垄覆膜集雨种植对二年龄苜蓿草地土壤养分的影响

Soil nutrient in two-year alfalfa field on condition of film-mulching rainfall harvesting cultivation

旱作条件下,垄覆膜集雨措施应用于紫花苜蓿种植,垄为集雨区,沟为种植区,研究不同沟垄宽比和覆膜方式对2年龄苜蓿草地土壤养分影响。结果表明,垄覆膜种植苜蓿第2年返青前、第2茬刈割后,各处理0～20,20～40cm土壤全磷(TP)含量均无显著差异,膜垄、土垄处理0～20,20～40cm土壤有机质(SOM)、全氮(TN)含量均随着垄宽度的增大而增加,且膜垄处理0～40cm土层SOM、TN、速效氮(AN)、速效磷(AP)、缓效钾(SAK)、速效钾(AK)含量均显著高于土垄处理及CK(平作),所有处理中MR60、MR75土壤养分含量最高。刈割后和返青前相比,膜垄处理0～40cm土层SOM的减少量显著低于土垄处理,膜垄处理0～40cm土层TN的增加量及AN、AP、SAK、AK的减少量均显著大于土垄处理;相关性分析表明,各处理0～40cm土层SOM的减少量与苜蓿的经济产量呈显著的负相关,0～40cm土层TN的增加量、AP的减少量、AK的减少量均与苜蓿的经济产量呈显著的正相关。说明垄覆膜集雨种植紫花苜蓿能够有效的抑制SOM含量的降低,且膜垄的抑制作用大于土垄,同时促进TN含量的增加,有效地提高0～40cm土壤养分,有利于土壤的可持续利用。

Film-mulching rainfall harvesting cultivation method was applied to alfalfa（Medicago sativa）planting on condition of dry farming,ridge was used as rainfall collection area,and furrow was used as planting area to study the effect of various ridge-furrow ratios and mulching methods on soil nutrients of two-year alfalfa fields.The result showed that no significant difference in total phosphorus（TP） contents was found among the treatments before reviving period on the second year and after the mowing of second crop in soil layers of 0 to 20 and 20 to 40 cm;accordingly,soil organic matter（SOM） and total nitrogen（TN） contents increased as the increase of ridge width for ridges covered with soil and film in the two soil layers,and within the soil layer of 0 to 40 cm,SOM,TN,available nitrogen（AN）,available phosphorus（AP）,slowly available potassium（SAK） and available potassium（AK） contents were found significantly higher than ridges compacted with soil and CK（conventional tillage）,among all the treatments,MR60 and MR75 were found with highest soil nutrient.Compared with after mowing and before reviving,decrease of SOM from 0 to 40 cm layer in ridges covered with film was found remarkably lower than ridges covered with soil,and the increase of TN as well as the decrease of AN,AP,SAK and AK in ridges covered with film were found remarkably higher than ridges compacted with soil.According to related analysis,within soil layers between 0 to 40 cm,significant negative correlation was found between the decrease of SOM and the economic yield of alfalfa,and significant positive correlation was found between the economic yield of alfalfa and the increase of TN,the decrease of AP and AK,indicating that film-mulching rainfall harvesting cultivation inhibited the decrease of SOM effectively,and the inhibition effect of film was found better than soil,simultaneously,increase in TN content was found promoted and soil nutrient in soil layers from 0 to 40 cm was found increased,which is good to the sustainable utilization of soil.