Abstract
Optimized fertilization practices are a promising management strategy for sustainable rice production. Green manuring, straw incorporation, postponing nitrogen (N) application, formula fertilization, combined application of organic and inorganic fertilizers, reducing fertilization, deep fertilization, slow/controlled-release fertilizers (S/CRFs), and biochar addition are nine frequently used optimized fertilization practices in China. The nitrogen use efficiency (NUE) improvement, yield increase, and N loss-reducing effects of these practices were analyzed based on multisite studies across China. An index system considering the applicability and effects of various practices was developed to identify their potential distributions. The results indicated that 76.5% of all paddies in China are overfertilized regions under the current rice yields. Optimized fertilization practices were mainly adopted in central and eastern China regions with serious water pollution and excessive fertilization. Postponing N application, S/CRFs, and formula fertilization had wide applicability nationwide, suitable for 100% of all paddies, followed by straw incorporation (98.8%), deep fertilization (81.4%), green manuring (67.0%), reducing fertilization (44.0%), biochar addition (33.7%), and combined application of organic and inorganic fertilizer (23.4%). Overall, except for reducing fertilization, which decreased yields by an average −2%, most practices increased yield by more than 5% and reduced total N losses by more than 15%. Reducing fertilization, postponing N application, S/CRFs, straw incorporation, and green manuring are five eco-friendly practices with wide distribution, low inputs, and good effects. By fully implementing the recommended combination scenarios based on the five preferred practices at the country level, the total yield increasing rate and N loss-reducing rate were 3~9% and 15~35%, respectively. Optimized fertilization in China has noticeable potential to alleviate agricultural non-point source pollution while ensuring rice yield.
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1 Introduction
Rice production not only consumes large amounts of irrigation water and fertilizer, but also poses a high risk of water pollution by delivering nitrogen (N) through surface runoff, which is the principal cause of agricultural non-point source pollution in major rice-producing regions (Liu et al. 2021b; Zhang et al. 2021a; Zhuang et al. 2020). Rice paddies in China account for 1/5 of the world’s planting regions (FAO 2019). To meet the demand of an expanding population in China, chemical fertilizers, especially N fertilizers, have been extensively applied in paddy fields to maintain high rice yields. Excessive use of N fertilizers and traditional fertilization methods have become major challenges for sustainable and intensive agriculture (Liu et al. 2021a). Nitrogen use efficiency (NUE), defined as the ratio of crop N uptake to the total input of N fertilizer, is one of the most critical concerns in rice cultivation to reduce N losses, increase yields, and improve crop management (Gil-Ortiz et al. 2020; Zhang et al. 2014a). In China, NUE is approximately 35% in paddy systems, and a considerable portion of N is discharged into water via surface runoff and leaching (Bai et al. 2020; Ju et al. 2009; Qi et al. 2020). Determining optimum N management and reducing environmental harm are critical in Chinese agriculture (Shi et al. 2020; Yao et al. 2018).
Agronomic measures, such as fertilization, irrigation, and tillage, can reduce N loss by affecting the NUE, the N concentration in paddy surface water and soil, and the N conversion process (Jiang et al. 2021; Zhuang et al. 2019). N fertilizer is usually supplied via multiple applications during rice production in China (Ye et al. 2019). Similar to water saving irrigation, optimized fertilization practices are an important source-control solution to mitigating pollution and eutrophication from paddy fields (Wu et al. 2020). Green manuring, straw incorporation, postponing N application, formula fertilization, reducing fertilization, deep fertilization, and combined application of organic and inorganic fertilizers, have been applied across China (Fig. 1) (Liu et al. 2015; Xia et al. 2020a; Xia et al. 2020b). As a traditionally sustainable source of nutrients, the appropriate substitution of green manuring for N fertilizers (e.g., 20–40%) is beneficial for improving the productivity and sustainability of paddy fields (Islam et al. 2019; Li et al. 2021; Xie et al. 2016). Straw incorporation is increasingly recommended due to its ability to increase the soil organic carbon (SOC) stock and improve soil fertility after microbial decomposition (Ku et al. 2019). Postponing N application optimizes the split proportion of N fertilizers in different growing stages according to the N demand of rice mainly by reducing the fertilizer amount in the basal period and increasing the fertilizer amount in the tillering stage and booting stage (Bai et al. 2020). Rational formula fertilization can efficiently restore and improve soil fertility, and increase nutrient uptake (Xiao et al. 2019). Reducing fertilization often reduces the N fertilizer application rate by 10–30% to decrease the risk of N runoff on the basis of cost savings and yield maintenance (Xu et al. 2020). Compared to broadcast application, deep fertilization can promote nutrient uptake by rice roots (Zhong et al. 2021b). The combined application of organic and inorganic fertilizers can maintain high soil productivities and high NUE to improve not only rice yield but also yield sustainability in low-productivity paddy soil (Jabbar et al. 2008; Mi et al. 2018; Qaswar et al. 2020). Meanwhile, some new optimized fertilization types, such as slow/controlled-release fertilizers (S/CRFs) and biochar addition, have shown good applied effects for reducing N losses, and enhancing NUE and rice yields (Liu et al. 2020; Lu et al. 2020; Shen et al. 2021; Sun et al. 2020). S/CRFs present the advantage of better matching the plants’ need for nutrients over time under current agricultural practice to decrease the environmental impact caused by fertilizer doses applied in excess of the plants’ uptake rate (Gil-Ortiz et al. 2020). Biochar application in farmland can effectively increase soil organic carbon content and improve soil properties (Chen et al. 2021). The management strategies and advantages of the nine common fertilization practices are listed in Table 1.
Coordinating grain production and environmental protection through improved NUE will be a key step in achieving sustainable rice production in Chinese agriculture (Jiao et al. 2016). In China, the three major rice planting regions are the Northeast Plain, Yangtze River Basin, and Southeast Coast, with approximately 14.9%, 63.5%, and 19.7% of the total rice planting areas, respectively. In recent years, optimized fertilization practices have been vigorously pursued nationwide. However, the potential effects and distribution of various practices for paddy fields in China are not clear, which hinders the popularization of efficient practices. The objectives of this study are to (1) compare different optimized practices in terms of their effects on yield increase, NUE improvement, and N loss reduction by analyzing of published data from multisite field studies; (2) identify the suitable application regions of optimized fertilization practices for paddy fields across China; and (3) estimate the potential overall effects under full implementation of optimized fertilization practices for rice production at the country level.
2 Data and methods
2.1 Data sources
To analyze the general effects of common fertilization practices in paddy fields, research data from multisite studies were collected from the Chinese National Knowledge Infrastructure (CNKI). To ensure representativeness and comparability of the data, only data that satisfied the following criteria were regarded as effective and used in subsequent analysis: (1) the control treatment must involve conventional fertilization; (2) the study period must cover the whole rice-growth season; (3) field monitoring (excluding laboratory experiments and pot experiments); (4) standardized monitoring method; and (5) the crop N uptake for NUE includes the above- and belowground plant biomass. The relevant studies covered 24 provinces/territories and 367 study sites in China during 1997–2021 (Fig. 2). Original data were extracted by WebPlot-Digitizer-3 from multidata studies.
Data on N fertilizer application, rice yields, precipitation, land use and cover change (LUCC), digital elevation model (DEM), and livestock were collected to analyze the suitable distribution of various fertilization practices. Information on N fertilizer application was recorded from the literature, which comprised 242 site-year data points for rice paddy fields and can be considered representative of the amount applied by farmers in China (Hou et al. 2018). The local recommendations for N fertilizer amounts with special planting patterns and yield levels were obtained from the Ministry of Agriculture and Rural Affairs of the People’s Republic of China (local recommendations of fertilizer amounts 2016). Rice yields in 2019 were obtained from the National Bureau of Statistics (Rice yield, 2019); precipitation, and LUCC were obtained from the Resource and Environment Data Cloud Platform, Chinese Academy of Sciences (RESDC) (Precipitation and LUCC data 2020); annual frost-free season was calculated based on the daily minimum temperature with an inclusive 2 °C threshold from China Meteorological Data Service Centre (Frost-free season, 2016–2020) (Tang and Niu 2011); DEM was obtained from the Geospatial Data Cloud to calculate the slope (DEM, 2019); soil conditions were calculated from soil property data of the FAO Harmonized World Soil Database (HWSD) (Soil property data 2018); and the number of livestock (total of large animals, hogs, sheep and goats) in 2019 was obtained from the China Statistical Yearbook in 2020 (Number of livestock, 2020). All data were unified into grid-scale images with a resolution of 1000 m in ArcGIS 10.2.
2.2 Methods
2.2.1 Analysis of the effects of various optimized fertilization practices
The load of total nitrogen (TN), lost from paddy fields via runoff in the whole growth period, was selected as the proxy indicator to estimate the loss risk of N from paddy fields (Zhuang et al. 2019). Based on the multisite studies collected from the CNKI, the NUE-improving rate (NIR, %), yield-increasing rate (YIR, %), and N loss-reducing rate (NLRR, %) of each study site were calculated by Equations 1–3.
where NUEopt is the NUE at specific optimized practice (%); NUEconven is the NUE at conventional practice (%); Yopt is the rice yield at specific optimized fertilization practice (kg/ha); Yconven is the rice yield at conventional practice (kg/ha); NLconven is the TN loss load at conventional practice (kg/ha); and NLopt is the TN loss load at special optimized practice (kg/ha).
Furthermore, these data were used to calculate the mean and standard deviation (SD) of YIR, NIR, and NLRR by specific fertilization practices. The differences in NUE increasing, yield increasing, and N loss-reducing effects between various practices were analyzed.
2.2.2 Analysis of fertilizer application status of paddy fields in China
Referring to the local recommendations of fertilizer application rates under specific yields, we first calculated the overapplied fertilizer amounts at the current rice yields in the local regions by Eq. (4), and further identified the overfertilized regions. The identification and visualization of overfertilized regions were finished in ArcGIS.
where Fover is the overapplied fertilizer amount of N (kg/ha) used in the local regions; Flocal is the actual fertilizer amount of N in the local regions (kg/ha); and Frecom is the recommended fertilizer amount of N at a specific yield level in the local regions (kg/ha). The overfertilized regions of paddies in China were divided into five levels based on the Fover:
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Not excessive
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Fover ≤ 50 kg/ha
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50 kg/ha < Fover ≤ 100 kg/ha
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100 kg/ha < Fover ≤ 150 kg/ha
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Fover > 150 kg/ha
2.2.3 Identification of the potential distribution of optimized fertilization practices at the country level
First, we analyzed the application conditions of various fertilization practices and identified the critical factors affecting their distribution across China by a literature survey (Hong et al. 2019; Liu et al. 2015; Zhang et al. 2014a; Zhou et al. 2020). Considering the applicability of various practices and the representativeness and measurability of the indices, these critical factors were selected as indicators to establish a new index system for fertilization practice selection, as shown in Table 2. The indices included five regional attribute factors (including soil condition, hydrothermal condition, terrain, current fertilization condition, and scale of livestock and poultry breeding) and two reference indicators (including labor and cost input effects). The reference factors are chosen as alternative indicators when the regional attributes related to optimized practices are similar.
The soil condition is subdivided into soil texture, soil fertility, and soil acidity. An American triangular chart for soil texture classification was used to classify soil texture as sandy, loamy, or clayey. In China, N surplus caused by excessive fertilization is common for cropping systems (Zhang et al. 2019); meanwhile, the fertility of most soils depends on the level of soil organic matter (SOM) (Adejuyigbe and Kodaolu 2012; Xie et al. 2021). Therefore, SOM was estimated to represent the soil fertility based on the topsoil organic carbon (T_OC), and topsoil pH (T_pH) was selected as indicative of soil acidity (Zhuang et al. 2019). The precipitation and frost-free season were selected to approximately express the hydrothermal conditions. In China, the growth periods of rice and green manure are approximately 110–160 days and 50 days, respectively, and the frost-free season of 210 days was determined to be the minimum requirement to assess whether the region is suitable to plant green manure. According to the terrain, paddy fields were divided into plain paddy (slope ≤ 6°), hilly paddy (6° < slope ≤ 15°), mountainous paddy (15° < slope ≤ 25°), and sloping paddy fields (> 25°). The number of livestock was used to analyze the scale of livestock and poultry breeding, which directly impacts the combined application of organic and inorganic fertilizers.
The potential distribution of optimized fertilization practices in China was simulated according to the new index system by spatial analysis in ArcGIS 10.2. The actual distribution of fertilization practices, acquired by survey, was used to verify the identification results.
2.2.4 Analysis of potential effects of optimized fertilization practices at the country level
According to the simulation results of the potential distribution of specific optimized fertilization practices, the spatial distribution of recommended scenarios was identified. Furthermore, based on the effects of a single optimized fertilization practice, the overall effects under recommended scenarios at the grid level and the country level were estimated successively. For each grid (i), the local yield-increasing rate (YIRlocal) and N loss-reducing rate (NLRRlocal) were calculated by Equations (5) and (6); then, the rice yield and the fertilizer amount in various regions were used as weights to calculate the total yield-increasing rate (YIRtotal) and N loss-reducing rate (NLRRtotal) at the country level by Equations (7) and (8).
where YIRi,j is the yield-increasing rate of jth single practice for ith grid (%); NLRRi,j is the N loss-reducing rate of jth single practice for ith grid (%); i is the ith grid at the country level; j is the jth optimized fertilization practice for the specific grid; and n is the number of all practices under the recommended scenario applied locally.
where YIRtotal is the yield-increasing rate of combined optimized fertilization practices at the country level (%); Ylocal is the rice yield in the local regions (kg/ha); NLRRtotal is the N loss-reducing rate of combined optimized fertilization practices at the country level (%); and Flocal is the amount of N fertilizer used in the local regions (kg/ha).
The potential effects of optimized fertilization practices at the country level were estimated by applying Eqs. (5–8) and visualized by raster calculator and zonal statistics in ArcGIS 10.2.
3 Results and discussion
3.1 Fertilizer application status of paddy fields in China
The local recommendations for fertilizer amounts specified the standard N fertilizer amounts under high, medium, and low yields; overall, with higher yields, the required fertilizer amounts were greater, which explained to a certain extent why overfertilization occurs when pursuing high yields for a long time. The overfertilized regions for rice production under current yields in China are identified in Fig. 3.
Under the current yields at the country level, 76.5% of all paddies in China were in overfertilized regions. Among these overfertilized regions, the regions with more than 150 kg/ha excessive N fertilizer cover 6.9%, scattered in Jiangsu, Hunan, Guangxi, Yunnan, Jilin, and Hebei Provinces; the regions with an excessive N fertilizer range of 100 to 150 kg/ha cover 8.3%, scattered in Jiangsu, Jiangxi, Yunnan, and Jilin Provinces; and 61.3% of all paddies had excessive N fertilizer less than 100 kg/ha, mainly distributed in Anhui, Jiangsu, Hunan, Sichuan, and Jiangxi of central China. Overall, the overfertilized regions were mainly concentrated in the Yangtze River Basin, which exhibits severe eutrophication (Shi et al. 2020). On the one hand, among the three main rice-producing areas, the Yangtze River Basin has an absolutely dominant position in terms of planting area and rice yield; on the other hand, the national investigation of water and N fertilizer use in paddy fields implied that non-point source pollution of N is expected to continue increasing, especially in the Yangtze River Basin (Liu et al. 2021b). Widespread overfertilization is the primary cause of TN losses and underutilization of N fertilizer. To change the current fertilization status, optimized fertilization with high NUE is necessary.
3.2 Individual effects of optimized fertilization practices for rice production in China
According to the spatial distribution of multi-research sites, most studies are clustered together in central and eastern China, such as Jiangsu, Zhejiang, Anhui, Hubei, Hunan, and Jiangxi provinces, which belong to the paddy-upland rotation area located in the Yangtze River Basin of central China; relatively few studies are scattered in the single cropping rice area of Northeast China and the double cropping paddy area of South China. In addition to increasing rice yield, environmental pollution control is another prime motivator to implement optimized fertilization practices. The effects of various fertilization practices on enhancing NUE, increasing yield, and reducing TN loss, as extracted from the literature data, are shown in Fig. 4.
In terms of NUE enhancing effects, the range of the average NIR of nine optimized fertilization practices was 1~11%. S/CRFs had the highest average NIR of 11%, followed by biochar, straw incorporation, and deep fertilization; the combined application of organic and inorganic fertilizers and the reducing fertilization had a relatively low NUE enhancing effect with the average NIR of 2% and 1%, respectively. Overall, optimized fertilization increased the NUE. S/CRFs and biochar addition increase the NUE by controlling the N release rate according to the N demand of rice in different growing stages (Solihin et al. 2019); postponing N application increases the NUE by selecting a reasonable time and frequency of fertilization to promote N uptake (Bai et al. 2020); and deep fertilization potentially increases the NUE by promoting root absorption (Zhao et al. 2021). Because of the different mechanisms, the NIR varied among fertilization practices. Due to the good NUE-improving effects, optimized fertilization practices, such as slow/controlled-release fertilizers, formula fertilization, and green manuring, can reduce N fertilizer amounts under the premise of ensuring stable and increasing rice yields to some extent (Achilea et al. 2010; Raheem et al. 2019; Xiao et al. 2019).
In terms of yield-increasing effects, the range of the average YIR of nine optimized fertilization practices was −2~15%. Reducing fertilization had the lowest average YIR of −2%; biochar addition had the highest average YIR of 15%, followed by formula fertilization (8%), S/CRFs (7%), deep fertilization (7%), green manuring (7%), straw incorporation (6%), postponing N application (5%), and combined application of organic and inorganic fertilizers (4%). The improvement of NUE and soil fertility is the important reason for the yield-increasing effects of most optimized fertilization practices. In addition, biochar addition increased crop yield by improving soil structure to reduce mechanical resistance to crop root growth and enhance water-retention capacity (Madari et al. 2017; Yang and Lu 2021; Yang et al. 2018); green manure improves paddy soil fertility and ecology through nitrogen fixation while improving soil structure (Ma et al. 2020). The main goal of reducing fertilization is to reduce the excessive fertilizer input under the premise of stable yield. Reducing fertilization may lead to negligible effects on yield increases and even yield reductions when the amount of fertilizer is probably less than the optimum fertilization rate.
In terms of the N loss-reducing effect, the range of the average NLRR of nine optimized fertilization practices was 15~40%. Biochar addition had the highest average NLRR of 40%, followed by S/CRFs, organic and inorganic fertilizer, and reducing fertilization. Overall, the NLRR of most fertilization practices was more than 15%. Biochar addition, organic and inorganic fertilizer, green manuring, and straw incorporation reduce TN losses mainly by improving soil structure and fertility; moreover, biochar also has strong absorbability and a larger ion exchange capacity with good void structure, which is observed to significantly reduce the TN contents of paddy surface water after fertilization, and has a high NLRR (Lu et al. 2020; Ni et al. 2021). On the basis of conventional fertilization, reducing fertilization can control the fertilizer amount from the source and effectively reduce the TN losses via surface runoff from paddy fields (Xu et al. 2020). Under the current conditions of excessive fertilization in China, reducing fertilization has huge potential for use.
NIR and YIR were positively correlated (r = 0.728, p = 0.026). In general, the higher the NIR was, the higher the YIR; the correlation between NIR and NLRR was not significant. NUE improvement directly promoted the yield increase, but the N loss-reducing effects did not only depend on NUE improvement. For a specific fertilization practice, a relatively large standard deviation (SD) of NIR, YIR, and NLRR arose. Between various practices, the variability of effects was mainly dependent on the fertilization strategy and mechanism. For example, biochar has strong absorbability and can enhance water-retention capacity, so its NLRR is apparently higher than that of S/CRFs, under a similar NIR (Madari et al. 2017). For the same practice, the variability of effects is mainly dependent on specific fertilization regimes and environmental factors, such as specific fertilization time, fertilizer amount and types, soil condition, precipitation, rice variety, and local planting habit. For example, the effectiveness of various N stabilizers of S/CRFs on rice yield and NUE varies greatly (Liu et al. 2020), and the effect of biochar application on soil N varies with biochar application mode, N form, and rice growth period (Lu et al. 2020).
3.3 Potential distribution of optimized fertilization practices for rice production in China
Fertilizing regimes vary in not only agronomic effects but also environmental impact factors, labor and cost inputs, technology maturity, etc. The spatial distribution of key factors that affect the applicability of optimized fertilization practices is shown in Fig. 5, and the index system and corresponding criteria for optimized fertilization practice selection of paddy systems in China are shown in Table 2.
In terms of soil conditions, soil texture, soil fertility, and soil acidity are the main factors. Only 14.1% of paddy fields are sandy soils in China. Highly permeable sandy soil often has a low holding capacity for nutrients and moisture (Yang et al. 2008). Deep fertilization is not suitable for use in sandy soils because of possible leaching loss of nutrients (Phongchanmixay et al. 2019). Straw incorporation, green manuring, and the combined application of organic and inorganic fertilizers are beneficial for rice cultivation in sandy soil by improving soil structure and properties while enhancing water-retention capacity (Barros et al. 2017; Jabbar et al. 2008; Choi et al. 2014). Strongly acidic soil covers approximately 25.3% of total paddy fields and soil acidification is relatively serious in paddy fields in central and southern China. Biochar can ameliorate soil acidification by providing a liming effect and strong nutrient adsorption (Madari et al. 2017; Dai et al. 2017). Straw incorporation, green manure, and organic fertilizer have the potential to adjust soil pH by changing the microbial communities and improving soil properties (Zhang et al. 2018; Gao et al. 2015; Zhai et al. 2011).
Rich water and heat resources represent that the region has good water and temperature conditions, such as abundant precipitation and a long frost-free season, which are beneficial for straw degradation and green manure planting (Tomasek et al. 2017; Zhang et al. 2021b). Most of China’s paddy fields occur in areas with precipitation exceeding 400 mm year-1 and a relatively short frost-free season results in green manure not having enough time to grow in the single-cropping rice region of Northern China (Zhang et al. 2014b). N runoff loss is predominantly governed by the fertilization rate (Xu et al. 2020), and reducing fertilization is an effective way to mitigate runoff pollution in overfertilized regions. According to terrain data, paddy fields in China are mainly distributed across both plains and hills, and only 4.2% of paddy fields are scattered in mountainous regions such as Guizhou, Yunnan, and Sichuan Provinces. Hilly or mountainous terrain is usually not beneficial for deep fertilization. Moreover, in China, planting and breeding are always separated, which results in a low utilization rate of livestock and poultry manure. Therefore, the combined application of organic and inorganic fertilizers has vast potential in well-developed livestock and poultry breeding regions, but the most optimum fertilization ratio needs to be identified to form a sustainable agricultural development pattern by combining the local breeding industry and planting mode.
In terms of labor and cost inputs, reducing fertilization, postponing N application, S/CRFs, straw incorporation, and green manuring can decrease the cost input by reducing chemical fertilizer application and simplifying rice culture management (Achilea et al. 2010; Xu et al. 2020; Han and He 2010; Solihin et al. 2019). Accordingly, high labor and cost inputs will restrict the application of other fertilization practices. Given the high labor requirement for deep fertilization, mechanical fertilization technology is necessary to overcome this difficulty (Liu et al. 2015; Su et al. 2015). Formula fertilization and biochar addition require constant technical support to determine the optimal fertilization scheme (Lu et al. 2020).
Based on the new regional attributes of various fertilization practices (Table 2), the potential distribution of appropriate fertilization practices for paddy systems in China was simulated based on the new index system, as shown in Fig. 6, which is consistent with the investigation results (Fig. 2). Postponing N application, S/CRFs, and formula fertilization had wide applicability nationwide, and the other six optimized fertilization practices had various degrees of regional restrictions. A total of 98.8% of all paddy fields in China were suitable for straw incorporation, followed by deep fertilization (81.4%), green manuring (67.0%), reducing fertilization (44.0%), biochar addition (33.7%), and combined application of organic and inorganic fertilizers (23.4%). Optimized fertilization has great potential in China, particularly under the coupling scenarios of multiple fertilization practices.
Straw incorporation and green manuring are mainly distributed in central and southern China, which have rich water and heat resources (Hong et al. 2019; Zhou et al. 2020). Reducing fertilization is mainly distributed in areas with excessive amounts of fertilizer, such as the Yangtze River Basin. As a new optimized fertilization practice, biochar addition is mainly used in Jiangsu and Zhejiang Provinces and scatters in the Northeast Plain. The combined application of organic and inorganic fertilizers is applied to regions with large-scale breeding industries, such as Hunan, Sichuan, Yunnan, and Henan provinces, and can realize the recycling of breeding waste.
With the development of technologies, the distribution of fertilization practices may change. For example, hydrothermal conditions and time affect the decomposition of rice straw (Luyima et al. 2019); microbial inoculants can be used to promote crop straw decomposition to solve these problems (Kumar et al. 2019; Wang et al. 2020); and machine-transplanted rice with side-deep fertilization (MRSF) is a recommended strategy to reduce labor costs and TN loss in sustainable production in China (Zhong et al. 2021a), which will promote the application of straw incorporation and deep fertilization.
3.4 Overall effect of optimized fertilization practices for rice production at the country level
Figure 5h and Fig. S1 show the spatial distribution of N fertilizer amount and rice yield at the country level. The high-yield regions were mainly distributed in Jilin and Liaoning Provinces in Northern China and Jiangsu, Hubei, Henan, and Shandong Provinces in central and eastern China, which also featured high N fertilization rates. China is still at the stage of raising rice yields with high fertilization and irrigation levels, which is the main reason why NPS pollution from paddy fields is severe in China (Zhuang et al. 2019).
By comparing the key factors for practice selection, formula fertilization, biochar addition, and deep fertilization have good yield-increasing and N loss-reducing effects, but their relatively high inputs of labor, mechanical power, or technology limit the promotion and application of practices to some degree at present; reducing fertilization, postponing N application, S/CRFs, green manuring, and straw incorporation are five eco-friendly and easy-to-operate fertilization practices with wide distribution, low inputs, and good effects in China.
The combination of multiple practices can significantly reduce TN loss and effectively improve rice yield (Shi et al. 2020; Zhou et al. 2020). Reducing fertilization is a necessary practice for cost savings and TN loss reduction in regions with excessive use of N fertilizer; moreover, with a greater number of adopted optimized fertilization practices, the YIR and NLRR are higher, but accordingly, the labor inputs are greater. Therefore, the recommended combination scenario would better have no more than three practices in the same region. On the basis of the above findings, nine recommended combination scenarios (Scenarios 1~9) of optimized fertilization practices at the country level were determined, as shown in Table 3. For an example of Scenario 3 (reducing fertilization and postponing N application), two practices were combined and applied at the country level, and the spatial distribution of the practice combination under Scenario 3 was identified, as shown in Fig. S2. Furthermore, the comprehensive effects of recommended combination scenarios were estimated at the country level (Table 3).
By fully implementing the nine given combination scenarios based on the above five practices at the country level, the YIRtotal and NLRRtotal reached 3~9% and 15~35% under suitable application areas of 81.4–100% of all paddy fields, respectively. Among the two-practice combination scenarios, Scenario 3 (reducing fertilization and postponing N application) and Scenario 4 (reducing fertilization and S/CRFs) had relatively good effects; among the three-practice combination scenarios, Scenario 7 (reducing fertilization, postponing N application, and straw incorporation) and Scenario 9 (reducing fertilization, S/CRFs, and straw incorporation) had relatively good effects. For Scenario 3, the YIRtotal and NLRRtotal were 4% and 25% suitable for 100% of all paddies, respectively, which were better than single reducing fertilization (–2% and 20% suitable for 44.0% of all paddies) and single postponing N application (5% and 18% under 100% of all paddies). Overall, the effects under combination scenarios were significantly better than those under single practice.
4 Conclusions
Optimized fertilization is a promising management practice for sustainable rice production. Green manuring, straw incorporation, postponing N application, formula fertilization, reducing fertilization, deep fertilization, S/CRFs, combined application of organic and inorganic fertilizers, and biochar addition are nine frequently used optimized fertilization practices. Environmental protection has become an important driver to promote the implementation of optimized fertilization practices, after yield-increasing demand. Biochar addition had the highest YIR (15%) and NLRR (40%). Overall, most practices generally increased yield by more than 5% and reduced TN losses by more than 15%.
Under the current rice yields at the country level, 76.5% of all paddies in China were overfertilized regions. Widespread overfertilization is the primary cause of TN loss and underutilization of N fertilizer. The application of optimized fertilization practices is largely affected by regional environmental factors (including soil conditions, hydrothermal conditions, and terrain), fertilization conditions, poultry and livestock breeding scales, inputs, effects, and planting habits. Postponing N application, S/CRFs, and formula fertilization were categorized under general applications without region restrictions, followed by straw incorporation (98.8% of total paddy areas), deep fertilization (81.4%), green manuring (67.0%), reducing fertilization (44.0%), biochar addition (33.7%), and combined application of organic and inorganic fertilizers (23.4%). Reducing fertilization, postponing N application, S/CRFs, green manuring, and straw incorporation are five eco-friendly and easy-to-operate fertilization practices with wide distribution, low inputs, and good effects in China. By fully implementing the recommended combination scenarios based on five practices at the country level, the total YIR and NLRR reached 3~9% and 15~35%, respectively.
The application of optimized fertilization in China has noticeable potential to improve fertilizer use efficiency and further alleviate non-point source pollution while ensuring a high yield. Future fertilization measures, tailored to local conditions, need to scientifically combine multiple fertilization practices. The integrated effects of optimized fertilization practices with other management practices, such as irrigation and tillage, will be a significant research direction in paddy systems. In addition, optimized fertilization practices have huge potential to mitigate greenhouse gas emissions. The positive versatility of optimized fertilization practices will be another research focus area in the future.
Data availability
The datasets analyzed during the current study are available in the file ‘Supplementary Material 1’.
Code availability
Not applicable.
References
Achilea O, Rottenberg O, Thomas M (2010) Using controlled-release fertilizers for perennials increases productivity while reducing fertilizer application rates. In: Pestana M, Correia PJ (eds) Vi International Symposium on Mineral Nutrition of Fruit Crops, vol 868. Acta Horticulturae. Int Soc Horticultural Science, Leuven 1:255–260
Adejuyigbe CO, Kodaolu EO (2012) Faunal population as parameter for soil fertility assessment: a case of soil microarthropod study in South-Western Nigeria. Arch Agron Soil Sci 58:S116–S121. https://doi.org/10.1080/03650340.2012.694137
Bai Z, Huang J, Zhu L, Cao X, Zhang J (2020) Effects of N application strategies on N leaching loss in paddy soil and N use characteristics in different super hybrid rice cultivars. Paddy Water Environ 18(27-41):835–849. https://doi.org/10.1007/s10333-019-00762-x
Barros JD, Medeiros JC, Dalla Rosa J, Lacerda JJD, de Sousa DC, Mafra MSH (2017) Corn yield in sandy soil fertilized with poultry litter. Emir J Food Agric 29(12):921–926. https://doi.org/10.9755/ejfa.2017.v29.i12.1562
Chen X, Yang SH, Ding J, Jiang ZW, Sun X (2021) Effects of biochar addition on rice growth and yield under water-saving irrigation. Water 13(2):209. https://doi.org/10.3390/w13020209
Choi B, Lim JE, Sung JK, Jeon WT, Lee SS, Oh SE, Yang JE, Ok YS (2014) Effect of Rapeseed green manure amendment on soil properties and rice productivity. Commun Soil Sci Plant Anal 45(6):751–764. https://doi.org/10.1080/00103624.2013.858728
Dai ZM, Zhang XJ, Tang C, Muhammad N, Wu JJ, Brookes PC, Xu JM (2017) Potential role of biochars in decreasing soil acidification — a critical review. Sci Total Environ 581:601–611. https://doi.org/10.1016/j.scitotenv2016.12.169
DEM, 2019: http://www.gscloud.cn/.
FAO, 2019: http://www.fao.org/faostat/zh/#data.
Frost-free season, 2016-2020, http://data.cma.cn/.
Gao SJ, Zhang RG, Cao WD, Fan YY, Gao JS, Huang J, Bai JS, Zeng NH, Chang DN, Katsu-Yoshi S, Thorup-Kristensen K (2015) Long-term rice-rice-green manure rotation changing the microbial communities in typical red paddy soil in South China. J Integr Agric 14(12):2512–2520. https://doi.org/10.1016/s2095-3119(15)61230-8
Gil-Ortiz R, Naranjo MA, Ruiz-Navarro A, Atares S, Garcia C, Zotarelli L, San Bautista A, Vicente O (2020) Enhanced agronomic efficiency using a new controlled-released, polymeric-coated nitrogen fertilizer in rice. Plants-Basel 9(9):1183. https://doi.org/10.3390/plants9091183
Han W, He M (2010) Short-term effects of exogenous protease application on soil fertility with rice straw incorporation. Eur J Soil Biol 46(2):144–150. https://doi.org/10.1016/j.ejsobi.2010.01.002
Hong X, Ma C, Gao JS, Su SM, Li T, Luo ZC, Duan R, Wang YN, Bai LY, Zeng XB (2019) Effects of different green manure treatments on soil apparent N and P balance under a 34-year double-rice cropping system. J Soils Sediments 19(1):73–80. https://doi.org/10.1007/s11368-018-2049-5
Hou XK, Zhan XY, Zhou F, Yan XY, Gu BJ, Reis S, Wu YL, Liu HB, Piao SL, Tang YH (2018) Detection and attribution of nitrogen runoff trend in China's croplands. Environ Pollut 234:270–278. https://doi.org/10.1016/j.envpol.2017.11.052
Islam MM, Urmi TA, Rana MS, Alam MS, Haque MM (2019) Green manuring effects on crop morpho-physiological characters, rice yield and soil properties. Physiol Mol Biol Plants 25(1):303–312. https://doi.org/10.1007/s12298-018-0624-2
Jabbar SMA, Begum MM, Cruz PCS, Harun-ur-Rashid M (2008) Evaluation of different nutrient management practices for wheat-rice cropping system under agroecological zone 1 in Bangladesh. Philipp Agric Sci 91(3):269–277
Jiang BS, Shen JL, Sun MH, Hu YJ, Jiang WQ, Wang J, Li Y, Wu JS (2021) Soil phosphorus availability and rice phosphorus uptake in paddy fields under various agronomic practices. Pedosphere 31(1):103–115. https://doi.org/10.1016/s1002-0160(20)60053-4
Jiao X, Lyu Y, Wu X, Li H, Cheng L, Zhang C, Yuan L, Jiang R, Jiang B, Rengel Z, Zhang F, Davies WJ, Shen J (2016) Grain production versus resource and environmental costs: towards increasing sustainability of nutrient use in China. J Exp Bot 67(17):4935–4949. https://doi.org/10.1093/jxb/erw282
Ju XT, Xing GX, Chen XP, Zhang SL, Zhang LJ, Liu XJ, Cui ZL, Yin B, Christie P, Zhu ZL, Zhang FS (2009) Reducing environmental risk by improving N management in intensive Chinese agricultural systems. Proc Natl Acad Sci U S A 106(9):3041–3046. https://doi.org/10.1073/pnas.0813417106
Ku HH, Ryu JH, Bae HS, Jeong C, Lee SE (2019) Modeling a long-term effect of rice straw incorporation on SOC content and grain yield in rice field. Arch Agron Soil Sci 65(14):1941–1954. https://doi.org/10.1080/03650340.2019.1583330
Kumar A, Singh S, Shivay YS, Das S, Pal M, Nain L (2019) Microbial priming for in situ management of paddy straw and its effects on soil microbiological properties under rice-wheat cropping system. Indian J Agric Sci 89(9):135–140
Li T, Ullah S, Liang H, Ali I, Zhao Q, Iqbal A, Wei S, Shah T, Luo Y, Jiang L (2021) The enhancement of soil fertility, dry matter transport and accumulation, nitrogen uptake and yield in rice via green manuring. Phyton-Int J Exp Bot 90(1):223–243. https://doi.org/10.32604/phyton.2020.012065
Liu C, Chen F, Li ZG, Le Cocq K, Liu Y, Wu LH (2021a) Impacts of nitrogen practices on yield, grain quality, and nitrogen-use efficiency of crops and soil fertility in three paddy-upland cropping systems. J Sci Food Agric 101(6):2218–2226. https://doi.org/10.1002/jsfa.10841
Liu LH, Ouyang W, Liu HB, Zhu JQ, Ma YH, Wu QX, Chen JR, Zhang D (2021b) Potential of paddy drainage optimization to water and food security in China. Resour Conserv Recycl 171:105624. https://doi.org/10.1016/j.resconrec.2021.105624
Liu S, Chi Q, Shan J, Zhu B, Müller C (2020) Evaluation of the effectiveness of N process inhibitors in paddy rice via 15N tracing approach. Soil Biol Biochem 147:107855. https://doi.org/10.1016/j.soilbio.2020.107855
Liu TQ, Fan DJ, Zhang XX, Chen J, Li CF, Cao CG (2015) Deep placement of nitrogen fertilizers reduces ammonia volatilization and increases nitrogen utilization efficiency in no-tillage paddy fields in central China. Field Crop Res 184:80–90. https://doi.org/10.1016/j.fcr.2015.09.011
Local recommendations of fertilizer amounts, 2016: http://www.moa.gov.cn/.
Lu H, Feng Y, Gao Q, JinchengXing CY, Yang L, Xue L (2020) Surface soil mixing is more beneficial than the plough layer mixing mode of biochar application for nitrogen retention in a paddy system. Sci Total Environ 718:137399. https://doi.org/10.1016/j.scitotenv.2020.137399
Luyima D, Jeong HC, Lee JH, Kim SH, Sienogi Y, Lee CH, Oh TK (2019) Effects of Straw incorporation time on rice yield and methane emissions from sandy loam paddy fields. J Fac Agric Kyushu Univ 64(2):213–218
Ma QY, Li JW, Aamer M, Huang GQ (2020) Increasing methane (CH4) emissions and altering rhizosphere microbial diversity in paddy soil by combining Chinese milk vetch and rice straw. PeerJ 8:e9653. https://doi.org/10.7717/peerj.9653
Madari BE, Silva MAS, Carvalho MTM, Maia AHN, Petter FA, Santos JLS, Tsai SM, Leal WGO, Zeviani WM (2017) Properties of a sandy clay loam Haplic Ferralsol and soybean grain yield in a five-year field trial as affected by biochar amendment. Geoderma 305:100–112. https://doi.org/10.1016/j.geoderma.2017.05.029
Mi W, Sun Y, Xia S, Zhao H, Mi W, Brookes PC, Liu Y, Wu L (2018) Effect of inorganic fertilizers with organic amendments on soil chemical properties and rice yield in a low-productivity paddy soil. Geoderma 320:23–29. https://doi.org/10.1016/j.geoderma.2018.01.016
Ni N, Li XN, Yao S, Shi RY, Kong DY, Bian YR, Jiang X, Song Y (2021) Biochar applications combined with paddy-upland rotation cropping systems benefit the safe use of PAH-contaminated soils: From risk assessment to microbial ecology. J Hazard Mater 404:124123. https://doi.org/10.1016/j.jhazmat.2020.124123
Number of livestock, 2020: http://www.stats.gov.cn/tjsj/ndsj/2020/indexch.htm.
Phongchanmixay S, Bounyavong B, Khanthavong P, Khanthavong T, Ikeura H, Matsumoto N, Kawamura K (2019) Rice plant growth and nutrient leaching under different patterns of split chemical fertilization on sandy soil using a pot. Paddy Water Environ 17(2):91–99. https://doi.org/10.1007/s10333-019-00701-w
Precipitation and LUCC data, 2020: http://www.resdc.cn.
Qaswar M, Jing H, Ahmed W, Li DC, Liu SJ, Lu Z, Cai AD, Liu LS, Xu YM, Gao JS, Zhang HM (2020) Yield sustainability, soil organic carbon sequestration and nutrients balance under long-term combined application of manure and inorganic fertilizers in acidic paddy soil. Soil Tillage Res 198:104569. https://doi.org/10.1016/j.still.2019.104569
Qi DL, Wu QX, Zhu JQ (2020) Nitrogen and phosphorus losses from paddy fields and the yield of rice with different water and nitrogen management practices. Sci Rep 10(1):9734. https://doi.org/10.1038/s41598-020-66757-5
Raheem A, Zhang J, Huang J, Jiane Y, Siddik MA, Denga AX, Gao JS, Zhang WJ (2019) Greenhouse gas emissions from a rice-rice-green manure cropping system in South China. Geoderma 353:331–339. https://doi.org/10.1016/j.geoderma.2019.07.007
Rice yield, 2019, https://data.stats.gov.cn/index.htm.
Shen HJ, Zhang QQ, Zhang X, Jiang XY, Zhu SG, Chen AF, Wu Z, Xiong ZQ (2021) In situ effects of biochar field-aged for six years on net N mineralization in paddy soil. Soil Tillage Res 205:104766. https://doi.org/10.1016/j.still.2020.104766
Shi XR, Hu KL, Batchelor WD, Liang H, Wu YL, Wang QH, Fu J, Cui XQ, Zhou F (2020) Exploring optimal nitrogen management strategies to mitigate nitrogen losses from paddy soil in the middle reaches of the Yangtze River. Agric Water Manag 228:105877. https://doi.org/10.1016/j.agwat.2019.105877
Soil property data, 2018: http://www.fao.org/land-water/en/.
Solihin, Handoko AD, Noviardi RR, Iop (2019) Preliminary synthesis of slow release fertilizer material by using obsidian rock. In: International Seminar on Metallurgy and Materials, vol 541. IOP Conference Series-Materials Science and Engineering. Iop Publishing Ltd, Bristol. https://doi.org/10.1088/1757-899x/541/1/012020
Su W, Liu B, Liu XW, Li XK, Ren T, Cong RH, Lu JW (2015) Effect of depth of fertilizer banded-placement on growth, nutrient uptake and yield of oilseed rape (Brassica napus L.). Eur J Agron 62:38–45. https://doi.org/10.1016/j.eja.2014.09.002
Sun HF, Zhou S, Zhang JN, Zhang XX, Wang C (2020) Effects of controlled-release fertilizer on rice grain yield, nitrogen use efficiency, and greenhouse gas emissions in a paddy field with straw incorporation. Field Crop Res 253:107814. https://doi.org/10.1016/j.fcr.2020.107814
Tang HY, Niu BL (2011) Spatial distribution characteristics of heat resources based on GIS. J Arid Land Resour Environ 25(2):66–71. https://doi.org/10.13448/j.cnki.jalre.2011.02.013
Tomasek BJ, Williams MM, Davis AS (2017) Changes in field workability and drought risk from projected climate change drive spatially variable risks in Illinois cropping systems. PLoS One 12(2):e0172301. https://doi.org/10.1371/journal.pone.0172301
Wang L, Qin T, Liu TQ, Guo LJ, Li CF, Zhai ZB (2020) Inclusion of microbial inoculants with straw mulch enhances grain yields from rice fields in central China. Food Energy Secur 9(4):e230. https://doi.org/10.1002/fes3.230
Wu Q, Wang YZ, Chen TT, Zheng JL, Sun YD, Chi DC (2020) Soil nitrogen regulation using clinoptilolite for grain filling and grain quality improvements in rice. Soil Tillage Res 199:104547. https://doi.org/10.1016/j.still.2019.104547
Xia L, Lam SK, Wang S, Zhou W, Chen D, Yan X (2020a) Optimizing nitrogen fertilization rate to enhance soil carbon storage and decrease nitrogen pollution in paddy ecosystems with simultaneous straw incorporation. Agric Ecosyst Environ 298:106968. https://doi.org/10.1016/j.agee.2020.106968
Xia LL, Lam SK, Wang SW, Zhou W, Chen DL, Yan XY (2020b) Optimizing nitrogen fertilization rate to enhance soil carbon storage and decrease nitrogen pollution in paddy ecosystems with simultaneous straw incorporation. Agric Ecosyst Environ 298:9. https://doi.org/10.1016/j.agee.2020.106968
Xiao Q, Wang J, Liang D, Xia H, Wang T, Lyu XL, Iop (2019) Effects of formulated fertilization on soil physical and chemical characteristics of early ripe peach orchard. In: 2019 5th International Conference on Energy Materials and Environment Engineering, vol 295. IOP Conference Series-Earth and Environmental Science. Iop Publishing Ltd, Bristol. https://doi.org/10.1088/1755-1315/295/2/012086
Xie SG, Li YH, Wang X, Liu ZX, Ma KL, Ding LW (2021) Research on estimation models of the spectral characteristics of soil organic matter based on the soil particle size. Spectroc Acta Pt A-Molec Biomolec Spectr 260:119963. https://doi.org/10.1016/j.saa.2021.119963
Xie Z, Tu S, Shah F, Xu C, Chen J, Han D, Liu G, Li H, Muhammad I, Cao W (2016) Substitution of fertilizer-N by green manure improves the sustainability of yield in double-rice cropping system in south China. Field Crop Res 188:142–149. https://doi.org/10.1016/j.fcr.2016.01.006
Xu YQ, Su BL, Wang HQ, He JY, Yang YX (2020) Analysis of the water balance and the nitrogen and phosphorus runoff pollution of a paddy field in situ in the Taihu Lake basin. Paddy Water Environ 18(2):385–398. https://doi.org/10.1007/s10333-020-00789-5
Yang CD, Lu SG (2021) Effects of five different biochars on aggregation, water retention and mechanical properties of paddy soil: a field experiment of three-season crops. Soil Tillage Res 205:104798. https://doi.org/10.1016/j.still.2020.104798
Yang SH, Xiao YN, Xu JZ, Jiao XY (2018) Effect of biochar addition on N2O emission from paddy field under water-saving irrigation. Int J Agric Biol 20(6):1260–1266. https://doi.org/10.17957/ijab/15.0610
Yang YG, He ZL, Stoffella PJ, Yang XE, Graetz DA, Morris D (2008) Leaching behavior of phosphorus in sandy soils amended with organic material. Soil Sci 173(4):257–266. https://doi.org/10.1097/SS.0b013e31816d1edf
Yao Y, Zhang M, Tian Y, Zhao M, Zhang B, Zeng K, Zhao M, Yin B (2018) Urea deep placement in combination with Azolla for reducing nitrogen loss and improving fertilizer nitrogen recovery in rice field. Field Crop Res 218:141–149. https://doi.org/10.1016/j.fcr.2018.01.015
Ye C, Huang X, Chu G, Chen S, Xu CM, Zhang XF, Wang DY (2019) Effects of postponing topdressing-n on the yield of different types of japonica rice and its relationship with soil fertility. Agronomy-Basel 9(12):868. https://doi.org/10.3390/agronomy9120868
Zhai LM, Liu HB, Zhang JZ, Huang J, Wang BR (2011) Long-term application of organic manure and mineral fertilizer on N2O and CO2 emissions in a red soil from cultivated maize-wheat rotation in China. Agric Sci China 10(11):1748–1757. https://doi.org/10.1016/s1671-2927(11)60174-0
Zhang AP, Liu RL, Gao J, Yang SQ, Chen Z (2014a) Regulating N application for rice yield and sustainable eco-agro development in the upper reaches of Yellow River Basin, China. Sci World J 2014:239279. https://doi.org/10.1155/2014/239279
Zhang C, Ju XT, Powlson D, Oenema O, Smith P (2019) Nitrogen surplus benchmarks for controlling n pollution in the main cropping systems of China. Environ Sci Technol 53(12):6678–6687. https://doi.org/10.1021/acs.est.8b06383
Zhang D, Xu WH, Li JY, Cai Z, An D (2014b) Frost-free season lengthening and its potential cause in the Tibetan Plateau from 1960 to 2010. Theor Appl Climatol 115(3-4):441–450. https://doi.org/10.1007/s00704-013-0898-9
Zhang YF, Wu H, Yao MY, Zhou J, Wu KB, Hu MP, Shen H, Chen DJ (2021a) Estimation of nitrogen runoff loss from croplands in the Yangtze River Basin: a meta-analysis. Environ Pollut 272:116001. https://doi.org/10.1016/j.envpol.2020.116001
Zhang YJ, Gowda P, Brown D, Rice C, Zambreski Z, Kutikoff S, Lin XM (2021b) Time-varying trends in frost indicators in the US Southern Great Plains. Int J Climatol 41(2):1264–1278. https://doi.org/10.1002/joc.6803
Zhang YK, Chen HZ, Ji GM, Zhang YP, Xiang J, Anwar S, Zhu DF (2018) Effect of rice-straw biochar application on rice (Oryza sativa) root growth and nitrogen utilization in acidified paddy soil. Int J Agric Biol 20 (11):2529-2536. 10.17957/ijab/15.0797
Zhao Y, Xiong X, Wu C (2021) Effects of deep placement of fertilizer on periphytic biofilm development and nitrogen cycling in paddy systems. Pedosphere 31(1):125–133. https://doi.org/10.1016/S1002-0160(20)60051-0
Zhong XM, Peng JW, Kang XR, Wu YF, Luo GW, Hu WF, Zhou X (2021a) Optimizing agronomic traits and increasing economic returns of machine-transplanted rice with side-deep fertilization of double-cropping rice system in southern China. Field Crop Res 270:108191. https://doi.org/10.1016/j.fcr.2021.108191
Zhong XM, Zhou X, Fei JC, Huang Y, Wang G, Kang XR, Hu WF, Zhang HR, Rong XM, Peng JW (2021b) Reducing ammonia volatilization and increasing nitrogen use efficiency in machine-transplanted rice with side-deep fertilization in a double-cropping rice system in Southern China. Agric Ecosyst Environ 306:107183. https://doi.org/10.1016/j.agee.2020.107183
Zhou GP, Gao SJ, Lu YH, Liao YL, Nie J, Cao WD (2020) Co-incorporation of green manure and rice straw improves rice production, soil chemical, biochemical and microbiological properties in a typical paddy field in southern China. Soil Tillage Res 197:104499. https://doi.org/10.1016/j.still.2019.104499
Zhuang YH, Liu HB, Zhang L, Li SS (2020) Research perspectives on paddy field systems: ecological functions and environmental impacts. Int J Agric Sustain 18(6):505–520. https://doi.org/10.1080/14735903.2020.1793652
Zhuang YH, Zhang L, Li SS, Liu HB, Zhai LM, Zhou F, Ye YS, Ruan SH, Wen WJ (2019) Effects and potential of water-saving irrigation for rice production in China. Agric Water Manag 217:374–382. https://doi.org/10.1016/j.agwat.2019.03.010
Acknowledgements
We thank Pr Yufeng Wang from Heilongjiang Academy of Agricultural Sciences for valuable advice and data.
Funding
This work was supported by the National Natural Science Foundation of China [grant number U21A2025]; the Hubei Provincial Natural Science Foundation of China [grant number 2021CFA083]; National Key Research and Development Program of China [grant number 2016YFD0800500]; and the Youth Innovation Promotion Association of the Chinese Academy of Sciences [grant number 2018370].
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Conceptualization: Y. Z and L. Z; methodology: Y. Z; formal analysis: Y. Z and S. R; investigation: S. R, J. C, S. L, and W. W; writing, reviewing, and editing: Y. Z, S. R, and L. Z; funding acquisition: H. L.
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Zhuang, Y., Ruan, S., Zhang, L. et al. Effects and potential of optimized fertilization practices for rice production in China. Agron. Sustain. Dev. 42, 32 (2022). https://doi.org/10.1007/s13593-022-00759-7
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DOI: https://doi.org/10.1007/s13593-022-00759-7