Biochar amendment improves water-fertilizer productivity of perennial ryegrass under different irrigation and fertilization regimes

Abstract

The quality of turfgrass often comes at the cost of consuming large amounts of water and nitrogen fertilizer resources. Soil management is the key to promote plant growth and achieve high water and nitrogen utilization efficiency. This experiment investigated the effects of biochar on soil physicochemical parameters and perennial ryegrass (Lolium perenne L.) growth under different nitrogen and irrigation regimes. The results showed that although biochar adversely affected soil electrical conductivity, biochar addition significantly increased soil nutrient availability, soil pH, and soil water content (SWC) compared to unamended soil. Although deficit irrigation negatively affected perennial ryegrass growth, biochar addition ameliorated the inhibitory effect of water deficit. Furthermore, biochar addition improved photosynthetic parameters of leaves and increased leaf nutrient content, including total N, total P, total K, total dry biomass, and nitrogen agronomic efficiency. Biochar addition also increased plant water use efficiency suggesting that biochar addition could achieve higher biomass with less water use. In addition, biochar addition reduced malondialdehyde and abscisic acid levels by increasing peroxidase and superoxide dismutase activity in perennial ryegrass. Principal component analysis indicated that soil nutrient content and SWC contributed significantly to the increase in growth and biomass of perennial ryegrass under biochar addition. Therefore, biochar addition may influence plant physiological and biochemical responses by increasing SWC and soil nutrient availability, which in turn maintains normal perennial ryegrass growth. These results suggest that biochar amendment may be an effective sustainable management practice to promote plant growth under deficit irrigation and nitrogen regimes.