Abstract:Ⅰ. Soil moisture problems in the North China Plain and its associated areas were grouped into five categories according to the mode of soil moisture loss. Ⅱ. The diffusion theory does not account for the movement of moisture, under capillary forces, from free water into an uncompressed air-dry soil. Ⅲ. The rate of diffusion of moisture in soil samples from the heavy clayey horizons was correlated with penetration pressure of horizons. The rate of diffusion in horizontal soil columns was lower in samples from horizon or horizons with higher penetration pressure (kg/cm²). Ⅳ. The frequency of fluctuation of water table in heavy clayey profiles also bore certain relationship with the penetration pressure of the heavy clayey horizon or horizons in the Lower position of the profile.

Abstract:After soil survey of the whole region, it is found that the soils of the North China Great Plain consist of four great soil groups including drab soil, light meadow soil, glei swamp soil and saline soil. The term "calcareous alluvial soils" formerly used hardly interprets any mean of soil formation and productive characteristics.The drab soils formerly named as "Shangtung brown soils" are generally located on the alluvial fan and the foot of mountains. Owing to the higher relief, excess drainage and deeper ground water (below 4-6 meters), salinization is not found. The drab soil is neutral to slightly alkaline in reaction. The chemical data show no evidence of chemical decomposition of clay, but the disintegration of soil particles-clay formation is quite obvious. Along the foot of Taihang range, the drab soils are covered with new calcareous material and bring out the process of recalcification shown by the presence of pseudo-mycelins in the soil profiles.

Abstract:Географическое положение субтропиков грузии и тропиков Китая,Какизвестно,пезко различно.

Abstract:Гора Хуаншань расположена в низовье реки янцзы,в южной части провинции Аньхой.

Abstract:Experiments were conducted in 1955-1957 to determine the merits of the use of gravel as a soil mulch material instead of a mixture of sand and gravel widely used in Kansu. The results showed that(1) the effect of the gravel mulch on the soil temperature was as favorable as that of the sand-gravel mulch, (2) the gravel mulch was more effective in retaining soil moisture and(3) the growth and yield of the wheat grown on gravel mulched soil were slightly higher than those on sand-gravel mulched soil. The possibility of lengthening the effective period of the gravel mulch and of operating of farm machineries in gravel mulched fields is discussed.

Abstract:A definite type of hydrometer with linear and fine stem and parabolic bulb is suggested. Before measurement, the hydrometer should be well calibrated. The contents of soil particles of different size can be directly determined at different time after sedimentation of particles. Grinding the soil sample for five minutes is available for mechanical dispersion of soil particles. 60 ml of 0.5 N NaPO₃ for 50 grams of soils is suggested for calcareous soils and 60ml of 0.5 N NaOH for 50 grams of soils is suggested for lateritic soils.