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. 2023 Jan 4:13:1077948.
doi: 10.3389/fpls.2022.1077948. eCollection 2022.

Maize-soybean intercropping at optimal N fertilization increases the N uptake, N yield and N use efficiency of maize crop by regulating the N assimilatory enzymes

Jamal Nasar  1 , Chang Jiang Zhao  1 , Rayyan Khan  1 , Hina Gul  2 , Harun Gitari  3 , Zeqiang Shao  4 , Ghulam Abbas  5 , Imran Haider  5 , Zafar Iqbal  5 , Waqas Ahmed  5 , Raheela Rehman  6 , Qing Ping Liang  7 , Xun Bo Zhou  1 , Juan Yang  1
Affiliations

Maize-soybean intercropping at optimal N fertilization increases the N uptake, N yield and N use efficiency of maize crop by regulating the N assimilatory enzymes

Jamal Nasar et al. Front Plant Sci. .

Abstract

Introduction: Surplus use of chemical nitrogen (N) fertilizers to increase agricultural Q9 production causes severe problems to the agricultural ecosystem and environment. This is contrary to N use efficiency and sustainable agricultural production.

Methods: Hence, this study was designed to investigate the effect of maizesoybean intercropping on N uptake, N yield, N utilization use efficiency, and the associated nitrogen assimilatory enzymes of maize crops under different N fertilization for two consecutive years 2021-2022.

Results: The findings of the study showed that intercropping at the optimal N rate (N1) (250 kg N ha-1) increased significantly maize grain yield by 30 and 34%, residue yield by 30 and 37%, and 100-grain weight by 33 and 39% in the year 2021 and 2022, respectively. As compared with mono-cropping, at this optimal N rate, the respective increase (of maize's crop N yield indices) for 2021 and 2022 were 53 and 64% for grain N yield, and 53 and 68% for residue N yield. Moreover, intercropping at N1 resulted in higher grain N content by 28 and 31%, residue N content by 18 and 22%, and total N uptake by 65 and 75% in 2021 and 2022, respectively. The values for the land equivalent ratio for nitrogen yield (LERN) were greater than 1 in intercropping, indicating better utilization of N under the intercropping over mono-cropping. Similarly, intercropping increased the N assimilatory enzymes of maize crops such as nitrate reductase (NR) activity by 19 and 25%, nitrite reductase (NiR) activity by 20 and 23%, and glutamate synthase activity (GOGAT) by 23 and 27% in 2021 and 2022, respectively. Consequently, such increases resulted in improved nitrogen use efficiency indices such as N use efficiency (NUE), partial factor nitrogen use efficiency (PFNUE), nitrogen uptake efficiency (NUpE), and nitrogen agronomic efficiency (NAE) under intercropping than mono-cropping.

Conclusion: Thus, this suggests that maize-soybean intercropping under optimal N fertilization can improve the nitrogen status and nitrogen use efficiency of maize crops by regulating the nitrogen assimilatory enzymes, thereby enhancing its growth and yield. Therefore, prioritizing intercropping over an intensive mono-cropping system could be a better option for sustainable agricultural production.

Keywords: agricultural sustainability; maize-soybean intercropping; nitrogen assimilatory enzymes; nitrogen use efficiency; nitrogen yield.

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Conflict of interest statement

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

Figures

Figure 1
Figure 1
Schematic diagram of the experiment. N0; 0 kg N ha-1, N1; 250 N kg ha-1, N2; 300 kg N ha-1. * maize crop; + soybean crop.
Figure 2
Figure 2
Weather forecast (temperature and rainfall) report of the experimental site during the experiment period (A); year 2021 and (B); year 2022.
Figure 3
Figure 3
Maize grain N content (A, D), residue N content (B, E); total N uptake (C, F) under different planting patterns (MM, maize mono-cropping and MI, maize intercropping) and N fertilizer application rates (N0; 0 kg N ha-1, N1; 250 kg N ha-1 and N2; 300 kg N ha-1) in 2021 and 2022 crop growing seasons. The column bars with dissimilar lowercase letters are significantly different from each other as per the LSD test (p< 0.05).
Figure 4
Figure 4
Maize nitrogen use efficiency (NUE) (A, C), partial factor nitrogen use efficiency (PFNUE) (B, D) under different planting patterns (MM, maize mono-cropping and MI, maize intercropping) and N fertilizer application rates (N0; 0 kg N ha-1, N1; 250 kg N ha-1 and N2; 300 kg N ha-1) in 2021 and 2022 crop growing seasons. The column bars with dissimilar lowercase letters are significantly different from each other as per the LSD test (p< 0.05).
Figure 5
Figure 5
Maize nitrogen uptake efficiency (NUpE) (A, C), nitrogen agronomic efficiency (NAE) (B, D) under different planting patterns (MM, maize mono-cropping and MI, maize intercropping) and N fertilizer application rates (N0; 0 kg N ha-1, N1; 250 kg N ha-1 and N2; 300 kg N ha-1) in 2021 and 2022 crop growing seasons. The column bars with dissimilar lowercase letters are significantly different from each other as per the LSD test (p< 0.05).
Figure 6
Figure 6
Maize nitrogen assimilatory enzymes: nitrate reductase (NR) (A, D), nitrite reductase (NiR) (B, E) and glutamate synthase (GOGAT) (C, F) activity under different planting patterns (MM, maize mono-cropping and MI, maize intercropping) and N fertilizer application rates (N0; 0 kg N ha-1, N1; 250 kg N ha-1 and N2; 300 kg N ha-1) in 2021 and 2022 crop growing seasons. The column bars with dissimilar lowercase letters are significantly different from each other as per the LSD test (p< 0.05).
Figure 7
Figure 7
Regression analysis of the total N uptake with nitrogen assimilatory enzymes (i.e., NR (A, D), NiR (B, E), and GOGAT activity (C, F)) of maize crop in 2021 and 2022.
Figure 8
Figure 8
Regression analysis of nitrogen use efficiency (NUE) for maize crop with nitrogen assimilatory enzymes (i.e., NR (A, D), NiR (B, E), and GOGAT activity (C, F)) in 2021 and 2022.
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References

    1. Ahmad S., Wang G. Y., Muhammad I., Chi Y. X., Zeeshan M., Nasar J., et al. . (2022). Interactive effects of melatonin and nitrogen improve drought tolerance of maize seedlings by regulating growth and physiochemical attributes. Antioxidants 11, 359. doi: 10.3390/antiox11020359 - DOI - PMC - PubMed
    1. Anbessa Y., Juskiw P. (2012). Nitrogen fertilizer rate and cultivar interaction effects on nitrogen recovery, utilization efficiency, and agronomic performance of spring barley. ISRN Agron. 2012, 531647. doi: 10.5402/2012/531647 - DOI
    1. Ben M. R. (2016). Effect of nitrogen source and concentration on growth and activity of nitrogen assimilation enzymes in roots of a moroccan sorghum ecotype. Plant 4, 71–77. doi: 10.11648/j.plant.20160406.14 - DOI
    1. Chen P., Du Q., Liu X., Zhou L., Hussain S., Lei L., et al. . (2017). Effects of reduced nitrogen inputs on crop yield and nitrogen use efficiency in a long-term maize-soybean relay strip intercropping system. PloS One 12, e0184503. doi: 10.1371/journal.pone.0184503 - DOI - PMC - PubMed
    1. Dang K., Gong X., Zhao G., Wang H., Ivanistau A., Feng B. (2020). Intercropping alters the soil microbial diversity and community to facilitate nitrogen assimilation: A potential mechanism for increasing proso millet grain yield. Front. Microbiol. 11. doi: 10.3389/fmicb.2020.601054 - DOI - PMC - PubMed