酥瓜连作对土壤环境及植株光合特性的影响

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。

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

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.