酥瓜连作对土壤环境及植株光合特性的影响

Effects of continuous cropping on soil environment and photosynthesis capacity of crisp melon

为研究酥瓜连作对土壤理化性状、植株生长和光合特性等的影响,分别选取连续种植酥瓜1、2、3和4年的塑料大棚内土壤,并以未种植过酥瓜的土壤为对照进行盆栽试验。结果表明:(1)连作土壤出现酸化,连作4年处理土壤的p H值比对照处理下降了17.0%;(2)土壤EC值随连作处理逐渐增加,连作4年处理土壤的EC值是对照的3.03倍;(3)酥瓜连作土壤的碱解氮、速效磷、速效钾逐年降低,而总氮、总磷和总钾含量出现明显上升的趋势;(4)土壤细菌和放线菌数量逐渐减少,真菌数量逐年增加;(5)土壤多酚氧化酶、过氧化氢酶和蔗糖酶活性显著下降,脲酶活性呈现出先增加后下降的趋势;(6)连作导致植株光合色素含量减少,光合能力下降,从而导致植株的株高、茎粗及干鲜重等指标均呈下降趋势。

To determine the effect of continuous cropping on the soil physical and chemical properties, plant growth and photosynthetic characteristics, the soils from the fields of continuous cropping for 1 year, 2 years, 3 years, 4 years and non-continuous cropping were collected for a pot experiment. The results showed that： （1） the continuous cropping soil showed acidification and the pH value of 4-year continuous cropping was decreased by 17.0% than the control; （2） the soil EC value was gradually increased, and the EC of a 4-year continuous cropping was 3.03-fold of the control; （3） available N, P, and K in the continuous cropping soil were reduced year by year, and total nitrogen, total phosphorus and potassium contents appeared upward; （4） the numbers of soil bacteria and actinomycetes were decreased, while the number of fungi was increased year by year; （5） soil polyphenol oxidase, catalase and invertase activities were significantly decreased, while urease activity showed a trend of first increase and then downward; （6） photosynthetic pigment content and photosynthetic capacity of crisp melon were decreased when grown in the continuous cropping soil, which resulted a decline of plant height, stem diameter, fresh weight and dry weight.