As a by-product generated from the pyrolysis of biomass, biochar is extraordinary for improving the soil environment of agricultural fields, improving soil fertility, and promoting nutrient uptake and the utilization of crops. In recent years, breakthroughs in progress have been made regarding the fertility value of biochar and in investigations into the physicochemical properties of soil and into plant nutrient utilization. This review focuses on the physicochemical and biological properties of soil, on soil pollution remediation, on greenhouse gas emissions, and on the effects of biochar on the uptake and utilization of soil nutrients and plant nutrients, as well as on the preparation of biochar, and on biochar produced under different conditions. The results of the relevant studies show that the main characteristics of biochar depend on the biochemical properties and pyrolysis temperature of raw materials, which play an important role in nutrient transport and transformation in the soil. At low temperatures (≤400 ℃), the biochar prepared from manure and waste contains a large amount of nitrogen, which can be used as a nutrient source for plants. In addition, biochar enhances soil fertilizer retention by reducing soil nutrient loss, which in turn promotes nutrient uptake and utilization by crops. By controlling pyrolysis temperature and by optimizing biochar input, one can effectively reduce soil respiration, as well as reduce carbon emissions to achieve the goal of controlling carbon sources and increasing carbon sinks. Therefore, a long-term series of mapping studies on the effects of biochar application on agricultural ecosystems should be conducted, which in turn, it is hoped, will provide a theoretical reference for the physiological and ecological effects of biochar croplands.

Organic fertilizers are an important source of nutrients for improving farmland fertility. To explore high-yield, efficient and green production technology for oilseed flax in dryland agricultural areas, a field split plot experiment was conducted in the semi-arid area of the Loess Plateau in northwest China from April to August in 2020 and 2021. The study compared and analyzed the effects of different nutrient sources and their application rates on water consumption characteristics, grain yield and water use efficiency of oilseed flax. The main plots were fertilizer types (sheep manure, chicken manure and chemical fertilizer), while the subplots were fertilizer application rates (sheep manure: S1-12,500 kg·hm⁻² and S2-25,000 kg·hm⁻²; chicken manure: C1-5800 kg·hm⁻² and C2-11,600 kg·hm⁻²; chemical fertilizer: F1-N 112.5 kg·hm⁻², P 75 kg·hm⁻², K 67.5 kg·hm⁻² and F2-N 225 kg·hm⁻², P₂O₅ 150 kg·hm⁻², K₂O 135 kg·hm⁻²). The results showed that compared with chemical fertilizers, organic fertilizers significantly increased the soil water storage capacity of the 0–160 cm soil layer during the whole growth period of oilseed flax and significantly reduced water consumption. During two growing seasons, the application of 25,000 kg·hm⁻² sheep manure significantly reduced water consumption during the seedling-bud period and green fruit period-maturity period of oilseed flax by 16.13% and 23.19% compared with CK, respectively. Thousand-grain weight, yield and water use efficiency were significantly increased by 14.70%, 48.32% and 61.29%, respectively. These results indicate that the application of 25,000 kg·hm⁻² sheep manure can significantly increase soil water storage capacity of the 0–160 cm soil layer, reduce water consumption during the whole growth period of oilseed flax and thus improve grain yield and water use efficiency of oilseed flax. It is a suitable fertilization technology for the high-yield, efficient and green production of oilseed flax in the semi-arid areas of northwest Loess Plateau.

The impact of climate change on crop production is a major concern in drought-prone regions, which are experiencing increasingly severe drought conditions. The goal of this study was to use the Agricultural Production System Simulator (APSIM) model to simulate and predict flax yield and water balance, as well as to determine the optimal irrigation and fertilizer for flax production to counteract the effects of climate change under arid and semiarid conditions. The model was calibrated using field experimental data from 2019 to 2020 and evaluated using field experimental data from 2021 to 2022 with a combination of four irrigation treatments (full irrigation, 180 mm, deficit irrigation at vegetative and reproductive stage, no irrigation) and four fertilizer rates (no fertilizer, NPK, NPK + flax oil residue, NPK + farm manure) using a plot design for a total of 16 treatments. To determine the key irrigation and fertility periods and irrigation and fertilization amounts that affect flax yield to address climate change, a combination of four irrigation and six fertilizer rates and six irrigation stages were simulated. The results showed that the model successfully predicted flax yield (R² = 0.98) and water-use efficiency (WUE) (R² = 0.79). When compared to inorganic fertilization, the grain yield and WUE improved by 16.47% and 13.83%; replacing 50% of inorganic fertilizer with flax oil residue achieved the optimal results. The flax yield and WUE increased by 3.37% and 1.25% under full irrigation (180 mm) compared to irrigation of 120 mm with a not-very-significant difference. The positive effect of irrigation on soil water content (SWC) was highest during the budding stage, followed by the flowering stage, fruiting stage, and stemming stage. Therefore, in arid and semiarid areas with scarce water resources, irrigation at a 55% deficiency during the vegetative growth period of flax combined with the application of flax oil residue and NPK (1550 flax oil residue, 45 N, 50.2 P₂O₅, and 33.9 K₂O kg ha⁻¹) might be an effective adaptation strategy for improved future flax production. Our results can facilitate the development of sustainable agriculture practices that reduce water input and improve WUE to counteract climate change effects.

Salt stress is a major abiotic factor limiting grapevine growth and yield. To elucidate the physiological and molecular regulatory mechanisms underlying salt tolerance in grapevine, this study used ‘Carménère’ (Vitis vinifera) and ‘Pinot Noir’ (Vitis vinifera) as experimental materials. Under 200 mmol/L NaCl stress, the physiological response characteristics of the two cultivars were systematically compared, and transcriptome sequencing combined with qRT-PCR analysis was conducted to explore the molecular basis of their differences in salt tolerance. The results showed that salt stress significantly impaired photosynthetic performance and disrupted cellular homeostasis in grapevine; however, the reductions in relative chlorophyll content (SPAD value), maximum photochemical efficiency of photosystem II (Fv/Fm), and photosynthetic performance were significantly smaller in ‘Carménère’ than in ‘Pinot Noir’, indicating greater stability of the photosynthetic apparatus in ‘Carménère’. Meanwhile, ‘Carménère’ maintained higher activities of antioxidant enzymes and higher levels of non-enzymatic antioxidants, effectively reducing reactive oxygen species accumulation and membrane lipid peroxidation. In addition, under salt stress, ‘Carménère’ accumulated greater amounts of osmotic adjustment substances and maintained lower Na⁺ content and higher K⁺ content, demonstrating a more efficient capacity for osmotic regulation and ion homeostasis. Transcriptomic analysis revealed that the plant hormone signal transduction, MAPK signaling, and glutathione metabolism pathways were significantly enriched in ‘Carménère’, with multiple key genes being coordinately upregulated under salt stress. Taken together, these findings indicate that ‘Carménère’ achieves enhanced salt tolerance through a multilayered signaling regulatory network that coordinates physiological defense responses. This study provides a theoretical basis for elucidating the mechanisms of salt tolerance in grapevine and for the molecular breeding of salt-tolerant cultivars.

To clarify the effects of planting density (PD) and potassium (K) application on the lignin synthesis of oil flax stalks and their relationship with lodging resistance, a two-year field experiment was conducted in the 2020 and 2021 growing seasons. The planting densities were 600 grains·m⁻² (D1), 750 grains·m⁻² (D2), and 900 grains·m⁻² (D3); the potassium application levels were 0 kg K·hm⁻² (K0), 60 kg K·hm⁻² (K1,) and 90 kg K·hm⁻² (K2). Then, the effects of PD and K on the stalk agronomic traits, lignin synthesis, lodging resistance, and grain yield (GY) of oil flax were studied. The results show that D3 increased the oil flax plant height and stem fresh weight, and K1 raised the height of the center of gravity. The enzyme activities of phenylalanine aminolyase (PAL), cinnamyl alcohol dehydrogenase (CAD), and peroxidase (POD) increased with an increase in planting density, whereby K1 promoted and K2 inhibited the lignin metabolic enzymes, respectively. The lignin and cellulose were significantly positively correlated with PAL. The combination of K with the D2 treatment increased the lignin and cellulose content in stems of oil flax at the kernel and maturity stages, and the effect of K1 on lignin metabolism and lodging resistance was better than that of K2. The increased GY was significantly correlated with the number of effective oil flax capsules per plant and the lodging resistance index, which were directly affected by K application. In conclusion, under the same ecological conditions as the experiment, the field management strategy of medium PD (750 grains·m⁻²) and low K (60 kg K·hm⁻²) was the best for improving the lodging resistance and GY formation of oil flax.

Improving water use efficiency is essential for the advancement of agricultural production, particularly in arid and semiarid regions. Two-year field experiments were conducted to study the effects of ridge–furrow (RF) and flat planting (FP) plastic film mulching combined with five different nitrogen (N) fertilizers, N1 (KNO₃), the nitrate (NO₃⁻)/ammonium (NH₄⁺) mixtures with different pure nitrogen ratios N2 (1:1), N3 (1:3), and N4 (3:1), and the control N5 (urea) on maize dry matter accumulation, soil water content, grain yield, water use efficiency (WUE), and N partial factor productivity. Our results showed that RF and N4 were more efficient than FP for increasing maize grain yield, WUE, and nitrogen partial factor productivity, and there was a significant interaction for cultivation practices × N formulation. RF and 3:1 NO₃⁻/NH₄⁺ significantly increased grain yield by 14.73% and 13.15%, and 20.07% and 24.14% in 2016 and 2017, respectively, compared to FP and nitrate only. RFN4 produced the highest grain yield in 2016 and 2017 due to the highest dry matter accumulation at filling and physiological maturity stage, ear rows per spike, and row grains per row. Over two growing seasons, the WUE and N partial factor productivity under RFN4 were 18.75% and 29.17% more on average than those of other treatments. Therefore, RFN4 is an effective planting system for increasing the simultaneity of grain yield and WUE for maize production in rain-fed agriculture.