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III(i) Water and Crops
Published in Richard J. Chorley, Introduction to Geographical Hydrology, 2019
It is obvious that soil moisture exists in several degrees of utility for plants; that in excess of field capacity is superfluous, leads to oxygen deficiency, and needs to be drained; whereas, at the other extreme, moisture below the permanent wilting point is not available for plant growth – indeed, at a tension greater than the hydroscopic coefficient (31 atmospheres) it loses most of its liquid properties. The amount of available soil moisture depends partly on the characteristics of the plant and partly on the soil type. Figure 4.III(i).2 shows the percentage of available water in four main soil types, sand having the least (7%) and silt loam the most (16%). Finer-textured soils can hold more available moisture because of a combination of greater total pore space, the greater wettable surface area of the soil particles and, usually, a greater proportion of water-retaining colloidal matter. Factors affecting the ability of plants to avail themselves of soil water are the extension of the root system, the drought-resistant properties of the plant, and the stage and rate of its growth. Plant roots only draw soil water from their immediate neighbourhood. It is not clear whether soil moisture is equally available to a plant throughout the whole range from permanent wilting point to field capacity, and it has been suggested that the optimum moisture zone occurs at a moisture content considerably above the permanent wilting point.
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Published in Megh R. Goyal, Susmitha S. Nambuthiri, Richard Koech, Technological Interventions in Management of Irrigated Agriculture, 2018
Precipitation is the most important climatic variable influencing soil moisture content. Studies have observed that as the soil becomes wet, variability in soil moisture increases, and decreases with increasing time since the last rainfall as Mohanty and Skaggs24 reported. But in the present study, an opposite trend was observed as also reported by others, for example, Famiglietti et al.7 The precipitation data (Fig. 5.5b) indicated obvious temporal variability of rainfall in the field. The weekly cumulative precipitation ranged from 42.96 to 0.00 cm. The largest precipitations occurred during winter months of December to March and the lowest during July to August of both the years. Da Silva et al.5 observed that during snow melt, soils approach saturation, spatial variability in soil water content begins to develop as drainage begins, evolves through the growing season, and then diminishes as evapotranspiration declines and late rainfalls become increasingly prevalent.
Drip and Surface Irrigation Methods: Irrigation Scheduling Of Onion, Cauliflower, and Tomato
Published in Ajai Singh, Megh R. Goyal, Micro Irrigation Engineering for Horticultural Crops, 2017
Irrigation scheduling is a critical management input to ensure optimum soil moisture status for proper plant growth and development, optimum yield, and fruit quality, water use efficiency, and economic benefits. Irrigation scheduling to determine the frequency and amount of water application is governed by various factors, but climate plays an important role. Therefore, it is essential to develop irrigation scheduling strategy under local climate conditions to utilize water source more effectively and efficiently. Irrigation provides means for optimum plant water use and crop yield. Implementing sound irrigation water management practices is necessary to overcome excessive irrigation and eliminate many associated problems. Irrigation scheduling becomes crucial element in reducing deep percolation and improving water quality downstream [1]. Soil moisture condition affects nutrient availability to crop. The relationship between yield and crop water use has been investigated and studies have been carried out also on development and evaluation of irrigation scheduling techniques under the wide range of irrigation system and management, soil, crop, and climatic conditions [12,24].
Recent advances in improving the remediation performance of microbial electrochemical systems for contaminated soil and sediments
Published in Critical Reviews in Environmental Science and Technology, 2023
Ruixiang Li, Jinning Wang, Tian Li, Qixing Zhou
Generally, there is a positive correlation between soil moisture and remediation performance (Wang et al., 2013). The increase in soil moisture can highly reduce the internal resistance and enhance the activity and metabolic rate of microorganisms, which is of benefit for electron transfer and pollutant degradation (Budihardjo et al., 2021). Bioremediation of unsaturated soil with low water content has been a great challenge. The pollutant removal efficiency can be efficiently enhanced by increasing the water content of the soil/sediment or reducing the evaporation of water (Domínguez-Garay et al., 2013). The application of a moisture retention layer of polyacrylamide hydrogel around the anodes in a SMES was proven to be beneficial in water retention, which could significantly extend and enhance hydrocarbon degradation in vadose zone soil (Wang, Cui, et al., 2020).
Effect of soil moisture on soil compaction during skidding operations in poplar plantation
Published in International Journal of Forest Engineering, 2021
Farzam Tavankar, Rodolfo Picchio, Mehrdad Nikooy, Meghdad Jourgholami, Francesco Latterini, Rachele Venanzi
Rut depth is a measure of the severity of traffic or soil disturbance and the deeper the rut, presumably the more severely the soil is disturbed (Heninger et al. 2002). The results showed that the average RD was significantly higher in moist soil than in the dry site, under the same traffic intensity. The soil moisture content had a significant effect on RD (P < 0.01). Consistent with these results, Naghdi et al. (2016a) reported RD was significantly affected by traffic intensity, slope gradient, and soil moisture content. When the soil moisture is close to saturation and soil voids are filled with water, skidding operations result in soil loss, rutting, breaking the natural drainage structure, and digging the surface layer of soil, leading to a reduction in soil stability (Nikooy et al. 2015).
Integrating satellite soil-moisture estimates and hydrological model products over Australia
Published in Australian Journal of Earth Sciences, 2020
M. Khaki, A. Zerihun, J. L. Awange, A. Dewan
Soil-moisture has a significant impact on hydrology and is essential for agriculture and the broader ecosystem functioning and productivity (Doraiswamy et al., 2004; Lakhankar, Krakauer, & Khanbilvardi, 2009; Lawless, Semenov, & Jamieson, 2008; Wyland et al., 1996). Water contents in the soil surface and root-zone layers are critical for applications such as drought monitoring and understanding soil-moisture effects on water cycles (e.g. Enenkel et al., 2016; Jupp, Guoliang, McVicar, Yi, & Fuqin, 1998; Roderick, Sun, Lim, & Farquhar, 2014; Xu, Wang, Ross, Liu, & Berry, 2018). Consequently, knowledge of soil-moisture status, in time and space, is important for management of water, soil and vegetation resources including fire-risk assessment. However, the utility of soil moisture for such applications is dependent on the accuracy of soil-moisture monitoring systems.