棉花秸秆还田对土壤速效养分及微生物特性的影响

连续4年以德农09068为试材,设棉花秸秆还田与未还田2个处理,调查棉花秸秆还田对土壤0~60 cm土层的速效养分含量和微生物特性的影响。结果表明,连续4年棉花秸秆还田显著提高0~20 cm土层土壤有机质、碱解氮、速效钾含量、土壤微生物量碳、土壤活跃微生物量及土壤基础呼吸速率,分别比未还田处理提高8.16%、13.23%、12.30%、13.63%、11.57%和13.14%;在20~40 cm土层中,分别提高6.08%、27.51%、11.47%、14.32%、15.03%和17.44%;在40~60 cm土层中土壤有机质、碱解氮、速效钾含量、土壤微生物量碳及土壤活跃微生物量分别提高6.05%、12.87%、8.08%、10.60%和20.30%,但对土壤基础呼吸速率的提高效果不显著。棉花秸秆还田显著提高了棉花的籽棉、皮棉产量、总铃数及单铃重,分别提高16.86%、15.03%、5.99%和10.25%,而对衣分无显著影响。在长期棉花秸秆还田的棉田中,应关注可能产生的连作障碍,注意磷肥的适量施入,以保证实现棉花稳产高产。

Effects of Cotton Straw Returning on Soil Available Nutrients and Microbial Characteristics

The experiment with two treatments of cotton straw returning and no straw returning was conducted using Denong 09068 at the Experimental Station of Shandong Agricultural University (Dezhou) to investigate the contents of soil available nutrients and microbial characters under cotton straw returning for four consecutive years. The main results indicated that compared with control (no straw returning), cotton straw returning significantly increased the contents of soil organic matter, alkaline hydrolyzed nitrogen, available potassium, soil microbial C and active microbial biomass by 8.16%, 13.23%, 12.30%, 13.63%, and 11.57% (0–20 cm soil layer), 6.08%, 27.51%, 11.47%, 14.32%, and 15.03% (20–40 cm soil layer), 6.05%, 12.87%, 8.08%, 10.60%, and 20.30% (40–60 cm soil layer) on average, respectively. Soil basal respiration rate of straw returning treatment was 13.14% and 17.44% in 0–20 cm and 20–40 cm soil layers respectively higher than that of no straw returning treatment, while no significant increase in 40–60 cm soil layer. Cotton straw returning significantly increased seed cotton yield (16.86%) and lint yield (15.03%), absolutely owning to larger total boll number (5.99%) and boll weight (10.25%), but there was no change in lint percentage, compared with no cotton straw returning treatment. Returning cotton straw can increase soil fertility, while applying appropriate P fertilizer and controlling obstacles in continuous cropping are necessary for long–term straw returning to enhance yield.