Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China

Cropping systems are structured to maximize crop yields and increase sustainability in agricultural production. A field study was conducted to investigate different long-term cropping systems on soil organic matter and microbial communities. The cropping systems studied were: (i) a 14-year continuou...

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Main Authors: Yining Niu, Zhuzhu Luo, Liqun Cai, Jeffrey A. Coulter, Yaoquan Zhang, Marisol Berti
Format: Article
Language:English
Published: MDPI AG 2020-07-01
Series:Agronomy
Subjects:
Online Access:https://www.mdpi.com/2073-4395/10/7/1054
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author Yining Niu
Zhuzhu Luo
Liqun Cai
Jeffrey A. Coulter
Yaoquan Zhang
Marisol Berti
author_facet Yining Niu
Zhuzhu Luo
Liqun Cai
Jeffrey A. Coulter
Yaoquan Zhang
Marisol Berti
author_sort Yining Niu
collection DOAJ
description Cropping systems are structured to maximize crop yields and increase sustainability in agricultural production. A field study was conducted to investigate different long-term cropping systems on soil organic matter and microbial communities. The cropping systems studied were: (i) a 14-year continuous alfalfa (<i>Medicago sativa</i> L.) (CA), (ii) a 9-year alfalfa removed and rotated with 4–5 years continuous annual crops (spring wheat (<i>Triticum aestivum</i> L.), maize (<i>Zea mays</i> L.), potato (<i>Solanum tuberosum</i> L.), and millet (<i>Panicum miliaceum</i> L.)), and (iii) a 5-year field fallow after alfalfa. Results showed that continued annual crops decreased total organic C and labile organic C by 10 to 20% and 17 to 34% in the topsoil (0–30 cm), and by 15 to 35% and 20 to 46% in the subsoil (30–60 cm), respectively, compared with CA. Similar trends were found in soil total N concentration, which decreased by 7 to 20% in the topsoil. Highest microbial biomass C was found in CA. Shannon-Wiener diversity and substrate richness of soil microbes measured by Biolog EcoPlates was significantly affected by cropping system with CA exhibiting a higher degree of soil microbial functional diversity in the topsoil, while the lowest values were found in the alfalfa-potato system. The higher soil organic matter content and functional diversity of soil microbe in CA indicates that soil nutrition and microbial activity did not limit alfalfa development and growth in the dryland area. The lower microbial activity and functional diversity observed in the potato field indicates the importance of crop selection in cropping systems.
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spelling doaj.art-f038bd371a904375b286fe81a2b8d14c2023-11-20T07:28:42ZengMDPI AGAgronomy2073-43952020-07-01107105410.3390/agronomy10071054Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of ChinaYining Niu0Zhuzhu Luo1Liqun Cai2Jeffrey A. Coulter3Yaoquan Zhang4Marisol Berti5Gansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, ChinaGansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, ChinaCollege of Resources and Environmental Science, Gansu Agricultural University, Lanzhou 730070, ChinaDepartment of Agronomy and Plant Genetics, University of Minnesota, St. Paul, MN 55108, USAGansu Provincial Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, ChinaDepartment of Plant Sciences, North Dakota State University, Fargo, ND 58108, USACropping systems are structured to maximize crop yields and increase sustainability in agricultural production. A field study was conducted to investigate different long-term cropping systems on soil organic matter and microbial communities. The cropping systems studied were: (i) a 14-year continuous alfalfa (<i>Medicago sativa</i> L.) (CA), (ii) a 9-year alfalfa removed and rotated with 4–5 years continuous annual crops (spring wheat (<i>Triticum aestivum</i> L.), maize (<i>Zea mays</i> L.), potato (<i>Solanum tuberosum</i> L.), and millet (<i>Panicum miliaceum</i> L.)), and (iii) a 5-year field fallow after alfalfa. Results showed that continued annual crops decreased total organic C and labile organic C by 10 to 20% and 17 to 34% in the topsoil (0–30 cm), and by 15 to 35% and 20 to 46% in the subsoil (30–60 cm), respectively, compared with CA. Similar trends were found in soil total N concentration, which decreased by 7 to 20% in the topsoil. Highest microbial biomass C was found in CA. Shannon-Wiener diversity and substrate richness of soil microbes measured by Biolog EcoPlates was significantly affected by cropping system with CA exhibiting a higher degree of soil microbial functional diversity in the topsoil, while the lowest values were found in the alfalfa-potato system. The higher soil organic matter content and functional diversity of soil microbe in CA indicates that soil nutrition and microbial activity did not limit alfalfa development and growth in the dryland area. The lower microbial activity and functional diversity observed in the potato field indicates the importance of crop selection in cropping systems.https://www.mdpi.com/2073-4395/10/7/1054continuous monocultureBiolog EcoPlatesrainfed cropping systemsmicrobial biomass C and Nfunctional diversity
spellingShingle Yining Niu
Zhuzhu Luo
Liqun Cai
Jeffrey A. Coulter
Yaoquan Zhang
Marisol Berti
Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
Agronomy
continuous monoculture
Biolog EcoPlates
rainfed cropping systems
microbial biomass C and N
functional diversity
title Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
title_full Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
title_fullStr Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
title_full_unstemmed Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
title_short Continuous Monoculture of Alfalfa and Annual Crops Influence Soil Organic Matter and Microbial Communities in the Rainfed Loess Plateau of China
title_sort continuous monoculture of alfalfa and annual crops influence soil organic matter and microbial communities in the rainfed loess plateau of china
topic continuous monoculture
Biolog EcoPlates
rainfed cropping systems
microbial biomass C and N
functional diversity
url https://www.mdpi.com/2073-4395/10/7/1054
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