Using two rice varieties, Suijing 309 (SJ309) and Longqingdao 31 (LQD31), as experimental materials, the effects of chromium (Cr) stress on the physiological traits and morphological characteristics of rice leaves were investigated. The results showed that Cr was primarily enriched in the roots of rice, and SJ309 was more effective than LQD31 in reducing the absorption and translocation of Cr. Under high-concentration Cr stress (100 μmol/L), the physiological characteristics such as stomatal conductance, transpiration rate, water use efficiency, and photosynthetic pigments decreased in both varieties, while leaf vapor pressure deficit, intercellular CO₂ concentration, and malondialdehyde (MDA) content increased. After Cr stress treatment, only LQD31 exhibited an increase in the stomatal area of guard cells and closure of the stomatal aperture, whereas no significant changes were observed in SJ309. Compared with SJ309, the contents of abscisic acid (ABA) and salicylic acid (SA) in LQD31 increased significantly, leading to the overexpression of NCED1 and NCED2 genes involved in the regulation of stomatal aperture, which indicated that LQD31 was more sensitive to Cr stress. Furthermore, Cr stress significantly increased the density and length of non-glandular trichomes in SJ309, suggesting its ability to withstand UV damage and various environmental stresses. In summary, SJ309 demonstrates superior tolerance to Cr stress, and its hyperaccumulation characteristics can be utilized for the phytoremediation of Cr-contaminated soils.

To address the issues of soil structure deterioration, decreased organic carbon content, and low maize yield caused by soil wind erosion in semi-arid aeolian sandy regions, a long-term field positioning experiment was conducted in Durbod Mongolian Autonomous County, Heilongjiang Province. Four treatments were established: rotary tillage with ridging (CK), no-tillage with straw mulching for one year (T1), continuous no-tillage with straw mulching for three years (T2), and continuous no-tillage with straw mulching for seven years (T3). The effects of each treatment on soil aggregate distribution characteristics, organic carbon accumulation, and maize yield across different soil layers were analyzed. The results showed that in the 0-30 cm soil layer, compared with the other treatments, the T3 treatment significantly reduced soil bulk density and significantly increased soil moisture content. Meanwhile, the T3 treatment enhanced the percentage of >0.25 mm water-stable aggregates, the organic carbon content, and the contribution rate within these aggregates, while also increasing the mean weight diameter and geometric mean diameter. No-tillage with straw mulching significantly increased maize yield, with the increase ranging from 14.98% to 39.54% compared with the CK treatment. In summary, no-tillage combined with straw mulching helps improve soil aggregate stability, the organic carbon content of aggregates across all size classes, and maize yield in semi-arid areas, with the T3 treatment yielding the best results.

Using Wanzhi 21 sesame as the experimental material, four harvesting periods of sesame leaf vegetable were set as follows: starting from the 40th day (P40), the 50th day (P50), the 60th day (P60), and the 70th day (P70) after the emergence of sesame, with the without harvesting sesame leaf vegetable as control (PCK). Through the two year continuous experiment, the effects of different harvesting periods on the main economic traits and yield of sesame leaf vegetable were studied, and a comprehensive benefit analysis was conducted. The results showed that the effects of the harvesting period of sesame leaf vegetable on the plant height, capsule axis length, effective node number, number of capsules per plant, number of seeds per capsule, and 1000-seed weight reached a significant level. The later the harvesting period of leaf vegetable, the slower the decline in the economic traits, which was specifically reflected as PCK > P70 > P60 > P50 > P40. The later the harvesting period of leaf vegetable, the higher the yield of sesame seeds, and the lower the reduction rate of seed yield. On the contrary, the earlier the sesame leaf vegetable harvesting, the higher the yield and net benefit of sesame leaf vegetables, but the lower the dry-fresh ratio of leaf vegetable. Specifically, the dry-fresh ratio showed an order of P40 < P50 < P60 < P70. The benefit from sesame seeds was just the opposite, and the later the sesame leaf vegetable harvesting, the higher the benefit from sesame seeds. The comprehensive benefit of harvesting leaf vegetable was the highest at P70 treatment, which increased by 39.06%-58.22% compared with PCK treatment. Therefore, the 70th day is the best harvesting period for sesame leaf vegetable, which can achieve the greatest comprehensive benefit of sesame cultivation.

Using wild oats and cultivated oats as research subjects, an experiment was conducted using wild population materials (Atl-03, Atl-05, Atl-06, Atl-08, Atl-11) and cultivated population materials (ITAO-32, ITAO-36, ITAO-38, ITAO-49, ITAO-50). Photosynthetic parameters including net photosynthetic rate, stomatal conductance, intercellular CO₂ concentration, transpiration rate, and relative chlorophyll content (SPAD value), as well as agronomic traits such as plant height, panicle length, total tiller number, 1000-grain weight, and mean surface area of seed, were measured at heading stage, early grain-filling stage, late grain-filling stage, and maturity, respectively. The results showed there were significant differences in photosynthetic characteristics between wild oats and cultivated oats. The coefficients of variation of wild oats were higher than those of cultivated oats, but cultivated oats exhibited stronger and more stable photosynthetic performance. Furthermore, significant differences were also observed in agronomic traits between wild oats and cultivated oats. Correlation analysis indicated that net photosynthetic rate, flag leaf area, and SPAD value were all significantly positively correlated with 1000-grain weight. Among the wild populations, Atl-11 exhibited the optimal photosynthetic characteristics and agronomic traits; among the cultivated populations, ITAO-36 showed the optimal photosynthetic characteristics and agronomic traits, and both can serve as excellent germplasm resources.

In order to precisely formulate weed control strategies for soybean field under maize-soybean and wheat-soybean rotation modes, the species and quantities of weeds were investigated in these two rotation modes. The results showed that during the two-year experiment, the weed occurrence in the maize-soybean rotation mode was 1.89 and 1.49 times higher than that in the wheat-soybean rotation mode, respectively. In the maize-soybean rotation mode, a total of 11 weed species were consistently observed over the two years, including two gramineous weeds and nine broadleaf weeds. The dominant weed species were the gramineous Echinochloa crusgalli and the broadleaf Chenopodium album and Abutilon theophrasti. The subdominant species were the gramineous Eriochloa villosa and the broadleaf Amaranthus retroflexus and Solanum nigrum. For the wheat-soybean rotation mode, eight weed species were commonly observed over the two years, including two gramineous weeds and six broadleaf weeds. The dominant species included the gramineous E.crusgalli and the broadleaf C.album and A.theophrasti, while the subdominant species was the broadleaf Solanum nigrum. The maize-soybean rotation mode exhibited two weed occurrence peaks: one from late May to mid-June, and another from late June to early July, with the weed occurrence during the first peak period being greater than that during the second. Conversely, the wheat-soybean rotation mode showed only one weed occurrence peak, primarily concentrated in early to mid-June.

To investigate the response of drought-resistant quinoa seedlings to drought stress, the strongly drought-resistant quinoa variety Longli No.1 (LL1) and the new breeding line LQ18 were selected as experimental materials. PEG-6000 solution was used to simulate drought environment. Three treatments were set: normal irrigation (CK), mild drought stress (5% PEG-6000), and severe drought stress (20% PEG-6000). We investigated quinoa seed germination rate, germination potential, germination index; seedling plant height, leaf area, root length, aboveground and underground dry weights; soluble protein and proline contents; superoxide dismutase (SOD) and peroxidase (POD) activities; and malondialdehyde (MDA) content. The results showed that severe drought stress reduced plant height, leaf area, and aboveground dry weight in both varieties (lines), but increased root length, underground dry weight, and root-shoot ratio. Specifically, the reductions in leaf area and aboveground dry weight, as well as the increases in root length, underground dry weight, and root-shoot ratio were all smaller in LQ18 than in LL1. Under drought stress, the soluble protein content of LL1 gradually decreased, while that of LQ18 first increased and then decreased to a level with no significant difference from CK. Under severe drought stress, the proline content of both varieties (lines) significantly increased, and the proline content of LQ18 was significantly higher than that of LL1. Drought stress influenced the activities of SOD and POD and increased MDA content in both varieties (lines). Under severe stress, the SOD activity of LQ18 decreased slightly, whereas its POD activity increased significantly; furthermore, its MDA content remained significantly lower than that of LL1.

A field experiments was conducted to investigate the effects of different microbial fertilizers of biological and compound formulations on soil physicochemical properties, growth and development, disease resistance, photosynthetic characteristics, economic traits, chemical composition, and sensory evaluation of tobacco leaves. The results showed that the application of microbial fertilizer could effectively improve the soil available nutrients, ameliorate soil acidification, and promote the growth and development of flue-cured tobacco, showing better plant height, leaf length, stem girth and effective leaf number. Among all the treatments, the treatment of biological agents, purple spotted fungus had the most obvious effect. In addition, the application of purple spotted fungus increased the net photosynthetic rate, intercellular CO₂ concentration and relative chlorophyll content (SPAD value). Compared with the CK treatment, the application of microbial fertilizer affected the occurrence of tobacco disease. The application of root rot control agent (double dosage) and thick- walled verticillium improved the resistance to common mosaic virus, while the application of root rot control agent, purple spotted fungus, oxmayl and fluorescent pseudomonad improved the resistance to black shank disease. The appearance quality of flue-cured tobacco, economic properties, chemical composition of cured tobacco leaves and the total score of sensory evaluation were the best in the treatment of biological agents. This indicated that the application of purple spotted fungus in biological-based microbial fertilizer could improve soil physicochemistry properties to a certain extent, promote the growth and development of flue-cured tobacco and improve disease resistance. At the same time, it could cause changes in the appearance quality and chemical composition of flue-cured tobacco, thus improving the quality and yield quality of flue-cured tobacco.

Aiming at the issues of poor soil structure, insufficient nutrient supply, and low potato yield in the agro-pastoral ecotone in the Northern piedmont of Yinshan Mountain, Inner Mongolia, a two-year field randomized block experiment was conducted. Taking conventional fertilization as the control (CK), three treatments were set up, including chemical fertilizer reduction combined with sheep manure (NPK+SD), chemical fertilizer reduction combined with biochar (NPK+B), and chemical fertilizer reduction combined with microbial fertilizer (NPK+MF). The dynamic changes of leaf area index (LAI), SPAD value, photosynthetic performance, plant nutrient accumulation and dry matter accumulation of potato plants under different treatments were compared and analyzed. The results showed that during the tuber bulking, NPK+MF treatment significantly improved LAI and leaf photosynthetic performance of potato, with leaf SPAD value significantly increased by 8.04% compared to CK, and no significant difference compared to NPK+SD and NPK+B treatments. The net photosynthetic rate of NPK+MF treatment was significantly increased by an average of 11.31%, 7.66%, and 4.92% compared to CK, NPK+SD, and NPK+B treatments, respectively. Under the NPK+MF treatment, with the growth process of potato, plant nutrients are transported from stems and leaves to tubers, and the accumulation of N, P, and K in potato leaves, stems, roots, and tubers were significantly increased. During the late stage of potato growth, the distribution ratio of nitrogen, phosphorus, and potassium in the tubers increased by 90.58%, 178.78% and 226.06%, respectively. The yield of NPK+MF treatment was the best, with an average of 40 054 kg/ha, which was 25.58% higher than that of CK. This experiment identified that chemical fertilizer reduction combined with microbial fertilizer was an effective fertilization method for soil fertility improvement and efficient utilization of soil and fertilizer resources in the agro-pastoral ecotone of the northern piedmont of Yinshan Mountain.

A two-year field experiment was conducted from 2022 to 2023 in Zunyi, Guizhou Province. Five fertilization treatments, no fertilization (T1), farmerʼs habit fertilization, basal application ordinary compound fertilizer 900 kg/ha and topdressing of pure N 45.0 kg/ha during panicle stage (T2), basal application type I fertilizer 1800 kg/ha, no topdressing (T3), basal application type II fertilizer 3000 kg/ha, no topdressing (T4), basal application type III fertilizer 1500 kg/ha and topdressing of pure N 90.0 kg/ha during panicle stage (T5) were set up to study the effects of different organic-inorganic compound fertilizers from distillerʼs grains on sorghum yield, quality, nutrient uptake and utilization. The result showed that compared with T2 treatment, the sorghum yield of T3, T4, and T5 treatment increased by 76.57, 107.57, 164.66 kg/ha and total biomass increased 328.40, 358.98, and 463.54 kg/ha. Compared with T2 treatment, the amylopectin content in sorghum from T3 to T5 treatment increased by 1.13%-7.02% and and tannin content increased by 1.63%-4.35%. Compared with T2 treatment, the nitrogen accumulation of T3, T4 and T5 treatments were increased by 7.27, 6.22, 9.07 kg/ha, the phosphorus accumulation were increased by 1.27, 1.72, 2.47 kg/ha, the potassium accumulation were increased by 13.35, 12.38, 9.15 kg/ha. After harvesting of sorghum, T3, T4 and T5 treatments could all maintain or increase soil nutrient content. The two-year average net benefit of T5 treatment were 45 189.7 yuan/ha, and output/input ratio were 2.679, higher than T2, T3, and T4 treatments. In summary, both the one-time basal application of Type I and Type II and basal application of Type III + topdressing of nitrogen at panicle stage methods could improve the yield, nutrient absorption and utilization, and maintain soil fertility levels. We suggested that when labor is in sufficient, the former is preferred; when labor is sufficient, the latter is an alternative.

To investigate the mechanism of the coupled effects of precipitation, nitrogen (N) fertilizer, and straw mulching on dryland spring wheat yield under different precipitation year types, the APSIM model was calibrated using spring wheat yield, soil, and meteorological data under no-tillage and no-tillage with straw mulching from 2013 to 2018. Combined with historical data from 1970 to 2022 to drive the calibrated model, yields were simulated under 5×5×5 combinations of precipitation changes (±20%, ±10% and 0%), nitrogen application rates (0.0, 52.5, 105.0, 157.5, and 210.0 kg/ha), and straw mulching rates (0, 1125, 2250, 3375, and 4500 kg/ha). The coefficient of variation of yield under single-factor was analyzed for each year type, and quadratic orthogonal polynomial stepwise regression, single-factor analysis, and interaction effects were employed to study the impacts of various factors on yield. The results showed that the APSIM model performed well, with R² > 0.8, NRMSE < 10%, and M_E > 0.8 for both tillage practices. In dry, normal, and wet years, the individual and interactive effects of the three factors all positively influenced yield, with the order of effect intensity being: precipitation change > nitrogen application rate > straw mulching rate. Based on the natural precipitation of the current year, the optimal yields and cultivation measures for each year type were as follows: in dry years, an optimal yield of 2203.65 kg/ha was achieved by increasing precipitation by 20%, applying 153.13 kg/ha of nitrogen, and mulching with 4500 kg/ha of straw; in normal years, an optimal yield of 2838.77 kg/ha required a 20% increase in precipitation, 170.76 kg/ha of nitrogen, and 4500 kg/ha of straw mulching; in wet years, an optimal yield of 3447.11 kg/ha required a 20% increase in precipitation, 188.58 kg/ha of nitrogen, and 4500 kg/ha of straw mulching. In conclusion, within the simulated experimental range, increasing precipitation, nitrogen application rate, and straw mulching amount under no-tillage conditions can enhance the simulated yield of spring wheat, but the degree of impact varies with precipitation year types. For local spring wheat, water, fertilizer, and mulching strategies should be formulated according to the specific year type to achieve high and stable yields.