不同覆膜方式对旱砂田土壤水热效应 及西瓜生长的影响

早春低温胁迫和生育期干旱胁迫是进一步提高旱砂田西瓜产量的主要限制因素。为提高旱砂田早春土壤温度和自然降水利用效率,在西北干旱区的旱砂田上开展了不同覆膜方式的对比试验,研究了全覆膜(FM)、起垄覆膜(RM)、半覆膜(HM)和不覆膜(CK)4个处理下旱砂田土壤水热效应及对西瓜产量和品质的影响。结果表明,不同覆膜方式0-25cm土壤温度日变化均以"S"的温波形式由表层向深层土壤传递,土层每加深5cm,土壤温波位相依次推移1h;不同覆膜方式0-25cm土层增温效应表现为FM>RM>HM>CK,日平均温度较CK分别提高2.8、2.0,1.8℃。FM和RM是影响旱砂田西瓜生长前期土壤水分变化的主要覆膜方式,播种至幼苗期,RM具有明显的集雨效果,抽蔓期FM具有显著的保墒效果。覆膜加快了旱砂田西瓜的生长,蔓长、叶绿素含量和叶面积指数均明显高于CK, FM、RM和HM产量分别较CK增加145.81%、99.32%和95.46%,西瓜可溶性固形物含量和可溶性糖含量均表现为FM>RM>HM>CK,而维生素C、粗纤维和有效酸含量受覆膜方式的影响较小。综合分析,FM和RM是旱砂田西瓜生产中优选的覆膜方式。

Influences of different plastic film mulches on temperature and moisture of soil and growth of watermelon in gravel-mulched land

Gravel-mulched land was the unique and conventional farming system and its planting area was enlarged year by year in arid region of northwest China.The planting area of watermelon in gravel-mulched land reached more than 33% of total area of gravel-mulched land.But the stresses of lower temperature in early spring and water shortage during growth period of watermelon were major limiting factors for watermelon yield increasing in gravel-mulched land.To find the ways improving soil temperature in early sprin...