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Planners need to fully understand the quantity of land supply and its matching relationship with population demand, as these are prerequisites for urban greenspace planning. Most papers have focused on single cities and parks, with little attention paid to comparative analysis between multiple cities on a macro scale, ignoring the influence of spatial effects and leading to a lack of basis for regional green infrastructure planning. This paper selected 102 cities in Hunan province as case studies to comprehensively conduct empirical research using the spatial mismatch model and the geographically weighted regression method. The urban parkland in Hunan province are characterized by significant spatial heterogeneity and correlation, and the mismatch between land supply and population demand should not be ignored, with oversupply and undersupply co-existing. The urban parkland and its mismatch with population are influenced by a number of factors, and each factor has a stronger influence on the latter than the former. Different factors vary widely in the nature and intensity of their effects, and the dynamics are more complex. Economic development, financial capacity, and air quality are key factors, with the former having a negative impact and the latter having opposite (positive) effects. We suggest that when the government allocates land resources and targets for urban parks, it should formulate a differentiated allocation plan based on the supply and demand conditions of each city; besides, it should also place emphasis on regional integration and coordination and support mutual cooperation. [ABSTRACT FROM AUTHOR]

Unmanned aerial seeding (UAS) is an efficient unmanned rice planting method with broad application prospects. But its optimum basic seedling number and yield and quality characteristics remain unclear. Field experiments were conducted to compare UAS, unmanned dry direct seeding (UDDS), and unmanned carpet transplanting (UCT) methods using inbred japonica rice variety Nanjing 5718. The UAS method was subdivided into four planting density treatments (UAS105, UAS150, UAS195, and UAS240 = 105, 150, 195, and 240 seedlings/m2, respectively). The results showed that increasing the basic seedling density first increased the yield but then it decreased, and UAS195 produced a significantly higher yield. On the other hand, the grain processing, appearance, and taste quality deteriorated with improved nutritional quality. Among the three planting methods, UAS (UAS195) yielded less than UCT due to there being fewer spikelets per panicle, a lower grain-filling rate, and less photosynthetic activity after heading. However, UAS (UAS195) produced more yields than UDDS by having more panicles, more spikelets per panicle, and more biomass accumulation. Both UAS195 and UDDS had poorer grain processing, appearance, and nutritional quality than UCT, but increased amylose content and taste values. Therefore, UAS195 could be an alternative planting method for inbred japonica rice with coordinated yield, quality, and production efficiency. [ABSTRACT FROM AUTHOR]

At present, there is a limited understanding of nitrogen (N) accumulation, translocation, and utilization in different types of rice grown using different planting methods in a rice–wheat rotation system. Systematic experiments were conducted with six rice cultivars, including two japonica-indica hybrids (JIHR), two japonica conventional rice (JCR) cultivars, and two indica hybrid rice (IHR) cultivars, to study the effects on N use of plants in three transplanting modes: (1) the pothole seedling machine transplanting mode (PM), (2) the carpet seedling machine transplanting mode (CM), and (3) the mechanical direct seeding mode (DM). Results showed that at stem elongation stage, for N content and uptake, the planting methods were ranked in the order PM < CM < DM, and at heading and maturity the order was PM > CM > DM. After stem elongation the rankings for N accumulation, ratio of N accumulation to total N, and N uptake rate were PM > CM >DM. Thus, on the basis of a certain amount of N accumulation in the early growth phase, increasing the N uptake rate and N accumulation in the middle and late growth phases are ways to increase total N uptake for the PM and CM modes compared to DM. In addition, the PM/JIHR treatment had the highest N uptake at maturity. The N contents of leaves, stem-sheaths, and panicles at heading and maturity for the three planting modes were ranked PM > CM > DM. Moreover, the N translocation amount, apparent N translocation rate, and translocation conversion rate of leaves under PM were significantly higher than for CM and DM, which would increase N accumulation in the grain. The N uptake per 100 kg grain and the partial factor productivity of applied N under PM were larger than for CM and DM, but the N use efficiency of grain yield and biomass were smaller for PM than for CM and DM. In conclusion, rice grown using PM, especially JIHR, had higher total N uptake and N utilization compared to the CM and DM modes, and cultivation measures to improve the N use efficiency of grain yield and biomass could be appropriately applied to further improve N use in a rice–wheat rotation system. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this paper is to study the effect of micro-nano surface texture on the corrosion resistance of a titanium alloy and investigate the correlation between corrosion resistance and hydrophobicity. Design/methodology/approach: The surface of the Ti6Al4V alloy was modified by laser processing and anodizing to fabricate micro-pits, nanotubes and micro-nano surface textures. Afterward, the surface morphology, hydrophobicity and polarization curve of the samples were analyzed by cold field scanning electron microscopy, contact angle measurement instruments and a multi-channel electrochemical workstation. Findings: The micro-nano surface texture can enhance the hydrophobicity of the Ti6Al4V surface, which may lead to better drag reduction to ease the friction of implants in vivo. Nevertheless, no correlation existed between surface hydrophobicity and corrosion resistance; the corrosion resistance of samples with nanotubes and high-density samples with micro-nano surface texture was extremely enhanced, indicating the similar corrosion resistance of the two. Research limitations/implications: The mechanism of micro-dimples on the corrosion resistance of the micro-nano surface texture was not studied. Practical implications: The density of micro-pits needs to be optimized to guarantee excellent corrosion resistance in the design of the micro-nano surface texture; otherwise, it will not fulfill the requirement of surface modification. Originality/value: The influence of the micro-nano surface texture on the corrosion resistance, as well as the relationship between hydrophobicity and corrosion resistance of the titanium alloy surface, were systematically investigated for the first time. These conclusions offer new knowledge. [ABSTRACT FROM AUTHOR]

BACKGROUND: Nitrogen management of crops, especially when mid‐stage nitrogen is applied, is a key factor affecting the yield and grain quality of rice (Oryza sativa). Here, the timing of mid‐stage nitrogen application was evaluated for its effect on rice grain quality by assessing the morphological structure and physicochemical properties of starch from two japonica rice cultivars growing in fields (Nangeng 9108 and Nangeng 5055). RESULTS: The experiment was arranged in a split‐plot design, with the two rice cultivars as the main plot factor and three timings of mid‐stage nitrogen application as the within‐plot factor. Briefly, three applications were made: at the emergence of the top‐sixth‐leaf (ahead), the top‐fourth‐leaf (normal), and the top‐second‐leaf (delayed) of the main stem. Delaying mid‐stage nitrogen application caused the starch granule surface to become uneven and significantly reduced its particle size, whereas it increased the polished rice rate, chalkiness degree, and protein content. Furthermore, the apparent amylose content decreased with a delay in mid‐stage nitrogen application, thereby resulting in higher relative crystallinity, swelling power, water solubility, gelatinization enthalpy, and low retrogradation. Finally, we also found that delaying this nitrogen application lowered the characteristic values of rice flour viscosities, leading to cooking quality deterioration. CONCLUSION: These results therefore suggest that delaying mid‐stage nitrogen application enhances the processing and nutritional qualities of japonica rice but evidently has an adverse effect upon its appearance and cooking qualities. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Optimizing sowing date is the key cultivation measure to raise rice yield. Blanket-seedling mechanically transplanted rice has been used in a large production area in China. But study of how yield component characteristics of blanket-seedling mechanically transplanted rice response to different sowing date is relatively few. Therefore, there is a need for asystematic comparative study. In order to reveal the effect of sowing date on the yield component characteristics of different varieties of mechanically transplanted rice, a series of field experiments were conducted in 2012 and 2013 in the rice region of the middle of Jiangsu provinces under typical annual rice-wheat cropping rotation system with widely used rice cultivars of super japonica rice Wuyunjing 24 and indica-japonica hybrid rice Yongyou 2640. These cultivars are high in yield potential. The research were aiming to systematically analyze the dynamics of population stems and tillers, panicle characteristics, grain filling properties, and so on in different sowing date for mechanically transplanted rice. The results indicated that, with the delayed sowing date, population stems and tillers of mechanically transplanted rice increased with tillers during the earlier stage of growth, but those tillers died out rapidly during the middle and last stage of rice growth, causing a reduction of panicle maturity and obviously reducing the ratio of productive tillers to total tillers. Stem population and tillers from seedlings of early sowing dates were significantly (P<0.05) different from those in late sowing dates. When the sowing date was delayed, the panicle of mechanically transplanted rice was lessened. All of the panicle length, grain density, grain weight per panicle, ratio of No. of primary branches to No. branches of secondary branches, No. of branches per primary and secondary branch, grain number per primary and secondary branch and grain number per branch, seed-setting rate of primary branch and secondary branch were decreased. But ratio of total grains of primary branches to total grains of secondary branches was increased. Variations of characteristics in the indica-japonica hybrid large panicle rice were more drastic. There was no difference in the ratio of No. of primary branches to No. branches of secondary branches, and the ratio of total grains of primary branches to total grains of secondary branches and grains of primary branch. However, the other indexes of panicle were of significant (P<0.05) difference between early sowing and late sowing date. The postponed sowing date reduced the final weight of kernel of both the superior grains and inferior grains, resulting in grain weight decrease. With the sowing date delayed, the maximum grain-filling rate and mean grain-filling rate of superior grains were weakened. The time reaching the maximum grain-filling rate was delayed, and both the active grain-filling period and effective grain-filling time prolonged. The maximum grain-filling rate and mean grain-filling rate of inferior grains were not significantly(P>0.05) different, but maximum grain-filling rate and mean grain-filling rate in the fifth sowing date was the lowest, from which the time required to reach the maximum grain-filling rate delayed, the active grain-filling period shortened, and the effective grain-filling time prolonged. In conclusion, the suitable early sowing dates for mechanically transplanted rice would benefit rice production as followings:1) stem population and tillers of mechanically transplanted rice was steadilyincreased;2) panicles of maturity was adequate, the panicle structure was optimized, and seed setting rate was improved; and 3) the grain-filling time was longer, while the grain-filling rate was advanced and steady, especially the grain-filling characteristics of the inferior grain was optimized, more grain was filled. All the advanced characteristics would contribute to a stable and high yield. Thus, to increase rice production, sowing date of mechanically transplanted rice should be advanced to May 26 appropriately in the central part of Jiangsu province, in combination with timely transplanting and scientific cultivation and management practices. [ABSTRACT FROM AUTHOR]

Crop straw boards, a novel nursery material, has proven effective for cultivating dense, young rice seedlings suitable for mechanized transplanting, thereby saving labor. However, under high-density nursery conditions, the biomass accumulation and yield formation in rice vary with different seedling ages, necessitating exploration of optimal seeding densities and seedling ages to achieve high yields. This study aims to determine the appropriate seeding densities and seedling ages using crop straw boards to maximize rice yield. Over two years, field studies were conducted using crop straw boards for rice cultivation at seeding densities of 150, 200, 250, 300, and 350 g/tray (labeled as D1, D2, D3, D4, and D5) and seedling ages of 10, 15, 20, and 25 days (labeled as A1, A2, A3, and A4).The results indicated that D4A2 significantly enhanced tiller number, dry matter accumulation, and photosynthetic capacity, resulting in a yield increase of 2.89% compared to the conventional method of D1A3. High-density and short-aged seedlings cultivated with crop straw boards can enhance rice yield by improving photosynthetic capacity and crop quality. This study emphasizes the importance of using crop straw boards for rice nursery practices, as well as selecting the appropriate seeding densities and seedling ages for optimizing rice production., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ling, Hu, Fu, Zhang, Xing, Gao, Wei and Zhang.)