Soil properties and the growth of wheat (Triticum aestivum L.) and maize (Zea mays L.) in response to reed (phragmites communis) biochar use in a salt-affected soil in the Yellow River Delta

Abstract

Soil salinity and its associated soil compaction and low fertility is a big problem for land management in the arid region or coastal zone. Here, a low-cost and potassium (K)-rich biochar of reed (phragmites communis) was demonstrated effective in alleviating the problem in wheat-maize rotation in the Yellow River Delta region. Adding the biochar at 0, 3, 6, and 12 t ha–1 to a soil with a 2.8‰ salt content via rotary tillage with straw returning, with or without fertilizers, reduced soil bulk density (BD) and increased saturated hydraulic conductivity (Ks). At 12 t ha–1 dose and by wheat and maize harvests, respectively, biochar lowered soil BD by 9.1% and 14.5%, increased Ks by 82.7% and 91.2%, and reduced sodium adsorption ratio (SAR) by 64.9% and 92.8% in comparison with the control (CK). Further, in comparison with conventional fertilization (CF: 375 kg ha–1 for each crop), biochar use (6 and 12 t ha–1), together with 75% of CF, enhanced the nitrogen use efficiency (NUE) by 20.5%–31.4% for wheat and 15.9%–30.9% for maize. It raised the yields of wheat by 11.3%–17.1% and maize by 9.7%–14.8%. By reducing BD, increasing Ks, and decreasing SAR, biochar alleviated soil compaction and salt stress and increased NUE and crop yields. This outcome suggests that the conversion of local bio-waste into biochar as a soil amendment is of agronomic and environmental benefits.