Effects of Growth Regulator and Planting Density on Cotton Yield and N, P, and K Accumulation in Direct-Seeded Cotton
Key Laboratory of Crop Genetics and Physiology of Jiangsu Province, Yangzhou University, Yangzhou 225009, China
*
Authors to whom correspondence should be addressed.
†
These authors contributed equally to this work.
Agronomy 2023, 13(2), 501; https://doi.org/10.3390/agronomy13020501
Submission received: 23 December 2022
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Revised: 5 February 2023
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Accepted: 7 February 2023
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Published: 9 February 2023
(This article belongs to the Special Issue Chemical Regulation and Mechanized Cultivation Technology of Cotton)
Abstract
:[Objective] This study aims to analyze the effects of the plant growth regulator Miantaijin (N,N-dimethyl piperidinium chloride and 2-N,N-diethylaminoethyl caproate) and planting density on yield and nitrogen (N), phosphorus (P), and potassium (K) uptake and accumulation in cotton. The results will clarify the high-yield cultivation techniques in the cotton direct seeding after wheat harvesting cropping system in the Yangtze River Basin. [Method] In 2017 and 2018, the cotton cultivar Guoxinzao 11-1 was planted at 3 densities (75,000, 90,000, and 105,000 plants·ha−1), and 3 Miantaijin doses (0, 1170, and 2340 mL·ha−1) were imposed. [Results] The results show that the highest yield (3551.3–3687.5 kg·ha−1) was achieved with a 90,000 and 105,000 plant·ha−1 density and 1170 mL·ha−1 of Miantaijin (seedling stage: 90 mL·ha−1, peak squaring stage: 180 mL·ha−1, peak flowering stage: 360 mL·ha−1, and peak bolling stage: 540 mL·ha−1). Under these conditions, the uptakes of N, P, and K were also the highest, up to 117.8 kg·ha−1, 77.4 kg·ha−1, and 116.4 kg·ha−1, respectively. N uptake was the highest from the peak flowering to peak squaring stage, while the highest uptakes of P and K were both detected from the peak squaring to peak flowering stages. We also found significant linear positive correlations between yield and the total absorptions and accumulations of N, P, and K, especially during the peak flowering–peak bolling stage. [Conclusions] The optimum dose of Miantaijin with a medium and high density could enhance the absorption of N, P, and K during the whole growth period of the cotton population, especially in the peak flowering–boll opening stage. This resulted in the highest yield of direct-seeded cotton after wheat harvesting.
1. Introduction
Cotton (Gossypium hirsutum L.) is not only the most important economic crop in China but also the most important agricultural product in addition to grain. It is of great significance for ensuring the healthy and sustainable development of the textile industry with cotton as the main raw material [1,2,3]. The seedling transplanting of cotton was initiated in China in the 1950s and was widely adopted in the Yangtze River Basin and the Yellow River valley, two of three dominant cotton-growing regions in China. However, there are many disadvantages, such as the high labor intensity of making soil blocks and transplanting seedlings to fields manually and a long growth period resulting in long boll developing and opening periods [4,5]. Thus, the cotton seedling transplanting method does not meet the requirements of mechanized harvesting and the development trend of the cotton producing industry in the future. Cotton direct seeding after wheat harvesting via mechanization and concentrated boll development and opening, together with machine harvesting, is considered as the main direction for cotton development. It occupies a dominant position in the cropping system in both the Yangtze River Basin and the Yellow River valley. For example, the area of the cotton direct seeding after wheat harvesting system in Hubei province in 2015 was 11.4 × 104 ha, and the average yield was 3300 kg ha−1 [6]; however, at present, its cultivation technology is not perfect and needs further study.
Studies have shown that cultivation technology, such as density and growth regulators, could significantly regulate nutrient absorption and utilization [7]. Dense planting has been the main measure used to improve cotton yield. However, with the planting density increased, the individual plants in a group would shade each other, which would deteriorate the permeability of the canopy, decrease the photosynthetic performance, increase plant height, and increase square and boll abscission. Bednarz et al. found that reasonably close planting was beneficial to the ventilation and light transmission of the cotton population [8], the interception of light and the utilization of light energy by the leaf area, and the absorption of N, P, and K by cotton, especially the nutrient accumulation in reproductive organs. Meanwhile, Li et al. found that under the condition of 1.2–2.4 × 104 plants·ha−1, total N and P contents in cotton plants decreased with the increase in density [9]. Plant growth regulators mainly affect plant growth and can effectively regulate the structural characteristics of the canopy and mineral nutrition absorption to improve yield and quality [10,11,12]. Plant growth regulators can also promote the absorption of the cotton root system, promote the delivery of root secretions to the ground, and promote the formation of yields. Miantaijin is a growth regulator for cotton, containing N,N-dimethyl piperidinium chloride and 2-N,N-diethylaminoethyl caproate, and can enhance the growth and development and promote the transformation of the cotton plant from vegetative growth to reproductive growth, as well as nutrient absorption and the cotton plant type, i.e., shorten the plant height and the length of the fruiting branch [13,14,15]. Miantaijin has been widely adopted in the main growing area in China. It is known that N, P, and K play important roles in promoting cotton growth and quality [16,17,18]. Zhang et al. found that the increased use of N, P, and K fertilizers could promote dry matter accumulation in all the organs of cotton and significantly increase the seed cotton yield by 9.42–81.71% [19].
Nevertheless, at present, the cultivation technology for high-yield and high-quality cotton in the Yangtze River basin is not perfect. We hypothesized that the interaction of density with Miantaijin regulates nutrient absorption and utilization, which affects the final yield formation. Therefore, our objectives were to investigate the following: (1) the effects of density and Miantaijin on the yield of direct-seeded cotton after wheat harvesting; (2) the changes in the absorption and utilization of N, P, and K under different treatments with density and Miantaijin; and (3) the relationship between the absorption of N, P, and K and yield. The results will provide practical guidance for the realization of high-yield and high-quality cultivation of cotton in the Yangtze River Basin.
2. Materials and Methods
2.1. Experimental Site
The experiments were conducted on a farm of Yangzhou University (32°30′ N, 119°25′ E), Yangzhou, Jiangsu Province, China in 2017 and 2018. The soil was previously planted with wheat and contained 17.8 g·kg−1 of organic matter, 1.78 g·kg−1 of total N (N), 64.8 mg·kg−1 of available P (P), and 25.6 mg·kg−1 of available K (K). Guoxinzao 11-1, an early-maturing variety, was used as the experimental material. The plant growth regulator Miantaijin was provided by China Agricultural University, China.
The average temperature during the cotton growing season was 24 in 2017, the rainfall was 471 mm in 2017, and the average temperature was 24 in 2018, and the rainfall was 314 mm in 2018 (Table 1).
2.2. Experimental Design and Field Management
Cotton was sown on 81 cm width rows on 7 June in 2017 and on 8 June in 2018 after wheat harvesting. The plot dimension was 38.4 m2, with 6 lines in each region. The experiment was established as a two-factor, randomized block design consisting of three replications. The density was set at 3 levels of 75,000, 90,000, and 105,000 plants·ha−1, represented by D1, D2, and D3, respectively. Cotton plants were sprayed with the plant growth regulator Miantaijin at doses of 0 mL·ha−1 (CK), 1170 mL·ha−1 (T1), and 2340 mL·ha−1 (T2), respectively. The Miantaijin for the whole growth period was applied at the seedling stage, squaring stage, flowering stage, and bolling stage, and the doses were 90 + 180 + 360 + 540 mL ha−1 for T1 and 180 + 360 + 720 + 1080 mL ha−1 for T2, respectively.
The plant materials were harvested on 5 November. Amounts of 150 kg ha−1 N, 75 kg ha−1 P2O5, and 150 kg ha−1 of K2O were applied during both growing seasons. Other field management practices were the same as those used in high-yield cotton fields.
2.3. Data Collection
2.3.1. Dry Matter and the Accumulations of N, P, and K
Five cotton plants from each plot were taken at the full squaring stage (15 July), full flowering stage (5 August), and boll opening stage (20 September). Then, they were divided into stems, leaves, and fruiting forms (squares + flowers + bolls). These materials were dried in an oven at 105 °C for 0.5 h. Afterward, the temperature was lowered to 80 °C until a constant mass (dry matter yield) was obtained, after which the samples were weighed and ground to pass a 40 mm stainless-steel sieve to determine the contents of total N, P, and K. P and K in each plant part were measured using a dry ash procedure [20]. N was determined using a LECO C-H-N determinator (LECO Corp., St. Joseph, MI, USA).
The accumulation of N, P, and K = dry matter yield × the content of N, P, and K.
2.3.2. Cotton Yield and Yield Components
Twenty successive plants were labeled and used for the boll density investigation until 20 September in both years. Seed cotton was handpicked two times in all plots on 20 September and 31 October, respectively. After the second harvest, all matured bolls from each plot were numbered and collected to store in a net bag and weighed after being sun-dried to a constant weight for boll weight. The yield was obtained after weighing the sun-dried seed cotton.
2.4. Statistical Analysis
The data were summarized to calculate the mean value. The mean value was compared via analysis of variance (ANOVA) to analyze the significant differences between samples with different treatments. The significance of the differences was determined with the Duncan multiple comparison method, at the significance level of p < 0.05. All statistical analyses were performed using SPSS 17.0. Tables were drawn with Microsoft Excel 2020.
3. Results
3.1. Seed Cotton Yield and Yield Components
It was found that density and Miantaijin significantly affected the seed cotton yield across two years (Table 2). Among all treatments, the yields for D3T1 were the highest in two years and were significantly higher than those for D1CK, D1T2, D2CK, and D2T2.
Further analysis showed that the D3T1 and D2T1 treatments resulted in more bolls in both years, and the difference between them was not significant. Analysis of variance showed that D3 achieved the highest bolls, followed by D2, but D1 exhibited the lowest bolls. D3 and D2 showed no difference in 2018, but D3 was significantly higher than D2 in 2017, while D3 was significantly higher than D1 in both years. No significant difference was detected between T1 and T2, but they were significantly higher compared with CK.
In 2017, the boll weight of D1T1 was the highest, followed by D3T1, while D3T1 and D2T1 were the highest, followed by D1T1 and D2T2 in 2018. Analysis of variance showed that density had no significant effect on boll weight, and Miantaijin significantly increased boll weight, especially in the T1 treatment. Therefore, the suitable amount of Miantaijin (1170 mL·ha−1) was beneficial for increasing boll weight.
In conclusion, with the higher density (90,000–105,000 plants·ha−1), together with the application of 1170 mL·ha−1 of Miantaijin, we could improve the bolls and boll weight to achieve a higher yield.
3.2. N Accumulation
Significant differences in total N accumulations among the treatments were detected (Table 3). D2T1 had the highest N accumulation, followed by D3T1 and D1T1. No significant differences among them were found; however, they were significantly higher than in other treatments. Further analysis showed that the application of Miantaijin (T1 and T2) increased the N accumulations by 12.4–2.5 kg ha−1 compared with CK during the whole cotton growing period. A higher planting density (D2 and D3) resulted in higher N accumulation compared with D1.
The correlation analysis of seed cotton yield with total N accumulation (Figure 1) further showed that within the scope of N accumulation in this study, a significant linear positive correlation between the seed cotton yield and the N accumulation (r = 0.757 *) was detected, indicating that the seed cotton yield increased with the increase in N uptake. Therefore, it was beneficial to increase the yield by increasing the N accumulation in the direct-seeded cotton after wheat harvesting.
The results of the N uptake at different growth stages further show that the N accumulations for D2T1 and D3T1 increased gradually with the growth development and achieved the highest accumulations at the boll opening stage, while those for other treatments increased first and achieved the maximum accumulations at the full squaring stage–full flowering stage, and then decreased. For all treatments, N was absorbed from the full squaring stage to the full flowering stage (Table 3).
The correlation analysis showed significant parabola relationships between the seed cotton yield and the N accumulations in both the seedling stage–full squaring stage and full squaring stage–full flowering stage (r = 0.640 *; r = 0.634 *), while a significant linear positive correlation between the full flowering stage–boll opening stage and the seed cotton yield (r = 0.742 *) was detected (Figure 2). The results indicate that the amount of N absorbed by direct-seeded cotton after wheat harvesting growing in the Yangtze River Basin should be kept within a reasonable range before the flowering period, and too much or too little N absorbed was detrimental to the formation of the final yield. However, the amount of N absorbed during the full flowering stage–boll opening stage had an important role in promoting the final yield and should be increased.
3.3. P Accumulation
D2T1 and D2T2 achieved the highest P accumulations, which were significantly higher than those for D1CK, D1T2, D2CK, and D3CK (Table 4). Miantaijin had a significant effect on P accumulation. T1 and T2 increased P accumulation by 9.7–11.0 kg ha−1 compared with CK. Density had no significant effect on P accumulation.
The correlation analysis (Figure 1) further showed that there was a significant linear positive correlation between total P accumulations and the seed cotton yield (r = 0.818 *), which indicates that the yield increased with the increase in P absorption. Therefore, increasing the P absorption was beneficial for increasing the yield of the direct-seeded cotton after wheat harvesting.
It was also found that the P accumulations at different stages for all treatments increased with the growth process, and more P was absorbed from the full flowering to the boll opening stages (Table 4).
The correlation analysis showed a significant parabola relationship between the seed cotton yield and the P accumulation in the seedling stage–full squaring stage and full flowering stage–boll opening stage(r = 0.790 **, r = 0.661 *), respectively, while no significant correlation was found in the full squaring stage–full flowering stage (Figure 3). The results indicate that the absorption of P in the seedling stage–full squaring stage and the full flowering stage–boll opening stage had a significant effect on the seed cotton yield, and promoting the absorption and accumulation of P in the above two stages would promote a high yield of direct-seeded cotton after wheat harvesting in the Yangtze River Basin.
3.4. K Accumulation
K accumulation was significantly affected by the Miantaijin dose and the interactions with density and Miantaijin. The suitable Miantaijin dose (T1) increased K accumulation by 15.7% compared with CK, while the higher Miantaijin rate (T2) only increased K accumulation by 10.0% (Table 5). No significant differences were found among different densities. As for the interactions with density and Miantaijin, D2T1 had the highest K accumulation, followed by D3T1 and D1T1, and no significant differences were found among them.
With the growth process, the K accumulations for each treatment showed an increasing trend, reaching the highest level at the full flowering stage–boll opening stage. More K was absorbed from the full flowering stage to the boll opening stage (Table 5).
The correlation analysis showed a significant linear positive correlation between the seed cotton yield and the K absorption during the full flowering stage–boll opening stage (r = 0.755 *) (Figure 4). This indicates that K absorption should be increased after the flowering stage to promote the final seed cotton yield.
4. Discussion
4.1. Application of 1170 mL·ha−1 Miantaijin with the Higher Density (90,000–105,000 Plants·ha−1) Achieved Higher Yield of Direct-Seeded Cotton after Wheat Harvesting with Higher Density
Density and plant growth regulators are two important cultivation practices to achieve high-quality and high-yield cotton [21,22,23]. Increasing the planting density is the main cultivation practice to increase cotton yield and achieve the mechanization of cotton production. An optimum planting density and plant growth regulators can improve the ventilation and light conditions of the plant populations in a field to increase the photosynthetic capacity of the leaves and, thus, laying a foundation for high yield. This study found that with the higher density (90,000–105,000 plants·ha−1), the application of 1170 mL·ha−1 of Miantaijin could achieve a higher yield (3551.3–3687.5 kg·ha−1) for the cotton cultivar Guoxinzao 11-1 in the cotton direct seeding after wheat harvesting cropping system. This is mainly due to the treatment easily regulating the plant architecture, which promotes photosynthesis and provides a good foundation for high cotton yield. This result is the same as that found by Wang et al. (8.9 plants m−2) and Liu et al. [5,24]. Moreover, the yield level under that condition attained or exceeded the local traditional transplanting mode [25].
Mepiquat chloride (DPC) can inhibit cotton apical dominance by affecting the apical part structure and is used as a traditional growth regulator in large-scale cotton production. Wei et al. found that the yield of direct-seeded cotton after wheat harvesting was high and bolls formed in a concentrated manner under the condition of 150,000 plants·ha−1 combined with the application of 240 mL·ha−1 of mepiquat chloride (DPC) [26]. This density is higher compared with our present study. This is probably because Miantaijin has a weaker ability to form the plant type, but a stronger capacity to improve photosynthetic production compared with DPC [27]. Thus, Miantaijin promotes production capacity per plant to achieve a high final yield.
There were no significantly different interactions between Miantaijin and the planting density for yield and nutrient accumulations in both years, which agrees with previous findings [24].
Previous studies showed that in the cropping system of cotton seeding after wheat harvesting in the Yangtze River Basin, the boll number in the cotton population exhibited a higher contribution to the final seed cotton yield [28]. The results are consistent with our study. The present study indicated that the main way to achieve a high yield was to increase the boll number in a cotton population. However, in this study, boll weight did not significantly contribute to yield in both years, which is not completely consistent with traditional cotton cultivation in which increasing boll weight can achieve a higher yield [29]. There are important practical and theoretical significances to further explore the possible reason for this.
Compared with the seedling transplanting of cotton [30], the treatment of 90,000–105,000 plants·ha−1 and application of 1170 mL·ha−1 of Miantaijin increased the seed cotton by 18.4%–22.9%. In the system of cotton seeding after wheat harvesting, the labor intensity and the employing labor quantity were highly decreased, and the economic gains for farmers increased by about eighty percent. Thus, research on the cultivation technology for the seeding of cotton has significant practical meaning. The results in this study are also useful to guide the high-yield production of cotton intercropping and other plants in other cotton-growing regions in the world.
4.2. Higher N, P, and K Accumulations during Whole Growth Period and during Full Flowering Stage–Boll Opening Stage Are the Guarantee of High Yield in Cotton Direct Seeding after Wheat Harvesting
In this study, Miantaijin had a significant effect on the absorptions and accumulations of N, P, and K. With the higher density (90,000–105,000 plants·ha−1), the application of 1170 mL·ha−1 of Miantaijin (90 + 180 + 360 + 540 mL·ha−1 applied at the seedling stage, squaring stage, flowering stage, and bolling stage, respectively) achieved the highest accumulations of N, P, and K, respectively. The results show that the higher density combined with the suitable Miantaijin dose could improve the absorptions of N, P, and K, laying a foundation for a higher yield of direct-seeded cotton after wheat harvesting in the Yangtze River Basin. Meanwhile, Ma et al. found that too high accumulations of N and P in plants may result in a loss of cotton yield [31]. In addition, we found that treatment with 90,000–105,000 plants·ha−1 and the application of 1170 mL·ha−1 of Miantaijin could increase nutrient absorption and decrease nutrient loss. This might be due to the increase in root activity and the increase in photosynthetic performance.
Then, we found that the seed cotton yield had significant linear positive correlations with the accumulations of N, P, and K. However, these results are different from previous studies. For example, Xu found that in a certain density range (10,000–30,000 plants·ha−1) for the transplanting of cotton, there were significant parabola relationships between density and the accumulations of N, P, and K, indicating that a higher total absorption of plant nutrients may not achieve a higher yield [32]. This was probably due to the fact that the N, P, and K fertilizer utilization ratio reduced by 40–50% in the mode of cotton direct seeding after wheat harvesting compared with the traditional transplanting mode, leading to the final accumulations of the above 3 elements still being lower than the optimum amount [31]. Thus, further systematic studies should be conducted to increase the accumulations of the above three elements by selecting a variety of high fertilizer utilization rates and adopting suitable cultivation practices in cotton direct seeding after wheat harvesting in the Yangtze River Basin.
In addition, the seed cotton yield had different relationships with the accumulations of N, P, and K at different stages, respectively. It was found that the final seed cotton yield had a significant and/or highly significant linear positive correlation with the accumulations of the three elements during the full flowering stage–boll opening stage, which is consistent with the previous study [33]. Therefore, promoting the absorption and accumulation of mineral nutrients in this period, such as by increasing nutrient use, will be conducive to high yield in this planting mode.
5. Conclusions
In the Yangtze River Basin, with the density of 90,000–105,000 plants·ha−1, the application of 1170 mL·ha−1 of Miantaijin (90 + 180 + 360 + 540 mL·ha−1 applied at the seedling stage, squaring stage, flowering stage, and bolling stage, respectively) achieved a high yield of the direct-seeded cotton population after wheat harvesting. Under this condition, the accumulations of N, P, and K during the whole growth period, especially during the full flowering stage–boll opening stage, can be improved, thus laying a foundation for yield formation. Therefore, attention should be paid to promoting growth regulator management in the high-density planting of direct-sowed cotton in future agricultural production in the Yangtze River Basin, China, as it plays a crucial role in improving cotton yield and quality.
Author Contributions
Conceptualization, T.H. and X.Z.; methodology, Z.L.; software, Z.L.; validation, T.H., Z.L. and D.J.; formal analysis, T.H.; investigation, T.H.; resources, Y.C.; data curation, T.H.; writing—original draft preparation, T.H.; writing—review and editing, Z.L., X.Z. and Y.C.; project administration, D.C.; funding acquisition, X.Z. and D.C. All authors have read and agreed to the published version of the manuscript.
Funding
This research was funded by the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (22KJA210005).
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.
Correlation between seed cotton yield and the total accumulations of N, P, and K during whole growing period. Note: N: y = 33.661x − 416.145 (R2 = 0.757; p = 0.018); P: y = 31.536x + 976.843 (R2 = 0.669; p = 0.049); and K: y = 28.603x + 181.991 (R2 = 0.775; p = 0.014).
Figure 1.
Correlation between seed cotton yield and the total accumulations of N, P, and K during whole growing period. Note: N: y = 33.661x − 416.145 (R2 = 0.757; p = 0.018); P: y = 31.536x + 976.843 (R2 = 0.669; p = 0.049); and K: y = 28.603x + 181.991 (R2 = 0.775; p = 0.014).
Figure 2.
Relationships between seed cotton yield and N accumulations at different growth stages. Note: seedling stage-full squaring stage: y = −60.8x2 + 2257.21x − 17,562 (R2 = 0.4061; p = 0.048); full squaring stage-full flowering stage: y = −10.029x2 + 917.0x − 17,568 (R2 = 0.4023; p = 0.049); and full flowering stage-boll opening stage: y = 26.125x + 2142 (R2 = 0.5519; p = 0.022). Note: Triangles are N uptake amount and seed cotton yield of each treatment in the seedling stage-full squaring stage. Squares are N uptake amount and seed cotton yield of each treatment in the full squaring stage-full flowering stage. Rhombuses are N uptake amount and seed cotton yield of each treatment in the full flowering stage-boll opening stage.
Figure 2.
Relationships between seed cotton yield and N accumulations at different growth stages. Note: seedling stage-full squaring stage: y = −60.8x2 + 2257.21x − 17,562 (R2 = 0.4061; p = 0.048); full squaring stage-full flowering stage: y = −10.029x2 + 917.0x − 17,568 (R2 = 0.4023; p = 0.049); and full flowering stage-boll opening stage: y = 26.125x + 2142 (R2 = 0.5519; p = 0.022). Note: Triangles are N uptake amount and seed cotton yield of each treatment in the seedling stage-full squaring stage. Squares are N uptake amount and seed cotton yield of each treatment in the full squaring stage-full flowering stage. Rhombuses are N uptake amount and seed cotton yield of each treatment in the full flowering stage-boll opening stage.
Figure 3.
Relationship between seed cotton yield and P accumulations at different growth stages. Note: seedling stage-full squaring stage: y = 58.995x2 − 439x + 3325 (R2 = 0.645; p = 0.025); full squaring stage-full flowering stage: y = 53.6x2 − 2421.9x + 30,375 (R2 = 0.3445; p = 0.163); and full flowering stage-boll opening stage: y = 2.757x2 − 202.3x + 6720.3 (R2 = 0.441; p = 0.045). Note: Triangles are N uptake amount and seed cotton yield of each treatment in the seedling stage-full squaring stage. Squares are N uptake amount and seed cotton yield of each treatment in the full squaring stage-full flowering stage. Rhombuses are N uptake amount and seed cotton yield of each treatment in the full flowering stage-boll opening stage.
Figure 3.
Relationship between seed cotton yield and P accumulations at different growth stages. Note: seedling stage-full squaring stage: y = 58.995x2 − 439x + 3325 (R2 = 0.645; p = 0.025); full squaring stage-full flowering stage: y = 53.6x2 − 2421.9x + 30,375 (R2 = 0.3445; p = 0.163); and full flowering stage-boll opening stage: y = 2.757x2 − 202.3x + 6720.3 (R2 = 0.441; p = 0.045). Note: Triangles are N uptake amount and seed cotton yield of each treatment in the seedling stage-full squaring stage. Squares are N uptake amount and seed cotton yield of each treatment in the full squaring stage-full flowering stage. Rhombuses are N uptake amount and seed cotton yield of each treatment in the full flowering stage-boll opening stage.
Figure 4.
Relationship between seed cotton yield and K accumulation during full flowering stage-boll opening stage.
Figure 4.
Relationship between seed cotton yield and K accumulation during full flowering stage-boll opening stage.
Table 1.
Average temperatures and rainfall during cotton growing season (2017–2018).
| Year | May | June | July | August | September | October | |
|---|---|---|---|---|---|---|---|
| Precipitation/mm | 2017 | 239.4 | 712.2 | 843.0 | 803.7 | 106.5 | 119.4 |
| 2018 | 120.9 | 97.5 | 770.3 | 682.9 | 159.9 | 54.0 | |
| Temperature/°C | 2017 | 22 | 26 | 28 | 27 | 22 | 20 |
| 2018 | 22 | 26 | 28 | 27 | 22 | 20 |
Table 2.
Effects of density and Miantaijin on yield and composition of direct-seeded cotton after wheat.
Table 2.
Effects of density and Miantaijin on yield and composition of direct-seeded cotton after wheat.
| Treatment | Seed Cotton Yield | Bolls | Boll Weight | ||||
|---|---|---|---|---|---|---|---|
| (kg·ha−1) | (×104·ha−1) | (g) | |||||
| 2017 | 2018 | 2017 | 2018 | 2017 | 2018 | ||
| D1CK | 2980.7 c | 2856.3 d | 80.9 d | 81.5 d | 3.7 b | 3.5 bc | |
| D1T1 | 3332.0 abc | 3137.3 cd | 85.8 bc | 88.2 cd | 3.9 a | 3.6 b | |
| D1T2 | 3276.3 bc | 2966.6 d | 87.6 bc | 85.2 d | 3.7 b | 3.5 bc | |
| D2CK | 3055.4 c | 3024.9 d | 84.9 c | 87.3 cd | 3.6 c | 3.5 c | |
| D2T1 | 3652.7 ab | 3551.3 a | 98.1 a | 95.9 ab | 3.7 b | 3.7 a | |
| D2T2 | 3282.6 bc | 3332.1 bc | 90.2 bc | 93.6 b | 3.6 c | 3.6 b | |
| D3CK | 3337.2 abc | 3151.7 cd | 90.9 b | 91.4 bc | 3.7 b | 3.5 c | |
| D3T1 | 3687.5 a | 3621.8 a | 98.1 a | 99.3 a | 3.8 ab | 3.7 a | |
| D3T2 | 3620.1 ab | 3354.5 b | 98.9 a | 95.1 ab | 3.7 b | 3.5 bc | |
| Source of variation (ANOVA) | |||||||
| Density | D1 | 3196.3 c | 2986.7 b | 84.8 c | 85.0 b | 3.8 a | 3.5 a |
| D2 | 3330.2 b | 3302.8 a | 91.1 b | 92.3 a | 3.6 a | 3.6 a | |
| D3 | 3548.3 a | 3376.0 a | 96.0 a | 95.3 a | 3.7 a | 3.6 a | |
| Miantaijin | CK | 3124.4 c | 3011.0 c | 85.6 b | 86.7 b | 3.7 b | 3.5 b |
| T1 | 3557.4 a | 3436.8 a | 94.0 a | 94.5 a | 3.8 a | 3.7 a | |
| T2 | 3393.0 b | 3217.7 b | 92.2 a | 91.3 a | 3.7 b | 3.5 b | |
Note: different letters following values within a column mean significant differences at p < 0.05.
Table 3.
Effects of density and Miantaijin on N accumulation (2018).
| Total Accumulation (kg·ha−1) | Accumulation and Proportion in Different Periods | |||||||
|---|---|---|---|---|---|---|---|---|
| Treatment | Seedling Stage–Full Squaring Stage | Full Squaring Stage–Full Flowering Stage | Full Flowering Stage–Boll Opening Stage | |||||
| Accumulation (kg·ha−1) | Proportion (%) | Accumulation (kg·ha−1) | Proportion (%) | Accumulation (kg·ha−1) | Proportion (%) | |||
| D1CK | 102.6 c | 16.5 cd | 16.0 c | 51.9 a | 50.6 a | 34.3 cd | 33.4 d | |
| D1T1 | 114.3 a | 16.3 cd | 14.3 d | 49.9 ab | 43.7 b | 48.1 b | 42.0 ab | |
| D1T2 | 103.8 c | 15.8 d | 15.2 d | 48.1 b | 46.3 b | 39.9 c | 38.5 c | |
| D2CK | 101.7 b | 18.9 b | 18.5 ab | 51.4 a | 50.5 a | 31.4 cd | 31.0 d | |
| D2T1 | 117.8 a | 17.4 c | 14.8 d | 48.5 b | 41.2 b | 51.9 a | 44.0 a | |
| D2T2 | 107.7 b | 17.4 c | 16.2 bc | 47.1 bc | 43.7 b | 43.2 bc | 40.1 b | |
| D3CK | 105.1 bc | 20.7 a | 19.7 a | 52.2 a | 49.7 ab | 32.2 cd | 30.6 d | |
| D3T1 | 114.3 a | 18.7 b | 16.4 bc | 47.7 b | 41.6 b | 48.1 b | 42.0 ab | |
| D3T2 | 105.4 b | 18.2 bc | 17.1 b | 44.4 c | 42.1 b | 43.0 bc | 40.8 b | |
| Source of variation (ANOVA) | ||||||||
| D1 | 106.9 a | |||||||
| Density | D2 | 109.1 a | ||||||
| D3 | 108.3 a | |||||||
| Miantaijin | CK | 103.1 b | ||||||
| T1 | 115.5 a | |||||||
| T2 | 105.6 b | |||||||
Note: different letters following values within a column mean significant differences at p < 0.05.
Table 4.
Effects of density and Miantaijin on P accumulation (2018).
| Treatment | Total Accumulation | Accumulation and Proportion in Different Periods | ||||||
|---|---|---|---|---|---|---|---|---|
| Seedling Stage–Full Squaring Stage | Full Squaring Stage–Full Flowering Stage | Full Flowering Stage–Boll Opening Stage | ||||||
| Accumulation | Proportion | Accumulation | Proportion | Accumulation | Proportion | |||
| (kg·ha−1) | (kg·ha−1) | (%) | (kg·ha−1) | (%) | (kg·ha−1) | (%) | ||
| D1CK | 65.1 c | 6.2 d | 9.5 b | 21.9 bc | 33.6 a | 37.0 c | 56.9 bc | |
| D1T1 | 75.3 a | 7.1 c | 9.4 b | 20.9 c | 27.8 b | 47.3 ab | 62.8 ab | |
| D1T2 | 71.1 b | 6.9 c | 9.7 b | 20.0 d | 28.1 b | 44.2 b | 62.2 b | |
| D2CK | 63.3 c | 7.0 c | 11.0 a | 23.3 a | 36.8 a | 33.0 d | 52.4 c | |
| D2T1 | 77.4 a | 7.6 b | 9.8 b | 20.5 cd | 26.4 b | 49.4 a | 63.8 a | |
| D2T2 | 77.1 a | 7.2 c | 9.4 b | 20.4 cd | 26.6 b | 49.4 a | 64.2 a | |
| D3CK | 64.4 c | 7.6 b | 11.8 a | 22.6 b | 35.2 a | 34.2 d | 53.2 c | |
| D3T1 | 73.2 ab | 8.0 a | 11.0 a | 19.8 d | 27.2 b | 45.3 b | 62.0 ab | |
| D3T2 | 73.8 ab | 6.9 c | 9.2 b | 20.1 d | 27.2 b | 46.9 ab | 63.6 a | |
| Source of variation (ANOVA) | ||||||||
| Density | D1 | 70.5 a | ||||||
| D2 | 72.6 a | |||||||
| D3 | 70.5 a | |||||||
| Miantaijin | CK | 64.3 b | ||||||
| T1 | 75.3 a | |||||||
| T2 | 74.0 a | |||||||
Note: different letters following values within a column mean significant differences at p < 0.05.
Table 5.
Effects of density and Miantaijin on K accumulations (2018).
| Treatment | Total Accumulation (kg·ha−1) | Accumulation and Proportion in Different Periods | ||||||
|---|---|---|---|---|---|---|---|---|
| Seedling Stage–Full Squaring Stage | Full Squaring Stage–Full Flowering Stage | Full Flowering Stage–Boll Opening Stage | ||||||
| Accumulation (kg·ha−1) | Proportion (%) | Accumulation (kg·ha−1) | Proportion (%) | Accumulation (kg·ha−1) | Proportion (%) | |||
| D1CK | 99.2 c | 12.1 c | 12.2 b | 32.9 b | 33.2 ab | 54.2 de | 54.6 bc | |
| D1T1 | 110.4 a | 11.9 c | 10.8 c | 33.8 a | 30.6 b | 64.7 bc | 58.6 b | |
| D1T2 | 106.3 ab | 11.3 cd | 10.6 c | 32.3 bc | 30.4 b | 62.7 cd | 59.0 ab | |
| D2CK | 94.9 c | 13.7 b | 14.4 a | 32.1 bc | 33.8 a | 49.1 e | 51.8 c | |
| D2T1 | 116.4 a | 12.8 bc | 11.0 c | 32.2 bc | 27.6 c | 71.4 a | 61.4 a | |
| D2T2 | 109.3 ab | 11.7 c | 10.8 c | 32.6 bc | 29.8 b | 65.0 bc | 59.4 ab | |
| D3CK | 99.5 c | 14.8 a | 14.8 a | 29.4 d | 29.6 bc | 55.3 d | 55.6 b | |
| D3T1 | 113.1 a | 13.1 bc | 11.8 bc | 32.5 bc | 28.8 c | 67.3 b | 59.4 ab | |
| D3T2 | 107.4 b | 13.0 bc | 12.2 b | 30.3 c | 28.2 c | 64.1 c | 59.6 ab | |
| Source of variation (ANOVA) | ||||||||
| D1 | 105.3 a | |||||||
| Density | D2 | 106.9 a | ||||||
| D3 | 106.6 a | |||||||
| CK | 97.9 c | |||||||
| Miantaijin | TI | 113.3 a | ||||||
| T2 | 107.7 b | |||||||
Note: different letters following values within a column mean significant differences at p< 0.05.
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MDPI and ACS Style
Hu, T.; Liu, Z.; Jin, D.; Chen, Y.; Zhang, X.; Chen, D. Effects of Growth Regulator and Planting Density on Cotton Yield and N, P, and K Accumulation in Direct-Seeded Cotton. Agronomy 2023, 13, 501. https://doi.org/10.3390/agronomy13020501
AMA Style
Hu T, Liu Z, Jin D, Chen Y, Zhang X, Chen D. Effects of Growth Regulator and Planting Density on Cotton Yield and N, P, and K Accumulation in Direct-Seeded Cotton. Agronomy. 2023; 13(2):501. https://doi.org/10.3390/agronomy13020501
Chicago/Turabian StyleHu, Tianran, Zhenyu Liu, Dian Jin, Yuan Chen, Xiang Zhang, and Dehua Chen. 2023. "Effects of Growth Regulator and Planting Density on Cotton Yield and N, P, and K Accumulation in Direct-Seeded Cotton" Agronomy 13, no. 2: 501. https://doi.org/10.3390/agronomy13020501
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