Economics of reduced tillage for cereal and legume production on rainfed farm enterprises of different sizes in semiarid conditions

Rainfed crop yields are low in semiarid central Spain because precipitation is limited and highly variable. Under these circumstances, producers have to adopt alternative tillage systems that convey a reduction in their unit costs of production to offset the continuous decline in commodity prices. Farmers respond to this situation in essentially two ways: there is a growing interest in adopting reduced tillage systems for seedbed preparation, and a trend to enlarge enterprises by acquiring more arable land either as ownership or tenancy. The objective of the present study was to assess, in semiarid conditions of central Spain, the economic feasibility of chisel ploughing (CP) and no-tillage (NT) systems compared to mouldboard ploughing (MP) for rainfed winter wheat (Triticum aestivum L.) and forage legume, either vetch (Vicia sativa L.) or pea (Pisum sativum L.), production on different farm sizes ranging from 100 to 1600 ha. A decision support system was used to solve for the least-cost machinery selection for each farm enterprise and tillage system considered. No differences were observed in either wheat or forage vetch crop yields averaged across several years, irrespective of the tillage system used. The economic performance was found to depend on the tillage system adopted and farm size. On average fuel consumption was 23% lower in CP and 62% in NT than in MP. Total variable unitary costs were 3.7 and 5.6% lower in CP and NT than in MP. The cost of herbicides in NT was €7.6 ha⁻¹ year⁻¹ higher than in MP and CP. Average unitary gross margins were 11.9 and 10.8% higher in NT than in MP and CP, respectively. If revenues were considered similar in the three tillage systems, MP would still exhibit the poorest economic results in all farm sizes, while CP performance would improve NT values in farm sizes with 200 ha, or less, of arable land. NT was clearly the most profitable system on farms with 400 ha or more of arable land. The 400 ha farm enterprise was observed to mark the breakeven point between the two reduced tillage systems, since up to that size CP was found to provide a better economic performance than NT.     

Rotation and tillage effects on soil organic carbon sequestration in a typic Hapludalf in Southern Ontario

Increased use of conservation tillage is being considered as a way to sequester atmospheric C in the soil. However, little information exists on the effect of rotation and its interaction with tillage on soil organic carbon (SOC). A research trial with combinations of rotations and tillage treatments was sampled 20 years after its establishment to assess the effects on SOC sequestration in a typic Hapludalf in southern Ontario, Canada. The cropping treatments included continuous corn (zea mays L.), six rotations comprised of 2 years of corn following 2 years of another crop or crop sequence, and continuous alfalfa (Medicago sativa L.). Each rotation was split into either fall moldboard plow (MP) or fall chisel plow (CP) treatments. Continuous alfalfa was plowed and replanted every 4 years. Soil samples were taken incrementally to a depth of 40 cm and SOC and bulk density determined. The average SOC concentration (0–40 cm) was greatest in continuous alfalfa (18.0 g C kg⁻¹). The treatments of soybean (Glycine max L.Merr.)+winterwheat (Triticum aestivum L.) or barley+barley (Trifolium pratense L.) (interseeded with red clover) followed by 2 years of corn had higher SOC concentrations (17.2–17.3 g C kg⁻¹) than continuous corn and the treatments of 2 years of corn following 2 years of alfalfa or soybean (16.4–16.5 g C kg⁻¹). The rotation of 2 years of barley followed by 2 years of corn had the lowest SOC concentrations (15.2 g C kg⁻¹). On an equivalent mass basis, the rotations of soybean+winterwheat or barley+barley (underseeded with red clover) followed by 2 years of corn, had 2–9 Mg ha⁻¹ more C than the other corn-based rotations. Including red clover in the winter wheat seemed to accelerate the rate of C mineralization compared to winter wheat without red clover; whereas interseeding red clover with barley increased SOC contents compared to excluding red clover in the barley rotation. More SOC was found in the top 10 cm and less in the 10–20 cm depth of the CP than in the MP soils. However, the CP did not increase the SOC content (0–20 cm) above that of MP indicating that this form of reduced tillage did not increase C sequestration in any of the rotations on this soil.     

休闲期不同耕作方式对洛阳冬小麦农田土壤水分的影响

采用连续5a的田间定位试验资料,研究了洛阳地区休闲期4种不同耕作方式对冬小麦农田土壤水分变化、水分利用效率及作物产量的影响。结果表明：休闲期不同耕作方式对冬小麦播种前底墒具有明显的影响,与传统耕作方式相比,免耕和深松覆盖处理可以显著增加土壤含水率,具有良好的保墒作用;各处理以深松覆盖作物产量和水分利用效率最高,其次为免耕处理,深翻处理效果较差。因此,洛阳地区采用深松覆盖保护性耕作方式比较有利。     

保持耕作麦田水分动态及水土流失的研究

通过对豫西夏休闲坡耕地不同耕作方式下冬小麦田水分变化规律及其生态效益的研究 ,结果表明 :免耕、深松的土体内含水量、接纳降水能力均明显高于传统耕作 ,免耕与深松处理降水贮蓄率分别比传统高 1 3 .3 3 %和 5 .84% ,能促使降水在不同坡位中均匀分布 ,其中免耕优于深松。免耕条件下 ,提高了冬小麦出苗率 ,明显地促进生长发育 ,产量比传统耕作增产了1 9.3 % ,水分利用效率也提高了 1 7.5 % ;深松也提高了冬小麦出苗率 ,但对冬小麦生长发育影响不明显 ,产量比传统耕作增产了 9.4% ,水分利用效率提高了 8.5 %。     

河西灌区不同耕作与秸秆还田方式对春小麦出苗及产量的影响

出苗率及出苗整齐度在很大程度上决定了作物生长状况和产量丰欠,针对不同耕作措施结合秸秆还田对绿洲灌区小麦出苗及群体动态影响研究薄弱问题,研究不同秸秆还田与耕作方式对小麦出苗与产量的影响,以及二者的相关关系,对于优化耕作措施具有重要指导意义。2014—2015年,在甘肃河西绿洲灌区,通过田间定位试验,研究了不同秸秆还田和耕作措施[少耕25~30 cm高茬收割秸秆立茬还田(NTSS)、少耕25~30 cm高茬收割秸秆覆盖还田(NTS)、翻耕25~30 cm高茬收割秸秆还田(TS)和不留茬翻耕(CT)]对小麦出苗状况及产量、产量构成因素的影响,以期为优化试区小麦栽培技术提供依据。结果显示,与CT相比,NTSS、NTS降低了小麦出苗率以及出苗整齐度,TS则提高了小麦出苗率以及出苗整齐度。NTSS、NTS较CT的分蘖数分别高7.4%~10.5%、14.6%~19.1%,分蘖成穗率分别高13.5%~20.1%、33.0%~34.7%,有效穗数分别高7.5%~9.3%、10.3%~11.2%,穗粒数分别高15.7%~16.1%、18.5%~22.6%,千粒重分别高7.2%~8.9%、13.9%~14.2%,但TS与CT在以上指标间没有显著差异。NTSS、NTS与CT相比较,分别增产16.6%~17.4%、18.6%~21.4%,以NTS增产幅度较大,比TS高10.3%~11.0%。穗数和穗粒数的增加是少耕秸秆还田获得高产的主要原因,出苗率及整齐度对产量影响不显著。同时NTSS和NTS均获得较高的收获指数,提高比例分别为9.4%~10.7%与10.5%~11.1%,说明少耕秸秆还田提高籽粒产量的另一原因是提高了光合产物向籽粒中的转化。本研究表明,少耕秸秆还田是适用于试区小麦高产的理想耕作措施。     

UV-B辐射增强和免耕对冬小麦冠层反射光谱特性的影响

通过田间模拟UV-B辐射增强,并采用FieldSpec Pro FR光谱仪进行田间观测,对UV-B辐射增强20％(U)条件下免耕(Z)和深耕(C)两种耕作方式对冬小麦冠层反射光谱和一阶导数光谱的影响进行研究,试验以无UV-B辐射增强(N)为对照,共设4个处理,分别为ZU、ZN、CN、CU.结果表明,冬小麦冠层光谱能有效监测UV-B辐射增强和两种耕作方式的复合作用.各处理间小麦冠层反射光谱的差异主要体现在近红外高台,灌浆期是最佳监测生育期.在灌浆期,U处理导致小麦冠层光谱近红外高台反射率明显降低,Z处理的近红外高台反射率明显低于C处理,且其受U处理的影响小于C处理,表明免耕具有延缓叶片衰老的作用.进一步采用一阶导数光谱分析发现,各处理在开花期和灌浆期均有显著差异.U处理导致红峰高度在灌浆期显著降低.Z处理的红峰高度明显低于C处理,红边位置比C处理偏红,并出现多峰情况.在未来UV-B辐射增强情景下,研究结果可为不同耕作方式下冬小麦采用冠层光谱进行无损检测的可行性提供理论参考.     

Agro‐ecological classification and spatial demarcation of Western Europe: Results of an EU‐funded research programme

The paper presents a hierarchic system of agro‐environmental classification of regions and landscapes. At the highest level are agro‐climatic regions (AKR). Allocating soil data, these units are broken down to soil‐climatic regions (Boden‐Klima Regionen, BKR). The next level is defined by geological data, topography “typical patterns of land uses”; and results in landscape types (LT). The AKR are used to define the intensification level and the energy surplus of agro production. The BKR allow specific analysis of impacts to environment factors of farm production systems. In the LT, specific targets for sustainable production and landscape rehabilitation are developed. The results are proposals to refine European agro‐policy towards more environmentally oriented schemes. The data is also valid to control the positive environmental effects of farmers adaptation of schemes.     

Assessment of cowpea and groundnut contributions to soil fertility and succeeding sorghum yields in the Guinean savannah zone of Burkina Faso (West Africa)

Atmospheric biological nitrogen fixation (BNF) by cowpea (Vigna unguiculata) and groundnut (Arachis hypogea) was evaluated using a 2-year (2000–2001) experiment with different fertilizer treatments. The ¹⁵N isotopic dilution method with a nonfixing cowpea as test reference crop was used. The effects of the two legumes on soil N availability and succeeding sorghum (Sorghum bicolor) yields were measured. Groundnut was found to fix 8 to 23 kg N ha-1 and the percentage of N derived from the atmosphere varied from 27 to 34%. Cowpea fixed 50 to 115 kg N ha⁻¹ and the percentage of N derived from the atmosphere varied from 52 to 56%. Compared to mineral NPK fertilizer alone, legumes fixed more N from the atmosphere when dolomite or manure was associated with mineral fertilizers. Compared to soluble phosphate, phosphate rock increased BNF by cowpea. Significant correlation (p<0.05, R ²=0.94) was observed between total N yields of legumes and total N derived from the atmosphere. Compared to monocropping of sorghum, the soils of cowpea–sorghum and groundnut–sorghum rotations increased soil mineral N from 15 and 22 kg N ha⁻¹, respectively. Cowpea–sorghum and groundnut–sorghum rotations doubled N uptake and increased succeeding sorghum yields by 290 and 310%, respectively. Results suggested that, despite their ability to fix atmospheric nitrogen, N containing fertilizers (NPK) are recommended for the two legumes. The applications of NPK associated with dolomite or cattle manure or NK fertilizer associated with phosphate rock were the better recommendations that improved BNF, legumes, and succeeding sorghum yields.     

耕作措施对温带半干旱地区土壤温室气体(CO2、CH4、N2O)通量的影响

通过设置在甘肃省定西市李家堡镇的不同耕作措施试验, 利用CO₂分析仪、静态箱-气相色谱法对双序列轮作次序下春小麦地、豌豆地生育期内CO₂、CH₄和N₂O通量进行了测定。试验结果表明: 4种耕作措施下春小麦地和豌豆地在生育期内均表现为CO₂源、N₂O源和CH₄汇的功能。传统耕作不覆盖、免耕不覆盖、免耕秸秆覆盖和传统耕作结合秸秆还田下, 春小麦生育期内平均土壤CO₂通量(μmol·m^-2·s^-1)分别为0.203 6、0.221 2、0.241 8、0.224 9, CH₄通量(mg·m^-2·h^-1)分别为-0.041 6、-0.078 0、-0.081 8、-0.053 7, N₂O通量(mg·m^-2·h^-1)分别为0.089 1、0.069 2、0.046 1、0.065 6; 豌豆生育期内平均土壤CO₂通量(μmol·m^-2·s^-1)分别为0.273 6、0.261 6、0.218 1、0.236 0, CH₄通量(mg·m^-2·h^-1)分别为-0.055 0、-0.073 7、-0.066 2、-0.054 5, N₂O通量(mg·m^-2·h^-1)分别为0.123 4、0.084 7、0.080 6、0.035 0。少免耕及小麦秸秆覆盖有利于减少土壤CO₂排放通量, 免耕不覆盖、免耕秸秆覆盖及传统耕作结合秸秆还田均能不同程度地增加CH₄吸收通量、减少N₂O排放通量。综合来看, 免耕不覆盖、免耕秸秆覆盖和传统耕作结合秸秆还田3种保护性耕作措施有助于减少土壤温室气体的排放量。春小麦地CO₂通量随着土壤温度、土壤含水量的逐渐升高而增大; CH₄吸收通量随着土壤含水量的逐渐升高而增大, 而随着土壤温度的逐渐升高而减小。豌豆地CO₂通量的变化与土壤含水量存在极显著正相关关系; 而春小麦地N₂O通量则与平均土壤温度呈显著正相关, 豌豆地则为极显著正相关。     

青海省春小麦条锈病害发生发展的农业气象条件

对青海省１９８５～１９９３年春小麦条锈病害资料和同期内的气象要素进行对照分析，从中揭示出青海省春小麦条锈病的发生源地为甘肃陇东、陇南地区和青海省东部民和、循化等冬麦区；青海省小麦条锈病的发生时间从５月下旬在东南部的循化、民和等地开始，逐渐向西北方向推进至６月下旬，长达１个月左右。分析确定了青海省条锈病害发生的农业气象指标，对春小麦条锈病害的预报及防治有现实意义。     

华北平原冬小麦/夏玉米轮作田能量闭合状况分析

对华北平原冬小麦/夏玉米轮作田连续3a(2003-11-2006-10)涡度相关观测的能量闭合状况进行综合分析,并探讨下垫面对能量闭合程度的影响.结果表明,能量平衡比率(EBR)日变化规律明显,以昼夜交替时波动最大,下午略高于上午,白天能量闭合状况明显优于夜间.将湍流能的相位提前0.5h,湍流通量和有效能的匹配度及能量闭合程度均得到提高.白天EBR呈秋冬高(分别为0.98和0.94)、春夏低(分别为0.85和0.70)的季节变化特征,EBR的波动幅度依次为:夏＞秋＞冬＞春.下垫面状况对地表能量闭合程度影响显著,裸地阶段、小麦季和玉米季的年均白天EBR分别为1.11、0.94和0.74,小麦季的能量闭合状况优于玉米季;EBR波动幅度依次为:裸地阶段＞玉米季＞小麦季.观测期间,白天EBR年均值范围在0.82 ～0.97,平均0.89,较好地满足了农田通量观测对数据质量的要求.     

耕作和保墒措施对冬小麦生育时期光合特征及水分利用的影响

为探明不同耕作保墒措施下冬小麦生育期间光合生理特征及其增产机理,采用田间试验,以常规耕作为对照,采用深松、秸秆覆盖、免耕、施用有机肥及保水剂等措施,研究了不同耕作和保墒措施对冬小麦生育期间光合作用、产量及水分利用效率的影响。结果表明:冬小麦光合速率和叶片水分利用效率均以孕穗期最高,而灌浆期最低。蒸腾速率和气孔导度均以扬花期最高。对不同处理而言,在各生育时期均以深松处理的光合速率和叶片水分利用效率最高,其次为秸秆覆盖处理。在拔节期、孕穗期和扬花期以有机肥处理的蒸腾速率最高,而灌浆期以秸秆覆盖的蒸腾速率较高,在全生育期对照的蒸腾速率均较低。气孔导度与蒸腾速率表现规律基本一致。不同耕作、保墒措施均提高了小麦的穗数、穗粒数及千粒重,以及小麦籽粒产量和水分生产效率,降低了小麦总耗水量;各处理中以深松处理的效果最佳,其产量和水分生产效率分别较对照提高19.6%和38.3%。相关分析表明:各时期的小麦光合速率及叶片水分利用效率均与小麦产量和水分生产效率呈正相关,且随生育期的推进,其相关性增强,特别在扬花期,光合速率对于小麦产量和水分生产效率的影响更显著。     

川中丘陵区紫色土冬小麦/夏玉米轮作氨挥发研究

大气中过量的氨会造成诸多环境问题并危害人类健康。我国农田氮肥施用后的氨挥发是一个重要的氨排放源。紫色土的土壤性质以及该区的气候条件导致其氨挥发潜力较大。与其他集约化农作区相比,该区农田氨挥发研究相对较少。本文探讨了川中丘陵区紫色土冬小麦/夏玉米轮作体系氨挥发情况,为开展陆地生态系统大气碳氮气体交换研究提供基础数据,同时也为氨排放清单的编制及农田氨减排措施研究提供依据。选取川中紫色土丘陵区典型的坡耕地作为研究对象,采用风洞法研究了紫色土冬小麦/夏玉米轮作体系的氨挥发动态过程。每次试验设置1个施肥处理,3次重复。风速、风向、大气温湿度、土壤温湿度等气象数据由试验田微型气象站获取。每隔2~3 d采集土壤样品用以测定土壤NH4+-N含量。两年的田间试验结果表明,受氮肥深施及低温的影响,冬小麦季氨挥发损失率明显低于夏玉米季;2013年和2014年冬小麦季氨挥发损失率分别为7.4%和8.8%;2013年夏玉米季三叶期氮肥撒施的氨挥发速率为34.1%;2014年夏玉米季三叶期氮肥条施覆土降低了氨挥发损失,损失率为21.4%;2014年夏玉米季十叶期出现极端干旱的气候条件,撒施氮肥后立即灌水使氨挥发损失率高达46.6%,这是由于干旱条件下施肥灌水提供了利于氨挥发的土壤水分条件。因此在极端干旱的气候条件下,应避免采用此施肥方式。综合分析两年的数据可得:紫色土冬小麦季氨挥发损失占施氮量的(8.1±1.0)%,夏玉米氨挥发损失占施氮量的(32.8±1.8)%。     

Resource utilisation and economy of soil tillage in crop production systems

Resource use in crop production is analysed with reference to the concept of potential yield, based on the relationships between the balances of energy and mass in plant growth. Three models of the production process are proposed: a bio-physical model which looks at the conversion of energy and mass into a potential yield of biomass, a business model which assesses the economics of the conversion process and a feed-back model which points the way towards on-line optimisation. The impacts of environmental, nutritional and physiological constraints on potential yield are discussed. The business model emphasises the importance of scale of operation in reducing the costs of crop production by spreading the fixed costs of machinery. The contributions of additional energy inputs in the form of fertilisers, agrichemicals and machinery in improving the overall efficiency with which solar energy is converted into biomass, together with the pivotal role of nitrogenous fertiliser in increasing yields, are examined. Nitrogenous fertilisers underpin high yields and account for about half the energy supplied by the farmer to a cereal crop. Tillage helps in ameliorating the environmental constraints on crop growth. The implications of sustainability, and climate change, for resource use in crop production are discussed briefly.     

Wear of spring tine cultivator points in sandy loam and light clay soils in southern Poland

Correct evaluation and forecasting of durability of soil cutting parts are the decisive factors for proper operation of agricultural machinery. During operation of cultivators, over two-fold difference in wear of cultivator points is observed, which makes establishing of their exchange periods extremely difficult. So, there is a need to conduct some research aimed for determination of relationship between arrangement of the points in individual cultivator rows and their wear. The presented experiments were performed under authentic farm conditions during spring soil loosening and levelling operations before sowing and planting, in sandy loam and light clay soils. Changes in length and thickness of the spring tine points, wear patterns and weight loss were measured. Loss in length of spring tine points was described by a complex function of the distance travelled or by an exponential function of the distance from the measuring point to the symmetry axis of a spring tine point; loss in thickness was described by a linear function. It was found that soil type, as well as arrangement of the points in individual cultivator rows and their position in relation to the tractor wheel track, significantly influenced their wear. It was also observed that wear of spring tine points was 40–100% higher in the sandy loam soil than in the light clay soil, and that wear within a tractor wheel track was 17–40% higher than outside the track. Moreover, wear of points positioned in the first row on the cultivator frame was 26–100% higher than wear of those in the third row. The research results emphasise the need for field experiments at compare wear of spring tine points made of different materials or of different designs to take into account differences in wear due to positioning of the points on cultivator frames.     

华北平原典型冬小麦农田生态系统能量平衡与闭合研究

准确量化分析地气之间的物质和能量交换对于水资源管理和农业可持续发展是十分重要的。能量平衡闭合是评估观测数据准确性和分析地表能量平衡的一个重要的评价指数。本研究利用开路涡度相关系统和全要素自动气象站对华北平原典型冬小麦农田生态系统2013—2014年度的能量通量及常规气象要素进行了连续观测,分析了冬小麦农田各能量通量的日变化和年变化特征,计算冬小麦在4个生育时期(出苗期、越冬期、拔节期和灌浆期)的能量闭合和波文比。结果表明:在日尺度上,选取的4个生育时期净辐射和各能量分量的日变化趋势均为单峰二次曲线,净辐射、显热通量和潜热通量的峰值出现在12:00—13:00,土壤热通量的峰值出现在14:00—15:00。在年尺度上,净辐射和潜热通量的变化趋势较为一致,均在越冬期达到最低值114.51 W·m~(-2)和13.47 W·m~(-2),而在灌浆期达到最大值327.02 W·m~(-2)和116.56 W·m~(-2)。选取的4个生育时期的代表性观测日期能量闭合良好,能量闭合率分别为0.49、0.77、0.81和0.76。4个生育时期内波文比值日变化趋势均呈倒\"U\"型,出苗期波文比在14:00达到最大值2.12;越冬期、拔节期和灌浆期在10:00左右达到最大值,分别为1.48、0.31和0.58。本文的定量化结果可为华北平原农田生态系统水热通量等研究提供依据。     

密度修正对冬小麦/夏玉米轮作田潜热、CO2通量及其能量闭合度的影响

本文利用涡度相关技术对青岛农业大学现代农业科技示范园试验站2013—2014年冬小麦/夏玉米轮作田与大气之间CO_2、水汽和能量交换进行测量,分别对潜热和CO_2通量进行两种密度修正(WPL修正和Liu修正)并进行对比,计算了两种密度修正前后冬小麦/夏玉米轮作田的能量闭合度。结果表明:WPL修正与Liu修正可以提高潜热通量,WPL修正后夏玉米田潜热通量约提高6%,冬小麦田约提高2%;Liu修正后夏玉米田提高不足1%,冬小麦田提高约2%。因此WPL修正对于夏玉米田潜热的修正效果明显优于Liu修正,而对冬小麦田潜热修正两种方法效果相同。两种修正方法对于CO_2通量具有降低的修正效果,WPL修正后夏玉米田和冬小麦田CO_2通量分别降低3%和4%;Liu修正后夏玉米田和冬小麦田CO_2分别降低2%和3%。可以看出,WPL修正和Liu修正对CO_2通量修正前后差别非常小(差距均为1%)。通过对青岛地区冬小麦/夏玉米轮作田能量闭合度的分析,发现密度修正可以提高能量闭合度,但不同下垫面有不同的修正效果。裸地情况下,WPL修正可以提高能量闭合度约2.53%~9.76%,夏玉米田为4.05%,冬小麦田为1.35%;而Liu修正对裸地能量闭合度的提高小于2.53%,对夏玉米田和冬小麦田提高约为1.35%。显然WPL修正对于能量闭合度的修正幅度大于Liu修正。能量闭合度大小关系为裸地Ⅰ(夏玉米出苗前)裸地Ⅱ(冬小麦出苗前)夏玉米田冬小麦田。     

气候变化对北方冬麦区冬小麦生育期的影响

利用北方冬麦区18个农业气象观测站1983-2005年气象资料和冬小麦生育期观测资料,采用统计分析方法,分析了该区域气象因素和冬小麦生育期变化特征,以及气候变化对生育期的影响。结果表明：1983-2005年,北方冬麦区降水量、日照时数和日较差的变化趋势不明显;而气温呈明显增加,以冬春季增加最为明显,最低气温的增幅较大;从总体上看,冬小麦播种期和返青期的变化趋势不明显,抽穗期和成熟期分别以0.46d/a和0.27d/a的趋势显著提前;在空间分布上,播种期和返青期的变化趋势差异不显著,而抽穗期和成熟期差异显著,特别是抽穗期表现出随纬度增加提前趋势变小的特点。相关分析表明：冬小麦关键生育期均表现为与日照时数和日较差呈显著正相关;与气温均呈显著负相关;除成熟期与5月降水总量相关性不显著外,其余均表现出显著负相关;从整体上看,最低气温升高是北方冬麦区冬小麦生育期提前的主要原因。北方冬麦区以气候变暖为主要特征的气候变化特征较为明显,其对冬小麦生育期的影响较为显著,研究结果可为北方冬麦区的农作物生产积极应对气候变化提供参考依据。