scholarly journals SOIL MOISTURE AND ITS INFLUENCE ON PASTURE PRODUCTION IN THE WAIKATO

Author(s):  
J.A. Baars ◽  
J.D. Coulter

The occurrence and distribution of soil moisture deficit days in the Waikato were determined for 43 years (1930-73) by calculating day-to-day changes in soil moisture for four soil types. The calculations were based on actual daily rainfall data and an estimate of mean daily potential evapotranspiration. Seasonal distributions of the number of deficit-days are given. On three soil types with 87, 102 and 117 mm of available soil moisture there were more than 20 such days in at least 15 of the 43 years. January to April inclusive are the "high-risk months". A significant negative correlation was obtained between the number of deficit-days and pasture production from a non-irrigated, "rate-of-growth" trial, such that 20 deficit-days gave a 21% reduction in expected annual pasture production (below that expected with no deficit-days).

Crop Science ◽  
1987 ◽  
Vol 27 (6) ◽  
pp. 1177-1184 ◽  
Author(s):  
R. B. Flagler ◽  
R. P. Patterson ◽  
A. S. Heagle ◽  
W. W. Heck

Forests ◽  
2015 ◽  
Vol 6 (12) ◽  
pp. 3748-3762 ◽  
Author(s):  
Ming-Han Yu ◽  
Guo-Dong Ding ◽  
Guang-Lei Gao ◽  
Yuan-Yuan Zhao ◽  
Lei Yan ◽  
...  

Science ◽  
2020 ◽  
Vol 370 (6520) ◽  
pp. 1095-1099 ◽  
Author(s):  
Peng Zhang ◽  
Jee-Hoon Jeong ◽  
Jin-Ho Yoon ◽  
Hyungjun Kim ◽  
S.-Y. Simon Wang ◽  
...  

Unprecedented heatwave-drought concurrences in the past two decades have been reported over inner East Asia. Tree-ring–based reconstructions of heatwaves and soil moisture for the past 260 years reveal an abrupt shift to hotter and drier climate over this region. Enhanced land-atmosphere coupling, associated with persistent soil moisture deficit, appears to intensify surface warming and anticyclonic circulation anomalies, fueling heatwaves that exacerbate soil drying. Our analysis demonstrates that the magnitude of the warm and dry anomalies compounding in the recent two decades is unprecedented over the quarter of a millennium, and this trend clearly exceeds the natural variability range. The “hockey stick”–like change warns that the warming and drying concurrence is potentially irreversible beyond a tipping point in the East Asian climate system.


1966 ◽  
Vol 46 (3) ◽  
pp. 299-315 ◽  
Author(s):  
W. Baier ◽  
Geo. W. Robertson

A new technique for the estimation of daily soil moisture on a zone-by-zone basis from standard meteorological data is herewith presented. The method, which is more versatile than existing meteorological budgets and therefore called "versatile budget" (VB), makes use of some basic concepts employed in the modulated budget, such as taking potential evapotranspiration (PE) as a possible maximum of actual evapotranspiration (AE) and subdividing the total available soil moisture into several zones of different capacities. The VB facilitates moisture withdrawal simultaneously from different depths of the soil profile permeated by roots in relation to the rate of PE and the available soil moisture in each zone. Adjustments for runoff, drainage, different types of soil-drying curves and the effect of different atmospheric demand rates on the AE/PE ratio are also incorporated.Comparisons between daily soil moisture readings from Colman blocks with estimates from the modulated budget and from the VB showed the feasibility of estimating daily soil moisture from standard meteorological data. The estimates of the VB were superior to those from the modulated budget on a zone-by-zone basis. The application of soil moisture statistics obtained from meteorological budgets is discussed.


Sign in / Sign up

Export Citation Format

Share Document