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RESEARCH ARTICLE

Soil amendment with biochar increases maize yields in a semi-arid region by improving soil quality and root growth

Qian Xiao A B , Li-Xia Zhu A C , Hong-Pei Zhang A C , Xiu-Yun Li A C , Yu-Fang Shen A C D and Shi-Qing Li A C D
+ Author Affiliations
- Author Affiliations

A State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A & F University, Yangling 712100, China.

B College of Forestry, Northwest A & F University, Yangling 712100, China.

C College of Natural Resources and Environment, Northwest A & F University, Yangling 712100, China.

D Corresponding authors. Email: shenyufang@nwsuaf.edu.cn; sqli@ms.iswc.ac.cn

Crop and Pasture Science 67(5) 495-507 https://doi.org/10.1071/CP15351
Submitted: 17 July 2015  Accepted: 8 December 2015   Published: 31 May 2016

Abstract

Biochar has been widely proposed as a relatively novel approach to improve soil quality and increase crop productivity, but its underlying mechanisms are not well understood. A large root system in plants is either a constitutive or an inducible trait dependent on the uptake of resources and the production of shoot dry matter. Here a field experiment was conducted to investigate the effects of biochar amendment on the dynamic growth and development of maize (Zea mays L.), both above- and belowground, and to explore the relationship between soil condition, root traits and shoot biomass over two growing seasons on the Loess Plateau in northern China. Biochar was added to a maize field at rates of 0, 10, 20 and 30 t ha–1 without mulching and at rates of 0 and 20 t ha–1 with film mulching before sowing the first crop. The application of straw biochar with 30 t ha–1 decreased soil bulk density by 12% and increased soil total porosity by 13% in the 0–10-cm soil layer 6 months after biochar addition. Biochar amendment increased soil organic carbon, total soil nitrogen, carbon : nitrogen ratio, and available phosphorus and potassium at the end of each growing season. Although, root growth was inhibited at a rate of 30 t ha–1 in the early stage of the first year, biochar amendment exhibited a positive effect in other stages, resulting in higher root weight density, root length density and root surface-area density. These responses led to higher growth rates, maize biomass, grain yields and uptake of nitrogen, phosphorus and potassium as the rate of biochar addition increased. Film mulching with biochar amendment achieved the greatest root and shoot biomass and grain yield in both crops, despite differences in climate conditions. Biochar aged in the field for 2 years had the same effect on soil properties and crop production, suggesting that the application of straw biochar may be a promising option for increasing productivity in semi-arid farmland.

Additional keywords: biochar, dry matter accumulation, film mulching, nutrient levels, root traits.


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