scholarly journals Spatial and Temporal Distribution of Soil Water Content in Fields under Different Vegetation Conditions Based on TDR Measurements

2003 ◽  
Vol 37 (4) ◽  
pp. 243-248 ◽  
Author(s):  
Teruhito MIYAMOTO ◽  
Mahithon PUTISO ◽  
Takahiro SHIONO ◽  
Hiroyuki TARUYA ◽  
Jiro CHIKUSHI
2019 ◽  
Vol 11 (3) ◽  
pp. 366 ◽  
Author(s):  
Jing Yuan ◽  
Xin Wang ◽  
Chang-xiang Yan ◽  
Shu-rong Wang ◽  
Xue-ping Ju ◽  
...  

The variation and the spatial–temporal distribution of soil water content have significant effects on heat balance, agricultural moisture, etc. A soil moisture (SM) retrieval model can provide a theoretical basis for realizing a rapid test and revealing the spatial–temporal variation of the surface water. However, remote sensors do not measure soil water content directly. Therefore, it is of great importance to establish a SM retrieval model. In this paper, the relationship between SM and diffuse reflectance was first derived using the absorption coefficient and scattering coefficient related to SM. Then, based on Kubelka–Munk (KM) theory, the SM retrieval model using reflectance information was further derived, which is a semi-empirical model with an unknown parameter obtained either from fitting or from experimental measurements. The validity and reliability of the model were confirmed with the validation set. The results showed that the root mean square errors of prediction (RMSEPs) of four soils were generally less than 0.017, while the coefficients of determination (R2s) of four soils were generally more than 0.85, and the ratios of the performance to deviation (RPDs) of four soils were greater than 2.5 (470–2400 nm). Therefore, the model has high prediction accuracy, and can be well applied to the prediction of water content in different sorts of soils.


2020 ◽  
Vol 12 (11) ◽  
pp. 234
Author(s):  
Alexsandro dos Santos Brito ◽  
Paulo Leonel Libardi ◽  
Jaedson Cláudio Anunciato Mota ◽  
Sergio Oliveira Moraes

The knowledge on the temporal stability of spatial variability of soil water storage in the crops’ root zone is of fundamental importance for soil and water management. The objective of this work was to characterize the temporal distribution of water storage in a Latossolo vermelho amarelo and identify field locations with spatial patterns of high, intermediate and low soil water storage, in 13 samplings every 14 days. The assessed period included periods of drying and water recharge of the soil, along which soil water content was determined at 60 sampling points arranged in a 5 × 5 m grid covering an area of 1250 m2 (25 × 50 m). Soil water content was determined by means of a neutron probe, at soil depths of 0.2, 0.4, 0.6, 0.8 and 1.0 m. Soil water storage was calculated by Simpson’s rule and data were analyzed by the temporal persistence of the spatial pattern. Maximum values of soil water storage were obtained at the portion of the area with water flux concentration (sampling points 4, 28 and 57), with and without outliers, and low values of soil water storage were obtained at the highers levels of the site (sampling points 12, 18 and 19), with and without outliers. The sites representing the mean soil water storage were 32, 51 and 11, considering outliers, and 8, 11 and 53, without considering outliers.


Author(s):  
M.C.H.Mouat Pieter Nes

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.


2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
Author(s):  
E. Tóth ◽  
Cs. Farkas

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.


Author(s):  
Justyna Szerement ◽  
Aleksandra Woszczyk ◽  
Agnieszka Szyplowska ◽  
Marcin Kafarski ◽  
Arkadiusz Lewandowski ◽  
...  

2014 ◽  
Vol 22 (3) ◽  
pp. 300-307
Author(s):  
Meijun ZHANG ◽  
Wude YANG ◽  
Meichen FENG ◽  
Yun DUAN ◽  
Mingming TANG ◽  
...  

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 549f-550
Author(s):  
Mongi Zekri ◽  
Bruce Schaffer ◽  
Stephen K. O'Hair ◽  
Roberto Nunez-Elisea ◽  
Jonathan H. Crane

In southern Florida, most tropical fruit crops between Biscayne and Everglades National Parks are irrigated at rates and frequencies based on experience and observations of tree growth and fruit yield rather than on reliable quantitative information of actual water use. This approach suggests that irrigation rates may be excessive and could lead to leaching of agricultural chemicals into the groundwater in this environmentally sensitive area. Therefore, a study is being conducted to increase water use efficiency and optimize irrigation by accurately scheduling irrigation using a very effective management tool (EnviroScan, Sentek Environmental Innovations, Pty., Kent, Australia) that continuously monitors soil water content with highly accurate capacitance multi-sensor probes installed at several depths within the soil profile. The system measures crop water use by monitoring soil water depletion rates and allows the maintenance of soil water content within the optimum range (below field capacity and well above the onset of plant water stress). The study is being conducted in growers' orchards with three tropical fruit crops (avocado, carambola, and `Tahiti' lime) to facilitate rapid adoption and utilization of research results.


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