Distance-based redundancy analysis is an extension of PCoA to model multivariate data and it was used to assess the amount the main food groups and confounding factors together explain of the compositional variation of gut microbiomes between individuals and visualizing the direction of the associations. PERMANOVA, factorfit, and dbRDA were run with 999 permutations. In per-taxa analyses we used a multivariate analysis by linear models to analyze associations of each main food group and their subgroups with all taxa at species level. Benjamini-Hochberg false discovery rate corrected P vlues were used to adjust for multiple comparisons. Prior to analysis the relative abundances of the taxa were centered log-ratio –transformed. For the cluster analyses, the taxa with significant associations with the main food groupsfrom per-taxa analysis were clustered based on proportionality using Ward minimum variance method and the optimal number of clusters was determined using KelleyGardner-Sutcliffe penalty function. The results were visualized with a heatmap. A pathway analysis was conducted between Kyoto Encyclopedia of Genes and Genomes orthology groups and the food groups using linear regression analysis. The relative abundances of KO-groups for each sample were obtained from the strain-level outputs of SHOGUN and the data on KO-groups were log10-transformed prior to analysis. Benjamini-Hochberg FDR corrected P values were used to adjust for multiple comparisons. Statistically significant associations of main food groups were further visualized using FuncTree 2. Analyses were controlled for potential confounding factors based on prior literature. These included age, sex, BMI, smoking status, 4×4 grow tray usage of possible microbiome-altering medications and total energy intake. The level of statistical significance for analyses was set at a P value<0.05 . Statistical analyses were performed using R version 3.6.3 and the following packages phyloseq, microbiome, vegan, maptree and ComplexHeatmap.
The method of engaging deeper spatio-historical understandings is not just to explain the multiple processes/forces driving China’s agrarian change, but more importantly to suggest a different analytical and political frame that “shed[s] light on the slippages, openings, and contradictions where pressure might be applied, as well as connections and alliances from which new possibilities might emerge”. In other words, my research marks a distinct approach by ‘denaturalizing’ social science bounded fields that operate in a bounded concept of space, place, and identity. The major difference between my theoretical and methodological approach and that of the authors just mentioned involves my open, non-teleological understanding of rural transformation in China, and the spatial dimension of possibilities within a globalizing world.Let me begin with the first form—the introduction of machinery to rice production. Just a few years ago, in Xialongkou and the surrounding hill counties, oxen constituted an indispensable animal power in small-scale household agricultural production. Its’ significance was not only in the ancient past, but also during the Maoist collectivization period, and continued after agricultural de-collectivization in 1978. This use of animal traction was of course not confined to western Jiangxi province. In Shanxi Province in the northwest, oxen were important in both traditional times and under the socialist era, as made clear in Liu Qing’s novel Epic of Creating Enterprise . Published at the height of the socialist collectivization movement, Liu describes how, for the first time, privately-owned oxen and other draft animals were leashed and placed under the roofs of collectivized pens, a key step towards collective agriculture. Liu Qing illustrates how dramatic and revolutionary an event it was. When the collective agriculture system was dismantled in the late 1970s, the important role of oxen was unaffected. In the case of Xialongkou and surrounding counties, oxen continued to be used in agricultural work until 2011 . What has been the impact of applying agricultural machines in Xialongkou? In the past, each family took from seven to fourteen days to plough rice paddies by oxen. Plouging was mostly men’s work. Now, villagers can hire a tractor to plough the entire village’s land in two to three days.
The mechanizing process was also noted in rural Taiwan in the 1990s . In Xialongkou, villagers generally agree that there has been no impact on output per unit of rice paddy. Experienced rice cultivators estimate that about one mu yields around five hundred kilograms of unhusked rice, whether using oxen or machines. However, for the same output per unit of land, each household, and especially its men, clearly now invests fewer workdays in the task of ploughing. In terms of harvesting, machines have also replaced hand-held sickles, by means of which it normally took seven to ten days for all family/household members working together to deal with this “agricultural busy work” . With a hired harvesting machine , the entire village’s “agricultural busy work” can now be finished in one or two days. Of course, hiring machines cost money. As of 2019, one mu cost 80 RMB for ploughing and 100 RMB for harvesting, though prices for hiring machines have been increasing over the past few years and will presumably continue to do so in the near future. The application of agricultural machinery is commonly associated with increasing economies of scale and efficiency, a sign of modern progress and science. The phenomenon of agribusiness companies, a new trend in China’s agrarian capitalism, has attracted considerable attention in scholarship . But large-scale agribusiness is rare in the hill country. What one encounters most commonly are small household farms that remain small and fragmented due to the socialist legacy and topographical conditions. On the surface, agricultural machines seem to accelerate agricultural capitalism in China. Ever since China’s economic reforms of the 1980s, concerns have grown about the rise of capitalist relations and its destruction of agriculture and land commodification in rural China . In Xialongkou, however, changes brought about by machinery like datian ji and gedao ji are integrated into small household agriculture. In the hill country, machines have merely replaced two tasks of rice production: ploughing and harvesting. Rather than expand cultivation, the net effect has been agricultural de-intensification—a decrease in annual agricultural work per person, especially men’s work. As a result, men now have the time to engage in diverse odd jobs in villages and small towns since the late 2000s.
The next section discusses the second form of agricultural de-intensification, land fallowing.Unlike the effect of agricultural machinery, de-intensification through land fallowing requires taking into consideration both temporal and spatial dimensions. One thing to note is that in Xialongkou, all rice fields are irrigated by hill streams flowing down from higher ground via natural gravity, not by the river that runs in front of the village yearlong. As will become clearer later, this water source is crucial to understanding both temporal and spatial aspects of land fallowing. Seen from a temporal perspective, de-intensification comes in three types: 1) shifting from multi-cropping to single cropping ; 2) shifting from multi-cropping to short fallowing; and 3) shifting from single cropping to short fallowing, bush fallowing, or forest fallowing. The first form is really a seasonal fallowing within an annual cycle, whereas the latter two involve a much longer fallow time extending beyond the yearly cycle. All three of these forms involve, fundamentally, greenhouse racking the reduction in agricultural intensity per unit of land. As Table 3 shows, in Xialongkou and its surrounding villages, at least from the 1980s to 2008, there were four major crops cultivated in paddy fields in a traditional lunar calendar year cycle. They were “early rice” , “big rice” , “second rice” , and “rape” . The “early rice” was transplanted from a seedling bed in early March and harvested in June. The “big rice” was transplanted from a seedling bed in early May and harvested around the time of the MidAutumn Festival . The “second rice” was transplanted from a seedling bed in June and harvested in October. It is called “second rice” because the rice is grown on a paddy where “early rice” has just been reaped; the paddy is immediately re-tilled and covered with a layer of animal manure and night soil . Thus, rice crops were formerly transplanted and harvested three times per year in this hill country, though not all of the three harvests made use of the same rice plots. From the perspective of rice cultivation, land use involved a mixture of single-cropping and double-cropping. It was labor intensive agricultural production that is not unusual in rural China. After the third harvest, some of the rice paddies were tilled again and fertilized once more with animal manure, with rapeseed then broadcasted on top as a winter crop. The agricultural calendar cycle came to an end when the rape crop was harvested in late February. As shown in Table 3,“early rice” and “second rice” have been largely eliminated since 2008. The three distinct rice crops have been reduced to just one—“big rice”—which is now grown after a winter rape crop.The daughter-in-law works at the Township post office, which was sub-contacted to her father one year ago. Regarding the family ox, the young couple believes using machinery is the way to go. It is the modernization process. The Daniu couple kept the family ox to save on the unnecessary expense of hiring “smashing field” machines. Many older villagers who praise the Daniu family for their industriousness and thrifty ethic share their views. At the heart of the generational divide lies the difference between waged labor and agricultural work as life styles. Although the Daniu couple lives at a level of semi-subsistence, making few purchases from the market, they are by no means resisting the market and consumption. The couple seeks market opportunities to sell their labor by doing varied odd jobs, just like the rest of Xialongkou residents. The difference is that the Daniucouple keeps agricultural work as their core way of life and other odd jobs as sidelines, while the younger generation like the son and daughter-in-law reverses the relationship between the family farm and outside waged labor. It is not uncommon to observe young adults remaining idle at their village home while their older parents work hard in the rice fields. One common reason is that they are uninterested in non-monetary returns as an alternative to waged jobs.5 But the generational tension is more complicated than simply the divide between different values and attitudes towards agricultural work. An interesting twist involves how both young and old integrate the traditional value of filial piety into agricultural work. Let me illustrate this point with the story of Shaogang. In brief, not all young villagers could avoid the “soil” —a pun in both vernacular and official discourse that refers both to agriculture and to family responsibility. Shaogang, an ex-migrant, in his late 30s, has had a middle school education. For many years, he worked and lived in Zhejiang province. He came back to Xialongkou Hamlet to till the family land with a small tractor in 2012. He is the youngest son and now has the duty to look after his elderly parents, the result of a collective decision made with his two older brothers. Although his peers have a low opinion of agricultural work, tilling the family land has become a moral duty linked to filial piety and family responsibility. Shaogang believes that village elders should “enjoy life” by not working in the rice fields. He came back to farm with the help of machines. Van de Ploge et al. have rightly pointed out the importance of family land that glued three generations of rural family/households. Yet their analysis falls short on rural population’s attachment to the land, especially the elderly generation that tirelessly reinvests and works on the family land for their adult children. They overlook the impact of the existing generational divide on work and lifestyles. The generational divide is real. Unlike Shaogang, most young people do not choose to return to till the land, even if they have the option now to use tractors. Instead, migrants can fulfill their filial duties and family responsibility through remittances, and by persuading their elderly parents to take a rest from hard physical work . One often overhears elderly villagers speaking highly of elderly who do not need to work under the sun: “Look at yourself.