No abstract available

[en] A method of determining the density and moisture content of in situ soil, using nuclear equipment is described. The advantages of this method over the two conventional methods, viz. the sand-replacement method and the core-cutter method along with the disadvantages are outlined. The various components of the equipment used are mentioned. (K.B.)

[en] The use of micropsychrometers with Peltier effect and tensiometers made possible the study of the variations in soil matrix potential under a maize culture in space and time. The simultaneous measurement of the voluminal humidity through the neutron method enabled to observe the relatonship of the potential and the humidity. No significant hysteresis effect could be stated, but it appears that the extrapolation of the relationships of potential and humidity stated on soil samples under laboratory conditions to the field must be cautiously undertaken, which stresses the interest of knowing techniques for measuring directly matrix potential and humidity

[en] Hydrophobic calibration standard for a soil moisture meter comprising successive layers of a material moderator containing hydrogen and a non-moderating material

[en] The evaporation of water from, and redistribution of water within, intact monoliths (23.6 cm diameter, 60 cm depth) of red earth were studied in a glasshouse under a wide range of evaporative conditions. A neutron moisture meter was appropriately calibrated and used to document changes in the distribution of soil water. This is a novel use for such equipment. Strongly curved and generally different calibrations were required for each depth

[en] Separate abstracts were prepared for only 4 papers of these proceedings that is to say only nuclear methods for moisture determination

[en] Every week, during two years and a half, the soil moisture was measured by means of neutron probe till 6 m depth under a dense moist forest of Ivory Coast, and till 2 m under a neighbouring irrigated banana trees plantation. The authors show that, under forest, the variations of the moisture totalize 120 mm in the first meter, and 200 mm in the whole soil profile; under banana trees, the roots activity is limited to 30 centimeters. The water balance under forest indicates that the real evapotranspiration (RET) reaches 79% of the rainfalls by neutron probe method, and 72% with the modified Thorntwaite method and in the next watersheds. Then, the difficulties of the use of neutron probe in humid tropical area and the signification of the moisture variations observed under forest till 4 to 6 m depth, are discussed

[en] Results of a field experiment on the effects of two irrigation treatments and rain-fed on yield and crop water use of groundnut is presented in this paper. Yield of groundnut (3.1 t. ha-' and 3.2 t. ha-' respectively) show good response to both irrigation treatments when earlier flowering stage coincide with a dry period. Data on changes in soil water content with time, measured by a neutron moisture gauge was used to estimate crop water use/crop evapotranspiration using a water balance approach in the presence of zero flux plane. The low water use of groundnut (64.5 mm) grown in the rain-fed plot when compared to both the irrigated plots (124.5 mm and 152 mm respectively) during a dry period resulted in a low yield of 1.9 t. ha-'. In the rain-fed plot, from early flowering to start of pod setting stage, the soil at 20 cm depth constantly dry, as indicated by a continuously decreasing value of the hydraulic head value to < -7OkPa. With the yield response factor ky for flowering stage being 0.74, the decrease in groundnut yield due to water deficit flowering stage is relatively large

[en] The precast concrete industry manufactures requires a good knowledge and control of the humidity factor: during the manufacturing process, in order to regulate the water content of aggregates, or the fresh concrete workability: during the quality control of the product characteristics. The principles of measurements: conductivity, dielectric characteristics and neutron moisture meters are compared for cost, humidity range, accuracy, temperature dependence, interfering elements, density dependence, grain size and shape

No abstract available