New methods and progress in research on the origins and evolution of prehistoric agriculture in China

China is one of the main global centers of origin of agriculture. Foxtail millet(Setaria italica), common millet(Panicum miliaceum), and rice(Oryza sativa) were the first crops to be domesticated in China. There remain many uncertainties and controversies in our current understanding of the chronology, locations, and plant types at the origins and the process of evolution of prehistoric millet and rice farming, and their relationships with climate change and human adaptation. This review summarizes the research progress made by Chinese scientists over the last decade on the origins and evolution of prehistoric agriculture. It highlights novel techniques and methods for identifying early crop remains, including plant macrofossils(carbonized seeds, spikelets), microfossils(phytoliths, calciphytoliths, starch, pollen), and biomarkers; new evidence on the origins, development, and spread of early agriculture; and research related to climate and environmental changes. Further, we pinpoint and discuss existing challenges and potential opportunities for further in-depth investigation of the origins and evolution of agriculture and the adaption of human activities to climate change.

Assessment of deforestation impact on soil erosion in loess formation using 137Cs method (case study: Golestan Province, Iran)

Golestan,a province in the North-East of Iran,is characterized by high coverage of loess deposits.Since 1963,the area has experienced approximately 200,000 ha deforestation due to land-use changes in agriculture and increasing demand for wood.Approximately,110,000 ha of the clear-cut lands are under dry-farming,mainly for wheat cropping,and about 86,000 ha have been reforested.This IAEA funded project is the first attempt to use nuclear techniques in the East of Hircanian Forest for determination of on-site impacts of deforestation due to two land-use changes(i.e.dry farming and reforestation).Practicing long-term dry-farming led to 60%soil losses with a mean rate of 2 mm per year.The net erosion rate of croplands on loess deposits in the study area was 32.27 t ha-1 yr-1.Reforestation,cultivation of even-aged Cypress trees since 1993,showed 13 to 60 percent effectiveness in soil conservation.Dry-farming land use resulted in the loss of 95 t ha-1 soil organic carbon(SOC)stock at a mean rate of 1.7 t ha-1 over 54 years.Cultivating Cypress trees successfully restored the SOC content by 100%compared with the SOC in original forests.The conversion of dry-farming lands to orchards of olive trees since 2004,brought more income for farmers but were less effective in soil conservation because of low canopy cover of olive trees.Our data provide key information and guidance for land users and decisionmakers about implementing strategic and sustainable conservation practices to restore degraded land.