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Determining the optimal plant architecture and canopy structure are important objectives in research on the breeding and cultivation of high-yielding crops. To address this challenge, a field experiment was conducted in Anyang, Henan, China, to assess cotton light interception, boll spatial distribution, leaf area index (LAI), plant height and biomass, lint yield and yield component during 2018–2019. Treatments including 10 cotton cultivars with belong to tower-shaped and tube-type canopy structure. Compared with compact cotton varieties, the loose and tower-shaped cotton varieties intercepted more light (average 28.6%) and had a higher LAI (average 34.2%), resulting in a higher cotton yield (average 14.8%). In addition, polynomial correlation showed that the maximum light interception rate occurred at the flowering and boll-forming stage, when the annual mean plant height (94.6 cm), LAI (3.58) and biomass (15,006 kg ha−1) all reached their peak. Moreover, yield was extremely significantly positively correlated with intercepted photosynthetically active radiation (IPAR) (R = 0.7) and positively correlated with light use efficiency (LUE) (R = 0.36). Overall, the results suggest that cotton cultivars with loose and tower-type canopy structures intercept more light and should be planted to increase cotton yield and LUE in the Yellow River basin of China and areas with similar conditions. [ABSTRACT FROM AUTHOR]

Identifying the ideal plant nature and canopy structure is of great importance for improving photosynthetic production and the potential action of plants. To address this challenge, an investigation was accomplished in 2018 and 2019 at the Institute of Cotton Research (ICR) of the Chinese Academy of Agricultural Science (CAAS), Henan Province, China. Six cotton varieties with diverse maturities and plant canopy structures were used to evaluate the light interception (LI) in cotton, the leaf area index (LAI), the biomass, and the yield throughout the two years of study. The light spatial distribution in the plant canopy was evaluated using a geographic statistical method, following the increasing quantity of radiation intercepted, which was determined using the rules of Simpson. Compared to the cotton plants with a compact structure, varieties with both a loose and tower design captured a comparatively higher amount of light (average 31.3%) and achieved a higher LAI (average 32.4%), eventually achieving a high yield (average 10.1%). Furthermore, the polynomial correlation revealed a positive relationship between the biomass accumulation in the reproductive parts and canopy-accrued light interception (LI), signifying that light interception is critical for the yield development of cotton. Furthermore, when the leaf area index (LAI) was peaked, radiation interception and biomass reached the highest during the boll-forming stage. These findings will provide guidance on the light distribution in cotton cultivars with an ideal plant structure for light capture development, providing an important foundation for researchers to better manage light and canopies. [ABSTRACT FROM AUTHOR]

Approximately 70% of global cotton production is under the threat of drought. Changing cropping systems is an agronomic measure that potentially coordinates production and ecology. However, little evidence is available on the characteristics of changes in the soil moisture under different cropping systems and their relationships with cotton production. This study assessed the temporal and spatial variation in the soil moisture and analyzed the relationships between the soil water content (SWC) and the biomass, yield, and water use efficiency (WUE) of cotton (Gossypium hirsutum L.) in three cropping systems (monoculture cotton (MC), wheat (Triticum aestivum L.)/delayed intercropped cotton (WIC), and wheat/direct-seeded cotton (WDC)). The spatiotemporal heterogeneity and autocorrelation of the soil moisture were affected by cropping systems and whether the soil was dry or wet. Compared with the values in 2016 (moist), the spatiotemporal heterogeneity in the SWC variation at a 10–110 cm depth in the three planting systems increased, and the autocorrelation decreased in 2017 (drought). This phenomenon was more pronounced in WIC than in MC and WDC. Compared with MC, the double-cropping system increased the SWC between cotton rows. In the double-cropping system, the cotton yield of WIC was significantly higher than that of WDC. The order of WUE from high to low was WDC>MC>WIC in 2016 and MC>WIC>WDC in 2017, and no significant difference was observed between MC and WIC in both years. Yield limitation in the double-cropping system was due to weak water absorption of roots. The growth curves of cotton roots with increasing SWC in WIC were similar to those in MC, while WDC showed faster root growth but a smaller maximum value. The roots in WDC stopped growing when the water consumption reached 150 mm. WDC with a small root system was suitable for humid regions, while WIC with a strong root system should be promoted in both humid and arid regions. The methods and results can be used to obtain a deeper understanding of the effects of different planting systems on soil moisture and cotton production and to determine their interrelationship to guide dryland cotton production and precision agriculture. [Display omitted] ● Soil water monitoring in cotton fields with high spatial and temporal resolution. ● The wheat-cotton double cropping improves the soil water status in the field. ● The yield limit in double-cropped cotton is due to weak water use by smaller roots. ● The wheat/delayed intercropped cotton is better in terms of efficient water use. [ABSTRACT FROM AUTHOR]

The number of cotton plants grown per unit of ground area has gained attention due to the high prices of inputs and lower production. Cotton yield per unit of area in Henan province has been stagnant in the last few years. The objectives of this study were to investigate cotton growth, yield, boll spatial distribution and biomass accumulation using different plant densities at cultivation and to find out the optimal plant density. A 2-year field experiment was conducted in a randomized complete block design under six plant densities (D1, 15,000; D2, 33,000; D3, 51,000; D4, 69,000; D5, 87,000 and D6, 105,000 ha−1). Cotton grown at lower plant density produced taller plants and high number of leaves per plant while greater number of branches, fruiting nodes and high number of bolls per unit of ground area were produced under high plant density. Boll retention rate decreased as plant population increased and at nodes 1–8 the rate decreased slowly and then increased dramatically. The highest seed cotton yield (4546 kg ha−1) and lint yield (1682 kg ha−1) was produced by D5. The seed cotton and lint yield produced by D5 were 51–55%, 40–37%, 22–26%, 11–15%, 12–15%, 28–30%, 21–24%, 15–20%, 7–13% and 13–17% higher than D1, D2, D3, D4 and D6 during both years of experimentation, respectively. The increase in seed yield was due to higher biomass accumulation in reproductive organs under D5 plant density. The highest average (110.4 VA kg ha−1 d−1) and maximum (126 VM kg ha−1 d−1) rate of reproductive organs biomass was also accumulated by D5 as compared to other plant densities. The results suggest that D5 is the optimal plant density for high reproductive biomass accumulation and high yield for the area of Henan province. [ABSTRACT FROM AUTHOR]

The serious problem of residual film pollution in the arid region of northwestern China has a severe negative impact on both the farmland environment and the benefits of cotton planting. Drip irrigation without mulch (DIWM) has the potential to serve as an effective alternative to mulch drip irrigation and address the issue of residual film pollution. However, there are few studies on how to formulate a rational irrigation regime under DIWM conditions and achieve water savings and productivity gains. Consequently, from 2020 to 2021, we established three DIWM treatments: W4, W6, and W8. None of the treatments were irrigated at the seedling stage, and the irrigation regime was the same for all the treatments at the squaring stage (2 irrigations at an irrigation quota of 45 mm). From the initial flowering stage, the frequency of irrigation was once every 6 d, 8 d, and 12 d for W4, W6, and W8, respectively, and the corresponding total numbers of watering times were 8, 6, and 4, respectively. The irrigation amount was 69 mm at each time point during the flowering and boll-forming stages in all the treatments, and the final irrigation amount was 52.2 mm in W8. The total irrigation amounts were 366 mm, 504 mm and 625.2 mm for W4, W6 and W8, respectively. This study explored the spatiotemporal characteristics of soil moisture via sensors combined with the spatial grid method. Additionally, the growth indices, biomass accumulation, yield components, and water use efficiency (WUE) of cotton were assessed across various treatments. The results revealed that, in 2020 and 2021, the W8 treatment resulted in the highest soil water content (SWC) in the 70–110 cm soil layer and soil water consumption (WC) in the 10–110 cm layer, with the WC in the 10 cm layer being 20 % and 44 % greater than that in W6, respectively. The excessive total irrigation amount (IA) in the W8 treatment led to high vegetative growth of cotton, diminishing the positive impact on yield. Across both years, the WUE observed in the W6 treatment significantly exceeded that of W8, while the seed cotton yield demonstrated only marginal decreases of 5 % and 0.9 % compared with that of W8. The irrigation amount and average WC in the 10–40 cm soil layer were 19 % and 29 % lower in W6 than in W8, respectively, but the economic benefits were only 2 % lower than those in W8. There was a significant positive correlation between the SWC and WC in all the different soil layers, and the effect of the SWC on the WC gradually decreased with increasing soil depth. Overall, the irrigation regime employed in the W6 treatment within the arid zone, devoid of mulch cover, proves to be an effective water-saving strategy, ensuring a consistent cotton yield and enhancing WUE. This study serves as a reference for developing an efficient irrigation system tailored to the DIWM cotton industry in arid zones, contributing to the promotion of green and sustainable agricultural development in this region. • Increased irrigation has a greater impact on deep soil moisture changes. • Increased irrigation will increase water consumption during the boll setting stage. • Deep soil moisture has a lower effect on water consumption than shallow layers. • The positive effect of excessive irrigation on cotton yield declined. [ABSTRACT FROM AUTHOR]

By quantifying the soil water movement (SWM) in crop planting systems, we can better understand the soil water consumption (SWC) and crop yield relationship; this finding is significant for determining the field water cycle and reducing agricultural water waste. In this paper, a case study was conducted on cotton production. Soil moisture sensors were set at depths of 10–110 cm under three cotton cropping systems (monoculture cotton (MC), wheat/delayed intercropped cotton (WIC), and wheat/direct-seeded cotton (WDC)) based on spatial grid methods; a geostatistical grid calculus was used to calculate SWM; and the crop and meteorological influence mechanisms on cotton lint yield were comprehensively analyzed. At the squaring stage, SWC and vertical SWM were significantly correlated with light, temperature and water conditions. At the flowering and boll development stage, SWC and vertical SWM were collectively affected by meteorological conditions and crops, and they were positively correlated with lint yield. The aboveground and belowground biomass accumulation at the flowering and boll development stage positively affected vertical SWM in and between cotton rows. Vertical SWM in cotton rows increased SWC in cotton rows. SWC in cotton rows and aboveground biomass positively impacted lint yield formation; SWC between rows negatively impacted lint yield. The SWC and vertical SWM between rows in the MC seedling stage exceeded those in cotton rows, and more precise irrigation at the seedling stage reduced water waste. The WIC horizontal SWC at the squaring and flowering and boll opening stages was relatively high, moving from the row midline to cotton row. A better SWC distribution in and between cotton rows promoted water utilization in the cotton rows; this method was feasible for improving cotton yield in diverse planting systems. The results could optimize precision irrigation management at different cotton growth stages and provide a theoretical reference for promoting sustainable agricultural production and climate adaptation. [Display omitted] • Quantifying soil water movement using novel geostatistical grid calculus method. • Diversified planting systems promotes horizontal soil water movement. • Water and cotton yield relationship are strongest at flowering and boll development stage. • Soil water consumption and vertical movement in cotton rows increase lint yield. [ABSTRACT FROM AUTHOR]

Non-film drip irrigation cotton planting mode can effectively solve the problem of residual film pollution in arid areas and promote sustainable agricultural development. However, the research on the efficient irrigation regime and soil hydrothermal microenvironment suitable for non-film drip irrigation cotton planting is scarce. Considering this, using the data monitoring technology based on internet of things sensors, we set 3 different irrigation treatments in 2020–2021. In the flowering and boll setting stage, cotton was watered for 4 times (W4), 6 times (W6), and 8 times (W8) with a single irrigation amount of 69 mm for each of these 3 treatments, and the last time irrigation amount under W8 treatment was 52.2 mm. At the seedling stage, the cotton was not irrigated under each treatment. At the squaring stage, the irrigation times and single irrigation amount were the same under each treatment. The results showed that the average soil water content (SWC) in the 50–110 cm soil layer was increased obviously with the increase in the total irrigation amount. Compared with W4 and W8 treatments, W6 treatment exhibited the highest the soil temperature in the 10–30 cm soil layer in the full boll stage and boll opening stage and the highest soil effective accumulated temperature (SEAT) from initial flowering stage to boll opening stage. The reproductive organ allocation rate in two years was 3.6 % and 2 % higher under W6 than under W8, respectively. With the increase of total irrigation amount, the cotton yield was increased, but the irrigation water use efficiency (IWUE) was decreased. The highest cotton yield was achieved under W8 treatment, but it was not significantly different from that under W6 treatment, while IWUE was significantly lower under W8 than under W6. The effective air temperature (EAT) had the greatest positive impact on the average effective soil temperature (EST) in 10–50 cm soil layer, while the cumulative irrigation amount (CIA) had a negative impact on average EST in 10–50 cm soil layer. Evapotranspiration (ET) and SEAT were positively correlated with biomass accumulation amount and lint yield. In summary, the irrigation regimes of 2 times of irrigation at the squaring stage with a single irrigation amount of 45 mm and 6 times of irrigation at the flowering and boll setting stage with a single irrigation amount of 69 mm can be applied to the non-film cotton cultivation mode in southern Xinjiang. Our findings provide a reference for the application of agricultural internet of things technology in soil hydrothermal microenvironment of non-film cotton fields in Xinjiang. • Using spatial grid method to deploy sensors and continuously monitor data. • Revealed changes in soil hydrothermal conditions in non-mulched cotton fields. • The ridge regression model can effectively explain changes in soil temperature. • The irrigation amount has a negative impact on the soil temperature. • The study provides a reference for setting up a non-film cotton irrigation system. [ABSTRACT FROM AUTHOR]

• A new method for visualizing the spatiotemporal change in soil water consumption. • The complexity of crop responses to multiple environmental factors is highlighted. • The main factor driving cotton biomass formation is water consumption. • Cotton yield exhibits a significant positive correlation with PE GDD and PE soil. • MC and WIC had high cotton yield and accumulated temperature production efficiency. In the context of intensified climate change, approximately 70% of global cotton (Gossypium hirsutum L.) production is in arid or high temperature environments. Improving cultivation practices is an effective measure to promote the adaptation of cotton production to the climate. To comprehensively study the characteristics of the hydrothermal microclimate in cotton fields and their relationship with cotton biomass and yield formation, a grid sampling method based on sensors with high spatiotemporal resolution was used in this study to monitor the soil temperature and soil moisture under three cropping patterns (monoculture cotton (MC), wheat (Triticum aestivum L.)/delayed intercropped cotton (WIC), and wheat/direct-seeded cotton (WDC)). The cropping patterns substantially changed the cotton hydrothermal resource utilization. WDC was the pattern with low cotton yield and low hydrothermal resource use efficiency, while MC and WIC were the patterns with high cotton yield and high accumulated temperature production efficiency. Cotton yield exhibited a very significant positive correlation with the accumulated temperature production efficiency of air and soil, and these relationships were less affected by different planting patterns. The climate in 2016 was relatively humid, and the water consumption (WC) of MC was mainly concentrated within a soil depth of 70 cm, WIC was 50 cm, and WDC was 30 cm. The climate in 2017 was relatively dry, and the main soil depth ranges of WC in MC, WIC, and WDC were 50, 30, and 20 cm, respectively. WC was the most important factor affecting cotton biomass, especially reproductive organ biomass, followed by the effective accumulated air temperature. The WC of cotton was most affected by changes in soil moisture at a depth of 30 cm. This study strengthens the application of smart agricultural technology in sustainable cotton production and highlights the complexity of crop responses to cultivation practices and multiple environmental factors. [ABSTRACT FROM AUTHOR]

• Intraspecific competition increased at diminishing rate with increasing plant density in cotton populations. • Optimal plant density to maximize cotton yield was identified at 4.0 plants m −2 in this study. • Maximum fruit production (W max) and fruit growth rate (c m) were also recorded at the same density threshold. • Cotton yield was positively correlated with W max and c m. Increasing plant density has been an effective way for cotton yield improvements. The density of plants in a community also determines competition intensity and the efficiency to exploit available resources. However, the competition response as well as optimal density for yields and the mechanisms of which in terms of fruit growth rate are poorly known. A field experiment was conducted on cotton (Gossypium hirsutum L. SCRC 28) at a wide range of plant densities from 1.5–10.5 plants m−2. The results indicated that intraspecific competition between cotton plants increased nonlinearly with increasing plant density. Seedcotton yield per unit ground area declined precipitously at plant densities below the 4.0 plants m−2 threshold and yield did not further increase above this threshold, which is interpreted as the minimum plant density at which yield should be maximized. Moreover, maximum fruit production and fruit growth rate were also recorded at the same density threshold, above which there was no significant response. Cotton yield was positively correlated with fruit production and fruit growth rate. We thus conclude that high fruit production and fruit growth rate are responsible for maximum yield under optimal plant density in cotton. [ABSTRACT FROM AUTHOR]