Groundwater resources are scarce in the cold and arid regions of north China. Moreover, regional water resource replenishment without external sources remains difficult. This water deficit has become a major factor restricting the sustainable development of regional vegetable production. The effective utilization of rainwater harvesting for irrigated agricultural production is necessary to suppress droughts and floods in farming under the semi-arid climate of this area in order to both guarantee a stable supply of vegetables to the market in south and north China and promote the balanced development of regional agriculture–resource–environment integration. In this study, based on continuous simulation and Python modeling, we simulated and analyzed the water supply and production effects of irrigation with harvests and stored rainwater on tomatoes under different water supply scenarios from 1992 to 2023. We then designed and tested a water-saving and high-yield project for rainwater-irrigated greenhouses in 2024 and 2025 under natural rainfall conditions in northwestern Hebei Province based on the reference irrigation scheme. The water supply satisfaction rate, water demand satisfaction rate, and volume of water inventory of tomato fields under different water supply scenarios increased with the rainwater tank size, and the corresponding drought yield reduction rate of tomato decreased. Under the actual rainfall scenarios in 2024 and 2025, a 480 m2 greenhouse with a 14.4 m3 rainwater tank for producing tomatoes irrigated with rainwater drip from the greenhouse film collected 127.7 and 120.5 m3 of rainwater, respectively. The volume of the rainwater tank was exceeded 8.3 and 8.0 times, and up to 93.8% and 95.0% of the irrigated groundwater was replaced; additionally, the average yield of the small-fruited tomato ‘Beisi’ was 50,076.6 kg·hm−2 and 48,110.2 kg·hm−2, reaching 96.1% and 92.3% of the expected yield. Conclusion: The irrigation strategy based on the innovative “greenhouse film–rainwater harvesting–groundwater replenishment” model developed in this study has successfully achieved a high substitution rate of groundwater for greenhouse tomato production in the cold and arid regions of north China while ensuring stable yields by mitigating drought and waterlogging risks. This model not only provides a replicable technical framework for sustainable agricultural water resource management in semi-arid areas but also offers critical theoretical and practical support for addressing water scarcity and ensuring food security under global climate change.

An x-ray imaging diagnostic system using the Timepix3 detector has recently been developed and installed on the Experimental Advanced Superconducting Tokamak (EAST). The diagnostic system measures the temporal evolution, spatial distribution, and energy spectrum of x-ray signals during plasma discharge with a 16° diagonal field of view, spatial resolution of 4 mm, and broad spectral-energy response range (5–200 keV). Equipped with event-driven capability, the Timepix3 detector captures the coordinates, energy, and arrival time of each photon event with a temporal resolution of 1.56 ns. Herein, the energy resolution and spatial resolution performances of the detector were tested in counting and time-over-threshold modes. The energy resolution of the detector in both modes was within 5 keV. The temporal resolution of the detector and the temporal evolution of x-ray signals were analyzed during plasma discharge experiments on the EAST, harnessing the event-driven capability of the detector for latter analysis. Furthermore, the detector-measured signals were compared with conventional diagnostic signals, confirming the reliability of the Timepix3 detector. Overall, this paper presents the parameter testing results and preliminary experimental diagnostic outcomes.

The petiole nitrate–nitrogen concentration (PNNC) has been an industry standard indicator for in-season potato (Solanum tuberosum L.) nitrogen (N) status diagnosis. Leaf sensors can be used to predict the PNNC and other N status indicators non-destructively. The SPAD meter is a common leaf chlorophyll (Chl) meter, while the Dualex is a newer leaf fluorescence sensor. Limited research has been conducted to compare the two leaf sensors for potato N status assessment. Therefore, the objectives of this study were to (1) compare SPAD and Dualex for predicting potato N status indicators, and (2) evaluate the potential prediction improvement using multi-source data fusion. The plot-scale experiments were conducted in Becker, Minnesota, USA, in 2018, 2019, 2021, and 2023, involving different cultivars, N treatments, and irrigation rates. The results indicated that Dualex’s N balance index (NBI; Chl/Flav) always outperformed Dualex Chl but did not consistently perform better than the SPAD meter. All N status indicators were predicted with significantly higher accuracy with multi-source data fusion using machine learning models. A practical strategy was developed using a linear support vector regression model with SPAD, cultivar information, accumulated growing degree days, accumulated total moisture, and an as-applied N rate to predict the vine or whole-plant N nutrition index (NNI), achieving an R2 of 0.80–0.82, accuracy of 0.75–0.77, and Kappa statistic of 0.57–0.58 (near-substantial). Further research is needed to develop an easy-to-use application and corresponding in-season N recommendation strategy to facilitate practical on-farm applications.

The behavior of energetic electrons in fusion plasma has been studied using the hard X-ray (HXR) camera on the EAST (Experimental Advanced Superconducting Tokamak). This study reports the construction of a tangential field two-dimensional HXR spectrum imaging system that has been running on the EAST for 2 years. The two heating modes, namely electron cyclotron current driving (ECCD) and low-hybrid current driving (LHCD), are crucial for sustaining the plasma discharge on EAST. The distribution of fast electrons and the wave deposition position can be reflected in the hard X-ray distribution characteristics. The built system can be used for real-time observation of hard X-ray distribution variations on the three discharge stages, including the plasma current climbing section, flat top section, and drop section. The built system may offer fast electron information for optimizing the wave-driving efficiency of the EAST device during discharge while supplying the spatial coordinate information of the wave deposition, in comparison to the original one-dimensional HXR diagnostic system. Under LHCD, the hard X-ray distribution is relatively scattered, but the peak position of hard X-ray counts can be observed; under ECCD, the hard X-ray counts are more peaked, indicating that the fast electron distribution at corresponding energies is also more peaked. The deposition location of EC waves is relatively localized, and this peaking effect decreases as the plasma density increases.

The external camera of ITER Radial X-ray Camera, which was designed and will be manufactured by China, is now in manufacture study phase. This paper is focused on the manufacture study of external camera. Many activities were carried out to explore the manufacture process for mechanical system, electronics and I&C. Mockups were fabricated and tested to validate the methods and performance.

Water and fertilizer are the two indispensable elements in agriculture. The rational use of soil water and fertilizer can not only improve crop yield and quality rate, but also alleviate land pollution and water shortage. Water and fertilizer management in Chinese cabbage (Brassica rapa spp. pekinensis) involves in improper irrigation and fertilization. This experiment was conducted to explore he shoot growth, root traits, nutrient contents, soil microbial population and soil enzyme activities of Chinese cabbage in response to different irrigation and organic fertilizer application rates. The experiment consisted of three irrigation levels (A1-A3: 90%-70% ± 5% of field water holding capacity), five organic fertilizer application rates (B1-B5: 10%-50% cattle manure with nitrogen replacement) and CK treatments (CK1: regular fertilizer, CK2: 100% cattle manure with nitrogen replacement). The results showed that irrigation rate A2 was the better irrigation rate. At this irrigation rate B2 treatment significantly increased shoot fresh weight by 22.65% and 31.09% compared to CK1 and CK2, respectively. Organic fertilizer application increased the SPAD value of Chinese cabbage, but the trend was not consistent under different irrigation and organic fertilizer levels. All irrigation levels showed more soil available K content in CK2. Compared to other treatments, CK2 was enhanced by 20.70%-317.42% under A1, 7.34%-235.68% under A2, and 28.16%-188.42% under A3 irrigation. Adequate irrigation is prerequisite to enhance root fresh weight, while lower irrigation and organic fertilizer helps to promote root length and root surface area. Soil enzyme activity and bacteria were significantly higher in A1 and A2 treatments than A3, while irrigation had no significant differences on soil actinomycetes and fungi. Under A1 irrigation, the B4 treatment had higher acid phosphatase and sucrase activities, 11.31%-22.46% and 4.30%-63.50%, respectively, compared to other treatments. In conclusion, the effect of organic fertilizer on soil enzyme activity and soil microbial population varied according to the irrigation levels, but generally organic fertilizer were beneficial to boost up the soil enzyme activity and soil microbial population.

Background/Objectives: Chinese cabbage (Brassica rapa ssp. Pekinensis, AA) growth and development is highly sensitive to cold temperatures. Prolonged low-temperature exposure during early growth stages can induce premature bolting, which reduces market quality and yield. Methods: Here, using comparative leaf RNA-seq transcriptome analysis of plants grown at 6, 9, 12, and 15 °C, we explored key genes and metabolic pathways regulating Chinese cabbage cold response. Results: RNA-seq transcriptome analysis identified a total of 1832 differentially expressed genes (DEGs) in the three comparison groups, with 5452, 1861, and 752 DEGs specifically expressed in the A6_vs_A15, A9_vs_A15, and A12_vs_A15 groups, respectively. KEGG enrichment analysis of DEGs showed that sulfur metabolism, secondary metabolites biosynthesis and photosynthesis pathways were mostly affected by cold stress. K-means clustering revealed distinct expression profiles among the DEGs enriched in cold stress response-associated clusters. Subsequently, DEGs were divided into 18 modules by WGCNA, whereupon co-expression genes that clustered into similar modules exhibited diverse expression and were annotated to various GO terms at different temperatures. Module-trait association analysis revealed M1, M2, M3, and M6 modules as key clusters potentially linked to vernalization-related processes. These modules harbored candidate hub genes encoding transcription factors (including MYB, bZIP, and WRKY), protein kinases, and cold-stress-responsive genes. Additionally, phenotypic analysis showed that 12 °C to 15 °C supported optimal growth, whereas <9 °C temperature inhibited growth. Physiological measurements showed increased antioxidant enzyme activity and proline accumulation at 6 °C. Conclusions: Overall, our study provides a set of candidate cold-stress-responsive genes and co-expression modules that may support cold stress tolerance breeding in Chinese cabbage.

In order to improve the quality of transplanting devices and solve the problems of the poor effect on soil moisture conservation and more weeds easily growing due to the high mulching-film damage rate with an excessive number of hole openings, we developed a dibble-type transplanting device consisting of a dibble-type transplanting unit, a transplanting disc, and a dibble axis. The ADAMS software Adams2020 (64bit) was used to simulate and analyze the kinematic track of the transplanting device. The results of the analysis show that, when the hole opening of the envelope in the longitudinal dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting angle was 95°, and the transplanting frequency had no influence. With the help of the ANSYS WORKBENCH software Ansys19.2 (64bit), an analysis of the process of the formation of an opening in the mulching film and a mechanical simulation of this process were completed. The results indicate that, when the maximum shear stress of the mulching film was the smallest, the transplanting characteristic coefficient was 1.000, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 95°. In addition, the device was tested in a film-breaking experiment on a soil-tank test bench to verify the hole opening in the mulching film. The bench test showed that, when the longitudinal dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 95°. When the lateral dimension was the smallest, the transplanting characteristic coefficient was 1.034, the transplanting frequency was 36 plants·min−1, and the transplanting angle was 90°. The theoretical analysis, kinematic simulation, and soil-tank test results were consistent, verifying the validity and ensuring the feasibility of the transplanting device. This study provides a reference for the development of transplanting devices.

The extent to which long-term no tillage alters the quantity and sources of soil organic matter (SOM) in the soil profiles remains elusive. Here, using a two-biomarker approach (i.e., lignin phenols and amino sugars), we quantified the origins of SOM, that is, plant lignin and microbial necromass, under three tillage practices in different soil layers, including moldboard plowing (MP), subsoiling (SS), and no tillage (NT) from a 20-yr trial in Northern China. The results showed that SS (cf. MP) enhanced soil organic C storage by 20% in the surface of 0-10 cm layer rather than the deeper profile (> 10 cm). In the surface soils, tillage affected plant-derived lignin phenol concentrations, NT > SS > MP, but not microbial necromass C (MNC), likely because of stubble enrichment in the topsoil. Instead, NT (cf. MP) increased the fungal necromass C and MNC concentrations by 60% and 14% in the sublayer (30-40 cm). Furthermore, NT enhanced microbial-derived C storage (mainly fungal-derived C) compared to MP in this deeper layer. The increased contribution and distribution of microbially derived C with soil depth refined our mechanistic understanding of SOM formation after tillage transition. We conclude that long-term no tillage can alter SOM origins rather than storage, and thus, the potential persistence is due to accumulated microbial necromass in the sublayer.

Since the last IAEA-FEC in 2021, significant progress on the development of long pulse steady state scenario and its related key physics and technologies have been achieved, including the reproducible 403 s long-pulse steady-state H-mode plasma with pure radio frequency (RF) power heating. A thousand-second time scale (similar to 1056 s) fully non-inductive plasma with high injected energy up to 1.73 GJ has also been achieved. The EAST operational regime of high beta(P) has been significantly extended (H-98y2 > 1.3, beta(P) similar to 4.0, beta(N) similar to 2.4 and n(e)/n(GW) similar to 1.0) using RF and neutral beam injection (NBI). The full edge localized mode suppression using the n = 4 resonant magnetic perturbations has been achieved in ITER-like standard type-I ELMy H-mode plasmas with q(95) approximate to 3.1 on EAST, extrapolating favorably to the ITER baseline scenario. The sustained large ELM control and stable partial detachment have been achieved with Ne seeding. The underlying physics of plasma-beta effect for error field penetration, where toroidal effect dominates, is disclosed by comparing the results in cylindrical theory and MARS-Q simulation in EAST. Breakdown and plasma initiation at low toroidal electric fields (<0.3 V m(-1)) with EC pre-ionization is developed. A beneficial role on the lower hybrid wave injection to control the tungsten concentration in the NBI discharge is observed for the first time in EAST suggesting a potential way toward steady-state H-mode NBI operation.

With the development of sustainable agriculture, trials on the benefits of the application of organic fertilizers around the world have been conducted. Herein, we investigated the impact of the pure chemical fertilizers (CFs) combined with organic fertilizers compared with the application of CFs (100% CFs) and no fertilizers (NFs) on soil properties as well as the yield and quality of Chinese cabbage through meta-analysis. Results indicate that: (1) Compared with NFs, the application of organic fertilizers can significantly improve the yield and quality of Chinese cabbage and increase soil nutrients. (2) Compared with CFs, the application of organic fertilizers can increase the fresh weight, number of leaves, transverse diameter, leaf length, and development of Chinese cabbage per plant, with increases of 8.54%, 6.6%, 9.905%, 8.42%, and 10.03%; Meanwhile, organic fertilizers can significantly increase the yield (total amount of above-ground parts produced) and commercial yield (the portion that meets the required quality standards and is intended for sale) of Chinese cabbage to increase the yield and commercial yield by 10.08% and 35.56%, respectively. However, it has no significant impact on the income from growing Chinese cabbage. (3) Compared with CFs, the application of organic fertilizers can significantly increase the content of vitamin C (11.06%), soluble sugar (19.16%), and soluble protein (8.83%) and reduce the content of nitrate and nitrite in Chinese cabbage, with a reduction of up to 19.02% and 20.9%, respectively. The application of organic fertilizers will also have a certain impact on the absorption of heavy metals in Chinese cabbage. (4) Compared with CFs, the application of organic fertilizers can significantly improve soil organic matter, soil carbon sequestration, nitrogen absorption, and potassium absorption, showing increases of 12.73%, 13.19%, 7.91%, and 7.37%, and the application of organic fertilizers reduces soil electrical conductivity and available nitrogen, showing decreases of 36.78% and 38.75%, respectively. (5) The application of organic fertilizers significantly increased the content of soil urease and soil sucrase, increasing by 9.42% and 17.16%, respectively. This study helps inform the application of organic fertilizers in Chinese cabbage production.

Fusarium oxysporum (FO) is a typical soil-borne pathogenic fungus, and the cucumber wilt disease caused by F. oxysporum f. sp. cucumerinum (FOC) seriously affects crop yield and quality. Vermiculite is increasingly being used as a culture substrate; nevertheless, studies exploring the effectiveness and mechanisms of biocontrol bacteria in this substrate are limited. In this study, vermiculite was used as a culture substrate to investigate the control effect of Bacillus subtilis strain Z-14 on cucumber wilt and the rhizospheric microecology, focusing on colonization ability, soil microbial diversity, and rhizosphere metabolome. Pot experiments showed that Z-14 effectively colonized the cucumber roots, achieving a controlled efficacy of 61.32% for wilt disease. It significantly increased the abundance of Bacillus and the expression of NRPS and PKS genes, while reducing the abundance of FO in the rhizosphere. Microbial diversity sequencing showed that Z-14 reduced the richness and diversity of the rhizosphere bacterial community, increased the richness and diversity of the fungal community, and alleviated the effect of FO on the community structure of the cucumber rhizosphere. The metabolomics analysis revealed that Z-14 affected ABC transporters, amino acid synthesis, and the biosynthesis of plant secondary metabolites. Additionally, Z-14 increased the contents of phenylacetic acid, capsidol, and quinolinic acid, all of which were related to the antagonistic activity in the rhizosphere. Z-14 exhibited a significant control effect on cucumber wilt and influenced the microflora and metabolites in rhizospheric vermiculite, providing a theoretical basis for further understanding the control effect and mechanism of cucumber wilt in different culture substrates.

In response to water scarcity in the Bashang area of northwest Hebei Province, a cold and arid region in north China, and to address the diminishing groundwater levels caused by pumping irrigation, this study investigated the impact of rainwater tank size and water supply on kidney beans production in greenhouses under various precipitation scenarios to determine the production potential and development strategies for regional precipitation resources. Under the background of average annual precipitation, kidney bean yield increased with increasing reservoir volume and shorter irrigation cycles. Under a 4-day irrigation cycle, the water demand satisfaction rate of kidney beans reached 100% water demand when the rainwater tank size was 15.7 m3. Against the wide variation in multi-year regional precipitation from 1992 to 2023, the annual effect of rainwater harvest was simulated using precipitation data collected 20 years with an 80% precipitation guarantee rate. The average minimum yield reduction rate obtained was 9.4%, and the corresponding minimum rainwater tank size was 29.5 m3. By superimposing the rainwater harvested in the shed and nonshed areas, the volume of the reservoir without yield reduction could be reduced to 20.0 m3. The sum of discharged and inventory water was much greater than the water scarcity in each water supply situation. Simulating and analyzing the effect of the relationship between rainwater tank size and water supply on rainwater harvesting in regional farmland by year provides important data affecting the construction of regional rainwater storage facilities and water supply efficiency. To achieve a high, stable yield of kidney beans grown in a greenhouse with shed film and shed area rainwater harvesting in north China, 2.6 m3 supplementary groundwater irrigation is still needed during the annual growing season.

In the environment of a fusion reactor, electronic systems are subjected to various influences including vibration, electromagnetic pulses, as well as irradiation from neutrons and gamma rays. Diagnostics systems on fusion reactors can accumulate radiation doses to a level where issues such as signal attenuation and system interruption can occur. Additionally, maintenance of electronic systems during fusion reactor experiments is often not feasible. Therefore, assessing the radiation tolerance of electronic systems used in fusion reactors is of paramount importance. To validate the radiation resistance of front-end electronics commonly used in various diagnostic systems, including charge, current, voltage, integrator amplifiers, and positive/negative power supply chips, a test circuit board was designed. This board integrates a variety of commonly used amplification chips and power supply chips to assess their performance in the environment of a fusion reactor. Gamma irradiation experiments were conducted using a cobalt-60 (Co-60) radiation source at the Irradiation Center of Nanjing University of Aeronautics and Astronautics. The test circuit board was exposed to continuous gamma irradiation at two test points, with dose rates of 6 Gy/min and 1 Gy/min, respectively, for a total of six hours thirty minutes, Data from the irradiation experiments were collected and analyzed. The results revealed anomalies such as abnormal signal amplitudes and circuit shutdowns for different circuit chips under continuous gamma irradiation. This demonstrated that the radiation tolerance of different chips varies significantly due to differences in functionality and manufacturing processes. The experiment provides valuable data support for the radiation-resistant design of electronic systems in the environment of a nuclear fusion reactor. It also provides crucial insights into the electronic design of various diagnostic systems in the radiation environment of future fusion reactors.

伴随着市场供应期的延长,华北高寒区晚茬青花菜与花椰菜两种花球甘蓝栽培面临着低温霜冻环境的胁迫.笔者监测了华北高寒区秋季间霜期气象因素变化,林带风障防护、无纺布覆被防护与未防护(CK)下的花球甘蓝光合指标、霜冻害指数以及产量等特征.结果表明,华北坝上高寒区秋季间霜期受霜冻胁迫的花球甘蓝叶片净光合速率(Pn)有降低趋势;对花球甘蓝叶片SPAD值降低不显著;对光能转化效率(Fv/Fm)产生了胁迫效应,其中花椰菜较青花菜更为敏感,但Fv/Fm总体维持 0.78 以上水平.花椰菜霜冻害指数较青花菜高,抗寒性差;其林带风障与无纺布覆被防护的产量较未防护(CK)提高 13.86%与 19.98%;青花菜林带风障防护较未防护产量提高了 6.48%.无纺布覆被增加了成本,净产值较未防护处理提高了 27.66%,成本收益率达 3.75%.因此,花球甘蓝中的青花菜与花椰菜对华北高寒区秋季间霜期低温环境有较强的生态适应性,无纺布覆被是防控菜田霜冻危害的实用技术.

Although crop rotation is a safe and effective measure for improving the soil environment and regulating soil microbial community compositions, its impacts on soil health and ecosystem multifunctionality are not yet well understood. This study involved an eight-year (from 2015 to 2022) field experiment where we compared the effects of potato continuous cropping (PP) and rotation cropping, specifically potato-forage maize rotation (PFM), potato-oat rotation (PO) and potato-beet rotation (PB), on ecosystem multifunctionality. We also assessed the contributions of the soil properties, nematode community to soil health and ecosystem multifunction. Results of this study showed that crop rotations supported greater soil substrate quantity and quality and improved soil environment compared to PP. Additionally, crop rotations increased soil microbial activities and nematode abundance. Meanwhile, crop rotations reduced soil-borne diseases such as black scurf and increase the potato yield. Using structural equation model (SEM) approach, our results revealed that cropping systems improved soil health by increasing soil microbial community activities which is being mediated by soil substrate quality and soil moisture content. Also, cropping systems improved ecosystem multifunctionality by regulating soil nematode communities, which is being mediated by soil microbial community activities and soil substrate quality. The findings of this study provide valuable insights into the advantages of crop rotation in improving soil health and ecosystem multifunction. It highlights the crucial role of soil nematode community and substrate quality in mediating the benefits of crop rotation. Overall, this study contributes to our understanding of the importance of sustainable agricultural practices that prioritize soil health and ecosystem functioning.

Continuous cropping of the same crop leads to soil degradation and a decline in crop production, and these impacts could be mitigated through rotation cropping. Although crop rotation enhances soil fertility, microbial community diversity, and potato yield, its effects on the soil ecosystem multifunctionality (EMF) remain unclear. In the present research, we comparatively examined the effects of potato continuous cropping (PP) and rotation cropping [potato-oat rotation (PO) and potato-forage maize rotation (PFM)] on the soil EMF as well as the roles of keystone taxa, microbes abundance, and chemical properties in EMF improvement. It was demonstrated that soil EMF is increased in rotation cropping (PO and PFM) than PP. Soil pH was higher in rotation cropping (PO and PFM) than in PP, while total phosphorus (TP) and available phosphorus (AP) were significantly decreased than that in PP. Rotation cropping (PO and PFM) markedly changed the bacterial and fungal community compositions, and improved the potential plant-beneficial fungi, e.g., Schizothecium and Chaetomium, while reducing the abundances of the potentially phytopathogenic fungi, e.g., Alternaria, Fusarium, Verticillium dahiae, Gibberella, Plectosphaerella, Colletotrichum, Phoma, and Lectera in comparison with PP. Also, co-occurrence patterns for bacteria and fungi were impacted by crop rotation, and keystone taxa, e.g., Nitrospira.1, Lysinibacillus, Microlunatus.1, Sphingomonas.3, Bryobacter.1, Micromonospora, and Schizothecium, were enriched in PO and PFM than PP. The structural equation model (SEM) further demonstrated that cropping systems increased soil ecosystem multifunctionality through regulating SOM and keystone taxa (Schizothecium1), and keystone taxa were mediated by soil pH. This study suggested that rotation cropping might contribute to the improvement of soil ecosystem multifunctionality as well as the development of disease-suppressive soils in comparison with potato continuous cropping.

为筛选出适合作饲草的优质燕麦品种和适宜收获期,以坝莜18号、坝莜3号、冀张莜4号、坝燕4号为材料,于2021年在河北坝上地区进行不同刈割期饲草产量和品质的比较研究.结果表明,在抽穗期刈割收获,冀张莜4号鲜草产量和坝莜18号干草产量最高,分别为32533.33、7794.80 kg/hm2;在灌浆期刈割收获,坝燕4号鲜草产量和坝莜3号干草产量显著高于其他品种,分别为29466.67、9425.07 kg/hm2;在成熟期刈割收获,冀张莜4号鲜草和干草产量均最高,分别为19394.27、9859.20 kg/hm2.不同刈割期饲草品质差异显著,在抽穗期刈割收获,坝燕4号的品质最优,其中,粗蛋白质(CP)、酸性洗涤纤维(ADF)、中性洗涤纤维(NDF)、水溶性碳水化合物(WSC)含量分别为14.5％、30.2％、48.8％、16.7％;在灌浆期刈割收获,坝莜3号的品质最优,其中,CP、ADF、NDF、WSC含量分别为9.1％、31.4％、49.6％、11.4％;在成熟期刈割收获,坝燕4号的品质最优,其中,CP、ADF、NDF、WSC含量分别为6.9％、49.1％、68.7％、7.8％.综合比较分析,坝燕4号和坝莜3号分别在抽穗期和灌浆期收获可获得较高的饲草产量和优质燕麦干草.

Determining the effects of fertilization regimes on soil aggregates, carbon (C) and nitrogen (N) distribution, and pH is essential for improving soil structure and soil organic carbon (SOC) accumulation to help in proper soil fertility management. Based on a 41-year field fertilization experiment conducted on dark brown soil in northeast China, we examined the soil aggregate size distribution and associated C, N, and pH to provide a scientific basis for elucidation of the mechanisms underlying the effects of fertilization treatments on soil structure and fertility. Six different fertilization treatments included no fertilizer (CK), low-dose chemical fertilizer (NP), moderate-dose chemical fertilizer (2NP), high-dose chemical fertilizer (4NP), normal-dose organic fertilizer (M), and normal-dose organic fertilizer plus moderate-dose chemical fertilizer (M+2NP). Our findings showed that compared to CK, M and M+2NP significantly increased the proportion of macroaggregates by 40% and 28%, respectively, whereas 4NP significantly decreased it by 19%. The mean weight diameter (MWD) and geometric mean diameter (GMD) under M and M+2NP were significantly higher than that under CK, at 12–21% and 24–36%, respectively. The fractal dimension (D) value of M+2NP was significantly lower than those of 2NP and 4NP by 4% and 5%, respectively. Soil pH under the M treatment was highest, followed by M+2NP. Soil pH under 2NP and 4NP more significantly decreased, by 0.1 and 0.2 units, than under M treatment. Soil pH values were correlated with the proportion of soil macroaggregates, MWD, and GWD, respectively (p < 0.05). Relative to CK, M and M+2NP increased the contents and stocks of SOC (by 40–49% and 89–93%, respectively) and total N (59–68% and 119–123%, respectively). Furthermore, the contents and stocks of aggregate-associated SOC and total N decreased following the order: NP > 2NP > 4NP. Overall, the long-term application of organic fertilization regimes (M and M+2NP) effectively improved soil aggregation as well as SOC accumulation and decreased soil acidification in dark brown soil in northeast China.

为了明确播期对燕麦田杂草种群变化以及燕麦草生产的影响,在冀西北寒旱区的砂质栗钙土农田,研究了不同播期(5月24日、6月8日、6月23日)对燕麦田杂草密度、优势杂草种类、杂草多样性以及杂草和燕麦生物量的影响.结果表明:5月24日播种与6月8日播种处理的燕麦田杂草密度始终差异不显著,晚播后燕麦田杂草密度明显降低.播期显著影响燕麦田杂草的群落结构,早播的燕麦田杂草以喜凉的灰绿藜为主,随着播期推迟,相对喜温的苋菜以及狗尾草、小画眉草和稗草等禾本科杂草成为优势种.早播和晚播的燕麦田植物群落Shannon多样性指数、Simpson多样性指数、Pielou均匀度指数和Margalef物种丰富度指数有降低趋势.在燕麦最适刈割期抽穗后第10～20天,5月24日和6月8日播种的燕麦生物量均高于6月23日播种.对杂草群落结构、杂草生物量和燕麦产量进行综合分析发现,在冀西北寒旱区燕麦适当早播在一定程度上有利于抑制田间杂草,提高饲草产量.