Appearance, components, pasting, and thermal characteristics of chalky grains of rice varieties with varying protein content.

This study investigated two rice varieties, GuichaoII and Jiazao311, with distinct protein content to determine the variation in appearance, components, pasting, and thermal properties of rice with different chalkiness degrees. Grain length, width, head rice weight, and whiteness of both varieties markedly increased as chalkiness increased from 0% to 50%. However, the variation in components, pasting, and thermal characteristics of chalky grain substantially differed between the rice varieties. The protein content of GuichaoII (low protein content) significantly increased with the chalkiness degree, along with a significant increase in onset, peak, and conclusion temperatures and gelatinization enthalpy. In Jiazao311 (high protein content), the chalkiness degree increased with the protein content but decreased with the starch content, along with increased trough, final, setback, and consistency viscosities. Compared to amylose content, protein content had a greater influence on the thermal properties and pasting characteristics of chalky grains of GuichaoII and Jiazao311, respectively.

Importance of controlling mesocotyl elongation in the development of rice seedlings intended for mechanical transplantation.

The mesocotyl facilities the emergence of deep-sown rice. However, the effects of mesocotyl elongation on mechanically transplanted rice seedlings remain unclear. In this study, the indica three-line hybrid rice Chuanyou 6709 (CY6709) and the indica conventional rice Guichao II (GCII) were selected as experimental materials. The seedlings were grouped based on mesocotyl lengths of 1.0 and 2.0 cm (M1 and M2, respectively), and seedlings without mesocotyl elongation were used as a control (M0). Seedling morphology, root morphology and physiology, and dynamic changes in soluble sugar and protein, malondialdehyde (MDA), and antioxidant enzyme activity in the mesocotyl were evaluated. The results showed that the elongation of mesocotyl is not conducive to improving the quality of mechanically transplanted seedlings, resulting in weak seedlings and poor root coiling force. The mesocotyl lengths of the seedlings showed a single peak with increasing seedling age, which gradually disappeared. The longer the mesocotyls, the slower their senescence. The MDA content of M2 was significantly lower than that of M1, and the activities of soluble sugar, soluble protein, and antioxidant enzymes of M2 were higher than those of M1, implying that seedlings with longer mesocotyls yielded lower-quality seedlings, reducing their suitability for mechanized transplantation. Compared with those of M0, the root-shoot ratio, stem base width, leaf age, leaf area, white root number, root coiling force, root length, root surface area, and root volume of M1 and M2 were reduced. Therefore, in the raising of rice seedlings, excessive elongation of the rice mesocotyl is not conducive to optimum root growth and development of aboveground structures for seedlings that are suitable for mechanized transplantation. Controlling the mesocotyl elongation can facilitate the cultivation of high-quality mechanically transplanted seedlings.

Accurate prediction of the eating and cooking quality of rice using artificial neural networks and the texture properties of cooked rice.

Accurate prediction of the eating and cooking quality (ECQ) of rice is of great importance. Statistical and machine learning models were developed to predict the overall acceptability of cooked rice. The results showed that the models developed using stepwise multiple linear regression, principal component analysis plus multiple linear regression, partial least square regression, k-nearest neighbor, random forest, and gradient boosted decision tree had determination coefficients (R2) of 0.156-0.452, 0.357, 0.160-0.460, 0.192-0.746, 0.453-0.708, and 0.469-0.880, respectively, which were improved to 0.675-0.979 by artificial neural networks (ANN) models. The ANN models also had lower root mean square errors (0.574-1.32). Further, the ANN model using textural properties could accurately predict 92.1 % of overall acceptability, which could be improved to >96 % using the components and/or pasting characteristics. Overall, the accuracy of ECQ prediction was substantially improved by the model developed using ANN with texture properties of rice.

Universal detection of curved rice panicles in complex environments using aerial images and improved YOLOv4 model.

Accurate and rapid identification of the effective number of panicles per unit area is crucial for the assessment of rice yield. As part of agricultural development, manual observation of effective panicles in the paddy field is being replaced by unmanned aerial vehicle (UAV) imaging combined with target detection modeling. However, UAV images of panicles of curved hybrid Indica rice in complex field environments are characterized by overlapping, blocking, and dense distribution, imposing challenges on rice panicle detection models. This paper proposes a universal curved panicle detection method by combining UAV images of different types of hybrid Indica rice panicles (leaf-above-spike, spike-above-leaf, and middle type) from four ecological sites using an improved You Only Look Once version 4 (YOLOv4) model. MobileNetv2 is used as the backbone feature extraction network based on a lightweight model in addition to a focal loss and convolutional block attention module for improved detection of curved rice panicles of different varieties. Moreover, soft non-maximum suppression is used to address rice panicle occlusion in the dataset. This model yields a single image detection rate of 44.46 FPS, and mean average precision, recall, and F1 values of 90.32%, 82.36%, and 0.89%, respectively. This represents an increase of 6.2%, 0.12%, and 16.24% from those of the original YOLOv4 model, respectively. The model exhibits superior performance in identifying different strain types in mixed and independent datasets, indicating its feasibility as a general model for detection of different types of rice panicles in the heading stage.

Low Light Stress Increases Chalkiness by Disturbing Starch Synthesis and Grain Filling of Rice.

Low light stress increases the chalkiness of rice; however, this effect has not been fully characterized. In this study, we demonstrated that low light resulted in markedly decreased activity of ADP-glucose pyrophosphorylase in the grains and those of sucrose synthase and soluble starch synthase in the early period of grain filling. Furthermore, low light also resulted in decreased activities of granule-bound starch synthase and starch branching enzyme in the late period of grain filling. Therefore, the maximum and mean grain filling rates were reduced but the time to reach the maximum grain filling rates and effective grain filling period were increased by low light. Thus, it significantly decreased the grain weight at the maximum grain filling rate and grain weight and retarded the endosperm growth and development, leading to a loose arrangement of the amyloplasts and an increase in the chalkiness of the rice grains. Compared to the grains at the top panicle part, low light led to a greater decrease in the grain weight at the maximum grain filling rate and time to reach the grain weight at the maximum grain filling rate at the bottom panicle part, which contributed to an increase in chalkiness by increasing the rates of different chalky types at the bottom panicle part. In conclusion, low light disturbed starch synthesis in grains, thereby impeding the grain filling progress and increasing chalkiness, particularly for grains at the bottom panicle part.

Changes in chemical composition and starch structure in rice noodle cultivar influence Rapid Visco analysis and texture analysis profiles under shading.

GuichaoII, a rice variety with high amylose content widely used to make rice noodles, exhibits high hardness (631.07-729.43), gel consistency (8.47-9.47 mm), and hold viscosity/peak viscosity (HPV/PKV) (0.85-0.88); however, it has a low protein content (5.74-6.96%) and swelling factor (5.49-9.77). Herein, GuichaoII was subjected to low-light stress (53% reduction) during the grain filling stage. The amylose content and crystallinity of GuichaoII and the control variety Shuhui 498 decreased while the protein content, short-chain branch ratio, and degree of branching increased, which affected the ability of the rice flour to absorb water and expand during the gelatinization process. The PKV, HPV, breakdown viscosity, and final viscosity were significantly reduced, while the hardness was significantly increased, and the gel consistency and the gelatinization quality of the rice were reduced, severely limiting the processing and production of rice noodles.

Low Light Conditions Alter Genome-Wide Profiles of Circular RNAs in Rice Grains during Grain Filling.

In animals and plants, circRNAs regulate gene expression and act as sponges that inhibit the activity of microRNAs. This study aimed to determine how specific circRNAs are expressed in rice grains at different stages of grain filling, under normal and low light conditions. We extracted total RNA from rice grains under low and sufficient light conditions. Deep sequencing was performed using circRNA libraries, and bioinformatics tools were used to identify the circRNAs. In addition, we analyzed targeted messenger RNA functions using two databases to predict the processes involved in rice grain development, and we conducted real-time PCR on 15 of the circRNAs as well as Sanger sequencing. During the grain development process, 8015 candidate circRNAs were isolated, among which the number of known circRNAs was 1661. We also found that the number of circRNAs changed with the time of development. Among them, six circRNAs acted as sponges that targeted more than two microRNAs at different stages of development, and these circRNAs showed a regulatory pattern consistent with the transcriptome sequencing results. More circRNA diversity was found under low light treatment compared to normal light. These findings reveal a possible link between circRNA regulation and the expression of the functional genes associated with photosignal-mediated rice grain development.

Correlation of taste values with chemical compositions and Rapid Visco Analyser profiles of 36 indica rice (Oryza sativa L.) varieties.

Yield, taste quality, and cultivar utilisation improvements are important research topics in indica rice breeding. Herein, we compared the relative effectiveness and relationship of three taste evaluation methods, namely, chemical composition, Rapid Visco Analyser (RVA), and taste analyser. We assessed associations among these methods using 36 indica varieties commonly grown in Yunnan, Sichuan, and Guizhou, China. Temperature and sunlight duration during grain filling influenced rice cooking quality. Varieties with high taste quality had low amylose and protein contents; high peak viscosities and breakdowns; and low hold viscosities, setbacks, and final viscosities. Protein and combined protein and amylose explained 38.6% and 62.1% of the variation in taste value, respectively. The RVA profile was affected by protein, amylose, and amylopectin contents and explained 60.5% of the taste-value variation. This study lays the foundation for taste evaluation of high-quality rice varieties early in the breeding process, which can improve cultivation and marketing potential.

Effect of Hydraulic Expansion on Arteriovenous Fistula of Hemodialysis Patients.

BACKGROUND: Chronic kidney disease has become a serious public health problem in China. Our study is to explore effect of hydraulic expansion on arteriovenous fistula (AVF) of hemodialysis patients. METHODS: A total of 190 patients with end-stage renal disease (ESRD) were randomly divided into hydraulic expansion group (n = 117) and conventional surgery group (n = 73). Age, sex, the cause of ESRD, height, weight, body mass index (BMI), blood pressure, and diameter of artery and vein from ultrasonography before surgery from patients were recorded. Doppler ultrasonography of vessel was performed with a 12-MHz scanning probe for vascular measurements. The time of first cannulation was recorded. Primary and secondary patency rates were compared between the two groups. RESULTS: The mean arterial pressure for this cohort of patients was around 98.12 mm Hg. The mean diameters of artery and vein ready for anastomoses measured by ultrasonography before surgery were 1.96 and 2.04 mm, respectively. Age, weight, BMI, sex ratio, the cause of renal failure, history of catheter insertion, mean arterial pressure, frequency of hemodialysis, blood flow of hemodialysis, and the mode of anastomoses of AVF in conventional surgery group were similar to hydraulic expansion group. There were no differences in stroke volume of radius arterial and venous pressure before dilation between the two groups. The stroke volume of radius artery increased significantly after hydraulic expansion than before dilation and control group. The primary patency rates of AVF in patients with hydraulic expansion were higher significantly than conventional surgery group. The secondary patency rates in conventional surgery group were not different from hydraulic expansion group. CONCLUSION: Hydraulic expansion showed no difference from conventional surgery in complication after operation, and could decrease the time reliance on catheters and the risk of catheter-related infection, thrombosis, and decrease the related medical care costs.

Hydraulic expansion facilitates remodeling of arteriovenous fistulas without increasing venous intimal hyperplasia in rabbits.

Background: An arteriovenous fistula (AVF) is considered essential for chronic hemodialysis. Objective: To determine the effects of hydraulic expansion on the intimal hyperplasia of an AVF. Methods: We divided 12 healthy male New Zealand white rabbits into a control group (vein without special handling and direct anastomosis with an artery, n = 6) and a hydraulic expansion group (vein dilated by hydraulic pressure before anastomosis, n = 6). Histopathomorphology was examined with hematoxylin and eosin staining and immunohistochemistry. Analysis of covariance (ANCOVA) was used to compare the data between the groups. Results: Immediately and 1 day after surgery, the diameter of the fistula vein in rabbits in the hydraulic expansion group was significantly larger than it was in the control group (P = 0.02 and 0.03 respectively), but not on subsequent days. After hydraulic expansion and before construction of the fistula, the wall of vein was noticeably thinner on macroscopic observation, and the anterior and posterior walls were indistinguishable. At 3 weeks after surgery in the hydraulic expansion group, cells in the vein wall were disordered, there were fewer elastic fibers, tissues from the endothelium to tunica externa were less dense, and there was less extracellular matrix than in the control group. Expression of connective tissue growth factor in the hydraulic expansion group was significantly less than that in the control group (P = 0.01). No differences were found in intimal thickness or immunohistochemistry scores for transforming growth factor-ß1 between the groups. Conclusion: Hydraulic expansion did not increase intimal hyperplasia of an AVF, but facilitates remodeling of AVFs in rabbits.

Relationship between chalkiness and the structural and thermal properties of rice starch after shading during grain-filling stage.

Chalkiness is a major concern in rice production and its acceptance and is increased by shade stress. However, the relationship between rice chalkiness and the structural and thermal properties of starch is unclear. Here, we investigated the effect of shade stress on rice starch properties. The chalky grain rate and chalkiness degree significantly decreased with the amylose content, Mn, and ΔH and increased with surface area- and volume-weighted mean diameters, branching degree, ratio of 1022/995 cm-1, and molecular weight polydispersity. Shade stress significantly increased the volume- and surface area-weighted mean diameters and Mw and decreased the amylose content, A chain proportion of amylopectin, Mn, and regularity of starch. These effects led to an increase in the molecular weight polydispersity and branching degree and a decrease in the crystallinity degree and 1045/1022 cm-1 ratio, thereby reducing starch ΔH and uniformity. These factors contributed to increased chalkiness of rice under shade stress.

Effect of different shading materials on grain yield and quality of rice.

Light is a basic environmental factor required for plant growth and development; however, these are not only affected by light quantity, but also by light quality - light and radiation of different wavelengths and different compositions. In four different rice varieties (Oryza sativa L.), two kinds of shading materials, white cotton yarn (Shading (W)) and black nylon net (Shading (B)) were used to simulate cloudy days. Yield decreased under Shading (W) (15.3-17.7%) and Shading (B) (16.6-20.0%) compared to under sunny day (CK), and different effects on rice quality, which is mainly affected by changes in light quality, were observed. The change in light quality (Blue, Green, Red and R/FR proportions) represented under Shading (W) was significantly different from that under CK and Shading (B) conditions. Red light composition under Shading (W) was closer to that of the cloudy day condition. The proportion of blue light under Shading (W) was significantly lower than that under CK conditions; under Shading (B), it was higher than that under all conditions. The differences in light quality may affect photosynthesis in leaves and final starch synthesis, resulting in increased chalky grain rate, chalkiness, and poor rice quality. White cotton yarn as the shading material for further research used to simulate the influence of the light environment on rice growth under cloudy conditions will be better than black net.

Environmental Compensation Effect and Synergistic Mechanism of Optimized Nitrogen Management Increasing Nitrogen Use Efficiency in Indica Hybrid Rice.

Modern rice cultivation relies heavily upon inorganic nitrogen fertilization. Effective fertilizer management is key to sustainable agricultural development. Field and pot trials were conducted in 2014-2016, including a 15N-labeled urea pot experiment (2014) to investigate mechanism by which optimized nitrogen fertilizer application (OFA) increases nitrogen utilization efficiency (NUE). Results showed that the applied nitrogen recovery efficiencies with OFA were 71.71%, 110.17%, and 51.38% higher than those obtained with traditional nitrogen fertilizer application (TFA) in 2014, 2015, and 2016, respectively. These improvements are attributed mainly to the high recovery efficiency rates derived from spikelet-developing and spikelet-promoting fertilizer applications at the jointing stage and 15-20 d after jointing. Under OFA, the amount of nitrogen fertilizer applied at the early stages was half that used in TFA, which not only promoted the absorption of soil nitrogen, but also reduced nitrogen loss to the environment, as the NUE of basal and tillering fertilizer was only about 22%. Nitrogen applied during the panicle differentiation stage increased the expression of ATM1;1, a NH4 + transporter in roots. This effect significantly improved the uptake of nitrogen derived from fertilizer from jointing to heading stage. Up-regulation of the expression and activity of GS and GOGAT at the panicle differentiation and grain-filling stages promoted nitrogen translocation from vegetative organs to reproductive organs. The uptake of nitrogen derived from fertilizer increased from 22.51% in TFA to 35.58% in OFA. Nevertheless, rice absorbs most of the nitrogen it requires from the soil. The OFA treatment could effectively utilize the environmental compensation effect, promote the absorption and transport of nitrogen, and ultimately lead to improvement in NUE. Future research should aim to understand the soil nitrogen supply capacity in order to apply nitrogenous fertilizer in such a way that it sustains the nitrogen balance.

Polyaspartic acid (PASP)-urea and optimised nitrogen management increase the grain nitrogen concentration of rice.

Increase in grain nitrogen concentration (GNC), which is directly affected by nitrogen (N) application, can help overcome the issues of malnutrition. Here, the effects of urea type (polyaspartic acid (PASP) urea and conventional urea) and N management method (two splits and four splits) on GNC and N concentration of head rice were investigated in field experiments conducted in Sichuan, China, in 2014 and 2015. N concentration of grain and head rice were significantly (P < 0.05) increased by N redistribution from the leaf lamina, activities of glutamine synthetase (GS), and glutamate synthase (GOGAT) at the heading stage, and N concentration and GOGAT activity in the leaf lamina at the maturity stage. Compared to conventional urea, PASP-urea significantly improved N concentration of grain and head rice by improving the activities of GS and GOGAT, thereby increasing N distribution in the leaf lamina. The four splits method, unlike the two splits method, enhanced N concentration and activities of key N metabolism enzymes of leaf lamina, leading to increased GNC and N concentration in head rice too. Overall, four splits is a feasible method for using PASP-urea and improving GNC.

Morphophysiological mechanism of rice yield increase in response to optimized nitrogen management.

The yield-increasing mechanism of an optimized nitrogen fertilizer application (OFA) in rice was reported in this work through a three-year test. Results showed that the number of branches and spikelets increased, panicle length, the diameter and vascular bundle number of panicle-neck internode improved with OFA. Under the condition of OFA, high effective leaf areas, especially for the flag and the second upper leaf areas, increased, the net photosynthetic rate of the upper three leaves promoted, so the photosynthetic productivity went up by a large margin; moreover, the content of soluble protein and chlorophyll of leaf also increased, and the content of soluble sugar and malondialdehyde (MDA) decreased, as a result in slowing down the senescence speed in leaves, and increasing the photosynthetic time. Gene expression level, including MOC1, LAX1, SP1, GS1;1, were up-regulated obviously in different panicle initiation stage under OFA condition, which conduced to the increase in the secondary branches and spikelets. So we concluded that the changes in organ formation and panicle structure, together with the responses in physiological and molecular made the photosynthetic area, rate and time all increased with OFA, which provided the matter basis for the big panicle development, consequently, got a higher yield.

Early use of autogenous arteriovenous fistula in patients with urgent hemodialysis.

PURPOSE: This study was designed to evaluate the long-term patency rate and complications associated with early use of the autogenous forearm arteriovenous fistula (AFAVF) in patients needing urgent hemodialysis. METHODS: The clinical data of all patients undergoing AFAVFs for hemodialysis access between June 1996 and June 2016 were retrospectively evaluated. The primary and secondary patencies were estimated using the life table method. RESULTS: A total of 104 AFAVFs were created for 102 patients. All patients had entered hemodialysis when fistulas were constructed. The mean time to the first cannulation of the AFAVF was 17.33 ± 4.60 (5-27 days). Four AFAVFs (3.8%) became occluded within 30 days of creation of the access, and five AFAVFs (4.8%) had hematomas after cannulation. There were no cases of infection of the wound or steal syndrome or prolonged arm edema. The primary patency rate was 77.81% at 1 year, 73.05% at 2 years, 64.64% at 3 years, 60.75% at 5 years and 47.48% at 10 years. The secondary patency rate was 96.78% at 1 year, 95.18% at 5 years and 85.81% at 10 years. CONCLUSIONS: In this study, the patency rates following the early use of the AFAVFs were not inferior to the previously reported patency rates in the literature. For patients entering hemodialysis with an inserted central catheter, the early use of the AFAVFs decreases the complications associated with catheters.

Comparison of the effect of bone marrow cells infusion through the portal vein and inferior vena cava combined with short-term rapamycin on allogeneic islet grafts in diabetic rats.

AIMS/INTRODUCTION: The study aimed to compare the impact of allogeneic bone marrow cells (BMCs) infusion through the inferior vena cava (IVC) and portal vein (PV) combined with rapamycin on allogeneic islet grafts in diabetic rats. MATERIALS AND METHODS: Recipient diabetic Wistar rats were infused with islets from Sprague-Dawley rats through the PV. PKH26-labeled BMCs of Sprague-Dawley rats were infused to recipients through the PV or IVC, followed by administration of rapamycin for 4 days. Blood glucose level was measured to evaluate the survival time of the islets. Lymphocytes separated from blood, BMCs, thymus, liver, spleen and lymph node were analyzed by flow cytometry. The peripheral blood smear, BMCs smear and frozen sections of tissues were observed by a fluorescence microscope. RESULTS: The survival time of the islets was significantly prolonged by the BMCs infusion combined with rapamycin. The rats receiving BMCs infusion through the PV induced a significantly longer survival time of the islets, and increased mixed chimeras of allogeneic BMCs in the thymus, liver, spleen and lymph node compared with the rats receiving BMCs infusion through the IVC. The amount of the mixed chimeras on day 14 was lower than that on day 7 after islet transplantation. Furthermore, PV transplantation had significantly more mixed chimera than IVC transplantation in all analyzed organs or tissues. CONCLUSIONS: BMCs infusion combined with rapamycin prolongs the islets survival and induces mixed chimeras of BMCs. PV infusion of BMCs might be a more effective strategy than IVC infusion of BMCs.

Urokinase can reduce heparin dose in patients with hypercoagulable states during hemodialysis.

Heparin is routinely administered at high doses during hemodialysis to patients with hypercoagulable states. This study aimed to evaluate the safety and efficacy of low-dose heparin in combination with urokinase in this patient population. The presence of a hypercoagulable state was confirmed by thromboelastography. Doses of heparin and urokinase were adjusted based on activated partial thromboplastin time (APTT). Clotting in the extracorporeal circuit was evaluated by a semi-quantitative index. Prothrombin time (PT) and APTT were measured before, during and after dialysis. Kt/V(urea) was used to assess the efficacy of dialysis. D-dimer levels were measured 2 h after the start of hemodialysis. Hemodialysis data with heparin administered alone prior to dialysis were used as control in the present study. With urokinase treatment, the initial dose of heparin was reduced by 45.0 ± 11.4% during hemodialysis and the maintenance dose by 46.8 ± 12.8% compared with heparin alone. No side effects due to urokinase were observed. Bleeding events were rare. Post-dialysis PT (12.99 ± 1.41 vs. 15.22 ± 3.12 s, p = 0.02) and APTT (97.75 ± 43.62 vs. 140.16 ± 30.12 s, p = 0.002) with urokinase plus heparin were significantly shorter than with heparin alone. Finally, during dialysis, D-dimer levels were significantly higher with heparin alone (0.21 ± 0.11 mg/L) than with heparin and urokinase (0.169 ± 0.122 mg/L, p = 0.017). In conclusion, urokinase significantly reduced the dose of heparin required during hemodialysis without any side effects in patients with hypercoagulable states during hemodialysis.

Selenium suppresses lipopolysaccharide-induced fibrosis in peritoneal mesothelial cells through inhibition of epithelial-to-mesenchymal transition.

Peritoneal fibrosis resulting from long-term clinical peritoneal dialysis has been the main reason of dropout from peritoneal dialysis. Peritonitis as a common complication of peritoneal dialysis treatment may lead to the occurrences of peritoneal fibrosis. We cultured peritoneal mesothelial cells with lipopolysaccharides (LPS) in order to stimulate the environment of peritonitis and investigate whether lipopolysaccharides could induce epithelial-to-mesenchymal transition (EMT). Oxidative stress could stimulate fibrogenesis while selenium has antioxidant properties. So, this study also explored whether selenium supplementation affects lipopolysaccharide-induced EMT and fibrosis. We found that lipopolysaccharides could activate EMT changes such as the loss of E-cadherin and the increase of α-smooth muscle actin (α-SMA), collagen I, vimentin, and fibronectin (FN), while selenium inhibits EMT by modulating reactive oxygen species (ROS) generation and ROS/MMP-9 signaling pathways in peritoneal mesothelial cells. Moreover, it was revealed that selenium decreased the EMT events of peritoneal mesothelial cells via inhibition of PI3k/AKT pathways. In conclusion, these findings enable a better understanding of the mechanism of peritoneal fibrosis and explore a new idea for the prevention and treatment.

Soil physicochemical and biological properties of paddy-upland rotation: a review.

Paddy-upland rotation is an unavoidable cropping system for Asia to meet the increasing demand for food. The reduction in grain yields has increased the research interest on the soil properties of rice-based cropping systems. Paddy-upland rotation fields are unique from other wetland or upland soils, because they are associated with frequent cycling between wetting and drying under anaerobic and aerobic conditions; such rotations affect the soil C and N cycles, make the chemical speciation and biological effectiveness of soil nutrient elements varied with seasons, increase the diversity of soil organisms, and make the soil physical properties more difficult to analyze. Consequently, maintaining or improving soil quality at a desirable level has become a complicated issue. Therefore, fully understanding the soil characteristics of paddy-upland rotation is necessary for the sustainable development of the system. In this paper, we offer helpful insight into the effect of rice-upland combinations on the soil chemical, physical, and biological properties, which could provide guidance for reasonable cultivation management measures and contribute to the improvement of soil quality and crop yield.