土壤耕作技术对小麦出苗质量、根系功能及粒重的影响

Impacts of Soil Tillage Techniques on Seedling Quality, Root Function and Grain Weight in Wheat

【目的】针对黄淮平原农作区一年两熟条件下玉米秸秆还田严重影响麦苗质量的突出问题,探索适宜的土壤耕作技术以提高小麦幼苗质量,最终提高产量。【方法】2016—2018年连续2年,在河南省新郑市辛店镇黄岗村开展田间试验。采用随机区组设计,将翻耕、耙、镇压3个因素组合配套实施8个处理,分别为深翻耕+旋耕(DT+RT;DT:30cm,RT:15cm)、深翻耕+耙(DT+H)、深翻耕+旋耕+镇压(DT+RT+C)、深翻耕+耙+镇压(DT+H+C)、旋耕(RT)、旋耕+耙(RT+H)、旋耕+镇压(RT+C)、旋耕+耙+镇压(RT+H+C)。对小麦出苗率及幼苗质量进行调查,并在越冬期、返青期、拔节期、抽穗期、灌浆期、蜡熟期对根系进行调查分析,分别在灌浆期对小麦籽粒性状、收获后对小麦产量及其构成因素进行调查分析。【结果】小麦播种后20d,不同土壤耕作处理间幼苗质量差异显著。旋耕后出苗整齐度高于深翻耕,而深翻耕后出苗率、基本苗数和株高高于旋耕。相同耕、镇压因素处理下,耙后出苗率增幅为1.0%—5.7%,相同耕、耙因素处理下,镇压后出苗率增幅为0.06%—8.3%;同时深翻耕后,极少出现缺苗、断垄,RT处理缺苗、断垄的累计长度最高,两年平均为55cm。从越冬期到蜡熟期,不同土壤耕作处理的根系活力均呈现“高-低-高-低”的变化趋势,DT+H+C处理最高;在越冬期和拔节期,镇压和耙处理后,与无镇压、耙处理相比,根系活力均提高。单株次生根数目在抽穗期达到最大,DT+H+C处理最高,两年最高值分别为45.2条与40.2条;与无耙处理相比,耙处理后,单株次生根数目最高增加14.8%,与无镇压处理相比,镇压处理后,单株次生根数目最高增加12.2%。花后5—10d,DT+H+C和RT+H+C处理的籽粒灌浆速率增长幅度显著高于其他处理,开花后20d达到峰值,其中DT+H+C处理籽粒灌浆速率比其他处理高1.0%—19.4%,达显著水平。灌浆期籽粒千粒重,在花后0—15d,DT+H+C处理增长最快,DT+RT处理增长最慢,花后25—30d,DT+H+C处理千粒重最高,较RT处理提高20.8%。从不同土壤耕作技术对籽粒产量及其构成因素的影响来看,DT+H+C处理的籽粒产量最高;耙和镇压处理的单位面积穗数、穗粒数和千粒重的变化并不规律,籽粒产量均有明显提升,幅度为1.4%—12.2%。经济效益方面,与当地以往耕作方式RT相比,RT+H、RT+H+C、RT+C、DT+H+C、DT+H处理所得效益均高于RT处理,其中DT+H+C处理产生经济效益最高,两年平均比RT处理高12.3%。【结论】黄淮平原农作区当前一年两熟制条件下,不同土壤耕作技术影响幼苗质量,旋耕有利于出苗的整齐度提高,而深翻耕则有利于出苗率及幼苗均匀度提高,株高增高,为冬前形成壮苗奠定基础;深翻耕将耕层加深,利于根系下扎,促进次生根数目的增加以及耕层根系活力的提高,间接影响籽粒产量。综合考虑植株根系生长发育、生育后期籽粒灌浆速率、粒重形成和产量表现等,研究认为黄淮农作区DT+H+C处理土壤耕作技术是当前的最佳选择。

【Objective】 In view of the prominent problem that corn straw to the field seriously affects the quality of wheat (Triticum aestivum L.) seedlings under the condition of double cropping per year of Huang-Huai Plain, appropriate soil tillage techniques were explored to improve quality of wheat seedlings and ultimately to increase wheat yield.【Method】The experiment was carried out at Huanggang village, Xindian town, Xinzheng city, Henan province for 2 consecutive years (from 2016 to 2018). By using a randomized block design, 8 treatments were carried out by combining three factors of plowing, harrow and compacting: deep depth tillage + rotary tillage (DT + RT;DT: 30 cm, RT: 15 cm), deep tillage + harrow (DT + H), deep depth tillage + rotary tillage + compacting (DT + RT + C), rotary tillage (RT), rotary tillage + harrow (RT + H), rotary tillage + compacting (RT + C), and rotary tillage + harrow +compacting (RT + H + C). Emergence rate and seedling quality of wheat were investigated, root characteristics were investigated during wintering stage, re-growing stage, jointing stage, heading stage, grain filling stage, dough stage, and grain characters, yield and its components were analyzed during the filling period, respectively.【Result】20 days sowing, quality of seedlings in different soil tillage treatments was significantly different. In rotary tillage treatments, emergence uniformity was higher than that in deep tillage treatments, while in deep tillage method, seedling emergence rate, basic seedlings and plant height were higher than those in rotary tillage method. Under the same plowing and compacting, emergence rate in harrow treatment emergence was 1.0%-5.7%;Under the same plowing and harrow, emergence rate in compacting treatment emergence was 0.06%-8.3%. At the same time, after deep depth tillage, seedling deficiency and wedging were rarely seen. Cumulative length of seedling deficiency and wedging under RT treatment was the highest, and the average length of the two years was 55 cm. From the wintering to dough stage, root activity in different soil tillage treatments showed a "high-low-high-low" trend, and it was the highest in treatment “DT + H + C”. In wintering and at jointing stage, root activity was increased after treated with compacting and harrow compared with that in treatments with neither compacting nor harrow. Secondary roots per plant reached the maximum in DT + H + C treatment at heading stage with the highest values were 45.2 and 40.2 in 2017 and 2018, respectively. After treated with harrow, secondary roots per plant were increased by 14.8% compared with those in treatments without harrow. After compacted treatment, secondary roots per plant were increased by 12.2% compared with those in treatments without compacting. Grain filling rate in DT + H + C treatment was significantly higher than that under other treatments during 5-10 days after anthesis, and reached its peak at 20 days after anthesis. Grain filling rate of DT + H + C treatment was higher than that under other treatments, while grain filling rate in DT + H + C treatment was higher than that under other treatments, and grain filling rate under DT + H + C treatment was 19.4% higher than that under other treatments (α=0.05). During grain filling stage, 1000-grain weight increased the most at 0-15 days after anthesis;Under DT + H + C treatments, it was increased the most;Under DT + RT treatments, it was increased the least;under DT + H + C treatments, it increased the most at 25-30 days after anthesis, which was 20.8% higher than that when treated by RT. According to the effects of different tillage techniques on grain yield and its components, the highest grain yield was obtained under DT + H + C treatment. Ears per unit area, kernels per ear and 1000-grain weight were not regular under harrow milling and repressing treatment, and grain yield increased obviously, with a range of 1.4%-12.2%. Economic benefits, in RT + H, RT + H + C, RT + C, DT + H + C, or DT + H treatment were all higher than those in RT treatment compared with the previous farming methods in the local area. Among them, the highest economic benefits was produced under DT + H + C treatment, and the two-year average was 12.3% higher than that under RT treatment【Conclusion】Under the current condition of two cropping systems in the Huang-Huai plain, different soil tillage techniques affected seedling quality, rotation tillage was beneficial to uniformity of seedling emergence, while deep tillage was beneficial to increasing seedling emergence rate, seedling evenness and plant height, laying a foundation for the formation of strong seedlings before wintering. The deep tillage deepened soil surface layer, which was beneficial to rooting, increased secondary roots and root activity in soil surface layer, and indirectly affected grain yield. Considering root system growth, grain filling rate, grain weight formation and yield performance, it was concluded that DT + H + C soil tillage technique was the best choice in Huang-Huai area.