Facility-based agriculture has rapidly advanced due to its capacity for high-intensity and year-round crop cultivation. This study evaluated the effects of different nitrogen fertilizer application rates on the growth of greenhouse tomatoes, while utilizing 15N tracing technology to explore nitrogen utilization efficiency during the growth process of facility-grown tomatoes. The results indicate that nitrogen application rates within the range of N60–N80 (93–128 kg N ha−1) can optimally balance yield, nitrogen-use efficiency, and crop growth. Application rates exceeding this range do not enhance yield and lead to reduced nitrogen-use efficiency. Tomato plants exhibited a low N requirement during the seedling stage, relying primarily on native soil N stocks during the flowering stage. Fertilizer-derived N use increased during the fruiting stage. These findings demonstrate that excessive N inputs lead to diminishing returns and potential nutrient imbalances, while fully utilizing soil N stocks during the seedling and flowering stages is essential. This study emphasizes the importance of adjusting nitrogen input according to the developmental stages of the crop to optimize yield and resource utilization.
Greenhouses, commonly used for vegetable production, are experiencing large nitrogen (N) inputs in North China, which leads to soil acidification, increases soil N availability, and affects microbial community structure and composition. However, it remains unclear how N enrichment influences soil microbial functional activities in this region. In this study, we conducted a two-year pot experiment in a greenhouse to evaluate the effects of four different rates of N addition (0, 334, 668, and 1002 kg N ha−1 year−1) on cucumber soil properties, extracellular enzyme activities, and community level physiological profiles (CLPP). We found that high-N addition (1002 kg N ha−1) caused a massive accumulation of inorganic nitrogen and soil acidification, which was not beneficial to soil microbial activities. The color development (AWCD) values for the metabolism of microbial carbon sources and the activities of soil extracellular enzymes also showed a significant decrease in high N(N3) treatment. Additionally, the activity of leucine aminopeptidase (LAP) and polyphenol oxidase (PPO) of N3 decreased by 36% and 50% compared to the N0 and could be a good predictor for microbial functional diversity and microbial biomass carbon (MBC). Structural equation modeling (SEM) confirmed that the reduction of microbial functional diversity is mainly coregulated by the decline of soil pH and the change of cucumber BGB (belowground biomass) resulting from soil C and N imbalance. Overall, excessive N-fertilizer amendment can be more dangerous to microbial community functional diversity, especially for carbohydrate utilization which adversely affects cucumber yield in current intensive management.
Long-term monoculture cropping and overfertilization degrade soil fertility, which reduces crop growth and promotes the development of soil-borne diseases. However, it remains unclear what the temporal effects of the above factors are on the tomato yield and microbial community structure. Thus, a greenhouse experiment with different amounts of fertilization [2,196 kg ha −1 (control) and 6,588 kg ha −1 (overfertilization) of inorganic fertilizers (NPK)] was carried out with the soils used previously for 1, 2, and 12 years under monoculture of tomato. A 12-year overfertilization decreased soil pH by 1.37 units. Soil electrical conductivity (EC) and concentrations of soil nutrients are enhanced with the increase in tomato cropping duration. Higher content of soil nutrients was found under overfertilization compared to the control in the 12-year soil. Overfertilization decreased the activity of β-1,4-glucosidase (BG) and oxidase compared to the control in the 12-year soil. Bacterial diversity and richness decreased by 6 and 31%, respectively, under overfertilization in 12-year soil compared to the control. The relative abundance of Gemmatimonas and Gp6 in 12-year soil under overfertilization was 17 and 78%, respectively, lower than in control soil. Soil pH and total carbon (TC) were the major factors explaining changes in microbial composition. A 38% decrease in yield was caused by overfertilization in 12-year soil compared to the control. Microbial community composition was the main factor that moderated tomato yield. In addition, fertilization rather than cropping duration had a greater impact on tomato yield. Therefore, our results suggest that long-term overfertilization influenced soil pH, soil TC, and soil microbial community composition to regulate tomato yield.
Harnessing cold-resilient and calcium-enriched peanut production technology are crucial for high-yielding peanut cultivation in high-latitude areas. However, there is limited field data about how exogenous calcium (Ca2+) application would improve peanut growth resilience during exposure to chilling stress at early sowing (ES). To help address this problem, a two-year field study was conducted to assess the effects of exogenous foliar Ca2+ application on photosynthetic carbon fixation and pod yield in peanuts under different sowing scenarios. We measured plant growth indexes, leaf photosynthetic gas exchange, photosystems activities, and yield in peanuts. It was indicated that ES chilling stress at the peanut seedling stage led to the reduction of Pn, gs, Tr, Ls, WUE, respectively, and the excessive accumulation of non-structural carbohydrates in leaves, which eventually induced a chilling-dependent feedback inhibition of photosynthesis due mainly to weaken growth/sink demand. While exogenous Ca2+ foliar application improved the export of nonstructural carbohydrates, and photosynthetic capacity, meanwhile activated cyclic electron flow, thereby enhancing growth and biomass accumulation in peanut seedlings undergoing ES chilling stress. Furthermore, ES combined with exogenous Ca2+ application can significantly enhance plant chilling resistance and peanut yield ultimately in the field. In summary, the above results demonstrated that exogenous foliar Ca2+ application restored the ES-linked feedback inhibition of photosynthesis, enhancing the growth/sink demand and the yield of peanuts.
Calcium, as the second messenger inside plants, is extensively involved in plant response and transduction of various stress signals.Plants shall generate calcium signals of specificity under stress, and this shall give a rise to a series of intracellular physiological and biochemical responses.Calcium ions, under cold stress, are able to lower phase transition temperature of membrane lipids, while also able to strengthen plant cold resistance through maintaining soluble sugar and protein content in cells, and increasing unsaturated lipid or fatty acid content in membrane lipids.A general review of research home and abroad over recent years is presented hereby on plant calcium nutrition and calcium/cold signal interaction and regulation.
Exogenous calcium is able to maintain photosynthesis level under low night temperature (LNT) stress. Nevertheless, the mechanism for supplementary calcium to mitigate photosynthesis barriers under LNT has not been as clear as expected so far. This study mainly covered the response rules to Ca 2+ and Ca 2+ inhibitors for Photosystem II (PSII) photoinhibition, photochemical activity and allocation of absorbed light in leaves of peanut seedlings under low night temperature stress and during their recovery process. As the results indicated, low night temperature stress boosted excitation energy at PSII reaction centers of peanut leaves, and inhibited electron transfer, leading to imbalanced excitation energy distribution with lower photochemical efficiency between these two photosystems. The ratio of antenna heat dissipation increased, while the ratio assigned to photochemical reaction reduced in the process of light absorption, so photosynthetic efficiency declined. Foliar spray of exogenous calcium ameliorates the imbalanced excitation energy between Photosystem II(PSII) and Photosystem I (PSI), increasing electron transfer rate (ETR) and efficiency of light energy conversion at PSII reaction centers (Fv/Fm). More light energy is used for photosynthesis, thus promoting the growth of peanut seedlings. Supplementary calcium available helped to adjust PSII activity via increasing electron transfer rate, more excitation energy was transported to PSI, and the damage of PSII reaction center caused by excess excitation energy reduced. The increase of active reaction centers has enhanced the utilization efficiency of light energy.
In this study, corn continuous cropping soil was sampled and five mechanical tillage and fertilization methods were compared, so as to explore the influences of different organic fertilization methods on soil physicochemical properties, and to provide reference for finding the best continuous soil fertilization methods and solving soil fertility decline in the future. The soil and corn samples were collected and measured to analyze soil physical and chemical properties and corn yield. The results showed that the mechanical spreading of decayed cow dung improved soil structure enhanced soil water retention and increased soil organic matter content. Straw mulching and breaking surface application can increase effective soil porosity, improve soil surface characteristics, improve soil ventilation and water permeability, which is expected to play an important role in improving soil surface compaction. The deep application of straw into the field can improve the soil viscosity and high fertility, and can be used in good sandy soil. Particle organic fertilization can effectively improve soil water permeability without causing loose soil texture, improve soil water permeability and water retention, and increase pH value of acidic soil.
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