沙区旱垄作对油菜生长环境的影响

垄作是沙区旱作农田常用的集水防风耕作技术。本文通过野外试验观测和土壤样品分析,对不同结构的垄作与平作下油菜生长环境进行了研究。结果表明,垄作相对于平作增加了生长季内土壤耕作层水分含量,降低了其波动幅度,改变了土壤水分在垂直剖面上的分布,使湿润锋位于耕作层,有利于油菜对土壤水分的吸收,对缓解干旱对作物生长的胁迫有积极作用。垄作下土壤易蚀性颗粒含量降低,地表粗糙度和垂直风速梯度增大,有效降低了土壤可蚀性和近地表风速,对防治土壤风蚀和保护作物幼苗有重要作用。不同结构的垄作比较,垄高15 cm、垄沟比1/12和垄高25 cm、垄沟比1/24的两种垄作在油菜生长季内集水效果较优,而垄高25 cm、垄沟比1/6的垄作在农田休闲期内防治风蚀效果较好。故结构合理的垄作是沙区旱作农田微观土地利用结构调整的有效措施。     

覆膜耕作方式对河套灌区土壤水热效应及玉米产量的影响

通过设置垄作全膜、垄作半膜、平作全膜以及平作半膜4个覆膜耕作处理,探究不同覆膜耕作方式对河套灌区土壤水热及春玉米产量的影响。结果表明:1)2个生长季内垄作全膜处理各阶段土壤含水率和温度均最高,保水保温效果明显。2)耕层土壤温度的变化规律和含水率的变化规律相反,随着土壤温度升高,土壤含水率逐渐降低。3)玉米生育期内随着温度升高和作物耗水量增大,全膜覆盖和垄作耕作方式的蓄水保墒效果愈加明显;干旱条件下,耕作措施较覆膜方式对地温的影响更为明显;而在水量充沛条件下,覆膜方式则表现出对地温更显著的影响。田间起垄耕作结合全膜覆盖的种植方式,可以获得较高的穗行数和穗粒数,有利于干物质的积累,促进滴灌条件下玉米产量的形成,同时提高水分利用效率,为河套灌区农业节水和玉米高产提供了技术依据。     

保护性耕作下大豆农田土壤呼吸及影响因素分析

为了探讨保护性耕作对旱作农田土壤呼吸的影响,采用LI6400-09仪器(LI6400便携式光合作用系统连接6400-09呼吸室)在重庆北碚西南大学试验农场对平作(T)、垄作(R)、平作+覆盖(TS)、垄作+覆盖(RS)、平作+覆盖+秸秆速腐剂(TSD)、垄作+覆盖+秸秆速腐剂(RSD)6种处理下的西南紫色土丘陵区小麦/玉米/大豆套作体系中大豆生长季节的土壤呼吸及其水、热、生物因子进行测定和分析,探讨西南丘陵区保护性耕作下大豆农田土壤呼吸及其影响因素。结果表明,大豆整个生育期内土壤呼吸先缓慢增强,到开花期开始增长迅速,成熟期明显下降。不同处理土壤呼吸速率存在差异,表现为TTSD>TS、R>RSD>RS,土壤呼吸的土温敏感指标Q10值排序为TS>TSD>RS=R>T>RSD。秸秆覆盖处理的土壤呼吸对于土壤温度敏感性较高,垄作则降低了土壤温度敏感性。5 cm土层的土壤含水量高低排序为TSD>RSD>TS>RS>T>R。本研究中土壤呼吸与土壤水分呈抛物线函数关系,垄作处理下土壤呼吸与土壤水分正相关,达到显著水平;其他处理均表现负相关,其中TS达到极显著水平。在大豆农田生态系统中优势类群有弹尾目、螨目和双翅目,干漏斗法、陷阱法捕获的土壤动物与土壤呼吸均没有显著的相关关系,两种方法所得土壤动物数量加总与土壤呼吸进行相关分析,发现处理T相关系数达到显著水平,r=0.901,P=0.037。     

垄作对旱作农田土壤风蚀影响的风洞实验研究

通过风洞实验,在5个风速下对6种不同结构的垄作及平作对照地的土壤风蚀速率、O～20cm风沙流结构进行了模拟观测研究。结果表明：垄作下平均土壤风蚀速率较平作下降低20％～60％。垄作和平作下土壤风蚀速率均随风速的增大呈幂函数递增,但平作下递增较快。风速为15m／s是早作农田土壤风蚀加剧的转折点,当风速大于15m／s时垄作下风蚀速率较平作下明显降低。0～20cm内,平作和垄作下输沙率与高度分别呈负指数和负线性关系。垄作下0～4cm输沙量和输沙量百分比(Q0～4／Q0～20)均低于平作。不同结构的垄作间进行比较,垄脊高度相同时,垄沟比(垄脊高度与垄顶距的比值)越大,土壤风蚀速率越小,而Q0～4／Q0～20越大;垄沟比相同时,垄脊越高,土壤风蚀速率越大,而Q0～4／Q0～20越小。     

稻田长期垄作免耕对水稻产量及土壤肥力的影响研究

不同耕作条件下的水稻生长发育、作物产量及土壤肥力状况的研究表明,稻田长期垄作免耕,水稻根系数量、白根率、根系活力比常规平作和水旱轮作高,分蘖时间早;垄作免耕水稻的株高、茎粗、穗长、穗粒数增加,11年水稻平均产量垄作免耕比常规平作和水旱轮作分别提高了10.3%和11.3%。垄作免耕改变了土壤的物理、化学性状,土壤容重、土壤养分含量明显提高,土壤微生物数量和酶活性增强,土壤表层松结态腐殖质含量比常规平作和水旱轮作高0.194和0.238个百分点,紧结态腐殖质降低0.098和0.037个百分点。垄作免耕有利于提高作物产量、培肥地力、改善土壤生态环境。     

寒地水稻垄作双深耕作栽培模式技术效果的评价

为评价垄作双深耕作栽培模式对土壤部分理化指标和水稻产量及肥料利用效率的影响,在3个试验地点,对垄作双深耕作栽培(简称垄作)和常规平作耕作栽培(简称平作)的产量、干物质生产、根部性状、肥料利用率及土壤容重、团聚体和温度进行了比较研究。结果表明:采用该技术模式,土壤容重下降,土壤温度和团聚体升高是普遍现象。垄作0—5 cm和5—10 cm土层的容重分别下降10.40%,10.26%,0—10 cm和10—20 cm土层团聚体分别增加27.85%,14.18%,6月上旬—9月上旬距地表5,10,15 cm位置旬平均温度分别升高2.35,0.58,1.12℃。垄作齐穗期干物重和叶面积指数、灌浆期干物重和叶面积指数、各时期根干重方面表现出显著优势。垄作平均增产7.85%,增产幅度为7.92%～9.86%,穗数或穗粒数增加是其增产的主要原因。垄作氮肥贡献率、土壤氮素依存率、氮肥农学利用率和氮肥偏生产力分别较平作提高13.85%,15.46%,20.86%,6.97%。因此,垄作双深耕作栽培模式改善了土壤理化性质,促进根系生长发育,从而使水稻地上部分表现出生长优势,提高了肥料利用率和产量。     

不同覆盖和耕作方式对紫色土著人坡耕地降雨土壤蓄积量的影响

利用模拟径流小区随机区组试验,在自然降雨条件下定量研究了覆盖和耕作方式对玉米全生育期雨水蓄积量的影响.结果表明:在不采取覆盖措施的条件下,雨水土壤蓄积量的顺序为:横坡分带耕作>横坡垄作>顺坡垄作>平作,横坡分带耕作是适用于四川盆地紫色土旱坡地的高效节水农耕措施,平作不利于该区域玉米抗旱稳产.秸秆覆益能够显著提高雨水的土壤蓄积量,提高降雨有效性,是适用于该区域的节水抗旱农艺措施.地膜覆盖增加雨水土壤蓄积量的效果不如秸秆覆盖显著,但地膜覆盖能够减少土壤水的无效的蒸发,在玉米生育前期还能提高地温,促进玉米生长,其增产效果较秸秆覆盖好.     

农牧交错带不同农田耕作模式土壤水分特征对比研究

通过在农牧交错带———内蒙古自治区太仆寺旗的野外实验研究,在作物(油菜)发育期间,观测了免耕、深松、传统翻耕、翻耕覆盖、浅耕与垄作处理等8种耕作模式的土壤水分特征;在秋收后的农田休闲期,观测了秸秆还田翻耕、深松耕作、传统翻耕、免耕低茬(茬高10cm)和免耕高茬(茬高4 5cm)等5种耕作模式的土壤水分特征。实验结果表明:在实验区,采用不同耕作模式,对田块土壤水分含量有着直接影响。在作物发育期间,垄作处理蓄水保墒能力相对较强,免耕、浅耕蓄水保墒能力相对较差,翻耕覆盖、深松耕作、传统翻耕蓄水保墒能力相对居中;秋收后,免耕高茬蓄水保墒效果最好,深松耕作、传统翻耕蓄水保墒能力居中,秸秆还田翻耕、免耕低茬蓄水保墒效果较差。本文所得结论对农牧交错带旱作农田有效保蓄土壤水分、提高农田土壤水分利用效率和增强农田防风抗蚀能力有积极借鉴意义     

不同种植方式麦田生态效应研究

试验研究2个小麦品种“烟农19”和“95(6)161”不同种植方式麦田生态效应结果表明,垄作栽培可显著降低耕作层土壤容重,提高土壤孔隙度,更适宜小麦根系生长。土壤呼吸强度垄作栽培20~40cm土层>平作栽培20~40cm土层>垄作栽培0~20cm土层和平作栽培0~20cm土层。相同灌水量垄作栽培渗入深层土壤中的水分显著高于平作,2个小麦品种垄作栽培水分利用效率分别为1·62kg/m3和1·56kg/m3,较传统平作栽培分别提高21·8%和16·4%。垄作栽培小麦群体内空气湿度较平作栽培降低3·5%~15·5%,同一品种不同种植方式群体透光率均为垄作栽培>平作栽培。且小麦籽粒光能利用率提高10·0%~13·2%,总干物质产量光能利用率提高10·3%~10·8%。     

保护性耕作下蚕豆/玉米/甘薯三熟制农田土壤呼吸、碳平衡及经济-环境效益特征

垄作和秸秆覆盖是实现西南丘陵区旱地农田稳产高产和固碳的适宜保护性耕作模式。为探讨该保护性耕作模式下蚕豆/玉米/甘薯三熟制农田土壤碳排放的特征,对平作无覆盖(T)、垄作无覆盖(R)、平作+秸秆半量覆盖(TS1)、垄作+秸秆半量覆盖(RS1)、平作+秸秆全量覆盖(TS2)、垄作+秸秆全量覆盖(RS2)6种耕作模式下西南紫色土丘陵区蚕豆/玉米/甘薯三熟制农田土壤呼吸、粮食产量特征进行测定,分析农田碳平衡及经济-环境效益,为量化评估农田生态系统碳收支提供理论依据。结果表明:在整个间套作系统内,蚕豆、玉米和甘薯全生育期内土壤呼吸速率均值分别为3.704μmol·m~(-2)·s~(-1)、4.847μmol·m~(-2)·s~(-1)和4.606μmol·m~(-2)·s~(-1),垄作降低了3种作物的农田土壤呼吸速率(P0.05),秸秆覆盖则增加了土壤呼吸(P0.05),垄作和秸秆覆盖配合使用后土壤呼吸总量和微生物呼吸总量增加(P0.05)。保护性耕作促进三熟制农田生态系统内作物固碳;土壤-作物系统碳平衡表现为碳汇,RS2、TS2、RS1、TS1、R分别较T高25.41%、25.37%、9.84%、26.74%、13.26%。与平作相比,垄作和秸秆覆盖提高了粮食产量,以RS2(17 460.45 kg·hm~(-2))最高,TS2(16 498.73 kg·hm~(-2))次之。蚕豆/玉米/甘薯三熟制农田生产每千克籽粒释放CO_2量处理间表现为T(1.88 kg?kg~(-1))TS1(1.83 kg?kg~(-1))R(1.76kg?kg~(-1))TS2(1.75 kg?kg~(-1))RS1(1.69 kg?kg~(-1))RS2(1.68 kg?kg~(-1))。垄作和秸秆覆盖提高了套作的经济-环境效益,秸秆覆盖量越高,经济-环境效益越好。从农田碳平衡和经济-环境效益综合考虑,垄作结合秸秆全量覆盖(RS2)具有最大的碳汇能力和最优的经济-环境效益,可以优先作为该地区农田实现固碳增汇减排的耕作措施。     

陕北黄土丘陵区山地苹果园的土壤水分动态研究

掌握土壤水分特征是实现果园科学管理、有限雨水资源合理高效利用、保证果树高产优质的关键。以陕北米脂山地6年生红富士苹果园为研究对象,于2015年4月—2016年6月采用FDR、中子水分仪和烘干法相结合的土壤水分监测方法,分析了山地苹果园的土壤水分总体特征、单株不同位点的水分动态以及不同旱作措施(秸秆覆盖、起垄覆膜垄沟集雨、有机肥覆盖)的土壤水分环境效应。结果表明:陕北山地果园时段干旱严重,最严重的为苹果树新梢生长和幼果发育期;春季土壤干旱程度取决于上年入冬前土壤储水量高低。果园0~60 cm土层(根系分布集中层)水分随降雨量而变化,表现为较一致的季节变化特征;土壤水分的变化滞后于降雨变化,且降雨对土壤水分的影响随土层加深而减弱,100 cm深土层受降雨影响减弱,土壤剖面200 cm以下土层土壤含水量保持相对稳定。6年生山地苹果园土壤已经出现干化现象,且在90~300 cm存在明显的低湿层,土壤体积含水量常年处在12%以下。苹果树单株尺度范围内,土壤含水量随距树干距离增加单调递增;土壤水分的平均值处在距树干105 cm处;沿行向距树干不同距离位点的土壤含水量显著高于沿株向距树干等距离位点的含水量(P0.05)。秸秆覆盖、起垄覆膜垄沟集雨和有机肥覆盖措施相较于空白对照(不覆盖、不灌溉)均能有效改善土壤水分环境,缓解果树生育期内水分供需矛盾,其中起垄覆膜垄沟集雨措施的保墒效果最佳,建议陕北黄土丘陵区山地雨养苹果园采用起垄覆膜垄沟集雨的保墒措施。     

Tillage and nitrogen effects on growth,nitrogen content,and yield of corn

Abstract

The use of conservation tillage methods, including ridge tillage, has increased dramatically in recent years. At the present time, there is great concern that farmers are applying more nitrogen (N) fertilizer than is environmentally or economically sound. In order to determine if N requirement for optimum yield differs with tillage system, tests were initiated to study tillage and N effects on N content, soil moisture content, and yield of corn (Zea mays L.). The study was established in 1987 on two soil types, an Estelline soil (Pachic Haploboroll) and an Egan soil (Udic Haplustoll), located in eastern South Dakota. Five rates of N (0, 65, 130, 195, and 260 kg ha^?1) were applied to plots managed with 3 tillage systems: chisel plow, moldboard plow, and ridge. On the Estelline soil, in both 1988 and 1989, ridge‐tilled plots contained a greater amount of water in the soil profile at emergence and at mid silk than did plots in the other two tillage systems. Soil moisture content at mid silk was significantly correlated with earleaf N, total N uptake, and grain yield in 1988 and earleaf N and grain yield in 1989. However, the correlation coefficients were higher in 1988 than in 1989. On the Egan soil, there were no significant differences in soil moisture content among tillage systems. On the Estelline soil, corn grain yield was affected by a tillage x N‐rate interaction in 1988. Maximum yield within the ridge system was achieved with the 130 kg ha^?1 rate. In 1989 on the Estelline soil, yield was affected by tillage and N rate, but there was no interaction between factors. When averaged over N rates, yields were 7.1, 6.6, and 6.5 Mg ha^?1 in the ridge, moldboard, and chisel systems, respectively. In 1988 plant total N uptake was greater in the ridge system than the moldboard or chisel systems; in 1989 uptake was affected by N rate alone. On the Egan soil, tillage did not affect soil moisture, total N uptake or grain yield in either year. Corn grain yield increased with increasing N rate up to the 195 kg ha^?1 rate. This study indicates that, on some soil types, ridge tillage can improve soil water holding capacity, N utilization and yield of corn.     

渭北旱塬果园自然生草对土壤水分及苹果树生长的影响

土壤水分不足是渭北旱塬苹果生产中的首要问题。为了提高果园土壤贮水量,促进果树生长,该试验以果园清耕和人工生草(三叶草)为对照,探讨渭北旱塬果园自然生草(繁缕和牛繁缕群落)对土壤水分及苹果树生长的影响。结果表明:自然生草在苹果开花坐果期可提高0~80 cm土层土壤水分,在幼果膨大期和花芽分化期可提高0~120 cm土层土壤水分,在果实采前膨大期可提高0~160 cm土层土壤水分,而人工生草则降低了土壤水分。自然生草和人工生草主要影响0~80 cm土层土壤水分,且对0~40 cm土层土壤水分影响较大,对120 cm以下土层影响较小。自然生草的土壤蒸散量较人工生草和清耕分别减少了17.30和8.07 mm,单果重分别提高了15.46%和6.21%,产量分别提高了21.29%和6.10%,土壤水分利用效率分别提高了25.09%和7.64%。自然生草不但可提高果园土壤贮水量,而且可提高果实单果重与产量,渭北旱塬应积极推广果园自然生草。     

Wind tunnel simulation of ridge-tillage effects on soil erosion from cropland

In the arid and semi-arid regions, ridge tillage was often used as an alternative practice for wind erosion control on the croplands without sufficient crop residues left during the fallow period. Through wind tunnel experiments, wind erosion rate and vertical mass flux profile of blown sand under the simulated conditions of ridge tillage and flat tillage were studied in 15, 10, 10, 5, 3 min exposures at the wind velocities of 8, 10, 15, 20, 24 m s⁻¹, respectively. The results for the soil tested indicate that the mean rate of wind erosion under flat tillage was 129.89 g m⁻² min⁻¹, while that under ridge tillage were 20–60% less. Under ridge tillage with different structures, average wind erosion rate had a positive correlation with the spacing between adjacent ridges. For the same ridge height, average wind erosion rate decreased with increasing ratio between the height of ridge and the width of furrow. For the same ratio between the height of ridge and the width of furrow, average wind erosion rate increased with increasing height of ridge. Power function relationships were found between wind erosion rate and wind velocity on all the simulated tillage conditions. A wind velocity of 15 m s⁻¹ was the critical velocity, above which wind erosion rate increased rapidly for the soil and simulated tillage conditions tested. Compared with flat tillage, ridge tillage remarkably decreased wind erosion rates when wind velocities were beyond 15 m s⁻¹. Under ridge tillage, the total mass of sand transported at a height of 0–20 cm above soil surface (Q_0–20), and the fraction of that travelling at a height of 0–4 cm (Q_0–4/Q_0–20), were less man mat under flat tillage. For the same ridge height, Q_0–4/Q_0–20 increased with increasing ratio between the height of ridge and the width of furrow. For the same ratio between the height of ridge and the width of furrow, Q_0–4/Q_0–20 decreased with increasing height of the ridge. Sand transport rate under flat tillage decreased with increasing height by a negative exponential function, while negative linear functions were found under ridge tillage. Thus ridge tillage decreased the rate of wind erosion and sand transportation near soil surface, reduced the loss of soil nutrient caused by wind erosion and plant damage caused by blown sand abrasion, which make it an effective agricultural technology for wind erosion control in the arid and semi-arid regions.     

Seasonal variation of microbial biomass, activity, and community structure in soil under different tillage and phosphorus management practices

No-tillage systems contribute to physical, chemical and biological changes in the soil. The effects of different tillage practices and phosphorus (P) fertilization on soil microbial biomass, activity, and community structure were studied during the maize growing season in a maize–soybean rotation established for 18 years in eastern Canada. Soil samples were collected at two depths (0–10 and 10–20 cm) under mouldboard plow (MP) and no-till (NT) management and fertilized with 0, 17.5, and 35 kg P ha^?1. Results show that the duration of the growing season had a greater effect on soil microbiota properties than soil tillage or P fertilization at both soil depths. Seasonal fluctuations in soil microbial biomass carbon (SMB-C) and nitrogen (SMB-N), in dehydrogenase and alkaline phosphomonoesterase activities, and in total phospholipids fatty acid (PLFA) level, were greater under NT than MP management. The PLFA biomarkers separated treatments primarily by sampling date and secondly by tillage management, but were not significantly affected by P fertilization. The abundance of arbuscular mycorrhizal fungi (AMF; C16:1ω5) and fungi (C18:2ω6,9) was lower under NT than MP at the 10–20-cm soil depth in July. Phosphorus fertilization increased soil microbial biomass phosphorus (SMB-P) and Mehlich-3 extractable P, but had a limited impact on the other soil properties. In conclusion, soil environmental factors and tillage had a greater effect on microorganisms (biomass and activity) and community structure than P fertilization.     

垄沟耕作条件下滴灌冬小麦田间土壤水分的动态变化

试验在池栽条件下研究了滴灌与垄沟耕作条件下冬小麦田间土壤水分的动态变化。结果表明：滴灌对0～60cm土壤水分含量影响比较明显，由于受土壤蒸发和作物根系吸收水分的影响，0～30cm土壤水分含量在整个生育时期内变化最为剧烈，其次是30～60cm层次的土壤，90～120cm层次的土壤整个生育时期水分含量最为稳定。灌溉后土壤水分0～120cm土层中呈现“Z”型分布，且与垄作相比，灌溉对沟播处理各层次的影响更大。另外，通过对不同生育时期各个层次土壤水分含量的分析可以看出，冬小麦的灌浆期是其活跃的耗水期，其次是抽穗期。不灌溉处理的耗水深度主要集中在土壤下层，灌溉处理的耗水程度变化较复杂。与畦播处理相比较（见讨论部分），灌溉后沟播处理土壤水分上升最明显，垄作处理次之，畦播最小。灌溉一周后畦播土壤水分下降最快，垄作次之，沟播最小。而就灌溉后土壤水分运动而言，垄作与沟播处理快于畦播处理。     

Spring wheat growth and 15N studies under zero and shallow tillage on the Canadian prairie

Zero-tillage (ZT) farming systems offer the potential of reducing soil erosion and conserving soil moisture on the semi-arid regions of the Canadian prairie. Since changes in soil tillage may alter the soil condition and environment, field experiments were conducted to assess the effect of ZT on spring wheat growth and ¹⁵N urea utilization and recovery. The study compared ZT and conventional shallow tillage (ST, 10 cm) systems, of 2–16-year duration, situated on a range of Chernozemic soils. Generally, ZT produced similar grain and straw yields as the ST; incidences of reduced yield under ZT were associated with poor seedling establishment. Characteristic lower soil temperature (1–4°C in seed row at 5-cm depth) under ZT was not related to crop yield, except for reduced early growth at one site. Soil moisture (to 120 cm) was similar between tillage systems, although moisture variations at the soil surface (0–5 cm), associated with differences in surface mulch, were apparent. Plant uptake of P and K was similar between tillage systems. Differences in N concentration, plant uptake of soil and fertilizer N and indices of available soil N between tillage systems over the growing season, tended to be small and did not differ substantially, although site or location differences were evident. Overall N yield was mainly related to the ability of the plant to utilize N for growth and plant yield. Recovery of the fertilizer N in the soil-plant system was not related to differences in soil tillage.