Effect of straw returned into field on quality of greenhouse cut chrysanthemum and soil nutrient status with continuous cropping

Objectives Due to the deterioration of soil properties and the quality decreasing of cut chrysanthemum in continuous cropping system year by year in greenhouse, the effect of straw returned into field on soil properties and the quality of cut chrysanthemum ‘Jimba’ was studied.

Methods Under subsurface pipe drainage (optimum spacing of buried pipe 2 m) condition, the different straw amounts (0, 800, 1600 and 2400 kg/hm²) were returned and their effect on the quality of cut chrysanthemum ‘Jimba’ and on soil properties were investigated through the determination of the nutrients, cation exchange capacity and total salt content in tillage layer soil (0–15 cm) and the main physiological parameters as well.

Results Under the condition of subsurface pipe drainage, different amounts of straw returned could significantly increase soil organic matter, available phosphorus and readily available potassium contents. Compared with the control, the content of available nitrogen in soil showed the lowest after applied with 1600 kg/hm² straw, while the soil cation exchange capacity was increased by 32.7%, 23.6%, 11.4%, and 8.23%, respectively compared with other treatments. In addition, the treatments of returning straw into field could effectively reduce the pH, total salt content and electrical conductivity of the tillage layer soil, and the electrical conductivity of tillage layer soil after applied with 1600 kg/hm² straw was the lowest (167.2 μS/cm), which was 31.1% lower than that of CK. The main physiological indexes such as plant height, stem diameter, ray florets, flower fresh weight, and biomass were significantly increased in all the treatments evaluated. Among them, application of 1600 kg/hm² straw into field had a significant increase in plant height, ray flowers, and biomass than other treatments.

Conclusions The application of 1600 kg/hm² straw was the optimal treatment of all the treatments evaluated, not only the soil physical and chemical properties were improved obviously, but also the soil fertility and the quality of the cut chrysanthemum ‘Jimba’ were increased significantly.