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When the Yellow River flows through the Hetao Plain in Inner Mongolia, north China, it forms a mountain-river-desert system with the Yin Mountains on one side and the Hobq desert on the other side. In this mountain-river-desert system, a dense growth of green grass is formed in the area fronting the river and with the mountains at the back, however, on the opposite the river, the area has an inherent trend to lost moisture, which might cause desertification. This study verifies this theoretical conjecture by analyzing the Yellow River-bed change from 2014 to 2021. The seven year change showed the river is the inherent boundary between the grassland and the dessert, and it was nothing to do with the river banks' past earth surfaces. [ABSTRACT FROM AUTHOR]

Soil quality is the basis for the development of sustainable agriculture and may be used for evaluating the sustainability of soil management practices. Soil quality status and integrated soil quality index (SQI) in sampled 97 farmlands distributed in 7 barley agro-ecological areas of China were analyzed by using 13 soil chemical parameters. The results showed six principal components totally explained 72% variability for the 13 parameters and identified 9 parameters (includes pH, NH4+-N, NO3--N, available P, available K, exchangeable Mg, DTPA-Fe, DTPA-Cu and Cl-) with high factor loading values as the minimum data set (MDS) for assessing soil quality. Average soil quality of all farmlands is moderate (SQI = 0.62). The SQI of barley farmlands in 7 agro-ecological areas showed the following order: Inner Mongolia Plateau (0.75 ± 0.02) > Yunnan-Kweichow Plateau (0.72 ± 0.06) > Qinghai-Tibet Plateau (0.63 ± 0.08) > Yangtze Plain (0.62 ± 0.10) > Huanghuai Region (0.58 ± 0.09) > Northeast China Plain (0.56 ± 0.07) > Xinjiang Province (0.54 ± 0.07). Total 29 out of 97 farmlands in 7 areas have low SQI level (< 0.55). Hence, these farmlands require urgent attention for soil quality improvement through modification of the soil parameters in the MDS. [ABSTRACT FROM AUTHOR]