覆黑地膜对旱作玉米根区土壤温湿度和光合特性的影响

明确雨养旱地地膜覆盖春玉米高产与水分高效利用的土壤环境条件,及其对玉米光合特性的作用,对延缓玉米衰老、提高玉米光合能力和促进玉米增产具有重要意义。以陕单609为材料,2012和2013年开展黑色地膜覆盖、白色地膜覆盖和裸地栽培试验,研究黑色地膜对玉米根区土壤水温环境、玉米叶片光合特性、产量和水分利用效率的影响。结果表明,黑色地膜较普通白色地膜和裸地栽培,能显著改善玉米根区土壤温湿条件,提高玉米叶片光合能力。黑色地膜覆盖下,玉米叶片衰老时间明显推迟,衰老速度显著下降,成熟期叶片叶绿素含量较普通白色地膜提高11.7%(P0.05),较裸地提高45.5%(P0.05)。与普通白色地膜和裸地栽培相比,黑色地膜覆盖提高了吐丝后玉米叶片光合速率、蒸腾速率、叶片水分利用效率、PSII电子传递速率、量子产量(灌浆期除外)和光化学猝灭系数。黑色地膜覆盖下玉米千粒质量、产量和水分利用效率显著增加,千粒质量较普通白色地膜和裸地栽培分别增加5.0%和14.9%(P0.05);产量分别提高10.4%和22.1%(P0.05);水分利用效率分别提高10.4%和25.3%(P0.05)。在雨养旱作地区,玉米采用黑色地膜覆盖具有延缓后期叶片衰老和促进增产的效果。

Effects of black plastic film mulching on soil temperature and humidity in root zone and photosynthetic characteristics of rainfed maize

Improving soil environmental conditions may help maximize crop productivity while delaying the senescence of maize.Plastic film mulching has been used for soil moisture conservation,and it is now becoming a well-evolved high yield technique for agriculture in rainfed dry land.This study included 3 treatments:black plastic film mulching (BFM),white plastic film mulching (WFM),and bare land without plastic film mulching (BL).The aims of this study were to investigate the changes of soil temperature and water content under different treatments in a dry and semiarid area,and the effects of black plastic film mulching on yield,yield components and leaf photosynthetic characteristics of maize (Zea mays L.).Maize (Shandan 609) was planted in 2012 and 2013 at the dryland maize experimental field of the Northwest A&F University,in the northwestem China (34°59′ N,107°38′ E).Soil temperature at 5,10 and 15 cm depth was measured and soil moisture at 0-200 cm was determined for water storage calculation based on water balance equation.In addition,measurements also included net photosynthetic rate,transpiration rate,water use efficiency of leaf,electron transport rate,quantum yield,photochemical quenching coefficient of photo-system Ⅱ,relative green leaf area at maturity,cholorophyll content at maturity,mean and maximum senescence rate.The results showed that the daily soil temperature was the highest for the WFM among the 3 treatments.The BFM also could increase soil temperature but the effect was lower than the WFM.The maximum daily soil temperature of the BFM was 2.3,1.2 and 1.6 ℃ lower than that of the WFM in 2012 and 1.8,0.8 and 1.0 ℃ in 2013,respectively (P＜0.05).The minimum daily soil temperature was not significantly different between the mulching treatments (P＞0.05).In 0-140 cm,the water storage was not significantly different between the mulching treatments (P＞0.05),both significantly higher than the BL (P＜0.05).The mulching treatments could increase the photosynthetic characteristics and the effect was the best in the BFM,especially after the silking stage.Leaf senescence of maize after the silking stage in the WFM and BL treatment appeared earlier than the BFM.The occurrence time of leaf senescence of BFM was delayed,and its leaf senescence rate after the silking stage was significantly lower than BL.The chlorophyll content of leaf at maturity in the BFM was significantly 11.7％ and 45.5％ higher than the WFM and BL,respectively.The photosynthetic ability of maize in black plastic film mulching treatment was high.The water consumption of the BFM and WFM was significantly lower than the BL.The water use efficiency of the former was significantly higher than the latter.Among the treatments,the yield was the highest in the BFM (P＜0.05).The yield of maize in the black plastic film mulching treatment was increased by 10.4％ and 22.1％ than white plastic film mulching treatment and bare land treatment,respectively.Therefore,black plastic film mulching could delay leaf senescence of maize after the silking stage and increase yield in rainfed farming area.