Subsoil tillage enhances wheat productivity,soil organic carbon and available nutrient status in dryland fields

Tillage practices during the fallow period benefit water storage and yield in dryland wheat crops.However,there is currently no clarity on the responses of soil organic carbon(SOC),total nitrogen(TN),and available nutrients to tillage practices within the growing season.This study evaluated the effects of three tillage practices(NT,no tillage;SS,subsoil tillage;DT,deep tillage)over five years on soil physicochemical properties.Soil samples at harvest stage from the fifth year were analyzed to determine the soil aggregate and aggregate-associated C and N fractions.The results indicated that SS and DT improved grain yield,straw biomass and straw carbon return of wheat compared with NT.In contrast to DT and NT,SS favored SOC and TN concentrations and stocks by increasing the soil organic carbon sequestration rate(SOCSR)and soil nitrogen sequestration rate(TNSR)in the 0-40 cm layer.Higher SOC levels under SS and NT were associated with greater aggregate-associated C fractions,while TN was positively associated with soluble organic nitrogen(SON).Compared with DT,the NT and SS treatments improved soil available nutrients in the 0-20 cm layer.These findings suggest that SS is an excellent practice for increasing soil carbon,nitrogen and nutrient availability in dryland wheat fields in North China.

The first factor affecting dryland winter wheat grain yield under various mulching measures: Spike number

Water is the key factor limiting dryland wheat grain yield.Mulching affects crop yield and yield components by affecting soil moisture.Further research is needed to determine the relationships between yield components and soil moisture with yield,and to identify the most important factor affecting grain yield under various mulching measures.A long-term 9-yearifeld experiment in the Loess Plateau of Northwest China was carried out with three treatments:no mulch (CK),plastic mulch (M_(P)) and straw mulch (M_(S)).Yield factors and soil moisture were measured,and the relationships between them were explored by correlation analysis,structural equation modeling and significance analysis.The results showed that compared with CK,the average grain yields of M_(P) and M_(S) increased by 13.0and 10.6%,respectively.The average annual grain yield of the M_(P) treatment was 134 kg ha^(–1) higher than the M_(S) treatment.There were no significant differences in yield components among the three treatments (P<0.05).Soil water storage of the M_(S) treatment was greater than the M_(P) treatment,although the differences were not statistically signifiant.Soil water storage during the summer fallow period (SWSSF) and soil water storage before sowing (SWSS) of M_(S) were significantly higher than in CK,which increased by 38.5 and 13.6%,respectively.The relationship between M_(P) and CK was not statistically significant for SWSSF,but the SWSS in M_(P) was significantly higher than in CK.In terms of soil water storage after harvest (SWSH) and water consumption in the growth period(ET),there were no signi?cant differences among the three treatments.Based on the three analysis methods,we found that spike number and ET were positively correlated with grain yield.However,the relative importance of spike number to yield was the greatest in the M_(P )and M_(S) treatments,while that of ET was the greatest in CK.Suifcient SWSSF could indirectly increase spike number and ET in the three treatments.Based on these results,mulch can improve yield and soil water storage.The most important factor affecting the grain yield of dryland wheat was spike number under mulching,and ET with CK.These findings may help us to understand the main factors influencing dryland wheat grain yield under mulching conditions compared to CK.

Study on Water-Preserving Effects of Mulching for Dryland Winter Wheat in Loess Tableland

Focused on the rainfall characteristics and the reality of agricultural production in the loess tableland , and based on previous results, new patterns for dryland winter wheat production, in which the emphasis was put on the film mulch with obvious water-preserving advantage, were designed to make effective use of rainfall. The results showed that the technique of the double mulch of film plus straw in summer fallow period can collect the rainfall in this period to the utmost extent and over 73.2% of it can be stored in the soil, which is 108. 4 mm more than that of conventional tillage. Furthermore, it can not only preserve water stored in soil in summer fallow, but also collect the rainfall in the growth period as much as possible by using the technique of making ridges plus film mulching and furrow sowing. So the patterns, which can greatly increase both the soil moisture and wheat yield, are the best choice for making full utilization of the rainfall and achieving a high and stable yield in the dryland wheat production of the loess tableland.

Effect of Fertilization on Soil Fertility and Wheat Yield of Dryland in the Loess Plateau

Long-term fertility experiments have become an important tool for investigating the sustainability of cropping systems.Therefore, a long-term (18-year) fertilization experiment was conducted in Changwu County, Shaanxi Province, China,to ascertain the effect of the long-term application of chemical fertilizers and manure on wheat yield and soil fertility in the Loess Plateau, so as to provide a scientific basis for sustainable land management. The experiment consisted of nine fertilizer treatments with three replicates arranged in a completely randomized design: 1) CK (no fertilizer); 2) N (N 120 kg ha-i); 3) P (P 26.2 kg ha-1); 4) NP (N 120, P 26.2 kg ha-1); 5) M (manure 75 t ha-1); 6) NM (N 120 kg ha-1,manure 75 t ha-1); 7) PM (P 26.2 kg ha-1, manure 75 t ha-1); 8) NPM (N 120, P 26.2 kg ha-1, manure 75 t ha-1);and 9) fallow (no fertilizer, no crop). N fertilizer was applied in the form of urea and P was applied as calcium super phosphate. The results showed that precipitation had a large effect on the response of wheat yield to fertilization. Manure (M), NP, PM, NM, and NPM treatments significantly increased (P ＜ 0.05) average yield. In the NP, PM, NM and NPM treatments, the percentage increases in yield due to fertilization were highest in normal years, and lowest in the drought years. Long-term P application enhanced soil available P markedly, and manure applications contributed more to soil fertility than chemical fertilizers alone. Chemical fertilizers applied together with manure distinctly improved soil fertility.The results also showed that the soil nutrient concentration changed mainly in the 0-60 cm layers and fertilization and planting only slightly affected soil nutrients below the 100 cm layers.

Response of yield increase for dryland winter wheat to tillage practice during summer fallow and sowing method in the Loess Plateau of China

Soil moisture is the most critical limiting factor impacting yields of dryland winter wheat(Triticum aestivum L.) and it is strongly affected by tillage practice and sowing methods. This study was to assess the link between sowing method and tillage practice during summer fallow and their subsequent effect on soil moisture and grain yield. Furthermore, we sought to identify a more appropriate farming management practice for winter wheat production in Loess Plateau region of China. The experiment was conducted from 2011 to 2013, using a two-factor split plot design, including subsoiling(SS) or no tillage(NT) during summer fallow for main plots, and conventional drill sowing(DS) or plastic film drill sowing(FM) for subplots. Results showed that the maximum soil water storage(SWS) was under SS×FM treatment with values of 649.1 mm(2011–2012) and 499.4 mm(2012–2013). The SWS during the 2011–2012 growing season were 149.7 mm higher than that in the 2012–2013 growing season. And adoption of SS×FM significantly increased precipitation use efficiency(PUE) and water use efficiency(WUE) compared to other treatments for both seasons. Moreover, adoption of SS×FM significantly increased yield by 13.1, 14.4, 47.3% and 25.9, 39.1, 35.7% than other three treatments during the two growing seasons, respectively. In summary, combining subsoiling during summer fallow with plastic film drill sowing(SS×FM) increased SWS at sowing and effectively improved WUE, thus representing a feasible technology to improve grain yield of dryland winter wheat in the Loess Plateau of China.

Response of dryland crops to climate change and drought-resistant and water-suitable planting technology:A case of spring maize

Climate change has a significant impact on agriculture.However,the impact investigation is currently limited to the analysis of meteorological data,and there is a dearth of long-term monitoring of crop phenology and soil moisture associated with climate change.In this study,temperature and precipitation(1957-2020)were recorded,crop growth(1981-2019)data were collected,and field experiments were conducted at central and eastern Gansu and southern Ningxia,China.The mean temperature increased by 0.36°C,and precipitation decreased by 11.17 mm per decade.The average evapotranspiration(ET)of winter wheat in 39 years from 1981 to 2019 was 362.1 mm,demonstrating a 22.1-mm decrease every 10 years.However,the ET of spring maize was 405.5 mm over 35 years(1985-2019),which did not show a downward trend.Every 10 years,growth periods were shortened by 5.19 and 6.47 d,sowing dates were delayed by 3.56 and 1.68 d,and maturity dates advanced by 1.76 and 5.51 d,respectively,for wheat and maize.A film fully-mulched ridge-furrow(FMRF)system with a rain-harvesting efficiency of 65.7‒92.7%promotes deep rainwater infiltration into the soil.This leads to double the soil moisture in-furrow,increasing the water satisfaction rate by 110‒160%.A 15-year grain yield of maize increased by 19.87%with the FMRF compared with that of half-mulched flat planting.Grain yield and water use efficiency of maize increased by 20.6 and 17.4%when the density grew from 4.5×10^(4)to 6.75×10^(4)plants ha-1 and improved by 12.0 and 12.7%when the density increased from 6.75×10^(4)to 9.0×10^(4)plants ha-1,respectively.Moreover,responses of maize yield to density and the corresponding density of the maximum yield varied highly in different rainfall areas.The density parameter suitable for water planting was 174 maize plants ha-1 with 10 mm rainfall.Therefore,management strategies should focus on adjusting crop planting structure,FMRF water harvesting system,and water-suitable planting to mitigate the adverse effects of climate change and enhance sustainable production of maize in the drylands.

夏闲期耕作下旱地土壤有机碳库与温度和含水量季节变化及关系研究

为明确夏闲期耕作下土壤有机碳(SOC)库与温度和含水量的季节变化及其相互关系,设置夏闲期免耕、翻耕和深松3种耕作处理,分析了黄土高原旱地麦田SOC和易氧化有机碳(POxC)含量的季节变化、土壤含水量和温度的季节变化、以及碳库与温度和含水量变化的关系。结果表明,在冬小麦生育期内,随着生育进程的推进,翻耕和深松处理0~5和5~10 cm土层SOC含量呈先升高后降低的变化趋势,而POxC含量呈“降低—升高—再降低”的变化趋势;土壤质量含水量变化均呈“增加—降低—再增加”的变化趋势,而土壤温度呈先降低后升高的变化趋势。回归分析发现,5~10 cm土层土壤质量含水量与SOC含量呈线性关系(P<0.05),与POxC含量呈二次多项式关系(P<0.05),尤其与免耕和深松处理相比,翻耕处理拟合效果更佳。此外,0~5和5~10 cm土层土壤温度变化与SOC含量无显著相关性,而日最高温度、日平均温度和日最低温度与POxC含量呈显著负相关。综上所述,不同夏闲期耕作下旱地麦田0~10 cm土层POxC含量季节变化与土壤质量含水量和温度变化密切相关,而SOC含量变化对土壤温度变化的敏感性较弱。本研究结果为旱地麦田碳库管理提供了理论依据。

施氮量对旱地小麦花后糖代谢及籽粒产量的影响

施用氮肥为当前农业增产措施之一,适量施用对小麦产量形成具有重要意义。本试验于2020—2021年在位于黄土高原东南部的山西农业大学小麦试验站开展,设置施氮(N)0 kg/hm^(2)(N0)、90 kg/hm^(2)(N90)、150 kg/hm^(2)(N150)、210 kg/hm^(2)(N210)共4个处理,采用池栽方式研究不同施氮量对旱地小麦地上部生长、花后糖代谢及产量等的影响,以探明提高产量的适宜施氮量及其糖代谢生理机制。结果表明,与对照(N0)相比,施氮肥可显著增加旱地小麦各生育时期株高,增加叶面积指数和花后旗叶蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)活性,且花后15~30 d间差异达显著水平;产量及其构成因素中,产量增加13.45%~42.18%,穗数增加7.68%~22.33%,穗粒数增加2.14%~3.45%,千粒重增加2.48%~13.54%;总淀粉含量增加1.8~8.8个百分点,尤以支链淀粉含量增加显著。从动态趋势上看,施氮量由90 kg/hm^(2)增至210 kg/hm^(2),各生育时期小麦叶面积指数、花后10~30 d旗叶SPS和SS活性、花后10~30 d籽粒淀粉含量均先增后减,且在施氮量150 kg/hm^(2)时达最高值。最终,旱地小麦产量以N150处理最高,而淀粉含量以N210处理最高,但与N150差异不显著。综上,施氮量150 kg/hm^(2)促进旱地小麦地上部生长,增强花后10~30 d旗叶糖代谢酶活性,增加蔗糖和淀粉含量,增产效果最好。

播种方式对旱地春小麦产量、干物质及水分利用效率的影响

为提高新疆旱地春小麦产量及水分利用效率,筛选出适宜的播种方式,采用单因素随机区组试验,设置传统平作(T1)、起垄沟播(T2)、起垄覆膜沟播(T3)3个播种方式,研究不同播种方式下旱地的土壤含水量及春小麦的叶面积指数(leaf area index,LAI)、干物质量、产量,并进一步比较土壤贮水量、耗水量及水分利用效率等。结果表明,在抽穗期之前,T2和T3处理均可显著增加旱地春小麦的LAI和干物质量;在抽穗期之后,T3处理较T2和T1处理更有利于提高旱地春小麦的LAI和干物质量。同时,T3处理可显著提高拔节期土壤0—80 cm土层的含水量和贮水量,分别较T2、T1处理显著提高32.09%、34.64%和38.20%、38.85%;T3处理降低了播种—拔节期土壤耗水量,增加了拔节期—收获期的土壤耗水量,有利于植株中、后期的生长发育。T3处理可提高旱地春小麦的有效穗数、单穗粒数、籽粒产量、水分利用效率和降水利用效率,其中产量最高为2474.43 kg·hm^(-2),较T1、T2处理分别显著增加50.13%和50.47%;水分利用效率和降水利用效率分别显著提高48.99%、51.02%和49.41%、50.15%。综上所述,起垄覆膜沟播有利于小麦增产和水分高效利用,为新疆旱地春小麦蓄水保墒和高产高效提供了理论依据及技术参考。

Improvement of Wheat Water Use Efficiency in Semiarid Area of China

The greatest fear of global climate change is drought since in most areas where wheat is grown water is the most important factor influencing wheat yield. Average wheat yield throughout the world is only 30-60% of the attainable yield potential because water shortage is the major factor preventing the realization of maximum yield. Periods of drought alternating with short periods of available water are common conditions to influence wheat productivity. Such conditions include variable frequency of dry and wet periods, intensity of drought, rate of drought onset and patterns of soil water deficit and/or atmospheric water deficit. It is this deficit and variable water conditions in semiarid environments that influence wheat productivity variously. This paper reviewed the physiological adaptation and benefits associated with deficit and variable water conditions. In addition, it also highlights the compensative effect of limited irrigation and breeding of new varieties for high water use efficiency (WUE) that could improve wheat productivity under water-limited environments in the semiarid regions. Considerable potential for further improvement in wheat WUE and productivity in semiarid environments seems to depend on effective conservation of moisture and efficient use of this limited water such as soil fertility improvement, conservation tillage, residues and film mulch, rain water harvesting for limited irrigation, and breeding for water saving varieties. Different crop, soil and water management strategies should be adjusted according to the conditions that prevail in various semiarid areas. By combining soil and water conservation approaches and adjusting the cropping system by growing drought-tolerant and water-saving cultivars, increase in wheat WUE and productivity could be achieved.

旱地小麦产量和水分利用对翻耕时间和降水量及其分布的响应

【目的】针对山西省麦区降水年际变化大,休闲期降水占比高、生育期降水少且分布不均,造成雨养旱地小麦年季间产量波动大、降水水分利用率(WUE)低等问题,探寻不同降水年型下旱地麦田休闲期翻耕时间对土壤蓄水量和产量的影响,为山西南部旱地小麦根据降水型“定产”提供理论依据。【方法】2010—2021年度,通过田间区组试验,设8月10日(P1)、8月20日(P2)和8月30日(P3)左右3个翻耕时间,研究翻耕时间、降水量及其分布对旱地小麦产量、休闲期土壤蓄水特性和生育期耗水及相关性的影响。【结果】(1)旱地小麦产量受降水年型、休闲期和生育期降水共同影响,且年型>休闲期>生育期。试验年度平均产量2400.0—6298.0 kg·hm^(-2),年季间变异系数为29.8%,其中丰水年(2012、2014和2015年度)、平水年(2011和2013年度)和枯水年(2010、2016、2019、2020和2021年度)平均产量分别为5524.6、3048.2和4088.7 kg·hm^(-2);休闲期降水量和生育期降水分布主要通过成穗数和穗粒数影响产量,年度和3—4月降水多则产量明显增加;翻耕时间对旱地小麦产量影响与休闲期降水分布密切相关,7—8月降水多,P1产量高,9月降水多,则P2或P3产量高。(2)降水量及其分布和翻耕时间共同影响播种前和收获期土壤蓄水特性。休闲期降水主要影响播种前和收获期下层(100—200 cm)土壤蓄水量;休闲期丰水型播前上层(0—100 cm)和下层土壤蓄水量相近或略低,平水型和枯水型则下层低于上层,分别比上层低6.17%和24.66%;7月降水多有利于下层土壤多蓄水,8—9月降水多有利于上层土壤多蓄水;生育期降水主要影响收获期上层土壤蓄水量,尤其是5月降水;播种前和收获期上层土壤平均蓄水量P2最高,收获期下层和0—200 cm土壤平均蓄水量P2或P3最高。(3)耕作时间和降水量对生育期耗水量和水分利用率影响相对较小,年度降水多则旱地小麦生育期耗水多,3月降水对生育期耗水量影响大。【结论】休闲期降水量及其分布影响旱地小麦播前0—200 cm土壤蓄水量,并与3—4月份降水量共同作用影响成穗数、穗粒数和旱地小麦产量,且水分利用率与旱地小麦产量间呈显著正相关。山西南部7—8月降水多旱地麦田于8月10日前后翻耕,降水少时则翻耕时间推迟10—20 d,可增加播种前土壤蓄水量使旱地小麦实现增产。

基于APSIM模型的旱地小麦叶面积指数相关参数敏感性分析及优化

为解决作物模型参数率定过程中参数众多导致的敏感参数定位迟缓和调参效率低的问题,本研究运用敏感性分析和智能优化算法相结合的方法对作物模型参数进行调整,以甘肃省定西市安定区李家堡镇麻子川村(2002—2004年)和凤翔镇安家沟村(2015—2017年)大田旱地小麦试验数据(叶面积指数)为参照,利用扩展傅里叶幅度检验法(EFAST),对APSIM-Wheat旱地小麦叶片生长子模型的23个参数进行敏感性分析,得到对模型结果较敏感的部分参数,然后利用粒子群优化算法对部分敏感参数进行优化。结果表明:1)影响旱地小麦叶片生长最敏感的参数依次为叶面积指数为0时最大比叶面积、叶片生长的氮限制因子、出苗到拔节积温、消光系数、拔节到开花积温、蒸腾效率系数;2)旱地小麦叶片生长子模型的参数优化结果:叶面积指数为0时最大比叶面积为26652 mm^(2)∙g^(−1),叶片生长的氮限制因子为0.96,出苗到拔节积温为382℃·d,消光系数为0.44,拔节到开花积温为542℃·d,蒸腾效率系数为0.0056;3)上述参数优化后的叶面积指数实测值与模拟值之间的均方根误差平均值从参数优化前的0.080减小到0.042,归一化均方根误差平均值从11.54%减小到6.11%,模型有效性指数平均值从0.962增加到0.988,优化后叶面积指数的模拟更好。该方法相对于传统的手工试错法,避免了优化参数的不确定性,实现参数自动率定,提高模型参数的率定效率,有利于模型快速地本地化应用,并指导农业生产。本研究方法也对APSIMWheat模型中其他作物模块的参数调整优化具有指导意义。

秸秆覆盖与施磷对旱地小麦小花发育与结实特性的影响

中国西南丘陵旱地气候冬干春旱且速效磷缺乏,是冬小麦生产的主要限制因素。为明确秸秆覆盖与施磷对西南丘陵旱地小麦小花发育与结实特性的影响,以川麦104为供试材料,采用裂区设计,主区为玉米秸秆覆盖(SM)和不覆盖(NSM),裂区为0、75和120 kg P_(2)O_(5)·hm^(-2)3个施磷水平,比较分析了不同处理下小麦小花分化及结实特性的差异。结果表明,秸秆覆盖与施磷均可提高小麦小花分化数和可孕小花数,且磷素效应大于秸秆覆盖效应。与不施磷相比,施磷75和120 kg·hm^(-2)条件下最大分化小花数分别增加了17.4%和78.0%,可孕小花数分别增加27.0%和94.1%,小花存活率提高了16.5个百分点。施磷后穗基部可孕小花数和结实粒数增幅较大,穗中部和顶部增幅较小。与不施磷相比,施磷75和120 kg·hm^(-2)条件下,穗基部可孕小花数均极显著增加,增幅分别为100.0%和127.2%;结实粒数显著增加,增幅分别为186.4%和193.2%。秸秆覆盖后产量较不覆盖提高20.5%;施磷75和120 kg·hm^(-2)下产量较不施磷分别提高62.5%和78.1%。综上所述,秸秆覆盖配施磷肥可减少小花退化,增加可孕小花数和穗粒数有利于产量形成。

Wheat Grain Yield and Yield Stability in a Long-Term Fertilization Experiment on the Loess Plateau

To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly (P < 0.01). In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysts combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.

Effect of Nitrogen Fertilization on Leaf Chlorophyll Fluorescence in Field-Grown Winter Wheat Under Rainfed Conditions

The effect of nitrogen fertilization on leaf chlorophyll fluorescence was studied in field-grown winter wheat during grain filling underrainfed conditions in Loess Plateau. Results showed that the actual photochemical efficiency of PSⅡ reaction center (F PSⅡ)decreased significantly as leaf water stress progressed, however, the F PS was increased by nitrogen fertilization. The F PSⅡ of 0, 90 and180 kg ha-1 nitrogen treatments at noon were 0.197, 0.279 and 0.283, respectively, which decreased by 57.7, 56.4 and 40.2% as comparedto those in the morning. In the afternoon, the F PSⅡ partialy or completely recovered to the levels in the morning. The values of F PS Ⅱin 0 and 90kgha-1 treatments recovered to 87.3 and 81.5% of those in the morning. In 180kgha-1 treatment, the F PSⅡ in the afternoonwas even higher than that in the morning. Application of nitrogen fertilizer significantly increased maximum photochemical efficiency(Fv/Fm), photochemical quenching coefficient (qP) and non-photochemical quenching coefficient (qNP). These results indicated thatapplication of nitrogen fertilizer could increase the light energy conversion efficiency, the potential activity of photosynthetic reactioncenter, and the non-photochemical dissipation of excess light energy, which can prevent leaf photosynthetic apparatus from damage ofenvironmental stress. However, there was no significant difference in the values of F PSⅡbetween 90 and 180kgha-1 nitrogentreatments, indicating that the excess nitrogen was unfavorable to photosynthesis.

垄沟种植对旱地玉-麦轮作体系生产力和土壤硝态氮累积量的影响

【目的】探究不同垄沟种植模式对旱地玉-麦轮作体系作物生产力、土壤性状及土壤硝态氮累积量的影响,为改善旱地土壤肥力,提高作物产量和效率,降低环境风险提供科学依据。【方法】基于中国农业科学院洛阳旱农试验基地始于2004年的长期定位试验,设置6行固定道垄沟种植(6RPRF)、6行每年起垄垄沟种植(6REYRF)、4行固定道垄沟种植(4RPRF)、4行每年起垄垄沟种植(4REYRF)和传统平作(CF)5个处理,分析了2015—2021年度玉米、小麦及其周年的产量、水分利用效率,2020年玉米收获期0—40 cm不同土层的容重、养分含量和酶活性,以及2019—2020年度小麦收获期0—380 cm土层土壤硝态氮累积量。【结果】与CF相比,4种垄沟种植下玉米、小麦、周年的6年平均产量分别显著提高8.6%—32.1%、12.5%—25.6%、11.3%—29.6%,水分利用效率分别显著提高8.6%—31.4%、12.5%—31.1%、12.8%—30.3%;0—5 cm和20—40cm土层的容重分别显著降低7.3%—11.3%和4.9%—11.5%;0—40 cm土层平均有机质、全氮、有效磷和速效钾含量及脲酶活性分别提高6.0%—19.8%、80.8%—100.0%、28.5%—80.9%、58.5%—141.2%和24.0%—46.9%,0—100 cm土层的硝态氮累积量显著提高38.8%—116.0%,其中,总体以4RPRF处理效果最优,其还可以在硝态氮累积量总量维持在CF水平的同时使0—100cm土层显著提高38.8%、200—380 cm土层显著降低15.0%,具有提高根层、降低深层土壤硝态氮累积量的作用。固定道垄作模式(PRF)与每年起垄模式(EYRF)相比,玉米和周年的6年平均产量分别显著提高10.6%和9.1%,垄面种植6行模式(6R)下玉米、垄面种植4行模式(4R)下小麦和周年的6年平均水分利用效率分别显著提高21.1%、15.2%和8.2%,土壤养分含量表层提高、下层降低,0—380 cm土层的硝态氮累积量显著降低4.9%—30.2%。4行模式较6行模式,玉米和周年的6年平均产量分别显著提高9.9%和6.8%,EYRF下玉米、PRE下小麦和周年的6年平均水分利用效率分别显著提高7.4%、16.5%和6.7%,土壤特性有改善趋势,但其效应因指标而异,且在不同起垄模式和不同土层表现不同。【结论】4行固定道垄沟种植(4RPRF)既可降低土壤容重,提高土壤有机质、全氮和速效钾含量,又可使玉米、小麦、周年的产量和水分利用效率在多数条件下表现最优,还可以有效降低200—380 cm土层的硝态氮累积量,是协同实现旱地雨养玉-麦轮作区作物高产高效和环境友好生产的种植模式。

拔节期灌溉和追施氮肥对旱地沟播小麦产量和品质的影响

为探究拔节期灌溉和追施氮肥对旱地沟播小麦籽粒产量、品质和氮素积累转运的影响,2019年10月至2020年6月,在沟播种植小麦的基础上,于拔节期设置不灌溉不追氮肥(NIND)、全沟灌溉不追氮肥(EFIND)、隔沟灌溉不追氮肥(AFIND)、全沟灌溉追施氮肥(EFITD)、隔沟灌溉追施氮肥(AFITD)5个处理,分析了小麦产量及其构成因素、主要品质指标和地上部氮素积累转运分配特性。结果表明,拔节期灌溉与否、灌溉方式和追施氮肥均可显著调控旱地沟播小麦产量、品质和氮素积累转运特性,且作用效果有叠加效应。与NIND相比,EFIND、AFIND、EFITD、AFITD的产量分别显著提高46.57%,67.72%,83.71%,95.88%;开花期氮素积累量、花后氮素积累量、花后氮素积累对籽粒氮素的贡献率均显著提高,从而使成熟期氮素积累量分别显著提高25.94%,41.00%,65.86%,82.64%。与NIND相比,EFIND、AFIND和EFITD显著降低小麦品质,而AFITD的品质不降低甚至显著提高。隔沟灌溉较全沟灌溉,开花期氮素积累量无显著差异,花后氮素积累量显著提高,从而使成熟期氮素积累总量和籽粒氮素积累量显著提高,不追施氮肥时产量显著提高,但除沉降值外各品质指标无显著差异,追施氮肥条件下产量和各品质指标均显著改善。追施氮肥与不追氮肥相比,开花期氮素积累量、花前氮素转运量、花后氮素积累量、花后氮素积累对籽粒的贡献率均显著增加,从而使成熟期地上部氮素积累量、籽粒分配比例显著增加,进而使籽粒产量和籽粒氮素积累量显著提高,品质多表现为显著改善,且隔沟灌溉的提质效应较全沟灌溉大。拔节期隔沟灌溉与追施氮肥结合不仅可显著提高开花期和开花后的氮素积累量,而且可显著提高花前氮素向籽粒的转运量,从而显著提高成熟期籽粒氮素积累量和分配比例,最终在提高产量的同时改善品质,是适宜旱地沟播小麦的灌溉施肥方式。

提升雨养夏玉米-冬小麦两熟体系生产力和土壤硝态氮累积的最优耕作模式

【目的】研究耕作模式对旱地雨养夏玉米–冬小麦(以下简称玉–麦)两熟体系生产力的影响,并对深松、翻耕在轮耕模式中的作用进行评价。【方法】定位试验于2015—2021年在中国农业科学院洛阳旱农试验基地进行。设置夏免耕秋免耕(SNAN)、夏深松秋免耕(SSAN)、夏免耕秋3年免耕1年翻耕(SNA3N1P)、夏深松秋3年免耕1年翻耕(SSA3N1P)和传统夏秋季均翻耕(CT)5种耕作模式,调查了玉米、小麦的产量和水分利用效率,2020年测定了玉米收获期0—40 cm土层土壤容重、养分含量和酶活性,以及2019—2020年度小麦收获期0—380 cm土层的硝态氮累积量。【结果】1)与CT处理相比,SNAN、SSAN、SNA3N1P和SSA3N1P处理的玉米、小麦和周年产量分别显著提高了28.4%~33.5%、23.7%~25.0%和27.1%~30.3%,水分利用效率分别显著提高了19.6%~39.2%、20.2%~29.3%和29.5%~34.5%,0—5 cm和20—40 cm土层土壤容重显著降低,0—5 cm土层的有机质含量以及0—40 cm多数土层的全氮、有效磷、速效钾含量和脲酶、蔗糖酶活性均显著提高;0—80 cm土层硝态氮累积量显著提高了44.3%~104.8%,120—380 cm土层硝态氮累积量显著降低了22.1%~34.1%。2)与夏免耕(SN)处理相比,夏深松(SS)处理对玉米和小麦产量没有显著影响,但显著降低了玉米水分利用效率,提高了10—20 cm土层有机质含量、0—20 cm土层全氮含量、0—5 cm和10—20 cm土层有效磷含量、10—20 cm土层速效钾含量、5—40 cm土层脲酶活性、0—40 cm土层蔗糖酶活性,也提高了20—40 cm土层容重和0—380 cm土层硝态氮累积量。3)与秋免耕(AN)处理相比,秋3年免耕1年翻耕(A3N1P)处理降低了0—5 cm土层的土壤养分含量,增加了5—20 cm各土层有机质含量、5—40 cm各土层速效钾含量、0—40 cm各土层脲酶和蔗糖酶活性;SN处理下的小麦水分利用效率6年均值显著提高了7.1%,SS处理下0—380 cm土层的硝态氮累积量显著降低了12.4%。4)虽然SSA3N1P处理的产量和水分利用效率与其他轮耕模式无显著差异,但其改善土壤性状和提高根层(0—80 cm)、降低深层(120—380 cm)土壤硝态氮累积量的效果最优。【结论】夏深松相比夏免耕、秋季3年免耕1年翻耕相比秋免耕均可改善土壤性状。夏深松秋3年免耕1年翻耕的改土、增产增效和优化土壤硝态氮分布的效果总体最优,是适宜雨养玉–麦两熟体系的耕作模式。

旱地条件下不同地理来源小麦品种的产量与氮磷钾积累利用差异

为了研究旱地条件下不同地理来源小麦品种及同一来源高低产小麦品种的产量和氮磷钾积累利用差异,以来源于中国(58个)、CIMMYT(国际玉米小麦改良中心,42个)和国外其他地区(65个)的165个品种(品系)为材料,分析了小麦产量、产量构成因素,以及成熟期氮磷钾积累分配利用和需求特征。结果表明,与国外其他品种相比,CIMMYT品种的籽粒产量、穗粒数、千粒质量以及氮、磷、钾生理效率分别显著提高21.3%,39.1%,26.4%,33.2%,22.6%,36.1%,中国小麦品种分别提高10.5%,18.1%,24.3%,29.4%,12.1%,24.3%,但二者的穗数,茎叶氮、磷、钾积累量,百千克籽粒需氮磷钾和干物质量均显著降低,且CIMMYT品种的增降幅均高于中国品种。同一地理来源下高产品种较低产品种,中国品种的产量、穗数、穗粒数和生物量分别显著提高122.4%,38.7%,39.3%和96.1%,CIMMYT品种的产量、穗数和生物量分别显著提高97.6%,68.2%和71.7%,国外其他品种的产量、穗数、穗粒数、千粒质量和生物量分别显著提高157.2%,33.0%,43.6%,35.9%和76.4%;中国品种的地上部和籽粒氮磷钾积累量分别显著提高98.8%,101.0%,83.7%和118.8%,104.7%,131.2%,氮磷钾吸收效率显著提高93.6%,84.6%,70.3%,籽粒氮磷钾含量形成的养分需求量显著提高102.8%,109.5%,75.9%,但百千克籽粒需钾、干物质量显著降低16.8%,11.1%;CIMMYT品种的氮磷钾吸收效率显著提高68.5%,71.4%,63.6%,籽粒氮磷钾含量形成的养分需求量显著提高79.2%,81.7%,76.5%,但百千克籽粒需氮、磷量分别显著降低10.7%,10.3%;国外其他品种的氮磷钾生理效率显著提高34.7%,30.2%,60.6%,籽粒氮磷钾含量形成的养分需求量显著提高73.0%,110.8%,52.1%,但百千克籽粒需氮、磷、钾、干物质量显著降低26.7%,23.6%,36.8%,24.7%。综上,不同地理来源小麦品种的产量及其氮磷钾吸收利用特征多表现出了显著差异,CIMMYT品种具有较高的穗粒数、千粒质量、收获指数、籽粒氮积累量、磷钾生理效率,国外其他品种具有较高的穗数、茎叶氮磷钾积累量、地上部氮钾积累量、氮钾吸收效率、百千克籽粒需干物质和氮磷钾量,中国品种的多数指标居于二者之间。同一地理来源高产品种较低产品种提高了产量构成因素、收获指数和氮磷钾吸收效率,但籽粒氮磷钾含量形成的养分需求量也显著提高,在以高产高养分含量为目标的生产体系中应适当增加氮磷钾投入量。

覆盖方式对旱地小麦花后旗叶抗氧化生理及粒重形成的影响

于2017—2018年和2018—2019年,在西北中部旱作雨养农业区以冬小麦‘康庄974’为试验材料,设秸秆带状覆盖(SM)、地膜覆盖(PM)和无覆盖对照(CK)共3个栽培处理,分析不同覆盖方式对小麦灌浆期土壤水分和温度及抗氧化能力的影响,探讨花后干物质积累量和粒重形成的关系。结果表明,随生育期推进,花后旗叶相对含水量(RWC)逐渐降低,丙二醛(MDA)含量逐渐升高,且PM较SM降、升幅度明显。与CK相比,覆盖显著提高花后旗叶抗氧化酶活性,增加渗透调节物质含量;开花时间越长,SM抗氧化酶活性升高的幅度越大,而PM主要提高花后7 d旗叶抗氧化能力。SM和PM的粒重分别较CK增加14.3%和19.1%(P<0.05)。相关分析表明,土壤水分(SW)是影响旗叶生理活性的关键因子,提高SW,有利于增加RWC(r=0.84**),从而提高旗叶抗氧化能力,其中RWC和抗坏血酸酶(ASA)活性呈极显著正相关关系(r=0.82**);ASA活性和脯氨酸(Pro)含量呈极显著正相关关系(r=0.94**),和MDA含量呈极显著负相关关系(r=-0.93**);同时发现,抗氧化能力和花后干物质积累量高度正相关(r=0.96**),和粒重正相关。可见,粒重的增加与旗叶RWC及其抗氧化能力的提高密切相关。秸秆带状覆盖对小麦花后旗叶生理活性的改善效果最佳,适宜在西北旱地推广应用。