To screen surfactants suitable for foliar application on Leymus chinensis and capable of enhancing the absorption efficiency of 6-benzylaminopurine （6-BA）， five surfactants （Silwet 408，SDS，MES，DDM，orange） commonly used on hydrophobic leaves of gramineous plants were evaluated based on surface tension， critical micelle concentration， contact angle， and maximum stable retention. The results showed that the leaves of L. chinensis exhibited super hydrophobicity， and the apparent surface free energy at the heading stage was significantly lower than that at the regreening stage（P<0.05）. Polyether-modified silicone Silwet 408 exhibited the optimal performance， achieving the lowest surface tension at the critical micelle concentration （21.27 mN·m^-1） and complete spreading （contact angle <5°） at both growth stages， followed by orange peel essential oil. SDS and orange peel essential oil showed the highest retention at the regreening stage （36.16 mg·cm^-2） and heading stage （34.60 mg·cm^-2）， respectively. Therefore， Silwet 408 is recommended as the preferred surfactant， while orange peel essential oil serves as a green alternative at the heading stage. This study provides a theoretical basis and technical support for efficient delivery of foliar regulators in L. chinensis.

Elephant grass （Pennisetum purpureum） and hybrid Pennisetum are high-quality forage grasses with remarkable biomass potential. However， evaluation of their adaptability and agronomic performance in Northern China remains insufficient. This study aims to systematically evaluate the agronomic traits of 80 Pennisetum accessions in Beijing and screen the excellent germplasm suitable for northern cultivation. Seven key agronomic traits， including plant height， leaf length， leaf width， tiller number， stem diameter， fresh weight， and dry weight were measured for the 80 accessions. Then coefficient of variation （CV） analysis， correlation analysis， principal component analysis （PCA）， and subordinate function analysis were employed for comprehensive evaluation. The results showed that the 80 accessions exhibited rich genetic diversity. The CVs of the seven traits ranged from 10.97% to 78.77%， with dry weight （78.77%） and fresh weight （69.85%） exhibiting the highest variation， this indicates that there are significant differences in biomass-related traits among different genotypes. By correlation analysis， individual that leaf length and leaf width， as well as fresh weight and dry weight， were both highly significantly positively correlated （P < 0.01）. Principal component analysis （PCA） revealed that four principal components accounted for a cumulative contribution rate of 89.70%， primarily representing biomass factors， plant architecture factors， and tillering factors. Based on the membership function values， the top 10 accessions with superior comprehensive performance were identified. P.americanum×P. purpureum ‘Sumu No.4’，P. purpureum ‘Chuanyu No.1’ ， P. purpureum ‘Zise’ ， P. purpureum ‘Huanan’， P.americanum×P. purpureum ‘No.11’， P. purpureum ‘No.31’，P. purpureum ‘Guiminyin’ ， P.americanum×P. purpureum ‘CHP31’，P. purpureum ‘No.10’ and P. purpureum ‘Dehong’. This study provides high-yielding Pennisetum germplasm for forage cultivation and breeding in Northern China.

To clarify the effects of the median lethal concentrations（LC₅₀） of lambda-cyhalothrin and thiamethoxam on the growth， development and reproduction of Frankliniella intonsa resistant populations in alfalfa fields， two field-resistant populations （YLC and MS） from Ningxia were used as test materials. Stress treatments were conducted based on laboratory toxicity assays， and the effects of the two insecticides on the fecundity， developmental duration， body length， body width， adult longevity and survival rate of the offspring of Frankliniella intonsa were investigated. The results showed that under the stress of median lethal concentration of the two insecticides， the fecundity of F₁ adults decreased significantly； the developmental duration of F₂ eggs and first-instar nymphs was significantly prolonged； the body length and body width of F₂ first-and second-instar nymphs were significantly reduced； the longevity of F₂ adults was significantly shortened； and the survival rate of F₂ at each developmental stage was significantly decreased. This study confirmed that the median lethal concentration of lambda-cyhalothrin and thiamethoxam could significantly inhibit the reproduction， growth， development and survival of Frankliniella intonsa populations， providing important technical support for the scientific management of field insect pests.

To optimize the lodging-resistant cultivation scheme for forage sweet sorghum （Sorghum bicolor （L.） Moench cv. ‘Jingxi’） in Kashi， Xinjiang， a split-plot design was used with two plant spacings （Z₁： 10 cm， Z₂： 20 cm） and six row spacing configurations （equal row spacing： 30， 40， 50 cm； wide-narrow row spacing： 20+40， 30+50， 40+60 cm）， resulting in 12 plant-row configuration treatments. Agronomic traits， stem chemical composition， stem mechanical strength， and field lodging rate were measured over two harvests. The results showed that plant–row configuration significantly affected lodging-related traits. Across both harvest s， equal row spacing of 50 cm and wide-narrow row spacing of 40+60 cm exhibited lower lodging rates. Among these， the equal row spacing of 50 cm （H₅） treatment produced the highest stem mechanical strength and the best accumulation of fiber components. Correlation analysis revealed fundamentally different lodging resistance mechanisms between the two stubbles： lodging resistance in the first stubble depended on the synergistic enhancement of stem diameter， wall thickness， and mechanical strength， whereas that in the second stubble relied on the accumulation of stem fiber components （acid detergent fiber， neutral detergent fiber， lignin） to maintain strength. Comprehensive evaluation of both stubbles indicated that the H5 configuration （equal row spacing of 50 cm）， whether combined with Z₁ or Z₂ plant spacing， significantly improved the overall lodging resistance of ‘Jingxi’ and was the optimal pattern under the experimental conditions. These findings provide a specific technical scheme and theoretical basis for lodging-resistant cultivation of forage sweet sorghum in arid regions.

To screen salt-tolerant Medicago sativa L. germplasm， 43 alfalfa hybrid F₂ materials were treated with four NaCl concentrations （0%， 0.3%， 0.6%， and 1.2%）. Agronomic traits， including germination potential， germination rate， fresh weight， shoot length， and root length， were measured， and key physiological indicators such as proline and malondialdehyde were analysed. Principal component analysis， membership function method， and cluster analysis were used to comprehensively evaluate salt tolerance at the germination stage. The results indicated that 0.6% NaCl was suitable for screening salt tolerance at this stage. Germination rate， root length， shoot length， and relative proline content （R-Pro） were identified as core indicators for evaluation. Seven highly salt-tolerant materials—GW141， GD131， GZ21， GW71， GD111， GD171， and GD301—were selected， which exhibited both agronomic advantages （“high germination rate and strong root development”） and physiological resistance （“strong osmotic adjustment and weak membrane lipid peroxidation”） under salt stress， providing valuable candidates for salt-tolerant breeding and saline-alkali soil improvement.

Clarifying the effects of different vegetation types on soil quality is of great significance for maintaining ecological stability in the hilly-gully region of the Loess Plateau. This study was conducted in the Anjiapo watershed， Dingxi City， Gansu Province as an example. Five vegetation types were selected， including spruce forestland， sea-buckthorn forestland， alfalfa grassland， wheat cropland and abandoned bare land. A total of 18 soil indicators were measured in the 0-20 cm soil layer. Soil quality indices were calculated based on the total data set， minimum data set， and revised minimum data set， combined with linear and non-linear scoring methods. The results showed that spruce forestland had the highest SQI of 0.53， which was 35.9% higher than that of abandoned bare land. The revised minimum data set combined with the linear scoring model （SQI-LRM） exhibited the strongest explanatory power. Partial least squares structural equation modeling revealed that different vegetation types primarily affected soil biological properties through their influence on soil chemical properties. Random forest combined with multiple linear regression analysis revealed that different vegetation types mainly drove soil quality by regulating soil pH， which in turn influenced protease activity. In conclusion， spruce forestland can significantly improve soil quality， and the SQI-LRM model can provide a quantitative basis for soil quality improvement and sustainable ecosystem development in the study area.

To investigate the effects of intercropping ratios and cutting periods on forage production performance in a rapeseed-oat mixed cropping system， this trial measured and analyzed forage yield and quality indicators across nine mixing ratios and three cutting periods for the rapeseed （‘Qingyou No. 21’）-oat （‘Lena’） system. Results indicated that dry hay yields at the late rapeseed flowering stage （A₂） and the rapeseed pod milk stage （A₃） were significantly higher than at the peak rapeseed flowering stage （A₁） （P<0.05）. The relative feed value at A₃ was significantly higher than at A₁ and A₂ （P<0.05）. At A₃， the 5∶5 rapeseed-oat mixture （A₃R₅O₅） exhibited the highest land equivalent ratio of 2.21. TOPSIS multi-criteria decision analysis indicated that during A₃， the 7∶3 rapeseed-oat mixture （A₃R₇O₃） achieved the highest fit index of 0.75. This treatment exhibited comparatively high hay yield （454.16 kg‧hm^-2） and land equivalent （2.16）， with lower acid-detergent fiber （69.19%） and neutral-detergent fiber （38.64%） content. This constitutes an agronomic practice suitable for promotion within the study area.

To reveal the regulatory mechanisms of different utilization methods on the relationship between plant diversity and soil phosphorus in temperate meadow steppe， this study selected the grassland within the Huihe National Nature Reserve as the object and systematically compared the response characteristics of plant diversity indicators and surface soil phosphorus activation coefficient （PAC） under grazing， mowing， and enclosure modes. The results showed that plant diversity responded significantly to the utilization methods. The number of species， Margalef index， Simpson index， and Shannon-Wiener index under mowing were significantly higher than those under enclosure and grazing （P<0.05）， and enclosure was significantly higher than grazing； the Pielou evenness index was only significantly higher under mowing than grazing （P<0.05）. Soil phosphorus and its availability varied depending on the utilization methods. The content of total soil phosphorus （TP） under mowing was significantly higher than that under enclosure and grazing （P<0.05）； grazing significantly increased the content of surface soil available phosphorus （AP） and PAC （P<0.05）. The relationship between plant diversity and soil phosphorus was regulated by the utilization methods. Under enclosure， AP was significantly negatively correlated with all diversity indices， and PAC was significantly negatively correlated with most indices； under grazing， TP was significantly negatively correlated with the Margalef index， while significantly positively correlated with the Pielou index， and AP was only negatively correlated with the Margalef index； under mowing， there was no significant correlation between soil phosphorus indicators and plant diversity indices. In summary， the utilization methods not only independently affected plant diversity and soil phosphorus availability， but also regulated the relationship between them.

Herbicide prevention and control of weeds in the field is a common weed control method for field crops. At present， China’s Ministry of Agriculture and Rural Affairs has not yet passed the registration of any herbicide on oats. Therefore， it is of great reference and guiding significance to explore the effects of phenoxycarboxylic acid （2，4-D derivative） herbicides on weed control and oat grass yield in oat fields. In this study， the ‘Zhongcao No.16’ oat variety was used as the background oat. By setting up 8 different components， dosage treatments and a blank control treatment， foliar spraying was carried out at the jointing stage of oats. The fresh grass yield of oats and the control effect of weed plant numbers and fresh weight were measured at the milky stage of oats. The results showed that the four phenoxy carboxylic acid herbicides had different degrees of control effects on the number and fresh weight of quinoa and Artemisia， but had no control effect on gramineous weeds， and had a certain yield increase effect on oat fields. On the whole， 2.5 mL and 5 mL 2，4-D dimethylamine salt， 4 mL and 8 mL 2，4-D isooctyl ester were suitable for weed control of quinoa and artemisia in oat field， and had a certain yield-increasing effect on oat.

To optimize the alfalfa-maize intercropping system in the Hexi Irrigation District and identify the suitable maize cultivars， 10 maize （Zea mays L.） cultivars were used to compare their agronomic traits， yield performance， and nutritional quality under sole-cropping and intercropping conditions. Structural equation modeling and a multi-criteria decision-making model were further employed for integrated analysis. The results showed that cultivar， cropping pattern， and their interaction had highly significant effects on plant height， stem diameter， effective plant density， fresh weight per plant， and dry matter yield （P<0.01）. Under intercropping， ‘Jinzhangye 1706’ had the highest dry matter yield （27.12 t·hm^-2）. ‘Tunyu 168’ had the highest ear fresh weight （522.33 g）， and its fresh weight per plant reached 1.32 kg. ‘Ganyu 23’ had the highest number of green leaves and the highest crude protein （CP） content （10.77%）. Structural equation modeling indicated that the pathways by which agronomic traits affected dry matter yield and relative feed value （RFV） differed between planting patterns. Based on the multi-criteria decision-making results， cultivar selection for the intercropping system should comprehensively consider agronomic traits， yield and nutritional quality. Among the tested cultivars， ‘Ganyu 23’ ‘Jinzhangye 1706’ and ‘Tunyu 168’ can be selected as optimal cultivars for the alfalfa/maize intercropping system in this region.