[Objective]Zn(Zinc)deficiency triggers'hidden hunger'.Enhancing Zn concentration in wheat grains and Zn fertilizer use efficiency through biofortification can effectively increase dietary Zn intake,thereby improving human Zn nutritional status.[Method]The study subjects were two distinctive colored-grain wheat varieties:'Taihei 5'(purple-grained)and'Tailan 8'(blue-grained).A two-year field experiment was conducted from 2022-2024 in Taigu District,Jinzhong City,Shanxi Province.Foliar Zn application was performed at 3-5 days after the flowering of colored-grain wheat(Over 50%of spikes in the wheat field had lemma and palea separation at middle-upper florets while anthers were dehiscing).Five Zn concentration treatments were applied:Zn0(deionized water),Zn1(Zn concentration:440 mg·L-1),Zn2(Zn concentration:587 mg·L-1),Zn3(Zn concentration:733 mg·L-1),Zn4(Zn concentration:880 mg·L-1).Through analysis of grain yield and Zn concentrations in grains,leaves,and stems across multiple post-anthesis periods for both colored-grain wheat types,Zn concentration variation dynamics,Zn accumulation and partitioning characteristics,Zn utilization efficiency,grain Zn biofortification index and grain Zn harvest indices were quantitatively analyzed to evaluate their Zn biofortification efficacy.[Result]Foliar Zn application significantly increased Zn concentrations in all organs and grain yield of colored-grain wheat,The Zn3 treatment produced the highest grain Zn concentration(21.79-67.90 mg·kg-1)and peak grain yield(4 937.36-5 097.27 kg·hm-2).Grain Zn accumulation reached its optimum(251.30-301.54 g·hm-2)under the Zn3 treatment,while Zn concentrations and accumulation in leaves and stems increased linearly with rising application concentrations.With increasing Zn application concentrations,the grain Zn accumulation proportion showed a declining trend(10%-18%),while the leaf Zn accumulation proportion rose to 66%,and stem Zn accumulation remained at 23%-30%.Furthermore efficient synergy in Zn utilization efficiency across all organs of colored-grain wheat was achieved under Zn3 treatment(5.68%-7.70%).With increasing Zn application concentrations,the grain Zn biofortification index and Zn harvest index declined.Compared with Zn1,other Zn treatments reduced the grain Zn biofortification index by 12.50%-47.02%,while relative to the control(Zn0),all Zn treatments decreased the Zn harvest index by 23.66%-60.44%.'Taihei 5'outperformed'Tailan 8'in grain Zn concentration,accumulation,utilization efficiency,and biofortification performance.Possibly influenced by precipitation,both types of colored-grain wheat performed better in the second growing season[Conclusion]Post-anthesis foliar Zn application effectively regulated Zn accumulation and partitioning in colored-grain wheat.The combination of purple-grained wheat varieties and foliar Zn application at 733 mg·L-1 achieved the optimal balance between grain Zn concentration and Zn utilization efficiency in colored-grain wheat systems.

Background Drought critically compromises agricultural productivity and threatens sustainable wheat production. Streptomyces pactum Act12 confers benefits to plant growth under drought stress, but its possible effects on root-associated microbiomes remain understudied. Here, shotgun metagenome sequencing and culture-dependent approaches were integrated to investigate the responses of rhizosphere and rhizoplane microbiomes in dryland winter wheat to exogenous S. pactum Act12 and their potential linkage to plant drought resistance. Results Seed biopriming with S. pactum Act12 increased plant aboveground dry weight at flowering (by 63.2%) and maturation (by 41.9%) stages, leading to improved grain yield (by 8.7%). Microbial inoculation reduced malondialdehyde contents in wheat leaves and roots at the flowering stage alongside compartment-specific alterations in soil microbiomes. Metagenomic analysis revealed inoculation-induced enrichment of distinct taxa in rhizosphere soils (flowering: Fibrobacterota, Altererythrobacter; maturation: Mucoromycota, Rhodospirillum) and rhizoplane soils (flowering: Pseudomonadota, Serratia; maturation: Candidatus_Pacebacteria, Variovorax). Functional profiling showed up-regulation of key pathways related to oxidative phosphorylation in inoculated rhizosphere soils at the flowering stage. In rhizoplane soils, ABC transporters and pyrimidine metabolism were up-regulated across stages upon inoculation. Two key strains isolated from rhizoplane soils, designated Glycomyces lechevalierae A4 and Microbacterium algeriense B3, demonstrated the ability to enhance drought resistance in wheat seedlings. Conclusions Inoculation of S. pactum Act12 heightens drought resistance in dryland winter wheat through compartment-specific phylogenetic restructuring and functional reprogramming of root-associated microbiomes.

Deep plowing and subsoiling are the primary methods for soil water retention in dryland farming areas of the Loess Plateau during the summer fallow period of winter wheat. Soil nematodes serve as biological indicators of the soil ecological health. However, we have limited understanding of the relationship between soil biological communities in the soil micro-food web of dryland tillage. This study investigated soil nematode and microbial communities, as well as the soil properties under deep plowing tillage (DT), subsoiling (SS), and no tillage (NT) in dryland wheat fields on the Loess Plateau, based on a 5-year experiment. The results indicated that nematodes were mainly distributed in the 0-20 cm soil layer. Plant parasitic nematodes (Pp) were dominant during the wheat growth period, while bacterivore nematodes (Ba) prevailed during the non-wheat growth period. With the lowest plant parasite index (PPI), highest maturity index (MI) and structure index (SI) of the nematode community, DT enhanced soil microecological stability. Additionally, DT demonstrated the highest overall soil quality, characterized by significantly higher soil moisture, available potassium contents, NH4+-N, and NO3--N levels, microbial abundance, and soil enzymatic activities. The highest soil organic carbon content and the most intricate interactions between nematodes and microbial communities were noted under SS, along with the highest level of cooperation among various soil biota. Furthermore, bacteria, fungi, and soil properties positively affected soil nematodes, with the soil properties exerting the most significant impact (P < 0.001), particularly through soil aggregate stability, moisture, and microbial biomass having significant effects. Soil moisture was positively correlated with the most dominant nematode and bacterial genera. In summary, DT significantly enhanced the structures of soil nematodes and microbial communities and stabilized the soil micro-food web by improving soil moisture and quality. It serves as an effective tillage practice for wheat fields in the dry-farming areas of the Loess Plateau.

To explore the impact of tillage and fertilization practices on enhancing the soil micro-ecological environment in the dry farmlands of the Loess Plateau, this study used nematodes as indicator organisms. We investigated the effects of three tillage methods (deep tillage, subsoiling, and no-tillage) and four fertilization methods (no fertilization, full chemical fertilizer, 50 % organic fertilizer substituting chemical fertilizer, and full organic fertilizer) on the soil nematode community and its functions. Our findings indicate that the interaction between tillage and fertilization significantly influenced the soil's total abundance of nematodes and trophic groups. Specifically, the total abundance of nematodes and the relative abundance of bacterial-feeding nematodes were higher under subsoiling in maize and no-tillage in wheat season. Moreover, the energy flux within the food web was more pronounced. Applying chemical fertilizers resulted in greater soil bulk density and a higher proportion of plant parasitic nematodes than other treatments, harming the diversity of soil nematode communities. The nematode community's abundance was positively correlated with alkali-hydrolyzable nitrogen content. In summary, reducing tillage in the wheat-maize annual rotation system, implementing subsoiling in the maize season and no-tillage in the wheat season, combined with organic fertilizer application, can improve soil quality, improve nematode community structure and maintain the stability of the soil food web. This approach positively contributes to improving soil health and ecological stability in the dry farming regions of the Loess Plateau.

Soil organic carbon (SOC) is crucial for mitigating global warming and significantly impacts crop production. While the relationship between SOC and wheat yield is well-documented, its effect on wheat grain protein content, which is essential for food security and human health, remains unclear. This study gathered management data from wheat farmers and collected plant and soil samples in the Huang-Huai winter wheat region, China's primary wheat-growing area, from 2015 to 2022. Boundary line analysis was used to quantify the responses of wheat yield and protein content to variations in SOC. Our findings reveal that increases in SOC significantly enhance wheat yield and protein content. The highest yields, reaching up to 10,848 kg ha(-1), and a maximum protein content of 17.3 % were observed in soils with SOC ranging from 7.8-18.1 g kg(-1), and high-yielding, high-protein wheat exhibited higher spike numbers and grain weights and more efficient nutrient accumulation from soil or fertilizer to shoots. Optimizing SOC levels to produce high-yielding, high-protein wheat could substantially reduce nitrogen (N), phosphorus (P), and potassium (K) fertilizer use by 9.42x10(4), 0.70x10(4), and 3.66x10(4) Mg per year, decrease greenhouse gas emissions by 3.36 Mt CO2 eq and generate an economic benefit of 2.77 billion USD. In conclusion, our study expands the understanding of SOC's role in crop production beyond crop yield, providing valuable insights for producing high-yielding, high-protein wheat.

探索黑糯玉米硒吸收利用和营养品质对叶面喷施有机硒肥的响应，对生产中合理施用硒肥，进而支撑山西“特”“优”农业高质量发展具有重要意义。本研究以品种晋鲜糯8号为试验材料，于2020—2021年连续2年在山西晋中黑糯玉米典型种植区开展田间试验，设置一次喷施不同用量有机硒0、6和12 g Se hm -2 ，以及喷施量12 g Se hm -2 条件下分2次喷施，共4个处理，研究叶喷有机硒对黑糯玉米产量、硒吸收利用、籽粒花青素和铁锰铜锌含量的影响。结果表明，喷硒量和喷硒次数对黑糯玉米鲜食期产量和成熟期地上部生物量无影响。相比不喷硒，喷硒可提高鲜食期籽粒和成熟期地上部各器官硒含量、硒积累。喷硒12 g Se hm -2 时，籽粒硒含量达到满足人体硒营养需求的最低目标值100 μg kg -1 ，增幅最大，介于110～181 μg kg -1 。成熟期，植株各器官硒积累从高到低依次为叶片、籽粒、茎秆、苞叶、穗轴。喷硒12 g Se hm -2 ，分2次喷施的平均籽粒硒强化指数和籽粒硒回收率分别为6.95 (μg kg -1 ) (g hm -2 ) -1和2.4%，优于1次喷施。同时，鲜食期籽粒花青素和铁锰锌含量也最高，2年平均值分别为209、27.9、15.9和22.8 mg kg -1 ，但各处理间籽粒铜含量无差异。因此，兼顾硒吸收利用和籽粒营养品质同步提升，该区黑糯玉米生产中叶喷有机硒肥用量至少应不低于12 g Se hm -2 ，且分2次喷施效果较优。

Content: Excessive fertilization reduces fertilizer efficiency and farm economic benefits, and causes various environmental problems.Objectives: This study aimed to produce high grain yield and protein content for wheat production in China using a High Nutrient-use efficiency Based Fertilizer Recommendation method (High NUFER) and limits for crop nutrient physiological efficiency and partial factor productivity of fertilizer.Methods: A farm survey covering 1575 fields was carried out in 17 major wheat production provinces in China from 2015 to 2019. The on-farm information included wheat planting area, varieties, field management, soil nutrient status and fertilization status, and wheat plant and soil samples were also collected from farmers' fields for measurement and analysis. The High NUFER proposed in this paper was verified in 46 sites in 7 major wheat production provinces from 2020 to 2021.Results: For the average grain yields > 6.0 t ha(-1) and protein content similar to 13.0% in major wheat production regions of China, the nutrient physiological efficiency of wheat should range from 36.5 - 36.8 kg kg(-1) nitrogen (N), 261.3-273.9 kg kg(-1) phosphorus (P), and 53.0-54.3 kg kg(-1) potassium (K), and partial factor productivity of N, P, and K fertilizers should range from 35.9 - 41.9, 153.5-177.9, and 132.5-158.9 kg kg(-1), respectively, when soil available nutrients ranged from 19.0 to 21.8 mg kg(-1) available N (nitrate-N (+) ammonia-N), 22.4-26.1 mg kg(-1) available P, and 153.9-157.3 mg kg(-1) available K. Using the High NUFER, China should save 0.62 MT yr-1 N fertilizer, 0.36 MT yr-1 P fertilizer, and 0.22 MT yr(-1) K fertilizer, with an additional economic benefit of 1.1 billion USD yr(-1) and reduction in greenhouse gas (GHG) emissions of 8.91 MT CO2 eq yr(-1) in major wheat production regions.Conclusions: The High NUFER can reduce farmers' fertilizer input, thereby increasing economic benefits and decreasing GHG emissions.Implications: The High NUFER proposed in this paper has practical value for nutrient management in China and is a potential reference for other wheat-growing countries.

小麦是重要的粮食作物,其微量元素含量高低直接影响人体健康。明确我国主要麦区小麦籽粒微量元素含量水平,对优化小麦微量元素营养品质,保障居民营养健康有重要意义。于2016—2020年,在我国17个小麦主产省区采集分析了1112份小麦及土壤样品,参考《中国营养学会人体微量元素摄入标准》和美国环境保护署健康风险评估方法,结合我国居民饮食特点,推荐了小麦籽粒微量元素适宜含量范围,并以此评价了我国小麦的微量元素营养状况。研究发现,我国小麦籽粒铁含量平均为43.8 mg kg -1 , 72.9%样本低于铁的推荐量下限50 mg kg -1 ,所有样本铁含量均低于推荐量上限140 mg kg -1 ;籽粒锰含量平均为43.0 mg kg -1 ,仅4.1%样本低于推荐锰含量下限22 mg kg -1 ,但23.7%样本高于推荐上限值50 mg kg -1 ;籽粒铜含量平均为4.6 mg kg -1 , 7.6%样本低于推荐量下限3 mg kg -1 ,所有样本铜含量均低于推荐量上限10 mg kg -1 ;籽粒锌含量平均为31.4 mg kg -1 , 85.8%的样本低于推荐量下限40 mg kg -1 ,仅4.1%样本高于50mgkg -1 的推荐量上限;籽粒硼含量平均为1.2mgkg -1 ,低于推荐量下限0.8mgkg -1 的样本占29.2%,所有样本均低于推荐值上限10 mg kg -1 ;籽粒钼含量平均为0.5 mg kg -1 , 18.8%的样本钼含量低于推荐量下限0.2 mg kg -1 ,仅有0.4%样本钼含量高于推荐值上限2 mg kg -1 。我国小麦籽粒微量元素含量也存在区域间变异,其中,铁、锌含量普遍偏低,部分地区硼、钼含量不足,而锰含量偏高,铜含量基本在推荐范围内。

A two-year positioning field experiment was conducted to determine the reasonable regulation measures of selenium (Se) fertilizer for improving wheat grain Se nutrition, and to explore the feasibilities of different Se application approaches in Se agronomic biofortification of wheat grown in the typical Se-deficient soils of Yongshou County, Shaanxi Province. To study the effects of different forms and application methods of Se fertilizers on wheat yield, Se concentration and its accumulation and utilization, with the goal of producing wheat grain with Se concentration of 100 μg kg -1, five Se application rates of 0, 15, 18, 700, and 45 g hm-2 were calculated for the treatments of no Se application (control), soil- and foliar-sodium selenate, and soil- and foliar-sodium selenite in the first year, respectively. In the following wheat season, for further investigating the residual Se availability, no Se fertilizer was applied and each plot was divided into straw removal and straw return. These results showed that the wheat grain yield and straw biomass were not influenced by Se forms and application methods. For the first wheat season, grain Se concentration reached the expected target value with a range of 109-397 μg kg -1, and the flour Se concentration varied from 101 μg kg -1 to 356 μg kg -1 for all the Se application treatments. In the next year, both grain and white flour Se concentrations were 100 μg kg -1 higher than under the treatment of soil-sodium selenite, and there was no significant difference of straw removal and straw return. Grain Se biofortification index was 4.7, 16, 0.3, 8.0 (μg kg-1) (g hm-2)-1 for soil- and foliar-sodium selenate, and soil- and foliar-sodium selenite, respectively. The Se use efficiency was the highest for foliar-sodium selenate (7.3%), whereas its cumulative use efficiency was only 0.3% in soil-sodium selenite treatment with the long-term residue effects. At wheat harvest, the highest soil available Se was observed for soil-sodium selenite, with 91 μg kg -1 and 107 μg kg -1 for the straw removal and straw return, respectively. In conclusion, both soil- and foliar-sodium selenate /selenite were beneficial for producing wheat grain with target Se concentration of 100 μg kg -1, and the sodium selenite requirement was the highest, and its residual availability should be taken into consideration for Se biofortification in wheat production in the Se-deficient area of Chinese Loess Plateau.

>Dear Editor,Globally, approximately two billion people suffer from micronutrient deficiencies(Tulchinsky, 2010; Myers et al.,2014).Soil micronutrient availability is of great importance for the evaluation of soil fertility and the determination of appropriate measures for improving crop quality and human health.The diethylenetriamine-penta-acetic(DTPA)

Precipitation has been recognized as the dominant factor driving crop grain yields and large yield variations in drylands, which suggests that some agricultural management practices can be optimized to achieve high yields and benefits. In this study, we investigated 804 farmers' wheat fields from 2015 to 2018 in the dryland area of the Loess Plateau in China and analyzed the relationships between wheat yield and the influence factors (including precipitation, wheat sowing rate, fertilizer inputs, and soil nutrients) to propose optimized agricultural management practices for wheat production. The results showed that wheat grain yield followed a linear plateau pattern relative to the precipitation in the summer fallow season, with a yield of 5344 kg ha(-1) obtained at a precipitation of 203 mm. In the L203 group (precipitation in the summer fallow season less than 203 mm), the Low-yield subgroup (0-33th in grain yield group (in order from low to high)) had a lower sowing rate, kernel weight, kernel number and spike number than the High-yield subgroup (68-100th in grain yield group); different levels of phosphorous (P) and potassium (K) fertilizer overuse were found among the three yield subgroups. However, in the H203 group (precipitation in the summer fallow season greater than 203 mm), differences in only kernel and spike numbers and nitrogen (N) fertilizer application rate were observed among the Low-, Moderate-, and High-yield subgroups. Additionally, there were no differences in the soil organic matter (SOM), total N or pH in the three subgroups in either L203 or H203, but significant differences in soil mineral N, available P and K were observed among the three subgroups (except mineral N in L203). Based on these results, the wheat sowing rate and fertilizer input rates can be optimized to increase wheat yield and farmers' income and promote agricultural management for dryland wheat production on the Loess Plateau.

Background: Naked oat (Avena nuda L.) is one of the most important, nutritionally rich grain crops produced worldwide. To determine the most reasonable selenium (Se) application method for naked oat, field experiments were conducted in the Loess Plateau from 2017 to 2018 to investigate the effects of Se fertilizer on grain yield, quality, Se content, and forms using a randomized block design with four treatments: foliar Se fertilizer application (S), soil Se fertilizer application (T), combined foliar and soil Se fertilizer application (TS), and control (CK) with no Se fertilizer. Results: Compared to CK, the grain yield and Se content under the Se fertilizer treatments increased by 4.86-10.04% and 72.5-203.08%, respectively. Se forms of naked oat grains in T, S, and TS were mainly selenomethionine (SeMet). The SeMet content average increased by 45.69% (T), 53.75% (TS), and 51.19% (S), and the SeCys (selenocysteine) content increased by 90.73% (TS) and 75.43% (S), the Se fertilizer treatment increased the Se content in the roots, stems, leaves, and ears of oats. TS treatment, the Se content in ears was the highest. Se application significantly affected the crude protein and crude ash contents with the maximum recorded value observed in TS. Moreover, TS had significantly higher content of globulin, glutenin, and lysine, leucine, cystine, glutamic acid, and total amino acid contents for two consecutive years (P < 0.05). Se application significantly affected the iron (Fe), zinc (Zn), and calcium (Ca) contents (P < 0.05) with the Ca and Zn contents in the seeds reaching the maximum recorded values in TS. Conclusions: Based on these findings, combined foliar and soil Se fertilizer was determined to be the best Se application method on naked oats.

小麦高产优质生产对保障我国粮食安全和人们营养健康有重要意义.通过实地调研和取样分析,研究了黄淮麦区276个田块的小麦籽粒锌含量与产量和产量构成、施肥和土壤养分、作物锌吸收利用等参数的关系.结果表明,黄淮麦区缺锌和非缺锌土壤的比例分别为42％和58％,两种土壤上的小麦籽粒锌含量分别介于16～52和17～58 mg·kg–1,分别有7％和9％样本的籽粒锌达到推荐值40 mg·kg–1.缺锌田块,籽粒锌含量与磷肥用量(r=–0.273,P<0.01)、0～20 cm土壤有效磷(r=–0.283,P<0.01)显著负相关,高低籽粒锌组的磷肥用量分别为73和137 kg·hm–2,土壤有效磷分别为13和20 mg·kg–1,有效锌分别为0.8和0.7 mg·kg–1,但籽粒产量低于非缺锌土壤(7204和7857 kg·hm–2).非缺锌田块,籽粒锌含量与磷肥用量显著负相关(r=–0.181,P<0.05),与0～20 cm(r=0.236,P<0.01)和20～40 cm(r=0.183,P<0.05)土壤有效锌显著正相关,高低锌组的磷肥用量分别为112和145 kg·hm–2,0～20 cm的土壤有效磷分别为29和30 mg·kg–1,有效锌分别为3.3和2.2 mg·kg–1.因此,在缺锌土壤上,应首先解决土壤缺锌问题,将有效锌提升至临界值1.0 mg·kg–1以上,非缺锌土壤有效锌保持在3.0 mg·kg–1以上,同时适当减少磷肥用量和降低土壤有效磷水平,以减少磷对小麦锌吸收的负面影响,维持黄淮麦区小麦高产并改善籽粒锌营养.

[目的]分析我国北方麦区不同土壤硝态氮残留梯度下减施氮肥后小麦籽粒产量、蛋白质含量变化,为保证合理减施氮肥,有效降低麦田土壤硝态氮残留提供理论依据.[方法]于2018—2019年在我国北方麦区43个地点进行田间试验,研究不同硝态氮残留情况下氮肥减施对小麦产量、蛋白质含量、产量构成及氮素吸收利用的影响.[结果]与农户施肥相比,监控施肥的氮肥用量减少55 kg·hm-2(26％),产量为5885 kg·hm-2,比农户施肥增产3.1％,籽粒蛋白质含量为132.4 g·kg-1,与农户施肥相比无显著差异.当1 m土层硝态氮残留量<55 kg·hm-2时,小麦产量最低,为4252 kg·hm-2,硝态氮残留在55—100 kg·hm-2时,产量达到最高,为7186 kg·hm-2,硝态氮残留量过高并不能持续提高小麦产量;当土壤硝态氮残留量<100 kg·hm-2时,不施氮肥小麦产量会显著降低,但采用监控施肥技术合理减施氮肥,无论土壤硝态氮残留多少,均不会减产.土壤硝态氮残留>300 kg·hm-2时,小麦籽粒的蛋白质含量达到最高,平均为146.93 g·kg-1;当土壤硝态氮残留量<200 kg·hm-2时,不施氮肥会显著降低籽粒蛋白质含量,但通过监控土壤硝态氮合理减施氮肥,无论硝态氮残留高低,均不会降低籽粒蛋白质含量;硝态氮残留介于55—100 kg·hm-2时,农户与监控施肥处理的小麦籽粒蛋白质含量分别为124.5和123.1 g·kg-1.采用监控施肥技术,小麦氮肥吸收效率(地上部吸氮量/施氮量)与氮肥偏生产力分别为1.36和45.7 kg·kg-1,较农户施肥显著提高61.5％和57.1％.[结论]综合考虑维持北方麦区小麦较高的产量和蛋白质含量,收获期1 m土层硝态氮残留量应介于55—100 kg·hm-2.基于小麦目标产量、籽粒蛋白质含量和土壤硝态氮监控,确定合理的氮肥用量,对实现小麦氮肥减施、绿色生产有重要意义.

[目的]明确我国主要麦区农户小麦施肥存在的问题及减肥潜力,为科学施肥、合理减肥提供依据.[方法]连续3年对我国主要麦区的小麦种植户进行施肥调研和取样,基于农户产量、养分需求量和土壤养分供应水平对其施肥状况和减肥潜力进行评价和分析.[结果]我国主要麦区农户小麦产量和生物量平均为6.0和13.2 t·hm-2,二者极显著线性相关.小麦产量与施肥量和土壤养分无显著相关.我国小麦氮(N)、磷(P2O5)和钾(K2O)肥用量平均分别为191.1、112.8和53.4 kg·hm-2,春麦区农户氮、磷和钾肥用量平均分别为171.7、108.9和10.6 kg·hm-2,旱作区分别为154.3、111.8和32.6 kg·hm-2,麦玉区分别为236.4、128.1和74.0 kg·hm-2,稻麦区分别为177.5、77.0和71.8 kg·hm-2.就施氮量而言,春麦区过量施氮的农户较少,为34％,其次是麦玉区、稻麦区和旱作区,分别为42％、55％和63％;产量较低的农户是氮肥减施的重点,减氮潜力最高达43.6％,平均需减氮2.3-135.5 kg·hm-2.过量施磷问题比较突出,各麦区施磷过量的农户分别占63％、87％、68％和57％,即使小麦高产时,仍有超过50％的农户施磷过量;各麦区不同产量等级的农户均需减施磷肥,减磷量平均为3.8-91.1kg·hm-2,旱作区减磷潜力最大,达55.6％.施钾状况因麦区而异,在春麦区,主要问题是施钾不足,占84％,平均需增施钾肥22.8 kg·hm-2;旱作、麦玉和稻麦区,减钾潜力分别达43.2％、25.7％和56.0％;产量较低的农户是减钾的重点,平均需减钾31.7-45.9 kg·hm-2.[结论]我国农户施肥状况和减肥潜力因农户产量和麦区不同存在差异,中低产农户过量施肥问题较为严重,应注意根据产量适量减少施用氮、钾肥,所有农户均需警惕磷肥过量投入问题,其中旱作区氮、磷肥减施潜力最高,稻麦区减钾潜力最高.

[目的]研究同一区域不同地点小麦籽粒养分含量差异与土壤养分供应和作物养分吸收利用之间的关系,为科学施肥和培肥土壤提供依据.[方法]于2017—2018年分别在陕西永寿和杨凌布置田间试验,在施N 180 kg·hm-2、P2O5100 kg·hm-2、K2O 75 kg·hm-2的条件下种植来自我国不同麦区的20个小麦品种,收获期取样测定籽粒产量、各器官养分及土壤养分含量,分析两地间土壤养分供应与籽粒大、中、微量元素含量差异的关系.[结果]永寿小麦籽粒氮和钾含量比杨凌低10.6％和6.7％,两地小麦磷含量无显著差异.永寿土壤氮磷供应能力、小麦氮磷钾吸收和向籽粒的转移均高于杨凌;但试验年份永寿的降水总量及其分布均比杨凌的更有利于小麦生长和产量形成,由此引起的产量增幅高于籽粒氮钾吸收量增幅、与磷吸收量增幅接近,产量稀释效应是导致两地间氮磷钾含量变化的主要原因.永寿小麦籽粒钙和镁含量比杨凌高19.0％和10.3％,两地硫含量无显著差异.永寿土壤交换性镁供应能力低于杨凌,交换性钙与杨凌无差异,但永寿土壤较低的pH、速效钾和较高的有效硫更有利于小麦钙镁硫的吸收和向籽粒的转移;与杨凌相比,永寿小麦籽粒钙镁吸收量增幅大于产量增幅、硫吸收量增幅与产量接近,这是两地籽粒钙镁硫含量变化的主要原因.永寿小麦籽粒铁、锰和铜含量比杨凌高9.3％、22.2％和12.7％,锌含量比杨凌低63.1％.永寿0—20 cm土层有效铁锰含量与杨凌无差异,铜锌含量低于杨凌;但永寿小麦灌浆期比杨凌长,有利于小麦从土壤中吸收微量元素,而锌吸收被较高的有效磷抑制,导致永寿小麦铁锰铜吸收和向籽粒的转移高于杨凌而锌吸收和转移低于杨凌,这是两地籽粒铁锰铜含量变化的原因.[结论]在同一区域的不同地点,土壤养分供应和降水差异引起的产量与养分吸收增减幅度不同是籽粒养分含量变化的主要原因.与杨凌相比,永寿小麦籽粒氮含量低的主要原因是产量稀释效应;小麦磷和硫含量不降低的原因是土壤较高的有效磷和有效硫供应使得小麦磷、硫吸收量与产量以相近幅度增加;小麦籽粒钾、锌含量低的原因分别是土壤钾锌供应不足和磷锌拮抗;小麦钙镁含量的增加主要是因为较低的土壤pH和速效钾促进了钙镁吸收和转移;小麦籽粒铁锰铜含量的增加主要归因于较长的灌浆期增加了这些元素的吸收和向籽粒的转移.农业生产中应根据当地土壤养分供应和气候特点有针对性地调控施肥,使小麦养分吸收与产量变化相协调,在实现增产的同时提高籽粒矿质营养品质.

Plastic film mulching systems are widely used in crop production because of great benefits in increasing crop yields, but transparent film mulching (TFM) has negative impacts on crop production due to the high soil temperature under certain conditions. Because of its lower impacts on soil temperature, black film mulching (BFM) is being considered as an alternative to TFM. A meta-analysis was therefore conducted to compare the benefits and trade-offs of TFM and BFM use in potato, maize, and wheat production. Overall, the plant height, aboveground biomass, water use efficiency, and yield under plastic film mulching increased by 7-17 %, 27-59 %, 20-47 %, and 17-35 %, respectively. However, film mulching shortened the crop phenology by 4-9 % due to the higher soil temperature compared with non-mulching. Compared with TFM, the mean soil temperature over the crop growing season under BFM reduced by 1.1 degrees C, which resulted in a 3-5 % increase in phenology. This is a crucial factor for BFM to increase maize yield by 6% and improve marketable tuber rate of potato by 9%, which led to higher profits, compared with TFM. In addition, no herbicide was used in BFM system, thereby eliminating the costs of herbicide and its application. As a result, the net economic benefits in BFM were 5-11 % higher than those in TFM for crop production. In conclusion, the BFM system leads to greater crop growth and higher economic benefits than the TFM system, especially for maize and potato. Policies and investment incentives that support the promotion of BFM technology should be prioritized in order to pursue these greater benefits.

It is useful to understand soil nutrients responsible for grain zinc (Zn) variation of winter wheat (Triticum aestivum L.) in different cropping regions, in order to adopt appropriate soil management measures to improve grain Zn nutrition and alleviate human Zn malnutrition. A total of 599 wheat plant and corresponding soil samples were collected from farmers' fields in three typical wheat cropping regions of China in 2015 and 2016, to determine the dominant soil nutrients related to high grain Zn concentration. Obtained results showed that a large variation in grain Zn existed within different regions, with 8%, 9% and 16% of grain samples reaching the recommended level of 40 mg kg(-1) in the single wheat, wheat-maize and rice-wheat regions, respectively. In the single wheat region, grain Zn was positively correlated with soil available potassium (K) and Zn, and negatively correlated with available iron (Fe) (P < 0.001), with the available K being 164 and 117 mg kg(-1), Zn 0.64 and 0.46 mg kg(-1), and Fe 3.3 and 5.2 mg kg(-1) for the high and low Zn groups, respectively. In the wheat-maize region, grain Zn was positively correlated with soil available Zn, while negatively correlated with available phosphorus (P) (P < 0.001), with the available Zn being 1.7 and 1.3 mg kg(-1), and P 24 and 25 mg kg(-1) for the high and low Zn groups, respectively. In the rice-wheat region, grain Zn was positively correlated with soil ammonium nitrogen (Amon-N) and available Zn (P < 0.001), with Amon-N being 7.2 and 4.6 mg kg(-1), and available Zn 1.9 and 1.2 mg kg(-1) for the high and low Zn groups, respectively. Therefore, it is possible to produce wheat with grain Zn higher than 40 mg kg(-1) in farmers' fields, and apart from available Zn, soil available K and Fe in the single wheat region, available P in the wheat-maize region, and Amon-N in the rice-wheat region should also be considered for the purpose of grain Zn improvement.

[目的]明确实际生产中农户小麦产量与养分需求的关系,为科学施肥、合理减肥提供理论依据.[方法]连续两年对中国小麦主产区多点的农户调研和取样分析,研究中国春麦、旱作、麦玉和稻麦4个典型种植区域农户小麦氮磷钾养分需求量与产量的关系.[结果]中国农户小麦产量平均为6.4t·hm-2,麦区间存在显著的产量差异,春麦、旱作、麦玉和稻麦区平均分别为6.0、4.0、7.7和5.5t·hm-2,产量越高的麦区小麦生物量越大、公顷穗数越多,收获指数随产量增加而增加.全国农户小麦平均需氮量为28.1 kg·Mg-1,4个麦区分别为28.6、28.3、29.3和25.0 kg·Mg-1,产量由低产增至高产时,旱作区和麦玉区小麦需氮量分别显著降低16.9％和14.6％,春麦和稻麦区有降低趋势,但未达差异显著水平.全国小麦平均需磷量为4.0 kg·Mg-1,4个麦区分别为4.5、3.2、4.1和4.1 kg·Mg-1,产量从低产增至高产时,麦玉和稻麦区分别显著降低11.4％、17.8％,旱作区需磷量降低8.6％,差异亦未达显著水平,春麦区低产时需磷量最低为3.7 kg·Mg-1,产量从偏低提高到高产水平时也显著降低21.4％.农户小麦平均需钾量为21.5 kg·Mg-1,各麦区存在显著差异,4个麦区分别为26.5、17.1、23.3和18.8 kg·Mg-1,产量由低产增至高产时,4个麦区需钾量分别降低4.0％、4.4％、12.7％和19.9％,仅稻麦区差异显著.[结论]中国各麦区农户的小麦产量存在显著差异,养分需求量与产量的关系因麦区而异,总体来看,随产量增加,小麦氮、磷、钾养分需求量呈降低趋势.可见,在向农户推荐肥料用量时,需针对不同区域,结合农户田块的小麦产量水平、作物养分需求特性和土壤养分供应能力,确定合理的养分需求量,避免肥料施用过量或不足.