Search Results (107)

Despite growing importance, agricultural landscapes face threats, like fragmentation, shrinkage, and degradation, due to climate change. Although remote sensing and GIS are widely used in monitoring croplands, integrating machine learning, remote sensing, GIS, and landscape metrics for the holistic management of this landscape remains underexplored. Thus, this study monitored crop patterns using random forest (94% accuracy), the role of geographical factors (such as elevation, aspect, slope, maximum and minimum temperature, rainfall, cation exchange capacity, NPK, soil pH, soil organic carbon, soil type, soil water content, proximity to drainage, proximity to market, proximity to road, population density, and profit per hectare production), diversity, combinations, and fragmentation using landscape metrics and a fragmentation index. Findings revealed that slope, rainfall, temperature, and profit per hectare production emerged as significant drivers in shaping crop patterns. However, anthropogenic drivers became deciding factors during spatial overlaps between crop suitability zones. Rice belts were the least fragmented and highly productive with a risk of monoculture. Croplands with a combination of soybean, black grams, and maize were highly fragmented, despite having high diversity with comparatively less production per field. These diverse fields were providing higher profits and low risks of crop failure due to the crop combinations. Equally, intercropping balanced the nutrient uptakes, making the practice sustainable. Thus, it can be suggested that productivity and diversity should be prioritized equally to achieve sustainable land use. The development of the PCA-weighted fragmentation index offers an efficient tool to measure fragmentation across similar agricultural regions, and the integrated approach provides a scalable framework for holistic management, sustainable land use planning, and precision agriculture. Full article

The contamination of paddy soils with arsenic (As) and cadmium (Cd), coupled with the depletion of soil organic carbon (SOC), poses significant threats to rice yields and quality. There is an urgent need to identify a suitable soil additive capable of achieving simultaneous heavy metal remediation and promotion of organic matter enrichment. The current study introduced two novel iron (Fe)/magnesium (Mg)-based bimetal-oxide-modified rice straw biochar (RSB), namely RSB-Fe/Mn and RSB-Fe/Mg. It evaluated their effectiveness in As/Cd immobilization and SOC preservation. An 8-week cultivation experiment was carried out in sequential drying–flooding moisture fluctuation conditions, with the soil pore water As/Cd (PWAs/Cd) and SOC fractions monitored. The mechanisms of As/Cd immobilization were investigated using Fourier Transform Infrared Spectroscopy (FTIR), X-ray Diffraction (XRD), and X-ray Photoelectron Spectroscopy (XPS) characterizations. Results revealed that PWAs and PWCd were reduced by up to 67.1% and 80.2% during the drying period and by 27.0% and 76.5% during the flooding period, respectively. Additionally, SOC content increased by 16.3% and 33.9% with RSB-Fe/Mn addition during the drying and flooding period, respectively, with an increase in the mineral-associated organic carbon (MAOC) fraction. The study proves that RSB-Fe/Mn and RSB-Fe/Mg are effective for soil As/Cd passivation and SOC stabilization, offering a promising solution to mitigate As and Cd pollution in paddy soils while maintaining soil quality. Full article

To explore the characteristics of soil microbial community structure diversity for different planting patterns in paddy fields, and to screen out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River, five typical planting patterns were set up in this study. The five patterns are Chinese milk vetch–early rice–late rice (CRR, CK), Chinese milk vetch–early rice–sweet potato || late soybean (CRI), rapeseed–early rice–late rice (RRR), rapeseed–early rice–sweet potato || late soybean (RRI) and potato–early rice–late rice (PRR). The variation characteristics of soil microbial community structure diversity and the correlation between soil environmental factors and soil microbial community structure diversity under the triple-cropping system in the double-cropping rice area of the middle reaches of the Yangtze River were studied by 16S rRNA high-throughput sequencing and real-time fluorescence quantitative polymerase chain reaction (PCR). The results showed that after two years of experiment, the pH values of each treatment increased, and the rapeseed–early rice–late rice (RRR) model performed better. The soil organic matter and total nitrogen content of the milk vetch–early rice–sweet potato || late soybean (CRI) model was the highest, which increased by 7.89~35.02% and 6.59~26.80% compared with other treatments. The content of soil available phosphorus and available potassium in the potato–early rice–late rice (PRR) model was higher than that in other treatments, which was increased by 29.48% and 126.49% compared with the control. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) models were beneficial to increasing soil nitrate nitrogen and ammonium nitrogen content. Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–late rice (RRR) patterns were beneficial for improving the microbial diversity index. Proteobacteria, Chloroflexi, and Actinobacteria are the top three dominant phyla in terms of the relative abundance of soil bacteria, and the top three dominant fungi are Ascomycota, Basidiomycota, and Mucor. The Chinese milk vetch–early rice–sweet potato || late soybean (CRI) and rapeseed–early rice–sweet potato || late soybean (RRI) patterns increased the relative abundance of soil Actinobacteria and Ascomycota. The contents of ammonium nitrogen, total organic carbon, nitrate nitrogen, and available phosphorus were the main environmental factors affecting soil microbial community structure. The findings can provide references for screening out the planting patterns suitable for the promotion of double-cropping rice areas in the middle reaches of the Yangtze River. Full article

In western Jilin Province, China, the presence of soda saline–alkali soil poses a significant threat to the raising of rice seedlings due to its harsh soil properties. The scarcity of suitable seedling-raising soil resources has become increasingly pronounced. A short-term soil-improvement experiment was conducted using the original saline–alkali soil sourced from the rice-growing region of Jilin Province, followed by the rice-seedling-raising test in the improved soil to identify an effective soil-improvement strategy. Four distinct treatments were established: no amendment (JCK); gypsum and straw (JCW); gypsum, straw, and sulfuric acid (JCWH); and gypsum, straw, and chemical fertilizer (JCWF). The effects of these amendment treatments on the soil physicochemical properties (pH, electrical conductivity, exchangeable sodium, total alkalinity) were evaluated, as well as the effects on soil organic carbon (SOC) and its components including humic acid carbon (HAC), and fulvic acid carbon (FAC). The results indicated that, compared to the control group, all amendment treatments effectively reduced the average soil pH by 0.53 to 0.79 units and decreased exchangeable sodium by 56.7% to 74.8%. Furthermore, the average SOC, HAC, and FAC increased by 48.3%, 89.4%, and 56.0%, respectively. Among the treatments, JCWH proved to be the most effective. After two years of improvement, the rice seedlings in the JCWH-treated soil exhibited the highest dry weight and plant height, surpassing those grown in the farmer’s seedling-raising soil. The scheme of utilizing soda saline–alkali soil for rice-seedling raising, following a short-term improvement treatment with corn straw, gypsum, and sulfuric acid (JCWH), provides technical support and an effective solution to the soil scarcity issue faced by seedling farmers in saline–alkali regions. Full article

The Upper Cikeruh Sub-watershed, part of the Citarum Basin and designated as one of Indonesia’s 15 Super Priority Watersheds, is facing severe degradation due to land use changes and deforestation, particularly in the upstream areas. This study assesses land criticality and suitability for agroforestry to guide sustainable land management practices. A semi-quantitative approach was used to evaluate land criticality through a scoring method, while qualitative match table analysis determined land suitability for specific agroforestry crops. Fieldwork was conducted in the upstream areas of the Cikeruh Sub-watershed, covering the administrative areas of Bandung and Sumedang. The results showed that most areas showed critical land conditions, with productivity identified as the most limiting factor, with scores as low as 30. The agroforestry suitability analysis showed that specific land mapping units (LMUs A, C, D, E, F, and N) were marginally suitable (S3) for crops such as legumes, upland rice, corn, soybeans, and chilies, with the main constraints being slope steepness and soil pH. This study highlights the urgent need to implement agroforestry practices as a restoration strategy in degraded landscapes. The findings provide actionable recommendations to improve land productivity while promoting sustainable watershed management in one of Indonesia’s critical areas. Full article

Cyanobacteria, ubiquitous phototrophic prokaryotes, can enhance soil fertility and crop productivity by promoting biological nitrogen fixation, phosphate dissolution, and mineral release. In this study, five nitrogen-fixing cyanobacteria were isolated and purified from paddy soil in Jilin Province. The effects of nitrogen-fixing cyanobacteria on soil fertility and rice seedling growth were examined through a pot experiment to clarify their growth and nitrogen-fixing characteristics. The results showed that the application of nitrogen-fixing cyanobacteria led to a significant increase in soil nitrogen content. GD2 and GD8 have the highest nitrogenase activity, at 75.33 U·mg⁻¹ and 50.34 U·mg⁻¹, respectively. It also enhanced the activities of urease, sucrase, phosphatase, and catalase in rice soil. In addition, it significantly promoted root development and plant height in rice plants. The total number of microorganisms in rice soil increased by 133–366%. Remarkably, the Desmonostoc muscorum GD2 strain was found to exhibit higher growth state indicators, including the growth curve, chlorophyll content, carbon and nitrogen content, and biomass accumulation, compared to other algae strains. The total nitrogen content of rice leaves treated with GD2 increased by 48.73%, and the soluble protein content increased by 52.89%. GD2 has great potential as an excellent nitrogen-fixing cyanobacteria inoculant for rice, suitable for agricultural production. In conclusion, the application of these nitrogen-fixing cyanobacteria significantly increased soil nitrogen levels and activated key enzyme activities involved in plant nitrogen metabolism. Moreover, it improved nitrogen utilization rates and promoted plant growth. Full article

Incorporation of plant residues in soil affects microbial community structure and ecological function, which can improve soil fertility. It is reported that substrate qualities could regulate microbial keystone taxa and their interactions, wielding an important effect on nutrient cycling in ecosystems, such as soil labile phosphorus (P) transformation. However, there is little understanding of the specific microbial mechanisms governing P’s availability in acidic soils following the incorporation of plant residues of various qualities. In this 210-day incubation experiment, two high-quality residues of pumpkin stover and mango branch and one low-quality residue of rice straw, different in terms of their labile carbon (C) content and carbon/phosphorus ratio (C/P), were separately mixed with an acidic soil. The aim was to investigate how the residues affected the community composition, keystone species, and interaction patterns of soil bacteria and fungi, and how these microbial characteristics altered soil P mineralization and immobilization processes, along with P availability. The results showed that adding high-quality pumpkin stover significantly increased the soil’s available P content (AP), microbial biomass P content (MBP), and acid phosphatase activity (ACP), by 63.7%, 86.7%, and 171.7% compared to the control with no plant residue addition, respectively. This was explained by both the high abundance of dominant bacteria (Kribbella) and the positive interactions among fungal keystone species. Adding mango branch and rice straw induced cooperation within fungal communities while resulting in lower bacterial abundances, thereby increasing AP, MBP, and ACP less than the addition of pumpkin stover. Moreover, the labile C of plant residues played a dominant role in soil P transformation and determined the P availability of the acidic soil. Therefore, it may be suitable to incorporate high-quality plant residues with high labile C and low C/P into acidic soils in order to improve microbial communities and enhance P availability. Full article

Rice is the staple diet for most of the world’s population and is considered a major staple crop in China. Anhui province of China is among the leading provinces for rice production, consumption, and commodities; it is well-known as the “land of fish and rice”. Japonica rice cultivation in Anhui Province is mainly categorized into late-maturing medium, early-maturing medium, and early-maturing late japonica. This review explores the suitable ecological zone distribution and corresponding climate characteristics of the three types of japonica rice in Anhui Province. Data on japonica rice varieties approved in the province over the past twenty years were collected, illustrating the development process of japonica rice varieties in the province and their quality and resistance to rice blast disease. The review shows that the yield is positively and significantly correlated with agronomic traits, such as the number of effective panicles and the total number of grains per panicle, plant height, etc. In addition, it elucidates the major problems faced by Anhui’s japonica rice breeding and cultivation, such as frequent events of high temperatures, rice blast disease, and medium to low soil fertility levels. Considering the existing issues in breeding japonica rice varieties in Anhui Province, this review proposes a strategy for breeding high-yield and disease-resistant japonica rice varieties, particularly varieties adaptable to medium and low fertility soil conditions. In brief, this article provides a theoretical basis and practical recommendations for the sustainable development of japonica rice in the Anhui Province of China. Full article

Rice is a water-intensive crop, conventionally grown under submerged conditions, with standing water for about 80% of its growth period. There is an urgent need for water-saving technologies to address challenges associated with conventional irrigation techniques for rice. The alternate wetting and drying (AWD) technique is one of these water-saving techniques; however, it requires continuous monitoring of water levels in the field. The implementation of real-time, electronic sensor-based precision irrigation technology may address the problems associated with conventional irrigation systems and AWD leading to high water use efficiency. Therefore, a study was undertaken to develop a suitable sensor-based automated irrigation system to maintain optimal water levels in rice fields. This study conceptualized an electronic sensor-based automated irrigation system for rice cultivated under the AWD technique. In this method, the rice field is initially flooded to a maximum depth of 5 cm. Irrigation is reapplied once the water level reduces to 10 cm below the soil surface. This developed system helps address water scarcity by regulating water levels, preventing excess ponding. It uses magnetic float-based sensors and electronic circuits to detect water levels, converting them into electronic signals transmitted wirelessly via radio frequency (RF) to a controller. The controller has been programmed for different growth stages that need to be set manually during the cropping period. The system is designed primarily for the AWD method but includes an option for continuous ponding (CP), needed during the flowering stage. The maximum water level at full maturity is set at 5 cm above the soil surface, while irrigation with the AWD method begins when the water level falls 10 cm below the soil surface. The developed system was tested during the Kharif season of 2018–19; the irrigation water productivity was 6.15 kg ha⁻¹mm⁻¹ with the automated system, compared to 3.06 kg ha⁻¹mm⁻¹ in the control (continuous ponding). Total water productivity was 4.80 kg ha⁻¹mm⁻¹ for the automated system and 2.63 kg ha⁻¹mm⁻¹ for the control. The automated system achieved 36% more water savings over the control, which used continuous ponding as farmers practice. The developed system supports AWD, a proven water-saving technique in rice cultivation. Full article

Selenium, as an essential trace element, is intricately linked to the onset and progression of numerous diseases due to deficiencies in selenium intake. Selenium compounds exhibit tumor specificity and can efficiently inhibit the growth of tumor cells, making them potential candidates for cancer treatment. Nevertheless, given its status as one of the most widely consumed crops globally, increasing the selenium content in rice could prove advantageous in alleviating the prevailing issue of selenium intake deficiency, particularly in China. This review explored the regulatory role of selenium in rice growth, the regional distribution characteristics of soil selenium content in various rice-growing regions in China, and the impact of cultivation practices on selenium fortification in rice, aiming to suggest improved rice cultivation management strategies to enhance the capacity for rice selenium biofortification. The findings revealed that: (1) In Northeast and North China, characterized by alkaline soils and severe selenium deficiency, it is advisable to moderately decrease the duration of flooding, elevate the soil redox potential, and apply organic and nitrogen fertilizers in a judicious manner. (2) In Southwest China, which is characterized by acidic soils, alternating wet and dry irrigation should be employed, and the biofortification of selenium can be facilitated by applying lime and foliar spraying of selenium fertilizer. (3) In the south-central region of China, distinguished by acidic soils and double-cropped rice, it is recommended that intermittent or alternating wet and dry irrigation be employed, and the reasonable application of organic, silica, and selenium fertilizers is advocated. (4) In the northwest region, characterized by slightly alkaline soil and mild selenium deficiency, it is recommended to implement various water management practices, including shallow water during the seedling stage, deep water during the booting stage, and wet grain filling. Additionally, a rational application of nitrogen, phosphorus, and potassium fertilizers, along with foliar application of selenium fertilizer, should be employed. (5) Cultivating selenium-enriched, high-yielding, and high-quality rice varieties proves to be an effective strategy in addressing selenium deficiency. In conclusion, the unique characteristics of diverse rice-growing regions in China indicate that suitable water management, fertilization techniques, and varietal selection practices can effectively enhance the selenium content in rice, thereby maximizing the nutritional requirements for selenium. Full article

Rice husk is a waste byproduct of rice production. This material has a moderate cost and is readily available, representing 20–22% of the biomass produced by rice cultivation. This study focused on the properties of rice husk in the remediation of soils contaminated by heavy metals. The effect of particle size, pH, and the presence of organic ligands on sorption efficiency was evaluated for Cd, Cu, and Mn. The continuous flow method was used to select suitable operative conditions and maximize the retention of heavy metals. Subsequently, pot experiments were carried out by growing two broadleaf plants, Lactuca sativa and Spinacia oleracea, in aliquots of soil collected in a Piedmont (Northwest Italy) site heavily contaminated by Cu, Cr, and Ni. Rice husk was added to the contaminated soil to evaluate its effectiveness in immobilizing heavy metals. The availability of Cr, Mn, Ni, Cu, Zn, Cd, and Pb in soil was studied using Tessier’s sequential extraction protocol. The content of the elements was also analyzed in plants and the uptake of heavy metals was evaluated in relation to the addition of rice husk. The growth of both plants was more efficient in the presence of rice husk due to its ability to reduce the mobility of heavy metals in the soil. The simplicity, cost-effectiveness, and scalability of its employment make the use of rice husk suitable for practical applications in soil remediation. Full article

Research on soil biochar fertilization has mainly been conducted on cereal crops, and information on its potential for radish production remains inconsistent. Therefore, a pot experiment was conducted to examine the short-term effects of rice husk biochar on radish growth and nitrogen use efficiency (NUE). An investigation was conducted with two application rates of biochar alone, (10 t ha⁻¹ (B10) and 25 t ha⁻¹ (B25), and biochar + chicken manure application with and without NPK fertilizer. The results indicated that the application of biochar 25 t ha⁻¹ + chicken manure (B25:CHM) and the combination of biochar 25 t ha⁻¹ + chicken manure + NPK fertilizer (B25:CHM:NPK) significantly increased root yield by improving NUE, fertilizer recovery efficiency (RE_N), agronomic efficiency (AE), nitrogen harvest index (NHI), and retaining soil NH₄⁺-N. Although biochar application alone did not significantly influence radish growth on a short-term basis, B10 and B25 increased root yields by 10% and 20%, respectively, compared with the control. Notably, the role of biochar application when combined with organic and inorganic fertilizers was to retain fertilizer N and promote N uptake efficiency by radishes, as higher rates of biochar resulted in higher NUE. Our results suggest that B25:CHM is a suitable combination for organic farming. Full article

Paddy-rice cultivation using the traditional continuous flooding method requires much water, up to 2500 L, to produce 1 kg of rice. Decreasing water availability is being exacerbated by climate dynamics, i.e., droughts and rainfall variability negatively affecting food security in developing regions, particularly Africa. Alternate wetting and drying (AWD) practice is a climate-smart water management strategy that, together with puddling (a critical field preparation process), significantly affects soil hydrological and physicochemical regimes, such as soil water dynamics and oxidation states in paddy fields. However, there are limited reviews on the effects and interaction of the AWD duration on hydrological conditions in the paddy-rice rhizosphere continuum under AWD practice at different rice growth stages. Our review synthesizes key scientific literature to examine water management and hydrological properties of paddy soils under AWD practice with climate change and sheds light on why farmers are skeptical in adopting the practice. To develop this paper, we reviewed scientific information from published journal articles, reliable reports, and our knowledge on paddy-rice cultivation and water management with climate change in Asia and Sub-Saharan Africa. Several studies confirm that AWD practice increases water–rice–crop productivity, yields, and reduces methane emissions. Limitations and challenges of AWD irrigation, including changes in soil structure that influence irrigation water application, variations in hydraulic conductivity caused by the duration and frequency of irrigation cycles, and frequent manual water level (WL) monitoring, are discussed. Opportunities to improve the integration of AWD strategies within government policies, irrigation schemes, and farmer acceptance due to skepticism, limited knowledge, and fear of unreliable water hindering adoption are highlighted. Future research suggestions include the following: (i) long-term measurement of water stress indices using infrared thermometers; (ii) seasonal suitability mapping using NDVI, GIS, and remote sensing; and (iii) application of smart sensors based on the Internet of Things (IoT) to address AWD challenges for precision water management in paddy fields with climate change. Full article

The crop straw returning to the field is a widely accepted method to utilize and remediate huge agricultural waste in a short period. However, the low temperatures and dry conditions of the winter season in Southwest China can be challenging for the biodegradation of crop straw in the field. With a similar aim, we designed a short-term study where rice straw was applied to the field with different concentrations of nitrogen (N) fertilizer while keeping phosphorus (P) constant; CK, (N0P0); T1, (N0P90); T2, (N60P90); T3, (N120P90); and T4, (N180P90) were added to evaluate its impact on straw degradation during cold weather. We found that high fertilization (T4) significantly improved crop yield, organic matter, and lignocellulose degradation under cold temperatures (21.5–3.2 °C). It also significantly improved soil nitrogen agronomic efficiency, nitrogen use efficiency, and nitrogen physiological efficiency. The yield was highest in T4 (1690 and 1399 kg/ha), while T3 acted positively on soil lignocellulolytic enzyme activity, which in turn resulted in higher degradation of OM and lignocellulosic material. Pearson’s correlation analysis revealed that total nitrogen, total phosphorus, available nitrogen, and available phosphorus were important variables that had a significant impact on soil EC, bulk density, water holding capacity, and soil enzymes. We found that nitrogen application significantly changed the soil bacterial community by increasing the richness and evenness of lignocellulolytic bacteria, which aided the degradation of straw in a short duration. This study’s finding indicates that the decomposition of crop straw in the field under cold weather stress was dependent on nutrient input, and N, in an appropriate amount (N120-180), was suitable to achieve higher yield and higher decomposition of straw in such an environment. Full article

To explore the effects of different water-saving treatments on rice plant growth and select suitable water-saving irrigation strategies for aerobic rice varieties, we conducted relevant field experiments from June to October 2023 at Jiangsu Runguo Agricultural Development Co., Ltd., China, which is located in a north subtropical monsoon climate where the soil is alkaline sandy loam. Four water treatments were set up, including the control of local conventional irrigation (CK, without water stress), mild water-saving treatment (W1, 20% more water saved than CK), moderate water-saving treatment (W2, 30% more water saved than CK), and severe water-saving treatment (W3, 40% more water saved than CK). The experiment results showed that rice plant heights were inhibited and leaf chlorophyll contents increased under all water-saving treatments compared to CK. Among them, the MDA content in paddy leaves under the W1 treatment decreased, while the activities of SOD and POD were enhanced and the membrane lipid peroxidation capacity of rice was also enhanced. Meanwhile, the results showed that the rice yield and quality under the W1 treatment significantly improved. Based on those experiments, a comprehensive evaluation of rice plant height, chlorophyll content, grain yield, yield components, and rice quality was conducted using the TOPSIS entropy weight method. It was preliminarily concluded that the suitable irrigation scheme for south and central Jiangsu was 20% water-saving irrigation compared with CK. In summary, under the premise of maintaining the economic yield of rice cultivation, an appropriate water irrigation plan helped save water resources and promote rice growth. Full article