【作者】 李玉鹏；

【导师】 贾志宽；

【作者基本信息】 西北农林科技大学 ， 生态学， 2010， 硕士

【摘要】 本研究连续两年在宁南半干旱区旱作农田通过设置不同秸秆覆盖量处理进行冬小麦和春玉米的栽培试验,通过对各处理下的土壤水分、养分、酶活性及作物生长响应的深入分析,旨在完善半干旱区秸秆覆盖栽培模式以及节水保墒综合技术。主要研究结果如下:1.进行覆盖处理以后,作物的长势明显优于对照。小麦的株高较对照提高7%～14.9%,生物量积累增加26.9%～40%。随着覆盖量的增加,春玉米的株高、茎粗、叶面积等农艺性状观测值均较对照明显提高,到成熟期,高、中、低三种覆盖量处理的玉米的株高较对照分别增加了25.9%、16.4%、13.2%;茎粗较对照分别增加了17.7%、16.3%、6.6%;叶面积较对照分别增加了48.9%、33.6%、21.4%。2.随着覆盖量的增加,作物的土壤含水量均高于对照。3000 kg/hm2、6000kg/hm2、9000kg/hm2三种覆盖量处理的小麦收获后,土壤贮水量较对照平均增加了13.1%﹑19.8%﹑26.1%。当覆盖量为3000 kg/hm2时,小麦的产量和水分利用效率较对照提高了16.7%和33.8%,产量达到3331.42 kg/hm2,小麦的穗长和穗粒数较对照分别增加了28.7%和27.6%。在玉米栽培试验中,随着覆盖量的增加,对土壤水分的保蓄作用也越强,覆盖处理以后,玉米全生育期的耗水量较对照平均减少了2.72%～6.66%。两年试验中,都是覆盖量9000 kg/hm2的处理产量最高,分别达到5439.3 kg/hm2和5516.5 kg/hm2,较对照分别增加了18.7%和14.9%,覆盖量为4500 kg/hm2的处理的保墒效果不是很明显,水分利用效率仅平均增加了3.25%,覆盖量为9000 kg/hm2和13500 kg/hm2的处理的保墒效果非常明显,玉米水分利用效率较对照平均增加了28.34%和27.26%。3.进行覆盖处理以后,对作物的光合速率和单叶水分利用效率有明显的提高。各覆盖处理下玉米的光合速率、蒸腾速率以及单叶水分利用效率均有所提高,且与覆盖量呈明显的正相关,在大喇叭口期玉米的光合速率较对照增加了22.5%～44.9%;蒸腾速率较对照增加了8.57%-33.6%;单叶水分利用效率对照分别增加了8.59%～21.4%。4.进行两年的覆盖之后,对土壤养分的含量也有较大提高。小麦田0～40cm土层中的碱解氮、速效钾的含量分别增加了11.8%～15.7%和6.4%～11.8%,有机质的含量提高了44.4%～55.5%。覆盖处理对玉米田土壤全效养分的影响主要集中在农田0～20cm土层,有机质的含量增加了24.9%～25.9%,全磷的含量增加了6.9%～16.7%,全钾的含量增加了3.7%～7.2%。秸秆覆盖对表层土壤速效养分的影响规律基本相似,经过覆盖处理以后, 0～20cm土层速效养分的含量都有所增加,且增加量与秸秆覆盖量成正相关。5.覆盖处理以后,对蔗糖酶和磷酸酶的活性有较大的提高,对脲酶和过氧化氢酶的活性影响不是很大。小麦田2009年收获后土壤蔗糖酶和磷酸酶较对照分别增加了7.7%～11.4%和30.9～42.9%。玉米田对土壤酶活性的影响主要集中在0～20cm土层,收获后蔗糖酶和磷酸酶较对照分别增加了3.1%～19.4%和13.7～35.3%。对20～40cm土层的酶活性影响不大6.覆盖以后明显降低了土壤容重。在作物收获后,小麦田0～20cm耕层土壤容重9000 kg/hm2、6000kg/hm2、3000kg/hm2三种覆盖量处理较CK分别降低了5.5%、2.3%、0.8%。玉米收获后,各覆盖量下,0～60cm耕层土壤容重较对照降低了0.7%～3.6%。覆盖对土壤团聚体的构成也产生了明显的影响,小麦田收获后,覆盖处理使农田20cm以下土层大于5mm的团聚体明显高于表层土壤,各处理介于0.25到1mm之间的颗粒均略高于对照,且以高覆盖处理的比例最高。玉米收获后该土层土壤>0.25mm粒径团聚体有随覆盖量增加而增加的趋势,该土层>0.25mm粒径团聚体含量最高的为覆盖量9000 kg/hm2处理。?更多还原

【Abstract】 This research conducted winter wheat and spring maize cultivation experiments by setting different stalk cover rates on dry farmlands in semiarid areas in Southern Ningxia for two successive years. Through deep analysis of soil moisture, soil nutrient, enzyme activity and crop growth response under different rates, this paper aims to perfect stalk cover cultivation model and comprehensive technology of water reducing and saving in semiarid areas.1. By mulching treatment, crop growth is significantly superior to the control group. Plant height of wheat improves by 7%～14.9% and biomass accumulation increases 26.9%～40% compared with the control group. Increasing with the stalk cover amount, agronomic characters observed values of spring maize, as plant height, stem diameter, leaf area, and etc, improve obviously. In mature period, plant height of spring maize receiving high, middle, low mulching cover amount treatment improve by 25.9%、16.4%、13.2% respectively; stem diameter increases by 17.7%、16.3%、6.6% respectively; leaf areas increase by 48.9%、33.6%、21.4% respectively.2. Increasing with mulching cover amount, soil water content is superior to the control group. After harvesting of wheat under treatment of mulching cover amounts of 3000 kg/hm2、6000kg/hm2、9000kg/hm2 ,soil water contents increase by 13.1%﹑19.8%﹑26.1% averagely compared with the control group. When mulching cover amount is 3000 kg/hm2 , wheat yield and water use efficiency improve by 16.7% and 33.8% respectively. When yield is 3331.42 kg/hm2, spike length and grain number per spike increase by 28.7% and 27.6% respectively. In maize cultivation experiment, increasing with mulching cover amount, soil water preserving and storage effect increases also. By mulching cover treatment, during whole growth period of maize, water consumption amount decreases by 2.72%～6.66%. In this two-year experiment, every year the crop yield reaches the highest when the mulching cover amount is 9000 kg/hm2, and the yield is 5439.3 kg/hm2 and 5516.5 kg/hm2 respectively, increasing by 18.7% and 14.9% compared with the control group. When mulching cover amount is 4500 kg/hm2, moisture conservation effect is not obvious, with water use efficiency increases by 3.25% averagely. When mulch cover amount is 9000 kg/hm2 and 13500 kg/hm2, moisture conservation effect is significant, with water use efficiency of maize increase by 28.34% and 27.26% averagely compared with the control group.3. By mulching treatment, Crop photosynthetic rate and single leaf water use efficiency improve obviously. Under different mulching cover amounts, maize photosynthetic rate, transpiration rate and single leaf water use efficiency all increase, positively correlated with the mulching cover amount. In big trumpet period, maize photosynthetic rate increases by 22.5%～44.9%, transpiration rate increases by 8.57%-33.6%, and single leaf water use efficiency increases by 8.59%～21.4%, compared with the control group.4. Under mulching cover treatment for two years, soil nutrient content amount increases greatly. Content of available nitrogen, available potassium and organic matters in soil layer of 0～40cm deep of cornfields increase by 11.8%～15.7%, 6.4%～11.8% and 44.4%～55.5% respectively. Influence of Mulching cover amount on comprehensive soil nutrients content amount in cornfields is mainly in the farmland deep of 0～20cm, with organic matters content increases by 24.9%～25.9%,total phosphorus content increase by 6.9%～16.7%,total potassium content increases by 3.7%～7.2%. Influence rules of straw mulching amount on surface soil available nutrients contents is generally similar. By mulching cover treatment, available nutrients content in soil deep of 0～20cm increase all, correlated with the mulching cover amount.5. By mulching treatment, invertase enzyme activity and phosphatase enzyme activity increase significantly, but urease membrane activity and catalase activity receive no obvious effect. After harvest in cornfields in year of 2009, invertase enzyme and phosphatase enzyme increase by 7.7%～11.4% and 30.9～42.9% respectively. Influence of cornfields on soil enzymes activity is mainly in the soil layer of 0～20cm, with invertase enzyme and phosphatase enzyme increase by 3.1%～19.4% and 13.7～35.3% respectively compared with the control group. Influence in the soil layer of 20～40cm is not obvious.6. By mulching treatment, soil bulk density decreases significantly. After crop harvest, mulching cover amounts of 9000 kg/hm2、6000kg/hm2、3000kg/hm2 on soil bulk densities in soil layer deep of 0～20cm decrease by 5.5%, 2.3% and 0.8% respectively compared with CK. After maize harvest, under different mulching cover amounts, soil bulk density in soil layer deep of 0～60cm decreases by 0.7%～3.6% obviously compared with the control group. Mulching cover amount also has obvious effect on soil aggregate composition. After maize harvest, mulching treatment makes soil aggregate bigger than 5mm in soil layer below 20cm obviously higher than that in surface layer. Contents of particles large between 0.25 to 1mm receiving different mulching cover amounts treatment is obvious higher than the control group. After maize harvest, agglomerates of particle size >0.25mm has trend of increasing with mulching cover amount in the soil layer deep under 20cm, and he highest content of agglomerates of particle size >0.25mm is receiving mulching cover amount treatment of 9000 kg/hm2.更多还原