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The current cotton (Gossypium hirsutum L.) fallow farming system causes soil degeneration and cotton yield reduction. Cover cropping is commonly associated with improved soil fertility and crop pro...

The cotton-wheat double-cropping system is widely used in the Yellow River Valley of China, but whether and how different planting patterns within cotton-wheat double-cropping systems impact heat and light use efficiency have not been well documented. A field experiment investigated the effects of the cropping system on crop productivity and the capture and use efficiency of heat and light in two fields differing in soil fertility. Three planting patterns, namely cotton intercropped with wheat (CIW), cotton directly seeded after wheat (CDW), and cotton transplanted after wheat (CTW), as well as one cotton monoculture (CM) system were used. Cotton-wheat double cropping significantly increased crop productivity and land equivalent ratios relative to the CM system in both fields. As a result of increased growing degree days (GDD), intercepted photosynthetically active radiation (IPAR), and photothermal product (PTP), the capture of light and heat in the double-cropping systems was compared with that in the CM system in both fields. With improved resource capture, the double-cropping systems exhibited a higher light and heat use efficiency according to thermal product efficiency, solar energy use efficiency (Eu), radiation use efficiency (RUE), and PTP use efficiency (PTPU). The cotton lint yield and biomass were not significantly correlated with RUE across cropping patterns, indicating that RUE does not limit cotton production. Among the double-cropping treatments, CDW had the lowest GDD, IPAR, and PTP values but the highest heat and light resource use efficiency and highest overall resource use efficiency. This good performance was even more obvious in the high-fertility field. Therefore, we encourage the expanded use of CDW in the Yellow River Valley, especially in fields with high fertility, given the high productivity and resource use efficiency of this system. Moreover, the use of agronomic practices involving a reasonably close planting density, optimized irrigation and nutrient supply, and the application of new short-season varieties of cotton or wheat can potentially enhance CDW crop yields and productivity.

A field experiment was performed to assess the carbon footprint (CF) of four cropping systems to identify the sustainable cropping system. The four cropping systems were cotton monoculture (CM), wi...

Cotton-winter fallow is the major cropping system of cotton in the Yellow River basin of China, which not only leads to a considerable waste of land and natural resources, but also high greenhouse emissions and a loss of reactive nitrogen. Replacing winter bare fallow in cotton production with February orchid as a cover crop is a new cropping system in this area, but its sustainability is still unknown. Therefore, a field experiment was conducted with two cropping systems (cotton-winter fallow and cotton-February orchid) under four nitrogen application rates (0, 112.5, 168.75, and 225 kg N ha−1). Field observations were incorporated into a life cycle assessment to estimate the carbon footprint, nitrogen footprint, net ecosystem economic benefits, and economic benefits. The estimated carbon footprint per unit of sown area was 43.6–76.1% lower in the cotton-February orchid system than in the cotton-winter fallow system, mainly because of the increase in soil organic carbon. The cotton-February orchid system significantly increased the nitrogen footprint per unit of sown area by 6.7–11.5% under different application rates mainly because of the increase in N2O emissions. The nitrogen application rate significantly impacted the carbon and nitrogen footprints. After accounting for changes in the nitrogen and carbon footprints, the cotton-February orchid system with 168.75 kg N ha−1, which resulted in the highest net ecosystem economic benefits and economic benefits, resulted in a 25.0% reduction in nitrogen fertilizer applied and a 9.5% increase in net ecosystem economic benefits compared with the conventional cotton-winter fallow system and nitrogen fertilizer application rate (225.75 kg N ha−1). Thus, adopting an integrated strategy combining February orchid as a cover crop and a reduced nitrogen fertilizer application contributes to improvements in green and sustainable cotton production systems in the Yellow River basin and other regions with similar ecological conditions.

Cotton (Gossypium hirsutum L.) yield variability over time is determined by weather and agronomic factors in site-specific soil conditions. Plant density is among the most important agronomic practices in cotton production. However, the relative importance of each factor remains unclear. Here, we addressed plant density effects and the relative importance against weather factors on yield variability over time using a decade-long (2008–2017) field experiment on cotton crops that consisted of a wide range of plant densities from 1.5 to 10.5 plants m–2 in the Yellow River Valley of China. The results showed that a plant density of 3.3 plants m–2 produced stable productivity across periods of contrasting weather conditions. However, the average plant density for maximum yield was 5.9 plants m–2. As such, there was a trade-off between yield potential and yield stability for cotton crops. Moreover, plant density and weather explained 46.4 % and 29.1 %, respectively, of the variation in cotton yield during 2008–2017. Among weather related factors, air temperature during the growing season had stronger independent explanatory power (25.8 %) than did sunshine hours (5.1 %) and annual precipitation (1.3 %). Taken together, our results not only highlight the importance of focusing on yield stability for sustainable agricultural management recommendations but also underline the necessity of considering the primary weather variations for accurately predicting agricultural yield under climate change.

Crop growth and yield depend on canopy light interception (LI). To identify a low-cost and relatively efficient index for measuring LI, several color attributes of red-green-blue (RGB), hue-saturation-intensity (HSI), hue-saturation-value (HSV) color models and the component values of color attributes in the RGB color model were investigated using digital images at six cotton plant population densities in 2012–2014. The results showed that the LI values followed downward quadratic curves after planting. The red (R), green (G) and blue (B) values varied greatly over the years, in accordance with Cai's research demonstrating that the RGB model is affected by outside light. Quadratic curves were fit to these color attributes at six plant population densities. Additionally, linear regressions of LI on every color attribute revealed that the hue (H) values in HSI and HSV were significantly linearly correlated with LI with a determination coefficient (R 2 )≥0.89 and a root mean square error (RMSE)=0.05. Thus, the H values in the HSI and HSV models could be used to measure LI, and this hypothesis was validated. The H values are new indexes for quantitatively estimating the LI of heterogeneous crop canopies, which will provide a theoretical basis for optimizing the crop canopy structure. However, further research should be conducted in other crops and under other growing and environmental conditions to verify this finding.

Background Within-canopy interception of photosynthetically active radiation (PAR) impacts yield and other agronomic traits in cotton (Gossypium hirsutum L.). Field experiments were conducted to investigate the influence of 6 cotton varieties (they belong to 3 different plant types) on yield, yield distribution, light interception (LI), LI distribution and the relationship between yield formation and LI in Anyang, Henan, in 2014 and 2015. Result The results showed that cotton cultivars with long branches (loose-type) intercepted more LI than did cultivars with short branches (compact-type), due to increased LI in the middle and upper canopy. Although loose-type varieties had greater LI, they did not yield significantly higher than compact-type varieties, due to decreased harvest index. Therefore, improving the harvest index by adjusting the source-to-sink relationship may further increase cotton yield for loose-type cotton. In addition, there was a positive relationship between reproductive organ biomass accumulation and canopy-accumulated LI, indicating that enhancing LI is important for yield improvement for each cultivar. Furthermore, yield distribution within the canopy was significantly linearly related to vertical LI distribution. Conclusion Therefore, optimizing canopy structure of different plant type and subsequently optimizing LI distribution within the cotton canopy can effectively enhance the yield.

Light interception (LI) by the canopy is an important environmental factor that determines dry matter production and crop development. Using a geostatistical sampling-based method, we studied the spatial distribution of LI at different points, in different layers and profiles and in the entire cotton canopy. The results showed that the LI decreased with increasing height. During early development, the horizontal changes in LI were large for a given vertical point. However, the horizontal changes in LI were smaller during later development. Profile maps of the LI for the six plant densities showed that different LIs occurred during the early growth stage. In addition, the linear regressions between the total accumulated LIs of the different layers and the cottonseed yield revealed that the LI in the bottom layer and in the middle of two cotton rows significantly contributed to the cottonseed yield. Thus, a higher economic yield could be obtained by improving the micro-environment in these two layers.

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.

15%, 28&ndash, 30%, 21&ndash, 1) and lint yield (1682 kg ha&minus, D2, 33,000, 55%, 40&ndash, D3, 51,000, 15%, 12&ndash, 20%, 7&ndash, 26%, 11&ndash, 37%, 22&ndash, 13% and 13&ndash, 1) was produced by D5. The seed cotton and lint yield produced by D5 were 51&ndash, 1) and maximum (126 VM kg ha&minus, D5, 87,000 and D6, 105,000 ha&minus, 8 the rate decreased slowly and then increased dramatically. The highest seed cotton yield (4546 kg ha&minus, 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&minus, 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., 1 d&minus, 24%, 15&ndash, D4, 69,000, 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&ndash, 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

In this study, transplanting cotton seedlings grown in artificial substrate is considered due to recent increased interest in cotton planting labor saving approaches. The nursery methods used for growing cotton seedlings affect root growth. However, the underlying functional responses of root growth to variations in cotton seedling transplanting methods are poorly understood. We assessed the responses of cotton (Gossypium hirsutum L.) roots to different planting methods by conducting cotton field experiments in 2012 and 2013. A one-factor random block design was used with three replications and three different cotton planting patterns (substrate seedling transplanted cotton (SSTC), soil-cube seedling transplanted cotton (ScSTC) and directly sown cotton (DSC). The distributions and variances of the root area density (RAD) and root length density (RLD) at different cotton growing stages and several yield components were determined. Overall, the following results were observed: 1) The RAD and RLD were greatest near the plants (a horizontal distance of 0 cm) but were lower at W20 and W40 cm in the absence of film mulching than at E20 and E40 cm with film mulching. 2) The roots were confined to shallow depths (20-40 cm), and the root depths of SSTC and DSC were greater than the root depths of ScSTC. 3) Strong root growth was observed in the SSTC at the cotton flowering and boll setting stages. In addition, early onset root growth occurred in the ScSTC, and vigorous root growth occurred throughout all cotton growth stages in DSC. 4) The SSTC plants had more lateral roots with higher root biomass (RB) than the ScSTC, which resulted in higher cotton yields. However, the early onset root growth in the ScSTC resulted in greater pre-frost seed cotton (PFSC) yields. These results can be used to infer how cotton roots are distributed in soils and capture nutrients.

119 Sn Mossbauer, X-ray diffraction and electrical conductivity measurements at room temperature were performed on Bi 1.68 Pb 0.32  Sr 1.75 Ca 1.75 Cu 2.65-x Sn x O y ( x = 0.2−0.8) samples. The relation between the Sn occupancy and the temperature dependence of the resistivity is discussed. It is suggested that the electric characteristics of the high-temperature superconducting phase are affected mainly by the square-coordinated Cu planes.

The partitioning of light is very difficult to assess, especially in discontinuous or irregular canopies. The aim of the present study was to analyze the spatial distribution of photosynthetically active radiation (PAR) in a heterogeneous cotton canopy based on a geo-statistical sampling method. Field experiments were conducted in 2011 and 2012 in Anyang, Henan, China. Field plots were arranged in a randomized block design with the main plot factor representing the plant density. There were 3 replications and 6 densities used in every replicate. The six plant density treatments were 15,000, 33,000, 51,000, 69,000, 87,000 and 105,000 plants ha(-1). The following results were observed: 1) transmission within the canopy decreased with increasing density and significantly decreased from the top to the bottom of the canopy, but the greatest decreases were observed in the middle layers of the canopy on the vertical axis and closing to the rows along the horizontal axis; 2) the transmitted PAR (TPAR) of 6 different cotton populations decreased slowly and then increased slightly as the leaves matured, the TPAR values were approximately 52.6-84.9% (2011) and 42.7-78.8% (2012) during the early cotton developmental stage, and were 33.9-60.0% (2011) and 34.5-61.8% (2012) during the flowering stage; 3) the Leaf area index (LAI) was highly significant exponentially correlated (R(2) = 0.90 in 2011, R(2) = 0.91 in 2012) with the intercepted PAR (IPAR) within the canopy; 4) and a highly significant linear correlation (R(2) = 0.92 in 2011, R(2) = 0.96 in 2012) was observed between the accumulated IPAR and the biomass. Our findings will aid researchers to improve radiation-use efficiency by optimizing the ideotype for cotton canopy architecture based on light spatial distribution characteristics.