[Effects of continuous cropping with straw return on particulate organic carbon and Fourier transform infrared spectroscopy in cotton field].

Abstract

A long-term field experiment was conducted to investigate the effects of continuous cotton production years (0 as control, 5, 10, 15 and 20 years) and straw return on soil organic carbon (SOC) structure and stability by using Fourier transform infrared spectroscopy (FTIR) in Manas River valley of Xinjiang. The results showed that the relative peak intensity of polysaccharide and aromatics decreased with increasing continuous cropping years, whereas the aliphatic and alcoholic phenols relative peak intensity and the CH/C=C increased. The content of soil particulate organic carbon (POC) increased significantly in the 5-yr of cotton production farmland and then decreased with the increases of continuous cropping years. POC content was 5.11 times higher in 5-yr than that of the control. The content of mineral-bound organic carbon (MOC) was the highest in 10-yr farmland, being 1.84 times higher than that of the control. The highest value of the ratio of POC and MOC content (ω(POC)/ω(MOC)) was observed in 5-yr farmland. Together, long-term continuous cotton production with straw return led to SOC structure aliphatic and soil mineral binding increased the protection of organic matter, thus increasing the stability of soil organic matter.