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.

Optimized NPK fertilizer recommendations based on topsoil available nutrient criteria for wheat in drylands of China

The optimized management of crop fertilization is very important for improving crop yield and reducing the consumption of chemical fertilizers.Critical nutrient values can be used for evaluating the nutritional status of a crop,and they reflect the nutrient concentrations above which the plant is sufficiently supplied for achieving the maximum potential yield.Based on on-farm surveys of 504 farmers and 60 field experimental sites in the drylands of China,we proposed a recommended fertilization method to determine nitrogen(N),phosphorus(P),and potassium(K)fertilizer input rates for wheat production,and then validated the method by a field experiment at 66 different sites in northern China.The results showed that wheat grain yield varied from 1.1 to 9.2 t ha^(-1),averaging 4.6 t ha^(-1),and it had a quadratic relationship with the topsoil(0-20 cm)nitrate N and soil available P contents at harvest.However,yield was not correlated with the inputs of N,P,and K fertilizers.Based on the relationship(exponential decay model)between 95–105%of the relative yield and topsoil nitrate N,available P,and available K contents at wheat harvest from 60 field experiments,the topsoil critical nutrient values were determined as 34.6,15.6,and 150 mg kg^(-1)for soil nitrate N,available P,and available K,respectively.Then,based on five groups of relative yield(>125%,115–125%,105–115%,95–105%,and<95%)and the model,the five groups of topsoil critical nutrient levels and fertilization coefficients(Fc)were determined.Finally,we proposed a new method for calculating the recommended fertilizer input rate as:Fr=Gy×Nr×Fc,where Fr is the recommended fertilizer(N/P/K)input rate;Gy is the potential grain yield;Nr is the N(N_(rN)),P(N_(rP)),and K(N_(rK))nutrient requirements for wheat to produce 1,000 kg of grain;and Fc is a coefficient for N(N_c)/P(P_c)/K(K_c)fertilizer.A 2-year validated experiment confirmed that the new method reduced N fertilizer input by 17.5%(38.5 kg N ha^(-1))and P fertilizer input by 43.5%(57.5 kg P_(2)O_(5) ha^(-1))in northern China and did not reduce the wheat yield.This outcome can significantly increase the farmers’benefits(by 7.58%,or 139 US$ha^(-1)).Therefore,this new recommended fertilization method can be used as a tool to guide N,P,and K fertilizer application rates for dryland wheat production.

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.

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 thr…

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.

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.

Release Characteristics of Release-controlled Nitrogen Fertilizer in Winter Wheat on Dry Land

[Objective] The aim was to study the release characteristics of different release-controlled fertilizers, as well as their effects on wheat growth and develop- ment under water stress. [method] With phosphorus-potassium fertilization and opti- mized fertilization （OPT） as the control, the release characteristics of 4 kinds of re- lease-controlled nitrogen fertilizers （A, B, C and D） coated with different materials were studied. [Result] Under the same phosphorus and potassium levels, the re- lease-controlled nitrogen fertilizers A and B significantly improved the yield of wheat. Spike number is the main reason leading to the difference in yield. The fertilizers A and B were released by 44.4% and 46.3% before winter, released by 72.1% and 69.8% at the jointing stage, and related by 88.0% and 91.5% in the harvest period, meeting the nitrogen requirement of dryland wheat across the growth period. Com- pared with OPT, the nitrogen accumulation amounts in treatments A and B were increased by 1.39 and 2.09 kg/667 m2, the nitrogen use efficiencies were increased by 8.66% and 13.04%, and the nitrogen partial factor productivities were increased by 9.00 and 7.22 kg/kg, respectively. [Conclusion] Among the 4 kinds of fertilizers, A and B were considered as the optimum release-controlled nitrogen fertilizers for winter wheat on dry land.

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 analysis 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.

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.

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.

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.

夏闲季不同耕作措施对旱地麦田土壤养分含量和酶活性的影响

为明确夏闲季不同耕作措施对旱地麦田土壤理化特性和酶活性的影响,基于2018年开始设置在黄土高原与黄淮海平原交汇处典型旱作区洛宁县小界乡的夏闲季定位耕作管理大区试验,2020—2022年研究了传统翻耕(CT)、一次深翻(DT)、免耕覆盖(NTM)、深松覆盖(STM)和深松垄沟覆盖(SRFM)5种夏闲季耕作措施对旱地麦田土壤三相比、养分含量和酶活性的影响。结果表明,优化夏闲季耕作措施可改善旱地麦田土壤三相比,提高土壤养分含量和酶活性,总体以SRFM效果最好。与CT相比,STM和SRFM的三相比R值显著降低4.7%~28.2%和10.9%~33.7%,DT、STM和SRFM在0~40 cm土层土壤全氮含量分别提高2.8%~11.2%、11.7%~21.4%和15.6%~30.6%,有效磷含量分别提高6.9%~39.5%、7.4%~68.8%和13.6%~80.3%,速效钾含量分别提高5.2%~19.7%、9.6%~25.8%和13.8%~35.0%;土壤蔗糖酶活性分别提高7.8%~21.5%、17.1%~75.9%和27.9%~99.1%,脲酶活性分别提高7.6%~97.0%、12.8%~165.5%和23.5%~194.9%,过氧化氢酶活性分别提高5.5%~15.2%、16.3%~26.7%和20.8%~50.3%,增幅多达到显著水平且表现为SRFM>STM>DT,NTM可显著提高0~10 cm土层但降低20~40 cm土层土壤养分含量和酶活性。综合来看,夏闲季深松垄沟并结合秸秆覆盖的措施可改善土壤三相比,提高土壤养分含量和酶活性,是利于提高旱地麦田土壤质量的耕作措施。

基于机器学习算法和ARIMA模型的旱地春小麦产量预测

为探究机器学习算法与时间序列结合预测春小麦产量的可行性,使用HP滤波算法,将1971-2021年甘肃省定西市安定区和2014-2021年定西市渭源县的产量数据分离为气象产量和趋势产量,利用研究区的气象数据,分别基于随机森林(random forest,RF)、循环神经网络(recurrent neural network,RNN)、支持向量机(support vector machine,SVM)、反向传播神经网络(back propagation neural network,BPNN)和长短期记忆网络(long short-term memory,LSTM)5种机器学习算法实现春小麦气象产量的预测对比;构建了ARIMA时间序列模型,探究旱地春小麦趋势产量的最佳预测模型。结果表明,旱地春小麦产量中气象产量占比大,趋势产量占比小,且气象产量的变化趋势基本与总产量一致。LSTM模型对研究区内气象产量的模拟效果最佳。通过参数率定,获得最优的趋势产量预测模型为ARIMA(4,1,2)模型,其残差基本为白噪声,符合正态分布。利用LSTM和ARIMA(4,1,2)模型组合,对2014-2021年渭源县的春小麦产量进行预测,并与研究区的实际产量数据比较,预测结果与实际值接近,模型精度较高,其R^(2)为0.96,MAPE为1.22%,MAE为32.12 kg·hm^(-2),RMSE为35.32 kg·hm^(-2)。在本研究条件下,LSTM和ARIMA(4,1,2)组合模型具有良好的预测精度,可实现旱地春小麦产量的预测。

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。

旱地春小麦新品种银春11号生产性能评价

为全面了解银春11号的生产特性,依据2016—2017年甘肃省旱地春小麦区域试验和2018年甘肃省旱地春小麦生产试验,对其丰产性、稳产性和适应性等进行了分析。结果表明,银春11号丰产性好,增产潜力大,2016、2017年的区域试验中,分别较对照品种西旱2号增产13.25%、9.90%;银春11号具有较好的高产稳产性,2016、2017年高稳系数分别为102.82、100.06,均高于对照品种西旱2号的90.90;银春11号具有广泛的适应性,2016、2017年适应度分别为80%、60%,在各试验点中增产点率为90%。综上,银春11号丰产性、稳产性较好,适应性较强,适宜在甘肃中部旱地春麦区栽培。

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。

陇东旱地冬小麦区域试验品系农艺性状及抗逆性分析

【目的】分析陇东片区区域试验小麦品系的农艺性状变异规律和抗逆性综合表现,为陇东旱地小麦品种改良提供依据。【方法】以2005—2022年陇东旱地区域试验共192份冬小麦品系(不含对照)为试验材料,通过相关性分析、多元回归分析、通径分析和聚类分析对参试品系的产量、生育期、基本苗、总茎数、有效穗数、株高、穗长、穗粒数和千粒重等主要农艺性状进行综合分析,同时,对参试品系的抗逆性(抗寒性、耐旱性、抗倒伏、条锈病、叶锈病、白粉病)进行评价。【结果】参试品系产量为2791.65~5979.29 kg/hm^(2),均产4635.75 kg/hm^(2)。农艺性状的变异系数排序为:产量(17.16%)>有效穗数(14.40%)>株高(11.37%)>穗粒数(9.65%)>千粒重(9.54%)>穗长(9.47%)>总茎数(8.55%)>基本苗(8.08%)>生育期(1.21%),产量、有效穗数、穗粒数、千粒重和株高均随参试年份的推进而缓慢提高,生育期则缓慢降低。相关分析结果表明,产量与穗粒数(r=0.645)、千粒重(r=0.594)和株高(r=0.475)呈显著正相关,有效穗数与穗粒数(r=0.729)呈极显著正相关。多元回归分析表明,穗长、穗粒数和千粒重决定了产量66%的变异。通径分析结果表明,千粒重对产量的直接作用(P=0.485)和综合作用(P=0.615)最大,穗粒数次之(P=0.471,P=0.543)。聚类分析将参试小麦品系分为5类,其中第一类群的品系产量高,千粒重较高,其余农艺性状较协调,占比7.29%,是选育优良品系(种)的理想材料。抗逆性分析表明,超过66%的参试品系具有较强的抗寒性、耐旱性和抗倒伏特性,同时,超过55%的参试品系对条锈病、叶锈病和白粉病表现为免疫或高抗。【结论】参试品系的产量整体水平低而不稳,产量与有效穗数受环境影响较大,穗粒数和千粒重是影响陇东旱地小麦产量的主要因素,可通过同时增加穗粒数和千粒重提高产量,而且高产广适型冬小麦品种应具备较强的抗寒旱等综合抗逆性。

耕作方式对旱作区麦-玉轮作体系小麦产量、氮素利用和土壤硝态氮残留的影响

为筛选适合黄河中游旱作区麦-玉轮作体系小麦生产的耕作方式,2019年10月至2022年6月在洛阳市小浪底镇进行定位试验,设置深松(SS)、翻耕(PT)和旋耕(RT)3种耕作方式,研究了小麦产量特性,氮素积累分配转运特性及利用效率和0~200cm土层硝态氮残留量.3年中SS较RT和PT显著提高了产量、穗数和穗粒数,但降低了千粒质量.PT较RT提高产量和穗数,但对穗粒数和千粒质量的影响存在年际差异.SS不仅增加了越冬至成熟期各时期的地上部氮素积累量,而且可提高花前氮素转运量及其对籽粒氮素的贡献率,最终使蛋白质产量较RT和PT分别提高17.90%~23.56%和7.92%~12.98%,氮肥偏生产力提高5.63%~15.89%和3.09%~11.00%,成熟期0~200cm土壤硝态氮残留量显著降低7.39%~21.24%和4.76%~23.04%.综上,SS不仅能提高小麦产量,而且能促进氮素积累、转运和利用,降低土壤硝态氮残留量,是黄河中游旱作麦-玉轮作区实现小麦高产高效和环境友好的耕作方式.

旱地小麦锌吸收转移与籽粒锌含量的关系

【目的】黄土高原旱地小麦籽粒锌含量较低,明确土施锌肥引起的小麦花前花后锌吸收转移和籽粒锌含量的变化,及其与土壤锌形态及有效性关系,为优化旱地小麦锌营养强化技术提供科学依据。【方法】基于2017年在黄土高原旱地石灰性土壤上开始的定位试验,于2021—2022和2022—2023年两个小麦生长季取样,研究锌肥用量对土壤有效锌及锌形态、小麦花前花后锌吸收转移及籽粒锌含量的影响。【结果】施用锌肥对小麦产量无显著影响,但两季小麦籽粒锌含量分别提高44.7%和38.2%,施锌25.6 kg/hm^(2)时,籽粒锌含量最高达33.6 mg/kg,花前锌吸收量分别提高38.8%~83.7%和13.4%~49.0%,花后锌转移量分别提高36.0%~73.9%和13.0%~39.6%;施锌对小麦花后锌吸收量的影响因年份而异。表层0—20和20—40 cm土壤有效锌含量分别提高11.6和11.3倍,最高分别达9.20和3.57 mg/kg,深层40—60、60—80和80—100 cm土壤有效锌含量分别提高4.4、1.8和1.9倍,最高分别达0.54、0.28和0.29 mg/kg。施用锌肥显著提高了土壤各形态锌含量,0—20和20—40 cm土层水溶态锌分别提高54.5%和75.0%,达0.17和0.14 mg/kg;松结有机态锌分别提高214.9%和90.8%,达5.70和3.11 mg/kg;碳酸盐结合态锌分别提高1178.0%和551.7%,达5.24和1.89 mg/kg;氧化锰结合态锌分别提高345.9%和183.9%,达15.52和9.37 mg/kg;紧结有机态锌分别提高91.5%和34.4%,达1.13和0.86 mg/kg;残渣态锌分别提高23.7%和24.3%,达56.57和56.80 mg/kg。【结论】施锌显著提高了土壤松结有机态、碳酸盐结合态和氧化锰结合态锌含量,并通过其向水溶态锌转化,维持了施锌后表层土壤有效锌提升和施入土壤的肥料锌的有效性,促进了小麦花前锌吸收,实现了花后地上部锌向籽粒的转移及籽粒锌含量提升,但干旱缺水影响了旱地小麦花后锌吸收,抑制了施锌后籽粒锌含量进一步提升。

秸秆还田配施磷肥对豫西旱地小麦碳同化物积累的影响及其生理机制

为明确秸秆还田配施磷肥对豫西旱地小麦碳同化物积累特性和产量的影响,2021-2022年度,以洛旱22为材料,采用裂区试验设计,主区为玉米秸秆还田处理,分别为秸秆不还田(S0)、秸秆全量还田(S1),副区为施磷量处理,分别为0 kg·hm^(-2) (P_(0))、75 kg·hm^(-2) (P_(1))、112.5 kg·hm^(-2) (P_(2))、150 kg·hm^(-2) (P_(3))、187.5 kg·hm^(-2) (P_(4)),测定了不同处理下小麦干物质积累特性和产量及其构成因素,以及花后旗叶净光合速率、相对叶绿素含量(SPAD值),旗叶和籽粒的可溶性糖、蔗糖含量及蔗糖酶活性。结果表明,同一施磷水平下,与秸秆不还田相比,秸秆还田提高了小麦旗叶SPAD值和净光合速率,增加了旗叶和籽粒中的可溶性糖、蔗糖含量、蔗糖合成酶和磷酸蔗糖合成酶活性,最终使成熟期干物质积累量和籽粒产量分别显著增加9.25%~14.60%和2.17%~6.31%。同一秸秆处理下,随施磷量的增加,旗叶SPAD值、净光合速率,旗叶和籽粒中的可溶性糖、蔗糖含量、蔗糖合成酶和磷酸蔗糖合成酶及干物质积累量呈先上升后下降趋势。从互作效应看,S1P_(3)处理下旗叶SPAD值和净光合速率,旗叶和籽粒中的可溶性糖和蔗糖含量,蔗糖合成酶和磷酸蔗糖合成酶活性等各指标均最高,从而获得最高产量,较S0P_(0)处理增产35.70%。因此,秸秆还田配施磷150 kg·hm^(-2) 是本试验条件下的最适宜种植方式,可在豫西旱地小麦栽培上推广。