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This paper reflects on the concept of the Plantationocene through an analysis of sugarcane plantations in Guangxi province, China. It argues that although these plantations are owned and operated by local villagers, they are de facto controlled by corporations, and subject to state intervention through a 'zoning scheme'. They are constructed and operated according to the same logic as other plantations all over the world, namely, the logic of extraction based on cheap land and labor. By demonstrating that plantations are not necessarily large-scale and do not always entail the alienation of land and labor, this paper hopes to empirically broaden the concept of the Plantationocene and to highlight the extractive nature of and the power relations around plantations. [ABSTRACT FROM AUTHOR]

The sugarcane plantations in China occupy large areas of undulated terrain. During the operation of a sugarcane harvester, the operator's vision is severely obstructed, and the height of the cutter needs to be adjusted frequently, resulting in low sugarcane harvesting efficiency and difficulty in ensuring harvesting quality. However, the current diversified non-contact methods are unable to distinguish or penetrate the interference well to provide feedback regarding the change in terrain height. Based on the proposed contact sensing method, a contact terrain sensing device is designed for application to the sugarcane harvester, and the orthogonal test is carried out with the standard orthogonal table L9(34) to study the influence of the working parameters of the device on the terrain height sensing performance. Through the analysis of the working principle of the device, three factors (moving speed, rotational torque, and preload) are tested in three levels, and index systems of the Fréchet distance and residual standard deviation are proposed. The range and variance analysis methods are used to statistically analyze the test results to determine the primary and secondary orders of operation parameters. Then, the regression model was obtained by regression analysis on the influencing factors. After analysis, the influences of moving speed and rotating torque were found to be the most significant, and the influence of preload was the smallest. The results show that the average relative errors between the experimental values and predicted model values of the Fréchet distance and residual standard deviation were 3.46% and 2.48%. According to the practical applications of the sugarcane harvester and the data of the two indexes, the optimal value ranges of moving speed (km/h) and rotating torque (Nm) are determined as (1.57, 1.75) and (0.73, 0.86), respectively, which provide a certain reference for the subsequent application of the terrain sensing device to sugarcane harvesters. [ABSTRACT FROM AUTHOR]

Farm size increase (FSI) accelerates soil erosion and sediment loss into the river. However, it is not clear how large-scale management, including FSI, changes the proportion of sediment from different land use types (LUTs) into rivers in intensive agricultural catchments. Thus, the aim of this study is to quantify and elucidate the contribution of different LUTs to river sediment before and after FSI using compound-specific stable isotopes (CSSI). The study was conducted in three parallel sub-watersheds in the sugarcane plantation region of subtropical southern China, each of which included four different LUTs (eucalyptus plantation, road, sugarcane plantation and channel). Following FSI, the contribution of sediment entering the river from the four LUTs was significantly different from that before FSI. The contribution per unit area of the road, sugarcane, and river channel to river sediment was significantly higher (P < 0.05) after FSI than before FSI. Overall, 1% increase in sugarcane farm size and stream channels caused > 2% and 0.3% increase contribution to river sediment, respectively. Field and road densities significantly correlated with river sediment sources. The FSI had a significant impact on the contribution of sediment entering the river from different LUTs within the watershed. Our results demonstrate that the increase river sediment depends on the increased hydrological connectivity of the watershed due to decreased field density and increased road density. Therefore, it is important to pay attention not only to the agricultural/economic benefits of FSI, but also the negative impacts on increasing erosion and ecological/environmental degradation. • The influence of farm size on river sediment sources was assessed. • Increasing farm size accelerates contribution of slope/channel to river sediment. • Contribution of slope/channel to river sediment depends on field and road density. [ABSTRACT FROM AUTHOR]

Stream Channel (SC) erosion results in immense soil and nutrient losses and eutrophication of downstream lakes and rivers. Among other factors, the lack of vegetation cover within SCs and on adjacent soils can accelerate soil and nutrient losses. The combined impact of perennial sugarcane plantation and grass cover on increasing SC erosion losses have not been previously studied. Current study determined SC erosion and associated nutrient losses and clarified the effect of grass roots within SCs and the ratooned sugarcane grown on adjacent lands in Nala watershed in southern subtropics of China. Six SCs in two sub-watersheds (SW1 and SW2) surveyed after revegetation during 2019 were compared with initial survey conducted in 2017 and 2018. The SC erosion was significantly (P < 0.05) reduced by 84.2% (5.19 ± 2.16 Mg ha−1) in entire watershed in 2019 compared to 2018 (43.9 ± 15.2 Mg ha−1). It notably decreased by 99.23% and 96.50% in SC-1-3 at SW1 and SC2-3 at SW2, respectively. Total N and P losses decreased by 84.9% and 82.5%, respectively, in entire watershed. The decreases in SC erosion and nutrient losses are attributed to increasing vegetative cover (R2 = 0.7543, P < 0.001), and grass root densities of <1 mm (R2 = 0.7543, P < 0.001), 1–2 mm (R2 = 0.7051, P < 0.001) and >2 mm (R2 = 0.5746, P < 0.001). Principal component regression analysis confirmed that root densities of SC grasses, perennial sugarcane, and organic matter had positive impacts on controlling SC erosion and consequent nutrient losses. • Less attention was paid to study effect of perennial sugarcane and grasses on erosion. • Lack of vegetation increased hydrological connectivity between hillslope and Stream Channels (SCs). • Perennial sugarcane and increased grass cover significantly reduced Stream Channel (SC) erosion. • Fine root densities entrapped more soil and minimized erosion and nutrient losses. [ABSTRACT FROM AUTHOR]

Sugarcane is an important sugar and biofuel crop with high socio-economic importance, and its planted area has increased rapidly in recent years. China is the world's third or fourth sugarcane producer. However, to our knowledge, no study has investigated the mapping of sugarcane cultivation areas across entire China. In this study, we developed a phenology-based method to identify sugarcane plantations in China at 30-m spatial resolution from 2016–2020 using the time-series of Landsat and Sentinel-1/2 images derived from Google Earth Engine (GEE) platform. The method worked by comparing the phenological similarity in normalized difference vegetation index (NDVI) series between unknown pixels and sugarcane samples. The phenological similarity was assessed using the time-weighted dynamic time warping method (TWDTW), which has less sensitivity to training samples than machine learning methods and therefore can be easily applied to large areas with limited samples. More importantly, our method introduced multiple and moving time standard phenological curves of sugarcane to the TWDTW by fully considering the variable crop life-cycle of sugarcane, particularly its long harvest season spanning from December to March of the following year. Validations showed the method performed well in 2019, with overall accuracies of 93.47% and 92.74% for surface reflectance (SR) and top of atmosphere reflectance (TOA) data, respectively. The sugarcane maps agreed well with the agricultural statistical areas from 2016–2020. The mapping accuracies using TOA data were comparable to SR data in 2019–2020, but outperformed SR data in 2016–2018 when SR data had lower availability on GEE. The sugarcane maps produced in this study can be used to monitor growing conditions and production of sugarcane and, therefore, can benefit sugarcane management, sustainable sugarcane production, and national food security. [ABSTRACT FROM AUTHOR]

This work is a contribution to applied water and fertilizer coupling efforts aiming at increasing crop productivity on sugarcane plantations through the analysis of average cane yields obtained following main agronomic traits in growth and sugar content of plantations, in order to improve irrigation scheduling practices. A field experiment was carried out, testing drip irrigation (D), with four levels (0%, 50%, 100% and 150%) of water (W) and four levels (0%, 50%, 100% and 150%) of fertilizer (F) with three replicates. Rain-fed crop (neither irrigation nor fertilizer DW0F0) and manpower irrigation were included as the control (W1F1). The effects of water and fertilizer on agronomic traits (plant high, stem diameter, effective stem number and single stem weight), sugarcane yield and sugar content were studied in Guangxi (southwest China) from 2018–2020. Compared with W1F1, the agronomic traits were higher under DW1F1 treatment; for sugar content, the benefit of the combined treatment was W0.5F0; for sugarcane yield, the best treatment was DW1F1, followed by DW1.5F1. To obtain maximum sugar yield, it is recommended to apply a N fertilizer dose of 292 kg ha−1, K2O fertilizer 146.55 kg ha−1 and P2O5 fertilizer 439.5 kg ha−1 with water 1778.4 m3 ha−1. The results could not only boost efficiency of water and fertilizer, but also establish the reasonable irrigation and fertilizer measure, and regulate yield of sugarcane. It could offer some ideas and techniques for developing precision farming. [ABSTRACT FROM AUTHOR]

On June 23 1855, Nicolas Tanco Armero (1830-1890) disembarked in Hong Kong after a voyage that took him through America, Europe, Africa and Asia. His departure point was Cuba, where he lived as an exile from his homeland, Colombia. His travelogue, Viaje de Nueva Granada a China y de China a Francia (1861), narrates his journey and three-year sojourn in China. Tanco Armero had been hired by the Cuban saccharocracy to work as a coolie trade agent in Amoy, a business which provided significant economic profit for the 25-year old entrepreneur. While he fervently critiques the institution of slavery in Cuba, he is a great admirer of the sugar plantations on which the Cuban economy thrived and which depended on the labour of the African slaves. This article is concerned with notions of racial and national identity negotiated by this white Creole male as they relate to the evident contradictions in his travelogue. [ABSTRACT FROM AUTHOR]

Sugarcane is a major crop for sugar and ethanol production and its area has increased substantially in tropical and subtropical regions in recent decades. Updated and accurate sugarcane maps are critical for monitoring sugarcane area and production and assessing its impacts on the society, economy and the environment. To date, no sugarcane mapping tools are available to generate annual maps of sugarcane at the field scale over large regions. In this study, we developed a pixel- and phenology-based mapping tool to produce an annual map of sugarcane at 10-m spatial resolution by analyzing time-series Landsat-7/8, Sentinel-2 and Sentinel-1 images (LC/S2/S1) during August 31, 2017 - July 1, 2019 in Guangxi province, China, which accounts for 65% of sugarcane production of China. First, we generated annual maps of croplands and other land cover types in 2018. Second, we delineated the cropping intensity (single, double and triple cropping in a year) for all cropland pixels in 2018. Third, we identified sugarcane fields in 2018 based on its phenological characteristics. The resultant 2018 sugarcane map has producer, user and overall accuracies of 88%, 96% and 96%, respectively. According to the annual sugarcane map in 2018, there was a total of 8940 km2 sugarcane in Guangxi, which was ~1% higher than the estimate from the Guangxi Agricultural Statistics Report. Finally, we identified green-up dates of those sugarcane fields in 2019, which could be used to support the sugarcane planting and management activities. Our study demonstrates the potential of the pixel- and phenology-based sugarcane mapping tool (both the algorithms and the LC/S2/S1 time series images) in identifying croplands, cropping intensity and sugarcane fields in the complex landscapes with diverse crop types, fragmented crop fields and frequent cloudy weather. The resultant annual maps from this study could be used to assist farms and sugarcane mills for sustainable sugarcane production and environment. • A sugarcane mapping tool was developed using time series Landsat and Sentinel-1/2. • Annual maps of sugarcane fields and phenology metrics at 10-m were developed. • Green-up dates of sugarcane fields were monitored in time for planting management. [ABSTRACT FROM AUTHOR]