Soil Water Storage

The family-based agriculture in the Western region of Santa Catarina State is characterized by a diversity of integrated crop-livestock systems, combining different uses and managements in a complex set of soil types. These systems can changes in their physical and hydrological properties and influence its physical qualities, including the capacity to storage of water available to crops. In the studied region, periods of water deficiencies frequently reduce the productivity of maize, the crop of major socioeconomic importance. This study complies a priority demand set in 2009 by Epagri – UGT9 in the field of water resources management, focusing methods of catchment, storage and use of water in agriculture. Our goals were to analyze the
changes in the soil's physical and hydrological properties in several production systems and the effects of water limitation on maize production. We analyzed the effect of land uses and management in the commonest soil types and on the readily
available water storage and estimated the reduction in productivity due to water limitation in simulations, considering different seeding seasons. We conducted the
research in 36 family-based properties in the West region of Santa Catarina State. We collected soil samples of three classes, in three land uses and management types, four properties and four soil layers (0-0.10, 0.10-0.20, 0.20-0.40 e 0.40-0.60 m), totaling 144 samples, following a factorial design. We used the software ISAREG to calculate the water balance according to the Penman-Monteith/FAO methodology
and estimated the loss of maize productivity for the seasons 1989/90 to 2010/11, simulating 19 different seeding dates and three different maturation cycles. We concluded that (1) the changes in the soil's physical and hydrological properties due
to the land uses and management didn't impair the physical quality of the soils in the region; (2) the managements of minimum tillage, direct seeding and permanent pastures didn't affected the readily available water storage; (3) that, otherwise, the variations in water storage were influenced by the soil classes; (4) the mean content of readily available water storage was 31.4 and 49.6% higher in Cambissoils,
comparing respectively with Latossoils and Nitossoils in the minimum tillage system; (5) the ISAREG model estimated a mean reduction of maize productivity of 25.1%; (6) the highest loss was for August seeding and the lowest for seeding in January and February, varying up to 3.9% among maturation cycles evaluated; (7) the ISAREG model was appropriate to estimate the loss in productivity, but overestimates the loss when Etr / Etc-1 rate is greater than 0.8; (8) there is a 50%
probability of maize productivity losses of 25% in the evaluated seasons for the western region of Santa Catarina.

Degraded soils in the sub-Saharan zone are often unproductive because of nutrient imbalance and an inadequate water supply. We conducted an experiment in the northern sudanian climate zone of Burkina to study the effect of integrated local water and nutrient management practices on soil water balance, sorghum performance and sorghum’s water use efficiency. The trial (Ferric Lixisol, 1.5% slope) consisted of two replications of nine treatments in which soil and water conservation (SWC) measures (stone rows, grass strips) and organic or mineral N-inputs (compost, manure, urea-N) were applied alone or in combination and compared to a control treatment with no N-input and no SWC measure. Application of compost improved soil water storage in the sorghum-rooting zone (0–80 cm) most when combined with stone rows or grass strips and when the year had well-distributed rainfall. However, during an erratic rainy season there was less soil water storage in the organic treatments than in the mineral treatment. Supplying compost increased evapotranspiration and soil drainage more than nutrient inputs did. Furthermore, stone rows allowed greater evapotranspiration and drainage than grass strips, and the two permeable barriers alone had a significant effect on soil water storage compared with treatments without barriers. In the rain-fed cropping system studied, we found that in an erratic rainy season with frequent periods of water stress, the stone rows or grass strips combined with compost reduced runoff and increased soil water storage and sorghum biomass production. These combined practices created sound soil water conditions and were able to satisfy the sorghum’s water demand for growth. We conclude that the synergistic effect of water-harvesting practices and the supply of organic or mineral resources increased water use efficiency. It seems that an optimum combination of organic resources and fertilisers could improve the water use efficiency (i.e. reduce runoff and drainage losses) and the productivity of Sahelian rain-fed agriculture.

Summary Th e aims of the study were to apply, test and to present the ability of the deterministic simulation models SIMWASER and CERES-Wheat computing soil-water balance components, percolation losses, ground water recharge and capillary rise. Two case studies for the assessment of percolation losses from irrigated carrots to deep groundwater at Obersiebenbrunn in the Marchfeld (Austria) and ground water recharge and capillary rise from shallow groundwater in grass lysimeters at Berlin-Dahlem (Germany) together with two test sites with similar climatic conditions and soil water storage potential but with (Grossenzesdorf, Austria) and without (Zabcice, Czech Republic) groundwater impact in a semi-arid agricultural area in central Europe were chosen. At Obersiebenbrunn, simulated percolation and evapotranspiration were 183 and 629 mm, while the respective measured values amounted to 198 and 635 mm. Up to 42% (194 mm) of evapotranspiration was provided by groundwater at s Grossenzesdo...

Rural land management is known to affect both the generation and propagation of flooding at the local scale, but there is still a general lack of good evidence that this impact is still significant at the larger catchment scale given the complexity of physical interactions and climatic variability taking place at this level. The National Trust, in partnership with the

Hillslope response to rainfall remains one of the central problems of catchment hydrology. Flow processes in a one-dimensional sloping aquifer can be described by Boussinesq's hydraulic groundwater theory. Most hillslopes, however, have complex three-dimensional shapes that are characterized by their plan shape, profile curvature of surface and bedrock, and the soil depth. Field studies and numerical simulation have shown that these attributes are the most significant topographic controls on subsurface flow and saturation along hillslopes. In this paper the Boussinesq equation is reformulated in terms of soil water storage rather than water table height. The continuity and Darcy equations formulated in terms of storage along the hillslope lead to the hillslope-storage Boussinesq (HSB) equation for subsurface flow. Solutions of the HSB equation account explicitly for plan shape of the hillslope by introducing the hillslope width function and for profile curvature through the bedrock slope angle and the hillslope soil depth function. We investigate the behavior of the HSB model for different hillslope types (uniform, convergent, and divergent) and different slope angles under free drainage conditions after partial initial saturation (drainage scenario) and under constant rainfall recharge conditions (recharge scenario). The HSB equation is solved by means of numerical integration of the partial differential equation. We find that convergent hillslopes drain much more slowly compared to divergent hillslopes. The accumulation of moisture storage near the outlet of convergent hillslopes results in bell-shaped hydrographs. In contrast, the fast draining divergent hillslopes produce highly peaked hydrographs. In order to investigate the relative importance of the different terms in the HSB equation, several simplified nonlinear and linearized versions are derived, for instance, by recognizing that the width function of a hillslope generally shows smooth transition along the flow direction or by introducing a fitting parameter to account for average storage along the hillslope. The dynamic response of these reduced versions of the HSB equation under free drainage conditions depend strongly on hillslope shape and bedrock slope angle. For flat slopes (of the order of 5%), only the simplified nonlinear HSB equation is able to capture the dynamics of subsurface flow along complex hillslopes. In contrast, for steep slopes (of the order of 30%), we see that all the reduced versions show very similar results compared to the full version. It can be concluded that the complex derivative terms of width with respect to flow distance play a less dominant role with increasing slope angle. Comparison with the hillslope-storage kinematic wave model of [2002] shows that the diffusive drainage terms of the HSB model become less important for the fast draining divergent hillslopes. These results have important implications for the use of simplified versions of the HSB equation in landscapes and for the development of appropriate analytical solutions for subsurface flow along complex hillslopes.

The groundnut cropping basin of Senegal suffers environmental degradation, with a negative impact on local agriculture, shown by intense soil erosion. Despite the existence of many extensive programmes, there are few results concerning actual effects, at the hillside scale, of rehabilitation practices. The object of the study, carried out from 1983 to 1993, was to give evidence of the actual

Conservation tillage (CT) is a key tool in sustainable production systems throughout the world. It has been particularly effective at sustaining crop production in semi-arid rain-fed regions. Wherever potential evaporation exceeds precipitation during most months of the year, proper application of water-conserving CT technology is critical. This paper reviews the progress made in CT management, with particular focus on the U.S.A. and Australia, two temperate developed countries with a long history of using CT. Parallels are drawn to other regions of the world when appropriate. Data on farmer’s use of CT are provided, as are some reasons for lack of adoption by farmers. Despite decades of research and education on the benefits of CT, a majority of farmers in the U.S.A. and Australia do not practice CT on their farms. In some regions, adoption of CT is high for one crop in rotation but low for another crop in the same sequence on the same soil. The unwillingness of farmers to adopt CT...

Abstract. Improved fallows are the deliberate planting of fast-growing species – usually legumes – for rapid replenishment of soil fertility. Improved fallows are rapidly spreading in several regions of the tropics as a sensible way for in situ accumulation of large quantities of N in ...

This article describes measurements made at each site and for each vegetation cover as part of the soils program for the HAPEX-Sahel regional scale experiment. The measurements were based on an initial sampling scheme and included profile soil water content, surface soil water content, soil water potential, infiltration rates, additional measurements on core samples, and grain size analysis. The measurements were used to categorize the state of the surface and profile soil water regimes during the experiment and to derive functional relationships for the soil water characteristic curve, unsaturated hydraulic conductivity function, and infiltration function. Sample results for different supersites and different vegetation covers are presented showing soil water profiles and total soil water storage on days corresponding to the experimental ‘Golden Days’. Sample results are also presented for spatial and temporal distribution of surface moisture content and infiltration tests. The results demonstrate that the major experimental objective of monitoring the supersites during the most rapid vegetative growth stage with the largest change of the surface energy balance following the rainy season was very nearly achieved. Separation of the effects of probable root activity and drainage of the soil profile is possible. The potential for localized advection between the bare soil and vegetation strips of the tiger bush sites is demonstrated.

Several North American broad-leaved tree species range from the northern United States at ∼47°N to moist tropical montane forests in Mexico and Central America at 15–20°N. Along this gradient the average minimum temperatures of the coldest month (T Jan), which characterize annual variation in temperature, increase from −10 to 12°C and tree phenology changes from deciduous to leaf-exchanging or evergreen in the southern range with a year-long growing season. Between 30 and 45°N, the time of bud break is highly correlated with T Jan and bud break can be reliably predicted for the week in which mean minimum temperature rises to 7°C. Temperature-dependent deciduous phenology—and hence the validity of temperature-driven phenology models—terminates in southern North America near 30°N, where T Jan>7°C enables growth of tropical trees and cultivation of frost-sensitive citrus fruits. In tropical climates most temperate broad-leaved species exchange old for new leaves within a few weeks in January-February, i.e., their phenology becomes similar to that of tropical leaf-exchanging species. Leaf buds of the southern ecotypes of these temperate species are therefore not winter-dormant and have no chilling requirement. As in many tropical trees, bud break of Celtis, Quercus and Fagus growing in warm climates is induced in early spring by increasing daylength. In tropical climates vegetative phenology is determined mainly by leaf longevity, seasonal variation in water stress and day length. As water stress during the dry season varies widely with soil water storage, climate-driven models cannot predict tree phenology in the tropics and tropical tree phenology does not constitute a useful indicator of global warming.

The presence of ice in soil dramatically alters soil hydrologic and thermal properties. Despite this important role, many recent studies show that explicitly including the hydrologic effects of soil ice in land surface models degrades the simulation of runoff in cold regions. This paper addresses this dilemma by employing the Community Land Model version 2.0 (CLM2.0) developed at the National

Within the scope of the HAPEX-Sahel experiment, the hydrological functioning of two small nested catchments was studied at two different scales: the plot scale (of the order of 100 m2) and the catchment scale (0.2 km2). At local scale, four runoff plots were set-up on the typical soil surface conditions observed on the catchments (plateau bare soil, two plots on

This paper investigates the application of data obtained from a field of spatial distribution of rainfall accumulated in area. In order to determine the water balance, this distribution was quantified by weather radar. Considerations related to spatial, temporal variability of rainfall and soil as well as a new methodology to obtain the water balance is presented. This methodology uses a