【作者】 邹聪明；

【导师】 王龙昌；

【作者基本信息】 西南大学 ， 作物栽培学与耕作学， 2010， 硕士

【摘要】 保护性耕作技术自20世纪60年代传入我国后,国内科研工作者开展了大量关于保护性耕作的研究工作。但现有研究、示范大多是在我国北方干旱、半干旱地区开展,其研究对象通常是一年一熟制或者一年两熟制为主,且耕作措施较为单一。而针对西南旱三熟种植区农田配套保护性耕作模式的研究尚少,对该区保护性耕作条件下的土壤养分、农田生态、水分时空分布、作物生长发育响应以及水分利用率规律的认识也较为缺乏。有鉴与此,本研究于2007年11月～2009年11月在重庆市北碚区西南大学教学实验农场开展,试验以西南地区的“小麦／玉米／甘薯”和“马铃薯／玉米／甘薯”农作制度下旱作农田为研究对象,探明保护性耕作条件下农田养分、生态、水分的变化规律以及作物对保护性耕作措施响应特征。以当地气象和试验数据为基础,借助SPSS和DPS统计软件,对不同保护性耕作模式进行比较分析,为西南旱作区保护性耕作技术推广应用提供科学依据。主要研究结果如下：1、在土壤养分方面,五种保护性耕作模式均改善了土壤养分的供应状况。RSD(垄作+秸秆覆盖+腐熟剂)、TSD(平作+秸秆覆盖+腐熟剂)、RS(垄作+秸秆覆盖)、TS(平作+秸秆覆盖)处理较对照T有机质提高率分别为：28.27%、21.30%、16.54%、19.16%,容重分别下降了3.33%、3.00%、4.00%、2.67%,显著增加了全钾、全氮、碱解氮在土壤中的含量。而R(垄作)处理除了提高有机质含量,其他指标与传统对照无显著差异。针对土壤养分含量的动态变化情况,由于每一种耕作模式都包括不同的保护性耕作措施,农田耕层土壤养分含量的动态变化复杂,与单一的秸秆覆盖处理不尽相同。2、在农田生态环境方面,有秸秆覆盖的处理RSD、TSD、RS、TS无论从蚯蚓数量还是从生物量上均比无秸秆覆盖CK与R高,但是总体上看,RS与TS的效果要比RSD与TSD好。同时,RSD、TSD、RS、TS模式显著降低了7月份5cm与10cm土层的在14：00时的温度,缓解了高温对玉米生长后期造成伤害,而垄作措施对此影响不大。在杂草控制方面,秸秆覆盖相处理对于无秸秆覆盖处理无论从杂草高度、密度、还是生物量上都具有极显著效果,而起垄与平作两种措施没有出现显著差异,控制效果从高到低的顺序为：RS>TS>TSD>RSD>T(CK)>R。3、在农田土壤水分方面,连续两年大田试验表明各个处理均提高了0-80cm土层土壤贮水量,其顺序从高到低依次为RSD>RS>TSD>TS>R>T(CK)；在土壤水分的垂直动态变化方面,0～40cm土壤含水变化剧烈在21.45%-30.78%之间,40-60cm土层变幅相对较小,60-80cm土层相对比较稳定。这说明了保护性耕作有利于提高土壤贮水量,增加土壤水库库存量,同时对0-40cm土层土壤水分影响要明显大于40～80cm土层。4、在作物生长发育和生理特性方面,与传统耕作相比,保护性耕作处理显著提高了小麦成熟期时旗叶和倒数第二叶的叶面积,净光合速率也提高了2.90%-5.74%。整个灌浆—成熟过程(4.17～5.12)中,分配指数增加了238.46%-242.31%。在连续两年玉米苗期根系发育状况考察中,与传统耕作相比,保护性耕作处理增加了玉米苗期的根长、根表面积,显著增加了直径1.0-2.5 mm范围内的根长；苗期玉米根系活力分别提高19.12%-27.46%,根冠比分别提高36.72%-37.50%,根系生物量分别提高62.53%-77.37%。这说明了保护性耕作措施不但有利于作物根系发育,也促进了作物地上部分的生长发育,从而提高叶的净光合速率与植株的分配指数。5、在粮食产量和水分利用效率方面,各模式的两年系统平均粮食产量排列顺序为：RSD>RS>TSD>TS>R>T(CK)。垄作处理包括RSD、RS、R能显著增加薯类作物的产量,处理R、TS、RS、TSD、RSD的耗水量比T(CK)均有减少的趋势。各个处理水分利用效率与降水生产效由高到低的顺序均为：RSD>RS>TSD>TS>R>T(CK)。6、在经济效益比较分析方面,与对照传统耕作(T)相比,其他各处理的产出、纯收入均显著提高,其中产出提高了4.41%-17.40%、纯收入提高了5.36%-15.37%；产投比提高了3.84%-19.21%,排列顺序由高到低为RS>RSD>R>T(CK)>TSD>TS。通过本试验研究发现,针对旱三熟种植区,以上五种保护耕作模式对土壤养分和土壤水分具有良好的调节作用,能够调节土温、控制杂草和促进蚯蚓生长,使农田生态环境处于良好的自我动态调节状态,显著增加了作物产量与效益,提高了水分利用率,其中以RSD、RS的综合效果最好,值得在西南旱三熟种植区大力推广更多还原

【Abstract】 Since the 1960s when conservation tillage technology came into our country, scientists have carried out a number of studies. However, researches and demonstration are mostly conducted in arid and semi-arid areas of northern China and the study usually focus on one crop a year or two crops a year system, and tillage treatment is single. There is little study on conservation tillage models of three crops a year system in southwest China and the law of soil nutrients, agricultural ecology, water distribution, crop growth and development, and water use efficiency under the condition of conservation tillage is also lacking. Given this situation, this study was implemented in experimental farmland of Southwest University, Beibei District, in Chongqing City, from November 2007 to November 2009. Taking dry field under "wheat/corn/sweet potato" and the "Potato/corn/sweet potato" tri-crop intercropping system as a study object, the experiments were conducted to investigate soil nutrient, farm ecology and soil moisture and crop response to conservation tillage. Using local meteorological and experimental data, and the statistical software SPSS and DPS to compare different tillage patterns, it may provide the scientific basis for promotion of conservation tillage in this area. The major findings are as follows:1. In soil nutrient’s aspect, the five modes of conservation tillage all improved soil nutrient supply. Compared to T, the improvement rate of the SOM of RSD, TSD, RS, TD models were respectively by 28.27%,21.30%,16.54%,19.16%, decreasing the rate of bulk density by 3.33%,3.00%,4.00%,2.67%, significantly increased the content of total potassium, total nitrogen, nitrogen in the soil. While the other indexes of R were not significantly different from those of tradition, except the SOM. Dynamic changes of soil nutrients are more complex than a single straw mulch treatment because each of tillage models includes some different tillage methods.2. In the aspect of field’s ecological environment, straw mulching treatments like RSD, TSD, RS, and TS were higher than no straw mulching treatments CK and R in terms of the number of earthworms or biomass. But in all, the effects of RS and TS were better. At the same time, RSD, TSD, RS, TS model significantly reduced soil temperature in the 5cm and 10cm at 14:00 hours in July enhance easing the high-temperature damage on maize in late growth stages. However, compared to traditional tillage, R’s effect was not remarkable. In the weed control aspect, straw mulching treatments had more efficient than straw mulching treatments in terms of weed height, density, or biomass, while the ridge’s effect was not remarkable. The order of control results from the high to lower is as follow:RS> TS> TSD> RSD> T (CK)> R.3. In the aspect of soil moisture, two consecutive years of field trials showed that each treatment increases the soil water storage in 0～80cm soil layer. The order of soil water storage from the high to lower is as follows:RSD>RS>TSD>TS>R> T(CK). In the aspect of the vertical dynamic change of soil moisture,0～40cm of soil water content changed dramatically between 21.45%～30.78%, amplitude in 40～60cm soil layer is relatively small,60～80cm soil layer is relatively stable. This indicates that conservation tillage will help improve soil water storage capacity, increase soil reservoir stocks, while its effects on 0～40cm layer of soil moisture is significantly greater than 40～80cm soil layer.4. In the aspect of Growth and physiological characteristics of crops, compared to traditional tillage, conservation tillage significantly increased the area of the flag leaf and penultimate leaf, increased the net photosynthetic rate by 2.90%～5.74% in maturity stage of wheat. The process of maturation (4.17-5.12), the distribution of index rising trends increased by 238.46%～242.31%. Two consecutive years of field trials showed that conversation tillage significantly increased root length in the diameter range of 1.0～2.5 mm, root surface area in the seedling stage of maize, meanwhile increased root vigor by 19.12%～27.46%, root-shoot ratio by 36.72%～37.50%, root biomass by 62.53%～77.37%. This indicates that conservation tillage is not only beneficial to root development, but also promoted the growth of plants, thereby enhancing the leaf net photosynthetic rate and plant distribution index.5. In the aspect of grain yield and water use efficiency, the order of the average grain yield is as follow:RSD> RS> TSD> TS> R> T (CK). Tillage treatments including RSD, RS, and R significantly increased the yield of potato crops. And compared with treatment T, the trend of R, TS, RS, TSD and RSD were decreasing. The order of various water use efficiency and production efficiency of precipitation is as follow:RSD> RS> TSD> TS> R> T (CK).6. In the respect of benefit analysis, compared with treatment T, the output, net income of other treatments were significantly increased, the output by 4.41%～17.40%, net income by 5.36%～15.37%, output ratio by 3.84%～19.21%. The order of benefit analysis is as follow:RS> RSD> R> T (CK)> TSD> TS.From the experimental study, it can be concluded that the five conservation tillage models have good regulation effects on soil nutrient and soil moisture, including the regulation of soil temperature, the control of weed, the promotion of earthworms, and the significant improvement of crop yield, economic benefit and WUE. Integrated effect of RSD, RS are the best, and are worthy of promotion in the region of tri-crop intercropping system in southwest China.更多还原