【作者】 史建国；

【导师】 刘景辉；

【作者基本信息】 内蒙古农业大学 ， 作物栽培学与耕作学， 2012， 博士

【摘要】 地膜再利用是增温保水、稳产高产、节本增效、固土减残留的重要耕作技术之一针对地膜残留污染加重的实际问题,开展覆膜玉米后茬免耕种植向日葵农田效应研究,对进一步发挥地膜增产效应具有现实意义。本研究在内蒙古河套地区临河区双河镇通过田间试验和室内测定分析,并结合走访调查等方法,以新覆膜和露地栽培为对照研究地膜再利用对土壤温度、水分、土壤微生物量、土壤酶活性、向日葵出苗、生育进程和产量及相关性状的影响,分析其经济效益及生态效应。研究结果如下：1.地膜再利用仍具有明显的增温和提高地积温的效果。地膜再利用仍能显著提高向日葵出苗期(前7天)的土壤温度,各土层(0-50cm)日均温均高于露地,增幅随着土层的加深略有减弱,其中旧膜的浅层(0-20cm)温度较露地高1.7～2.1℃,深层(30-50cm)高1.8～2.0℃。旧膜浅层土温较新膜低1.3-2.0℃,深层差异不明显。新旧膜对向日葵不同生育阶段的增温作用均表现为：出苗期>现蕾期>收获期>始花期>终花期。出苗期旧膜5cm和10cm土层有效地积温均高于露地约21.6℃,略低于新膜约12.4℃。全生育期旧膜5cm土层总积温高于露地229.5℃,低于新膜101℃。2.地膜再利用仍具有保水保墒和提高水分利用效率的作用。在播前初始土壤含水量补齐到一致的前提下,旧膜1m土层的生育期土壤平均相对含水量较露地均提高约1.5个百分点,其中0-10cm土层相差最大,两年分别提高1.9和2.6个百分点,差异均显著。旧膜较露地两年分别为后茬向日葵田节水46.4mm和56.5mm,与新膜无显著差异。旧膜的土壤剖面水分稳定性较露地提高,水分变异系数两年分别比露地降低3.6%和4.8%；旧膜籽粒水分利用效率分别较露地显著提高15.7%和22.7%,与新膜相比差异不显著(P<0.05)。3.地膜再利用能增加土壤微生物量碳、氮、磷含量。在0-40cm土层,土壤微生物量碳、氮、磷含量大小均表现为：旧膜>新膜>露地。旧膜的生物量碳含量较露地和新膜分别显著提高13.8%和12.1%(P<0.01)；旧膜的土壤微生物量氮含量较露地和新膜分别显著提高5.0%和4.0%(P<0.05)；旧膜的土壤微生物量磷含量较露地和新膜分别显著提高34.2%和18.3%(P<0.01)。土壤微生物量碳、氮、磷含量生育期变化有所不同。土壤微生物量碳含量生育期变化总体上受灌水影响呈波动下降；土壤微生物量氮含量全生育期降低趋势,土壤微生物量磷含量呈先增加后降低的变化趋势。土壤微生物量碳、氮、磷含量垂直变化均表现为随土层加深而减少。4.地膜再利用可明显提高土壤酶活性。在0-40cm土层,旧膜全生育期土壤过氧化氢酶活性较露地和新膜分别显著增加4.2%和2.6%；旧膜的土壤脲酶活性较新膜显著增加7.4%,较露地增加1.1%,无显著差异；旧膜的土壤蔗糖酶活性较露地显著增加3.8%,较新膜增加3.0%,差异不显著。土壤酶活性生育期变化各不相同。土壤过氧化氢酶活性在播前到现蕾变化较为平稳,花期下降到最低,之后上升,到收获期达最高；土壤脲酶活性的生育期变化具有上升-下降-小幅上升的规律；土壤蔗糖酶活性的生育期变化呈下降一上升一下降的变化趋势。土壤氧化氢酶、脲酶、蔗糖酶活性的垂直变化均表现为随土层加深而减少的趋势。5.地膜再利用仍具有促苗早发,加快生育进程和提高产量的作用。旧膜较露地提前1-2天出苗,新旧膜间无明显差异。旧膜生育期较露地缩短5-6天,较新膜延长2天。旧膜的株高、茎粗、盘径、叶干重和地上部总干重均显著高于露地；旧膜的茎粗略高于新膜,但差异不显著,旧膜的株高、盘径、叶干重和地上部总千重均略低于新膜,无显著差异。旧膜覆盖下向日葵的每盘粒重、百粒重及产量均显著高于露地。其中,旧膜与露地相比,两年的每盘粒重分别高3.3%和10.4%,百粒重分别高3.7%和5.8%,产量分别高11.4%和16.8%。旧膜的每盘粒重、百粒重均略低于新膜,两年的产量较新膜分别低3.3%和2.6%,差异均不显著(P<0.05)。6.地膜再利用具有节本省工、增值增效的协同作用。地膜再利用的机械人工投入两年分别较露地耕作减少419.3元/hm2和371.6元/hm2,较新膜节省494.4元/hm2和518.0元/hm2,农资投入分别较新膜少1394元/hm2和817元/hm2,产值较露地两年分别显著提高4189元/hm2和5641元/hm2,稍低于新膜1420元/hm2和965元/hm2,差异不显著,纯收益两年分别比露地提高5059元/hm2和5863元/hm2,比新膜仅低26元/hm2和147元/hm2。地膜再利用的产投比最大,两年分别为3.0和2.68,比露地增大18.5%和19.9%,比新膜增大6.7%和3.2%。7.地膜再利用对休闲期农田具有增温、保水、减蚀、降低膜残留的作用,改善了农田生态环境。在农田休闲期,地膜再利用的0-100cm土壤含水量较露地平均提高2.1个百分点,土壤贮水量较露地增加24.8mm-33.0mm,其中0-10cm和10-20cm土层土壤墒情得到显著改善；地膜再利用的0-50cm土层土壤温度两年分别提高3.1℃和2.8℃,其中5cm土层高4.6℃和1.7℃,10cm高4.1℃和2.8℃；地膜再利用的风蚀量比露地显著减少了68.77%。地膜再利用使地膜利用率提高约1倍,而农田残留量降为新膜的一半,有力缓解了农田污染,改善了农田生态环境。更多还原

【Abstract】 Film mulching plays a very important role in soil warming, water preserving, soil conservation, reducing soil erosion and increasing yield, which is widely used in agricultural production. However, every year crop mulching with new film come into being of a large number of film residue, leading to the "white pollution", which make agricultural ecological environment degenerated. At the same time, in the Hetao region the farming practice such as plough and irrigation is after harvest in autumn that soil was completely exposed during fallow period of cropland from November to next early May (about7months), combined with climatic drought and windy, which result in excessive cropland evaporation, poor capacity of soil water, severe soil erosion, and finally the cropland deteriorated. Aiming at reducing agricultural pollution caused by plastic film, the effects of re-used plastic film mulching on soil temperatures, seed emergence and all seedlings period, sunflower’s growth and development, sunflower’s yield, soil moisture, water use efficiency and soil erosion during fallow period of cropland were studied, investigated the effects of re-used plastic film mulching on sunflower’s economic benefit, the study also investigated plastic film residue and sunflower’s yield, which compared with new plastic film mulching and bare field in Hetao region. The results were as follows:1. Re-used film could increase the soil temperatures. Compared with bare field, the soil temperature of re-used film mulching increased1.3～4.0℃and0.7～1.8℃separately in the highest and lowest temperature stage. The soil average temperature increased significantly1.7～2.1℃in upper layer (0-20cm) and1.8～2.0℃in lower layer (30-50cm); compared with new film mulching lower1.3～2.0℃in upper layer, and similar as in lower layer. Compared with bare field, Daily maximum and minimum temperatures of re-used film mulching were postponed about1hour, similar as new film mulching. Re-used plastic film mulching can increase the soil temperatures in sunflower earlier and later stage, it’s warming effect was:sowing stage> seedling stage> maturing stage>blooming stage> after flowering stage; During emergence stage (7days after sowing), effective accumulated temperature of re-used film mulching was21.6℃and23.8℃higher than that of bare field in depth of5cm and10cm. Compared with new film mulching, it was12.4℃and10.0℃lower in depth of5cm and10cm. During all stage, effective accumulated temperature of re-used film was229.5℃higher than that of open field,101℃slightly lower than new film in the depth of5cm. 2. Re-used tilm could improve the soil moisture, increasing water use efficiency. The soil moisture of re-used plastic film mulching was increased1.5percentage points in the soil depth of0-100cm and maximum of1.9or2.6higher in the soil depth of0-10cm than that of open field in sunflower’s growth stage. Soil water of re-used film was more than open field’s24.8mm or33.0mm before seeding and after soil water was replenished to same level,21.6mm or24.5mm was more than open field’s at harvest. Re-used film’s C.V of vertical soil moisture was dropped in3.6%or4.8%than that of open field. Meanwhile, water use efficiency of re-used film were higher significantly than that of open field15.7%or22.7%respectively in2010and2011, no significant with new film.3. Soil microbial biomass carbon, nitrogen and phosphorus content of re-used film mulching increased at different degree. compared with bare field and new film mulching, soil microbial biomass carbon content in0-40cm of re-used film were higher significantly (p<0.01)13.8%and12.1%respectively, soil microbial biomass nitrogen content in0-40cm of re-used film were higher significantly (p<0.05)5.0%and4.0%respectively, soil microbial biomass phosphorus content in0-40cm of re-used film were higher significantly34.2%a nd18.3%respectively(p<0.01). Growth stage changes of Soil microbial biomass carbon, nitrogen and phosphorus content are different. The soil microbial biomass carbon content decline with fluctuation effecting by irrigation; microbial biomass nitrogen content decreased; microbial biomass phosphorus content was increased first and then decreased. Vertical changes of the soil microbial biomass carbon, nitrogen, phosphorus content are reduced with increasing soil depth.4. Soil enzyme activity of re-used film mulching increased at different degree. compared with bare field and new film mulching, soil catalase activity in0-40cm of re-used film were higher significantly4.2%and2.6%respectively, soil urease activity in0-40cm of re-used film were higher no significantly1.1%and significantly7.4%respectively, invertase activity in0-40cm of re-used film were higher significantly3.8%and3.0%respectively(p<0.05). Growth stage changes of soil catalase activity, soil urease activity, soil invertase activity are different from each other. The soil catalase activity is relatively stable Beginning from sowing to squaring, decreased to a minimum in flowering, after rising up to the maximum in harvest: soil (?)rease activity beginning with a minimum in sowing rise up to the maximum in squaring: then decreased decreased to flowering; soil invertase activity was f(?)uctuating decline effecting by irrigation, and with a minimum in squaring. Vertical changes of the soil catalase activity, soil urease activity, soil invertase activity are reduced with soil deepening.5. Re-used film could also decrease sunflower’s growth and development time and increase the yield of sunflower. Mulching with re-used film could effectively shorten seed germination for1-2days. Meanwhile, growth period of re-used film was significant earlier than open field5-6days and not significant later than plastic film2days. In addition, plant height; stem diameter, disc diameter, leaf dry weight and total dry weight of re-used film mulching was significantly higher than that of bare field; Except stem diameter, plant height, disc diameter, leaf dry weight and total dry weight of re-used film mulching was slightly lower than that of new film mulching, but the difference was not significant. Compared with bare field, yield per plant of re-used film mulching was significantly increased3.3%(2010) and10.4%(2011),100-seed weight of re-used film mulching was significantly increased3.7%(2010) and5.8%(2011), and they were lower than that of new film mulching, but the difference was not significant. In addition, compared with bare field, sunflower yield of re-used film mulching was significantly increased11.4%(2010) and16.8%(2011), and compared to the new film treatment, the yield decreased3.3%(2010) and2.6%(2011)(p<0.05).6. Re-used plastic film mulching had significantly increased the economic benefit. Compared with bare field, the sunflower’s yield of re-used film mulching increased9.6to15%significantly, and lower than new film by2.6to4.9%(p<0.05). Compared with bare field, the input of re-used film mulching was reduced by5.6%to9.4%, which was1.6%to6.1%lower than that of new film mulching. The output of re-used film mulching was9.6%to18.1%significantly higher than that of bare field and2.5%to4.9%lower than that of new film mulching. The net income of re-used film mulching was22590RMB·hm-2to26914RMB·hm-2, obviously increased by19.6%to34.4%than that of open field and0.6%to2.4%less than that of new film mulching. The ratio of output to input of re-used film mulching was the highest (3.0and2.6), higher than that of open field (18.5%and19.9%) and new film (6.7%and3.2%).7. Re-used plastic film mulching can improve the ecological environment of cropland in fallow period, reduce the film pollution. Compared with bare field, the average soil moisture in0-100cm of re-used film mulching increased2.1%, the water storage capacity in0-100cm and0-20cm increased24.8～33.0mm and14.9～15.5mm separately. The soil average temperature significantly increased3.1～2.8℃, especially soil temperature in5cm and10cm increased1.7～4.6℃and2.8～4.1℃separately (p<0.05). Re-used plastic film mulching can reduce the amount of soil erosion significantly by68.77%. Compared with new plastic film mulching, the residual plastic film of re-used film mulching cropland significantly reduced50%, and the film use efficiency increased one time.更多还原