce the amount of chemical fertilizer used in this region

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Discussion

Conclusion