Response of Rice Yield and Grain Quality to Combined Nitrogen Application Rate and Planting Density in Saline Area
by
,
Yinglong Chen
1,2,3,4,
Yang Liu
2,3,4,
Shiqi Dong
2,3,4,
Juge Liu
5,
Yang Wang
2,3,4,
Shahid Hussain
2,3,4,
Huanhe Wei
1,2,3,4,
Zhongyang Huo
1,2,3,4,
Ke Xu
1,2,3,4 and
Qigen Dai
1,2,3,4,* 1
Key Laboratory of Saline-Alkali Soil Improvement and Utilization (Coastal Saline-Alkali Lands), Ministry of Agriculture and Rural Affairs, Yangzhou University, Yangzhou 225009, China
2
Jiangsu Key Laboratory of Crop Genetics and Physiology/Jiangsu Key Laboratory of Crop Cultivation and Physiology, Yangzhou University, Yangzhou 225009, China
3
Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China
4
Research Institute of Rice Industrial Engineering Technology, Yangzhou University, Yangzhou 225009, China
5
College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
*
Author to whom correspondence should be addressed.
Agriculture 2022, 12(11), 1788; https://doi.org/10.3390/agriculture12111788
Submission received: 1 October 2022
/
Revised: 26 October 2022
/
Accepted: 26 October 2022
/
Published: 28 October 2022
(This article belongs to the Special Issue Effects of Salt Stress on Crop Production)
Abstract
:To determine the combining effects of nitrogen application rate and planting density on rice yield and grain quality formation under salinity conditions, a field experiment was conducted in the coastal saline area using Oryza sativa L. cv. Nangeng 9108 from 2019 to 2020. The experiment was designed with six nitrogen rates (0, 210, 255, 300, 345, and 390 kg ha−1; denoted as N0-N390, respectively) and two transplanting densities (334,000 and 278,000 hills ha−1; denoted as D1 and D2, respectively). The results indicated that, with the increase of nitrogen input rate, the panicles number and spikelets per panicle increased first, subsequently decreased, and peaked under 300 kg ha−1 N, whereas the filled-kernel rate and grain weight displayed a decreasing trend. The panicle number and grain weight were higher under D1 treatment compared to those under D2 treatment, while the spikelet number per panicle and the filled-kernel rate displayed an opposite trend. The grain yield displayed highest under N300D1 treatment among all treatments, accompanied by the highest agronomic N use efficiency, and the actual yield reached 8060.4 kg ha−1 and 7869.8 kg ha−1 in 2019 and 2020, respectively. Increased nitrogen application rate significantly improved the grain processing quality and nutritional quality, while reducing the appearance quality and cooking/eating quality. Higher transplant density was conductive to grain nutritional quality, but notably reduced the processing quality, appearance quality and cooking/eating quality. Overall, a combination of 300 kg ha−1 nitrogen rate and 334,000 hills ha−1 planting density was recommended for relatively higher rice yield and better grain quality in the saline area.
1. Introduction
Salinity is one of the main adverse abiotic factors that will limit crop productivity in the coming decades [1]. Salinity not only affects the crop yield, but it may also negatively impact the ecological, social, and even economic aspects in saline areas [2]. Therefore, with the increase in global demand for food and the decrease in land resource, the rational utilization of saline-land is more and more crucial to the food security of the world population.
As a widely grown cereal crop especially in Asia, rice (Oryza sativa L.) feeds billions across the world [3]. Nearly a quarter of the cultivated land worldwide is currently salinized, and a large portion of rice in China is planted along coastal areas, which is exposed to varied salinity stresses [4]. However, rice is irrigated and has aquatic characteristics. The cultivation of rice in coastal areas can not only increase food production, but also accelerate the improvement of saline land through paddy field irrigation [5].
It is reported that salinity affects plant growth through iron toxicity, osmotic stress, nutrient disparity and the interactive effects of all these factors [6]. Great efforts have been made by scientists to increase the productivity of saline land, such as selection and conventional breeding approaches, soil desalination and improvement, irrigation improvement, exogenous application of chemicals, and agronomic management [7]. Agronomic management, especially nutrient management is without doubt the easiest and the most practical way of combating salt stress [2].
Saline soil has poor soil structure, high dispersion of soil particles, poor fertilizer retention, and high risk of soil nutrient loss and leakage. In addition, rice plants experience imbalanced nutrition (N, K, Ca, Mg, etc.) due to competitive uptake and upward transport of Na+, leading to the irregular growth and limited productivity of rice under salt stress [8]. Therefore, rice cultivation in saline soils usually requires higher fertilizer input, especially nitrogen, than those in normal soils.
The formation of rice yield and grain quality is essentially a process of carbohydrate synthesis and metabolism, in which nitrogen plays a vital role. Appropriate nitrogen application could balance rice yield and grain quality, while inefficient utilization of nitrogen would obviously reduce rice yield and nitrogen use efficiency (NUE), deteriorate grain quality (especially taste quality), and even have negative environmental impacts [9,10]. In China, the average N rate in rice production is 180 kg ha−1 [11,12], whereas at least 255 kg ha−1 N is required in saline soil [13]. The NUE of rice is strongly associated with the population structure, which is directly determined by the planting density. It is reported that a combination effect exists between planting density and nitrogen rate, and a suitable combination of these two factors benefits rice yield and NUE in rice production [14]. Hou et al. [15] addressed that a combination of 165 kg ha−1 nitrogen with 24–27 × 104 hills ha−1 planting density resulted in higher grain yield and NUE in mechanically transplanted hybrid rice. The objectives of this study were: (1) to compare rice NUE and yield and grain quality under different nitrogen input rates and planting densities in saline conditions, and (2) to identify the combing effects of factors accounting for the differences in grain yield and quality under salt stress, by which the results provide a theoretical basis for the high-yield and superior-quality cultivation in the coastal area.
2. Materials and Methods
2.1. Plant Material and Experimental Designs
The field experiment was conducted at Jinhaidao experimental base (33°67′ N, 120°50′ E), Yancheng city, Jiangsu Province, China, in 2019 and 2020. The meteorological conditions were shown in Figure 1.The test site was about 2 km away from the coastline and the average electrical conductivity (EC) of 0–20 cm soil was 4.8 mS cm−1. The field soil was a sandy loam with the following properties: 2.8 g kg−1 organic carbon, 71.3 mg kg−1 alkali-hydrolyzable nitrogen, 21.1 mg kg−1 available phosphorus, 85.0 mg kg−1 available potassium, 2.7 g ka−1 NaCl, and pH 8.49.
Rice cultivar Nangeng 9108, which is widely cultivated in Jiangsu Province, was chosen and used. The seeds were sown on 15 May and seedlings that had developed three true leaves were subsequently hand-transplanted to field with four seedlings per hill on 19 June. The experiment was arranged in a randomized block design and each experimental plot covered 25 m2 with three replications. The experiment contained six nitrogen application rates (0, 210, 255, 300, 345, and 390 kg ha−1, denoted as N0-N390, respectively) and two transplanting densities (334,000 and 278,000 hills ha−1; 12 cm × 25 cm and 12 cm × 30 cm; denoted as D1 and D2, respectively). Nitrogen was applied in fractions of 3:1.5:2:3.5 at the stages of pre-transplanting, 7 d after transplanting, mid-tillering, and panicle initiation. Before transplanting, 600 kg ha−1 of calcium superphosphate was applied as base fertilizer. During the whole growing season, rice was continuously flooded with the river water (EC was 0.4–0.8 mS cm−1). The weed and pest management were consistent across the experimental plots and followed local recommendations.
2.2. Determination of Rice Yield and Yield Components
Number of panicles, filled-kernel percentage, and kernel weight were determined from 50 plants (excluding border plants) sampled randomly from each plot. Panicles were hand-threshed, and all spikelets were subsequently separated into filled and unfilled spikelets by submerging them in tap water. Grain yield was determined from all plants in a 5 m2 area in each plot and adjusted to the standard moisture content of 0.14 g H2O g−1 fresh weight.
2.3. Leaf Area Index (LAI), N Concentration and Nitrogen Use Efficiency
Five hills of rice plants were collected to measure the LAI using a LI-3100C Leaf Area Meter (Lincoln, NE, USA). The nitrogen uptake of the whole rice plant at the full-ripening stage was analyzed. Nitrogen concentration was determined with the micro-Kjedahl method [16]. The nitrogen use efficiency was analyzed as below:
PFP (N partial factor productivity) = Grain yield (kg)/N rate (kg);
AE (agronomic N use efficiency) = [Grain yield in N application plots − Grain yield in N omission plots (kg)]/N rate (kg);
RE (apparent recovery efficiency of N fertilizer) = [N uptake in N application plots − N uptake in N omission plots (kg)]/N rate (kg) × 100;
PE (physiological N use efficiency) = [Grain yield in N application plots − Grain yield in N omission plots (kg)]/[N uptake in N application plots − N uptake in N omission plots (kg)];
IE (internal N use efficiency) = Grain yield (kg)/N uptake of plants (kg).
2.4. Determination of Grain Quality
The harvest grains were air-dried to 14% moisture content and stored at 4 °C for 90 days. Grain quality traits were analyzed according to GB/T 17891-2017.
2.4.1. Processing Quality
The grain sample (150 g) was passed twice through a huller (SY88-TH, Ssangyong, Korea) to obtain brown rice, which was subsequently polished with a rice polisher (LTJM-2099, Zhejiang Bethlehem Apparatus Co., Ltd., Zhejiang, China.) to obtain milled rice. The rate of brown rice, milled rice, and head rice was determined with the weight percentage of total rice grains (150 g) [8].
2.4.2. Appearance Quality
The grain length, width, length/width, chalkiness rate, and chalkiness degree were obtained using the grain appearance analyzer ScanMaker i800 plus (Microtek, Shanghai, China).
2.4.3. Nutritive Quality
A 30 g sample of milled rice was chosen to determine the protein content and amylose content with a grain analyzer (Infratec 1241, Foss, Hillerød, Denmark). The content of protein components was analyzed according to the continuous extraction method of Luthe [17]. After all components were separated and extracted, the contents of albumin, globulin, gliadin, and glutelin were determined with the Coomassie brilliant blue method. Gel consistency and amylose content were obtained following rice quality measurement standards.
2.4.4. Cooking/Eating Quality
A Cooked Rice Taste Analyzer STA1A (Satake Co., Ltd., Hiroshima, Japan) was used to measure the taste value of rice grains. The taste value is a comprehensive evaluation of cooked grain which consists of the appearance, hardness, viscosity, and degree of balance [18].
2.4.5. Pasting Properties of Starch
The pasting properties of starch were obtained with a rapid viscosity analyzer (RVA-TecMaster, Perten, Stockholm, Sweden) [19].
2.5. Statistical Analysis
The statistical analyses consisted of analyses of variance (ANOVAs). The variance of the data was analyzed with SPSS ver. 18.0. Differences between mean values were compared at the least significant difference (LSD) test (p = 0.05) and were indicated by asterisks or different letters. All figures were prepared using the Origin 2021 software program.
3. Results
3.1. Rice Grain Yield and Yield Components
As shown in Table 1, with the increase in nitrogen rate, filled-kernel percentage and kernel weight decreased significantly, whereas the number of panicles and spikelets per panicle and rice yield increased first and then decreased significantly, which peaked at N300. Plant density had varied effects on grain yield under different nitrogen rates. D2 treatment significantly decreased grain yield by 1.4% to 5.5% compared to those under D1 treatment for N0-N300, where an opposite trend occurred for N345 and N390 in 2019. The actual grain yield was highest under N300D1 treatment, reaching 8060.4 kg ha−1 and 7869.8 kg ha−1 in 2019 and 2020, respectively. Nitrogen rate and plant density showed significant interaction effect on spikelets per panicle and filled-kernel percentage, especially on grain yield. Effects of nitrogen rate and plant density on grain yield and its components were consistent across two rice growing seasons.
3.2. Rice Leaf Area Index
Rice leaf area index increased gradually after booting stage and peaked at the heading stage (Table 2), and the trend was consistent across the two years. With the increase in nitrogen rate, leaf area index was significantly enhanced and arrived highest under N390 at booting stage, whereas it peaked under N300 treatment at the heading and maturity stages. Effects of plant density on leaf area index varied among different growth stages and nitrogen rates, with a significant decrease (by 0.9–12.4%) trend under lower plant density at booting stage, whereas no significant difference occurred at maturity stage.
3.3. Nitrogen Use Efficiency
As shown in Table 3, there were significant combining effects of nitrogen rate and planting density on nitrogen uptake, PFP, and AE. Increased nitrogen rate was conductive to the nitrogen uptake of rice plants, whereas the effect of plant density was opposite below N300 and was same above N300. The effects of nitrogen rate and planting density were consistent across the two years. With the increase of nitrogen rate, the PFP, PE, and IE displayed a decreasing trend, whereas AE and RE increased first and decreased subsequently and peaked at N300. The LAI, nitrogen uptake, AE, and RE were significantly and positively correlated with grain yield (Figure 2), while the LAI and nitrogen uptake displayed significant negative correlation with IE.
3.4. Rice Grain Quality
3.4.1. Processing Quality
The brown rice rate, milled rice rate, and head milled rice rate were enhanced with the increase in nitrogen rate and arrived highest at N390, while no significant difference occurred between two plant densities (Table 4). The changing trend was same across 2019 and 2020.
3.4.2. Appearance Quality
No significant differences appeared in rice grain length, grain width, and length/width ratio under different nitrogen rates and plant densities (Table 5). However, the chalkiness rate and chalkiness degree were significantly enhanced with the increase of nitrogen rate, which were enhanced by 17.9–70.3% and 8.6–39.2%, respectively. No significant differences occurred in grain appearance quality in the current study.
3.4.3. Nutritive Quality and Protein Content of Rice Grain
With the increase of nitrogen rate, the grain amylose content and gel consistency were significantly decreased, while protein content was significantly enhanced (Table 6). Increased planting density significantly decreased grain amylose content, whereas it had no significant effects on gel consistency and protein content. The content of albumin, globulin, gliadin, and gluten in rice grain were significantly enhanced under the higher nitrogen rate by 3.3–31.1%, 2.5–9.9%, 11.7–40.8%, and 9.6–40.4%, respectively, compared with those under N0 (Table 7).
3.4.4. Cooking/Eating Quality
As shown in Table 8, increased nitrogen rate significantly enhanced grain hardness and decreased grain appearance, viscosity, degree of balance, and taste value. Planting density displayed no significant effects on grain appearance, hardness, viscosity, and degree of balance, but notably enhanced the taste value under D2 compared with D1. The appearance, viscosity, degree of balance, and taste value were significantly and positively correlated with nitrogen application rate (Figure 3), whereas a negative correlation occurred between hardness and nitrogen rate.
3.4.5. Pasting Quality
As shown in Table 9, the peak viscosity, trough viscosity, breakdown, and final viscosity were decreased with nitrogen rate and increased with planting density (peaked at N0D2), whereas they displayed the opposite trend in subtractive value (peaked at N390D1). No significant difference occurred at peak time and pasting temperature under varied nitrogen rate and planting density combinations.
4. Discussion
4.1. Effects of Combined Nitrogen Rate and Planting Density on Rice Yield and NUE
Nitrogen is not only an important component of amino acids, ribonucleic acid, chloroplasts, ATP, and plant hormones, but also participates in biological processes such as carbon and nitrogen metabolism and protein synthesis in rice plants. Appropriate nitrogen application could enhance rice yield, while excessive nitrogen input was not conductive to higher nitrogen use efficiency (NUE) and could result in lodging and reduce grain yield. In addition, the nitrogen rate also impacts the rice storage capacity and grain plumpness. It is reported that the average N rate in rice production is 180 kg ha−1 [11,12], and Chen addressed that rice yield peaked at 300 kg ha−1 N in saline soil [13], which was consistent with our results (Table 1). Panicle number, spikelets per panicle, filled kernel percentage, and grain weight are the four components of rice yield. Increased panicle number and spikelet number per panicle ensured the number of spikelets in rice population and sufficient rice storage capacity, which resulted in increased grain yield under N300 treatment in saline soils. Additionally, leaf area index is an important indicator for measuring whether “source” can adequately supply “sink” in rice. The higher LAI under N300 treatment ensured sufficient photo-assimilate products, which turned to be the material basis for the formation of high yield of rice. As an important indicator for evaluating the economic and environmental impacts of nitrogen fertilizer, the level of nitrogen use efficiency has been a hot research topic. Consistent to previous reports [15,20], rice PFP, AE, RE, PE, and IE were notably decreased with the increase of nitrogen application rate. There may be two reasons to explain the decrease of NUE. The first reason may be that excessive nitrogen fertilizer was not absorbed and utilized competitively by rice plants, resulting in nitrogen loss to soil, atmosphere, water and other environments through denitrification, ammonia volatilization, leaching, etc.; another reason may be that the increased absorbed nitrogen could not be transported to grain to form yield. Even though the LAI N345 and N390 maintained relatively high levels, the nitrogen rate higher than 300 kg ha−1 was not conductive to grain plumpness. Thus, the dramatically decreased filled kernel rate and kernel weight resulted in declined grain yield under N345 and N390. In addition, excessive N can lead to excessive population density (Table 2), declined NUE (Table 3), and higher risk of plant collapse [20,21].
Nitrogen input and density control are the two most important crop management practices that significantly affect crop growth and yield formation [22]. It is reported that high planting density was recommended to reduce the N input rate in rice production [14,23]. Liu et al. [24] indicated that a relatively high grain yield could be maintained when seeding density was raised by 32% accompanied with a decline of N input rate by 18% in conventional seedling broadcasting. Consistent to those in normal soils, when N application was lower than 300 kg ha−1, higher planting density was of benefit for the grain yield formation while significantly decreasing grain yield under N345 and N390 treatments in the current study. The main reason may come from the unreasonable population structure which resulted in slender rice individuals and higher risk of lodging [25]. Hou et al. [15] addressed that a combination of 165 kg ha−1 nitrogen with 24–27 × 104 hills ha−1 planting density resulted in higher grain yield and NUE in mechanically transplanted hybrid rice. In our study, the grain yield and nitrogen agronomic utilization efficiency were highest under a combination of a nitrogen rate of 300 kg ha−1 and a planting density of 334,000 hills ha−1, which displayed a notably combing effect of the two factors. Compared with that in the normal field, rice cultivated in saline soil requires more nitrogen to enhance its resistance to salinity. In addition, salinity is unfavorable to the tillering capacity of rice. Thus, to ensure a reasonable and sufficient population structure, higher planting density is essential for rice cultivated under salinity conditions.
4.2. Effects of Combined Nitrogen Rate and Planting Density on Grain Quality
Rice grain quality is a comprehensive index composed of four aspects: processing quality, appearance quality, nutritional quality, and cooking and eating quality. Numerous papers have addressed the role of nitrogen input in regulating grain quality formation [26,27]. Consistent with previous results [19,28], the current results indicated that increasing the nitrogen application rate improved grain processing quality (Table 4) with improved brown rice, milled rice, and head milled rice rates. Planting density displayed no significant effect on grain processing quality in our results. Rice grain appearance quality includes grain length/width characteristics, chalkiness rate and chalkiness degree. Increased nitrogen input was not conductive to the grain appearance quality due to the increased chalkiness rate and chalkiness degree in saline soils (Table 5). This may be because the excessive nitrogen prolonged the period of grain filling, leading to a lower grain filling rate, which subsequently resulted in the loose arrangement of starch granules and eventually increased grain chalkiness [29]. Similar to processing quality, no significant difference occurred on appearance quality between two planting densities. Amylose content is an important indicator of rice quality, while protein content tends to be the core of grain nutritive quality [30]. Most researchers addressed that the increase in nitrogen application rate and planting density could enhance the grain protein content [31]. Our experiments indicated that amylose content was significantly decreased under higher nitrogen and density, whereas protein content was significantly enhanced under higher nitrogen rate and slightly decreased under higher density (Table 6). Some scholars believed that the proportion of gluten and gliadin in the total protein content of rice was closely related to rice quality traits [31], and our results also indicated that the glutelin content and gliadin content were highly affected by nitrogen (Table 7), which was beneficial to the improvement of grain nutritive quality. Recently, more and more researchers have been focusing on the study of grain quality, especially the cooking and eating quality of rice. It is widely reported that rice grain yield was negatively correlated with grain cooking and eating quality [32,33]. Our experiment showed that the increased nitrogen application rate significantly enhanced grain hardness, and decreased the appearance, viscosity, degree of balance, and taste value (Table 8). Planting density displayed no obvious effect on grain hardness and viscosity, while the taste value was apparently enhanced under higher density. The characteristics of the RVA spectrum directly affects the cooking and eating quality of steamed rice, and a significant correlation occurs between RVA parameters and the amylose content [34]. In addition, the peak viscosity and trough viscosity were usually considered positively correlated with the rice taste value. The subtractive value has a significantly positive effect on rice hardness, while the breakdown value is the opposite [35]. Zhu et al. reported that a high dose of nitrogen resulted in a higher pasting temperature and lower peak viscosity, trough viscosity, and final viscosity in rice grain [19], which was slightly different from our results in saline soil. The results of studies on the effect of planting density on cooking and eating quality are inconsistent. Some researchers reported that the cooking and eating quality could be improved under lower planting density [36], while others argued that the amylose content decreased and the gel consistency increased with the increase of planting density [37], which was consistent with the current results. Overall, in terms of grain yield, nitrogen utilization rate, rice processing quality, appearance quality, nutritional quality, cooking and eating quality, and other traits, relatively high yield and high quality of rice can be obtained under a combination of a nitrogen rate of 300 kg ha−1 and transplanting density of 334,000 hills ha−1 under the current saline condition.
5. Conclusions
Agronomic management is without doubt the most practical and easiest way of combating salt stress. As the two most important crop management practices, nitrogen rate and planting density interactively affect crop growth and yield formation. Increased nitrogen application can promote the grain yield of rice in a certain range, where the grain yield peaks at N300. The increase of nitrogen application rate improved the processing quality and nutritional quality of rice grain, while reducing the appearance quality and cooking and eating quality. The effect of planting density on grain yield was varied according to the nitrogen application rate. Overall, a combination of 300 kg ha−1 of nitrogen and 334,000 hills ha−1 of transplanting density was recommended for relatively higher rice yield and better grain quality in the saline area.
Author Contributions
Conceptualization, Y.C., Z.H., K.X. and Q.D.; methodology, Y.C. and Q.D.; software, Y.C. and S.D.; validation, Y.C.; formal analysis, Y.C., J.L. and H.W.; investigation, Y.C., Y.L., S.D., J.L., Y.W. and S.H.; resources, Y.C.; data curation, Y.C. and S.D.; writing—original draft preparation, Y.C.; writing—review and editing, Y.C., Z.H., K.X. and Q.D.; supervision, Q.D.; funding acquisition, Y.C. and Q.D. All authors have read and agreed to the published version of the manuscript.
Funding
This research was financially supported by the Scientific and Technological Innovation Fund of Carbon Emissions Peak and Neutrality of Jiangsu Provincial Department of Science and Technology (BE2022304), the National Natural Science Foundation of China (32101817), Jiangsu Agriculture Science and Technology Innovation Fund (CX (21) 3111), and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).
Institutional Review Board Statement
Not applicable.
Data Availability Statement
Not applicable.
Conflicts of Interest
The authors declare no conflict of interest.
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Figure 1.
The daily maximum temperature, daily minimum temperature, and rainfall during rice sowing and full-ripening period in 2019 and 2020.
Figure 1.
The daily maximum temperature, daily minimum temperature, and rainfall during rice sowing and full-ripening period in 2019 and 2020.
Figure 2.
Correlation analysis between rice grain yield components and nitrogen use efficiency. PN, panicle number; SP, spikelets per panicle; FP, Filled kernel percentage; KW, kernel weight; GY, grain yield; LAI, leaf area index; NU, nitrogen uptake; PFP, partial factor productivity; AE, agronomic N use efficiency; RE, apparent recovery efficiency of N fertilizer; PE, physiological N use efficiency; IE, internal N use efficiency. *: Significant at the p < 0.05 level.
Figure 2.
Correlation analysis between rice grain yield components and nitrogen use efficiency. PN, panicle number; SP, spikelets per panicle; FP, Filled kernel percentage; KW, kernel weight; GY, grain yield; LAI, leaf area index; NU, nitrogen uptake; PFP, partial factor productivity; AE, agronomic N use efficiency; RE, apparent recovery efficiency of N fertilizer; PE, physiological N use efficiency; IE, internal N use efficiency. *: Significant at the p < 0.05 level.
Figure 3.
The correlation analysis between grain cooking/eating quality and nitrogen application rate.
Figure 3.
The correlation analysis between grain cooking/eating quality and nitrogen application rate.
Table 1.
Rice grain yield and its components under combined nitrogen rate and planting density in saline soil.
Table 1.
Rice grain yield and its components under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Panicles per m2 | Spikelets per Panicle | Filled Kernel Percentage (%) | Kernel Weight (mg) | Actual Grain Yield (kg ha−1) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 182.5h | 181.8j | 92.7i | 90.7j | 94.0b | 92.2b | 27.0a | 24.0a | 4013.6j | 3589.9j |
| D2 | 173.8i | 169.4k | 96.1h | 92.6i | 94.9a | 93.5a | 26.6b | 23.8b | 3872.4k | 3415.4k | |
| N210 | D1 | 270.8fg | 271.6h | 100.1g | 97.1h | 91.9d | 90.2d | 26.3bc | 23.6c | 6061.4h | 5518.1h |
| D2 | 260.0g | 260.0i | 104.9f | 100.9g | 92.4c | 91.0c | 26.1cd | 23.4d | 5727.0i | 5305.2i | |
| N255 | D1 | 290.9e | 306.1f | 108.9e | 104.3f | 89.7f | 88.8f | 25.9d | 23.2e | 6915.4f | 6249.2f |
| D2 | 283.9ef | 287.3g | 110.5d | 106.8e | 90.5e | 89.4e | 25.8de | 23.0f | 6816.5g | 6058.0g | |
| N300 | D1 | 363.0a | 361.4a | 117.2b | 114.4b | 86.8gh | 86.5h | 25.6ef | 22.7g | 8060.4a | 7869.8a |
| D2 | 360.4ab | 351.4b | 119.8a | 117.3a | 87.3g | 87.4g | 25.3f | 22.5h | 7893.8b | 7638.5b | |
| N345 | D1 | 343.5bc | 338.7c | 114.3c | 112.0c | 85.0i | 84.6j | 24.9g | 22.2i | 7597.6d | 6801.5d |
| D2 | 334.0cd | 334.1cd | 116.1b | 113.3bc | 86.8h | 85.7i | 24.8g | 22.1j | 7814.6c | 7010.1c | |
| N390 | D1 | 327.9cd | 328.4de | 109.6de | 106.6e | 83.1k | 83.0l | 24.7g | 21.8k | 6980.9f | 6110.2g |
| D2 | 316.5d | 323.7e | 114.8c | 109.3d | 84.5j | 84.0k | 24.1h | 21.6l | 7076.2e | 6329.7e | |
| Significance of factors | |||||||||||
| Nitrogen rate (N) | ** | ** | ** | ** | ** | ** | ** | ** | ** | ** | |
| Density (D) | ** | ** | ** | ** | ** | ** | ** | ** | ** | ** | |
| N × D | ns | ns | * | ** | * | ** | ns | ns | ** | ** | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. Values followed by a different letter within the same column are significantly different at p = 0.05 probability level; ns, not significant; *, **: Significant at the p < 0.05 and 0.01 levels, respectively.
Table 2.
Rice leaf area index under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Booting Stage (m2 m−2) | Heading Stage (m2 m−2) | Maturity Stage (m2 m−2) | |||
|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 1.91g | 1.74g | 4.02f | 3.85f | 1.60f | 1.54f |
| D2 | 1.67h | 1.46h | 3.82f | 3.61f | 1.56f | 1.41g | |
| N210 | D1 | 3.30e | 3.12e | 6.58d | 6.37d | 2.78d | 2.67d |
| D2 | 2.78f | 2.63f | 6.21e | 6.05e | 2.46e | 2.30e | |
| N255 | D1 | 3.91c | 3.71d | 6.95c | 6.84c | 3.24c | 3.18c |
| D2 | 3.52d | 3.27e | 6.61cd | 6.39d | 3.13c | 3.02c | |
| N300 | D1 | 4.17b | 4.05b | 8.03a | 7.90a | 3.45b | 3.43b |
| D2 | 3.80c | 3.72d | 7.97a | 7.85a | 3.42b | 3.39b | |
| N345 | D1 | 4.23b | 4.19b | 7.33b | 7.10b | 3.69a | 3.66a |
| D2 | 4.07b | 3.96c | 7.56b | 7.37b | 3.67a | 3.72a | |
| N390 | D1 | 4.40a | 4.28a | 7.39b | 7.24b | 3.78a | 3.76a |
| D2 | 4.16b | 4.05b | 7.48b | 7.46b | 3.74a | 3.72a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 3.
The nitrogen uptake, N partial factor productivity (PFP), agronomic N use efficiency (AE), apparent recovery efficiency of N fertilizer (RE), physiological N use efficiency (PE), and internal N use efficiency (IE) under combined nitrogen rate and planting density in saline soil.
Table 3.
The nitrogen uptake, N partial factor productivity (PFP), agronomic N use efficiency (AE), apparent recovery efficiency of N fertilizer (RE), physiological N use efficiency (PE), and internal N use efficiency (IE) under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Nitrogen Uptake (kg ha−1) | PFP (kg kg−1) | AE (kg kg−1) | RE (%) | PE (kg kg−1) | IE (kg kg−1) | ||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 53.9h | 50.4j | / | / | / | / | / | / | / | / | 74.5b | 71.2a |
| D2 | 50.7i | 48.6k | / | / | / | / | / | / | / | / | 76.4a | 70.3a | |
| N210 | D1 | 112.8f | 107.8h | 28.9a | 26.3a | 9.8d | 9.2d | 28.1e | 27.3e | 34.7c | 33.6e | 53.7b | 51.2b |
| D2 | 109.4g | 103.4i | 27.3b | 25.3b | 8.8e | 9.0e | 28.0e | 26.6e | 31.6e | 33.9d | 52.3b | 50.8b | |
| N255 | D1 | 136.7d | 125.7f | 27.1b | 24.5c | 11.4b | 10.4b | 32.5d | 29.5d | 35.1b | 35.3c | 50.6c | 49.7c |
| D2 | 131.5e | 120.0g | 26.7c | 23.8d | 11.5b | 10.4b | 31.7d | 28.0d | 36.4a | 37.0b | 51.8c | 50.5b | |
| N300 | D1 | 178.1b | 164.9d | 26.9c | 26.2a | 13.5a | 14.3a | 41.4a | 38.2a | 32.6d | 37.4a | 45.3d | 47.7d |
| D2 | 174.3c | 160.6e | 26.3d | 25.5b | 13.4a | 14.1a | 41.2a | 37.3a | 32.5d | 37.7a | 45.3d | 47.6d | |
| N345 | D1 | 174.2c | 167.2c | 22.0f | 19.7f | 10.4c | 9.3c | 34.9c | 33.9b | 29.8g | 27.5g | 43.6e | 40.7e |
| D2 | 179.4b | 167.8c | 22.7e | 20.3e | 11.4b | 10.4b | 37.3b | 34.6b | 30.6f | 30.2f | 43.5e | 41.8e | |
| N390 | D1 | 178.2b | 175.7b | 17.9h | 15.7g | 7.6g | 6.5g | 31.9d | 32.1c | 23.9i | 20.1i | 39.2f | 34.8f |
| D2 | 182.0a | 177.9a | 18.1g | 16.2g | 8.2f | 7.5f | 33.7c | 33.2c | 24.4h | 22.5h | 38.9f | 35.6f | |
| Significance of factors | |||||||||||||
| Nitrogen rate (N) | ** | ** | ** | ** | ** | ** | ** | ** | ** | ** | ** | ** | |
| Density (D) | ** | ** | ** | ** | ** | ** | ns | ns | ns | ns | ns | ns | |
| N × D | ** | ** | ** | ** | ** | ** | ns | ns | ns | ns | ns | ns | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. Values followed by a different letter within the same column are significantly different at p = 0.05 probability level; ns, not significant; **: Significant at the p < 0.05 and 0.01 levels, respectively.
Table 4.
Grain processing quality under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Brown Rice Rate (%) | Milled Rice Rate (%) | Head Milled Rice Rate (%) | |||
|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 79.8d | 79.4e | 69.9d | 68.7f | 61.1c | 60.4d |
| D2 | 80.7d | 79.8e | 71.1cd | 69.8f | 61.4c | 60.5d | |
| N210 | D1 | 82.4c | 81.6d | 71.8bcd | 71.2e | 63.4bc | 61.2cd |
| D2 | 82.7c | 82.1bcd | 73.1abc | 72.9d | 64.3bc | 61.4cd | |
| N255 | D1 | 83.0bc | 82.9bc | 73.3abc | 73.0d | 64.8abc | 62.3c |
| D2 | 83.0bc | 83.1bc | 73.6abc | 73.2d | 64.9abc | 62.7c | |
| N300 | D1 | 83.2abc | 83.5b | 74.0abc | 74.0c | 66.4abc | 66.2b |
| D2 | 83.3abc | 83.4b | 74.4ab | 74.2c | 68.0ab | 67.5b | |
| N345 | D1 | 83.4abc | 83.6b | 75.1a | 75.3b | 68.3ab | 68.6ab |
| D2 | 84.1ab | 84.0ab | 75.4a | 75.3b | 69.8ab | 68.9ab | |
| N390 | D1 | 84.4a | 84.5a | 76.1a | 76.6a | 70.0ab | 70.4a |
| D2 | 84.6a | 84.5a | 75.8a | 76.3a | 71.16a | 70.8a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 5.
Grain appearance quality under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Grain Length (mm) | Grain Width (mm) | Length/Width | Chalkiness Rate (%) | Chalkiness Degree (%) | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 4.32b | 4.33b | 2.55a | 2.56a | 1.70ab | 1.69a | 18.8fg | 18.4g | 4.7g | 4.5e |
| D2 | 4.34ab | 4.33b | 2.58a | 2.55a | 1.68ab | 1.70a | 16.9g | 16.2g | 4.6g | 4.5e | |
| N210 | D1 | 4.33b | 4.34b | 2.59a | 2.57a | 1.67b | 1.69a | 22.0def | 22.7f | 5.1ef | 4.9d |
| D2 | 4.36ab | 4.34b | 2.55a | 2.54a | 1.71ab | 1.71a | 20.1efg | 21.6f | 4.9fg | 5.0d | |
| N255 | D1 | 4.35ab | 4.34b | 2.55a | 2.56a | 1.70ab | 1.70a | 25.8bcd | 26.8d | 5.4cdef | 5.5c |
| D2 | 4.36ab | 4.34b | 2.60a | 2.55a | 1.68ab | 1.70a | 23.3cde | 24.2e | 5.3def | 5.2d | |
| N300 | D1 | 4.37ab | 4.36b | 2.58a | 2.55a | 1.69ab | 1.71a | 27.1abc | 28.0d | 5.7cd | 5.8b |
| D2 | 4.37ab | 4.36b | 2.56a | 2.55a | 1.71ab | 1.71a | 26.0bcd | 26.3d | 5.5cde | 5.5c | |
| N345 | D1 | 4.37ab | 4.41a | 2.60a | 2.58a | 1.68ab | 1.71a | 29.1ab | 29.2c | 6.2ab | 6.4a |
| D2 | 4.41ab | 4.42a | 2.58a | 2.56a | 1.71ab | 1.73a | 28.9ab | 28.9c | 5.9bc | 5.9b | |
| N390 | D1 | 4.45a | 4.44a | 2.57a | 2.56a | 1.73a | 1.73a | 31.2a | 32.0a | 6.5a | 6.5a |
| D2 | 4.42ab | 4.42a | 2.58a | 2.58a | 1.72ab | 1.71a | 29.6ab | 31.2b | 6.4a | 6.5a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 6.
Grain nutritive quality under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Amylose Content (%) | Gel Consistency (mm) | Protein Content (%) | |||
|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 17.0a | 17.0a | 97.5a | 97.2a | 6.6hi | 6.4g |
| D2 | 16.7b | 16.6b | 97.0a | 96.8a | 6.3i | 6.0h | |
| N210 | D1 | 16.3c | 16.1c | 94.5b | 94.7b | 6.9gh | 7.0f |
| D2 | 16.1d | 15.8d | 94.0b | 94.3b | 6.6hi | 6.5g | |
| N255 | D1 | 15.9e | 15.6e | 91.5c | 92.0c | 7.4ef | 7.4e |
| D2 | 15.8e | 15.3f | 90.5c | 91.6c | 7.2fg | 7.2ef | |
| N300 | D1 | 15.1f | 14.8g | 86.5d | 86.2d | 7.9cd | 8.1c |
| D2 | 14.9g | 14.5h | 85.5d | 86.3d | 7.7de | 7.7d | |
| N345 | D1 | 14.5h | 14.4h | 83.5e | 83.1e | 8.5b | 8.6b |
| D2 | 14.2i | 14.1i | 82.5e | 82.7e | 8.2bc | 8.0c | |
| N390 | D1 | 13.6j | 13.6j | 80.5f | 80.2f | 9.2a | 9.4a |
| D2 | 13.3k | 13.2k | 79.5f | 79.7f | 8.9a | 9.2a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 7.
Protein content in rice under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Albumin (%) | Globulin (%) | Gliadin (%) | Glutelin (%) | ||||
|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 0.31e | 0.32e | 0.41de | 0.41d | 0.52g | 0.50f | 4.8ef | 4.9e |
| D2 | 0.30e | 0.31e | 0.40e | 0.41d | 0.51g | 0.51f | 4.6f | 4.6f | |
| N210 | D1 | 0.32cde | 0.32e | 0.42cd | 0.42cd | 0.58ef | 0.56e | 5.2def | 5.1d |
| D2 | 0.31de | 0.32e | 0.41de | 0.42cd | 0.57f | 0.56e | 5.1def | 5.1d | |
| N255 | D1 | 0.35bc | 0.36c | 0.43bc | 0.43c | 0.61de | 0.62d | 5.3cde | 5.2d |
| D2 | 0.33bcde | 0.34d | 0.42cd | 0.43c | 0.60ef | 0.60d | 5.3cde | 5.3d | |
| N300 | D1 | 0.35b | 0.36c | 0.43bc | 0.44bc | 0.67bc | 0.66c | 5.8bc | 5.9c |
| D2 | 0.34bcd | 0.34d | 0.43bc | 0.45b | 0.64cd | 0.65c | 5.7bcd | 5.7c | |
| N345 | D1 | 0.36b | 0.38b | 0.44bc | 0.45b | 0.71ab | 0.69b | 6.1ab | 6.2b |
| D2 | 0.35b | 0.37b | 0.43bc | 0.45b | 0.70ab | 0.69b | 6.0ab | 6.2b | |
| N390 | D1 | 0.41a | 0.42a | 0.45a | 0.47a | 0.73a | 0.73a | 6.6a | 6.8a |
| D2 | 0.39a | 0.41a | 0.44ab | 0.45b | 0.72a | 0.72a | 6.6a | 6.6a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 8.
Cooking/eating quality under combined nitrogen rate and planting density in saline soil.
| Nitrogen Rate | Plant Density | Appearance | Hardness | Viscosity | Degree of Balance | Taste Value | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 9.0a | 9.2a | 5.4f | 5.3e | 9.4a | 9.5a | 9.1a | 9.2a | 87.0a | 87.8a |
| D2 | 9.2a | 9.1a | 5.2f | 5.4e | 9.5a | 9.3a | 9.2a | 9.2a | 88.3a | 88.0a | |
| N210 | D1 | 8.4b | 8.6b | 5.9d | 5.7d | 8.8b | 8.8b | 8.5b | 8.4b | 80.3c | 81.5c |
| D2 | 8.9a | 8.8b | 5.7e | 5.7d | 9.3a | 8.7b | 9.0a | 8.9a | 82.3b | 83.5b | |
| N255 | D1 | 7.8c | 7.7c | 6.1cd | 6.2c | 8.2c | 8.4c | 7.9c | 8.2c | 76.0e | 76.5e |
| D2 | 8.0c | 7.8c | 6.1cd | 6.0c | 8.4bc | 8.3c | 8.0c | 8.0c | 78.3d | 78.8d | |
| N300 | D1 | 7.0d | 7.2d | 6.6b | 6.7b | 7.7de | 7.6d | 7.0e | 7.1e | 73.0fg | 73.7f |
| D2 | 7.1d | 6.9d | 6.2c | 6.2c | 8.1cd | 8.1c | 7.4d | 7.5d | 74.3f | 74.5f | |
| N345 | D1 | 6.4e | 6.4e | 6.8b | 6.7b | 7.4ef | 7.5e | 6.5fg | 6.4f | 69.5h | 69.7h |
| D2 | 6.8d | 6.3e | 6.7b | 6.8b | 7.6e | 7.5e | 6.7f | 6.5f | 72.3g | 71.4g | |
| N390 | D1 | 6.2e | 6.3e | 7.1a | 7.2a | 7.1f | 7.4e | 6.0h | 6.1g | 65.5i | 65.1i |
| D2 | 6.3e | 6.2e | 7.0a | 7.2a | 7.2f | 7.5e | 6.3g | 6.1g | 68.3h | 66.8h | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
Table 9.
Grain pasting quality under combined nitrogen rate and planting density in saline-alkali land.
Table 9.
Grain pasting quality under combined nitrogen rate and planting density in saline-alkali land.
| Nitrogen Rate | Plant Density | Peak Viscosity (cP) | Trough Viscosity (cP) | Break Down (cP) | Final Viscosity (cP) | Subtractive Value (cP) | Peak Time (min) | Pasting Temperature (°C) | |||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | 2019 | 2020 | ||
| N0 | D1 | 3088c | 3074c | 2119bcd | 2106b | 969bc | 978bc | 2687c | 2681c | −401g | −393g | 6.18b | 6.17b | 73.0a | 72.8 a |
| D2 | 3181a | 3201a | 2173a | 2167a | 1008a | 1014a | 2738a | 2735a | −444i | −466i | 6.17b | 6.17b | 72.7a | 72.8a | |
| N210 | D1 | 3029d | 3011d | 2107cde | 2100b | 922d | 917d | 2647de | 2640de | −382f | −371f | 6.33ab | 6.35ab | 72.8a | 72.8a |
| D2 | 3138b | 3154b | 2150ab | 2154a | 988ab | 987b | 2720ab | 2726b | −418h | −428h | 6.37ab | 6.36ab | 73.0a | 72.9a | |
| N255 | D1 | 2990e | 2976e | 2089de | 2062cd | 901de | 914d | 2637de | 2621d | −353e | −355e | 6.37ab | 6.37ab | 73.4a | 73.3a |
| D2 | 3087c | 3072c | 2127bc | 2112bc | 960c | 963c | 2701bc | 2689c | −386f | −383f | 6.43ab | 6.45a | 72.9a | 73.1a | |
| N300 | D1 | 2920g | 2918g | 2044g | 2028e | 877f | 884e | 2604f | 2597f | −316c | −321c | 6.30ab | 6.31ab | 73.1a | 73.1a |
| D2 | 3019d | 3030d | 2099cde | 2034de | 920d | 918d | 2660d | 2685c | −359e | −345e | 6.30ab | 6.32ab | 73.3a | 73.2a | |
| N345 | D1 | 2854i | 2846i | 2027gh | 2020ef | 827g | 834f | 2565g | 2549g | −289b | −297b | 6.33ab | 6.32ab | 73.6a | 73.3a |
| D2 | 2961f | 2950f | 2079ef | 2066cd | 882ef | 890e | 2629e | 2613e | −332d | −337d | 6.47a | 6.46a | 73.8a | 73.4a | |
| N390 | D1 | 2799j | 2812j | 2010h | 2006f | 790h | 786g | 2549g | 2568g | −251a | −244a | 6.40ab | 6.41ab | 73.2a | 73.1a |
| D2 | 2888h | 2924h | 2053fg | 2057cd | 835g | 841f | 2596f | 2630d | −292b | −294b | 6.27ab | 6.32ab | 71.7a | 73.2a | |
N0–N390 indicate nitrogen application rates of 0, 210, 255, 300, 345, and 390 kg ha−1, respectively; D1 and D2 indicate planting densities of 334,000 and 278,000 hills ha−1, respectively. The values in the same column followed by different letters indicate statistical significance at the 0.05 probability level.
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Chen, Y.; Liu, Y.; Dong, S.; Liu, J.; Wang, Y.; Hussain, S.; Wei, H.; Huo, Z.; Xu, K.; Dai, Q. Response of Rice Yield and Grain Quality to Combined Nitrogen Application Rate and Planting Density in Saline Area. Agriculture 2022, 12, 1788. https://doi.org/10.3390/agriculture12111788
AMA Style
Chen Y, Liu Y, Dong S, Liu J, Wang Y, Hussain S, Wei H, Huo Z, Xu K, Dai Q. Response of Rice Yield and Grain Quality to Combined Nitrogen Application Rate and Planting Density in Saline Area. Agriculture. 2022; 12(11):1788. https://doi.org/10.3390/agriculture12111788
Chicago/Turabian StyleChen, Yinglong, Yang Liu, Shiqi Dong, Juge Liu, Yang Wang, Shahid Hussain, Huanhe Wei, Zhongyang Huo, Ke Xu, and Qigen Dai. 2022. "Response of Rice Yield and Grain Quality to Combined Nitrogen Application Rate and Planting Density in Saline Area" Agriculture 12, no. 11: 1788. https://doi.org/10.3390/agriculture12111788
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