The North China Plain suffers excessive application of nitrogen (N) and soil degradation. Recently, biochar has been promoted as an agricultural soil amendment to ameliorate soil quality, increase crop yield and mitigate greenhouse gas emissions. However, most proofs on the positive effects of biochar addition have been based on small plots or short-term field studies located in tropical or subtropical regions with defective soils. A long-term field experiment was designed with five N levels and two biochar rates to observe the changes in crop (winter wheat and summer maize) growth and soil chemical quality. Notably, crop yield was strongly dependent upon N application, with both wheat and maize yields increasing with N application. Biochar addition increased crop yield but not significantly, although the increase in grain yield was 0.96 t/ha in a rotation. Correlation analysis revealed that the optimal root-layer soil mineral N (Nmin) for crop production was around N120, especially with biochar addition. The effect of fertilization on soil chemical quality was mainly reflected in the increase in soil organic carbon (SOC), and the highest value was obtained at N60 whether or not biochar was applied. Overall, biochar addition did not appear to promote wheat and maize growth or increase the yield on calcareous alluvial soils in temperate regions, but significantly enhanced SOC content, especially at N60, which may play an important role in sustainable agricultural production.

This article argues that the study of China's history has long been caught in a teleological trap that presumes that history could have had only one evolutionary track. The author explains how he came to recognize the problems inherent in the teleological trap and to reconceptualize his approach. The article contrasts the history of the North China Plain, culturally rooted in dry-land grain agriculture and from time immemorial deeply intertwined with that of the adjacent grasslands, with that of the south, a culturally and linguistically diverse land of river valleys and riziculture. It concludes that the holistic empire we know today was not an inevitable outcome of these contrasting trajectories and that alternative paths are plausible, and asserts that scholars must recognize that until history is accomplished it does not follow a teleological trajectory.

We evaluate the relative importance of climate change, fluvial dynamics, and anthropogenic environmental modification in forming the Holocene sedimentary record of the Luoyang Basin, a tributary drainage basin of the Yellow River, located in western Henan Province, China. Our 2011 fieldwork south of the Erlitou site in the Luoyang Basin indicates that an unconformity dating to ca. AD 1100 is roughly coincident with a major southward shift in the lower course of the Yellow River. In AD 1128, the governor of Kaifeng breached the dikes of the Yellow River to impede an advancing army, causing the Yellow River to flow south out to the Yellow Sea. We argue that the dike breach not only changed the fluvial dynamics of the Yellow River but also switched the rivers in the Luoyang Basin from an aggrading to an incising system. The resumption of sedimentation in the Luoyang Basin is roughly coincident with the next major shift of the Yellow River’s main course northward to the Bohai Sea in AD 1855. The unconformity found in the Luoyang Basin may be a legacy of historically contingent human agency rather than climatic shifts or gradual environmental modification.

Japanese bindweed was found to be one of the most abundant and most difficult-to-control weed species during a 2-yr weed survey in more than 100 winter wheat fields in the North China Plain region. Multivariate data analysis showed that Japanese bindweed is most abundant at sites with comparative low nitrogen (N) fertilization intensities and low crop densities. To gain deeper insights into the biology of Japanese bindweed under various N fertilization intensities, winter wheat seeding rates, herbicide treatments, and their interactions, a 2-yr field experiment was performed. In nonfertilized plots, a herbicide efficacy (based on density reduction) of 22% for 2,4-D, and of 25% for tribenuron-methyl was found. The maximum herbicide efficacy in Nmin-fertilized plots (target N value based on expected crop yield minus soil mineral nitrogen content, ) was 32% for 2,4-D and 34% for tribenuron-methyl. In plots fertilized according to the farmer's practices, a maximum herbicide efficacy of 72% for 2,4-D and of 64% for tribenuron-methyl could be observed. Furthermore, medium and high seeding rates improved the herbicide efficacy by at least 39% for tribenuron-methyl and 44% for 2,4-D compared to the low seeding rate. Winter wheat yield was not significantly affected by seeding rate itself, whereas at low and medium seeding rates, Nmin fertilization was decreasing winter wheat yield significantly compared to the farmer's usual fertilization practice. At the highest seeding rate, Nmin fertilization resulted in equal yields compared to the farmer's practices of fertilization.