Synergies and trade-offs of crop diversification system for productive, energy budget, economic, and environmental indicators in Northeast China

Abstract

Context

Continuous maize monoculture in Northeast China maintains higher productivity as well as results in excessive environmental costs. Integrating legume or gramineous crops into maize cropping system is an effective way to achieve high productivity while reducing carbon footprint (CF). However, the performance of different crop diversification systems is not clear so far.

Objectives

The present study aimed to comprehensively evaluate the effects of diversified maize, peanut, and wheat cropping systems on 1) crop productivity, energy budget and economic benefits; 2) environmental costs including CF, net ecosystem economic budget (NEEB), and carbon sustainability index (CSI) in Northeast China.

Methods

A four-year field experiment was conducted in Northeast China, including continuous maize (CM), continuous wheat (CW), continuous peanut (CP), maize and wheat intercropping (M||W), maize and peanut intercropping (M||P), maize and wheat rotation (M→W), maize and peanut rotation (M→P). The life cycle assessment (LCA) and Z-score methods were employed to analyze carbon emission related performance for these treatments.

Results

Crop diversification (i.e., rotation and intercropping system) decreased biomass and grain yield but increased maize equivalent yield (MEY) and protein yield (PY). In particular, the M||P treatment showed 20.9 % and 24.6 % higher MEY and PY, respectively, compared to the CM treatment. Total revenue and net income for the M||P treatment were 20.8 % and 23.7 % higher than the CM treatment. However, M||W, M||P, M→W, and M→P treatments had lower energy yield (EY) and energy use efficiency compared to CM. The CSI was significantly higher for M||W (86.3 %), M||P (81.6 %), and M→W (46.4 %) treatments compared to CM. The M||P showed the lowest CF per unit equivalent yield (CF_MEY), per unit energy yield (CF_EY), and per unit economic benefit (CF_E), which were 58.6 %, 47.3 %, and 59.5 % lower than CM, respectively. Additionally, the M||P treatment had the highest NEEB of 15307.6 CNY ha⁻¹, which was 24.4 % higher than CM. Overall, M||P treatments demonstrated more positive effects with the highest comprehensive score of 20.1 due to higher yield, economic return, and lower environmental cost among the treatments.

Conclusions

It is indicated that crop diversification practices, particularly the M||P system, can achieve higher profitability and NEEB while maintaining a lower CF in Northeast China.

Implications

This study underpins that maize and peanut intercropping is a viable alternative to traditional maize monoculture in Northeast China, which offers improved economic returns and environmental sustainability. However, the potential negative impact on energy yield should be considered when implementing such systems.