scholarly journals A two layer soil moisture model for estimating crop evapotranspiration and runoff

MAUSAM ◽  
2021 ◽  
Vol 50 (4) ◽  
pp. 375-382
Author(s):  
H. P. DAS ◽  
A. CHOWDHURY ◽  
R. S. BHAGWAT

In the present study, a two layer model has been proposed to estimate evapotranspiration, soil moisture storage and runoff. For this purpose soil profile has been assumed to be composed of two layers : the top layer having a fixed field capacity of 100 mm and the underlying layer having field capacity depending on the soil texture. Normal values of rainfall and potential evapotranspiration have been used in the study.   The model, applied to kharif and rabi seasons furnishes crop evapotranspiration period when soil in two layers reach wilting point and surface runoff and its duration.   The model developed has been applied to 411ocations representing most of the soil types found in India. The analysis revealed that lowest ET is seen over Himalayan foothills and northeast India in kharif and rabi seasons. Enough residual soil moisture is available to the crops at the end of kharif season over NE India; most of it being in the top layer. Eastern India record largest runoff of 800-1000 mm. Arid to semi-arid region in NW India does not seem to experience much runoff.

2017 ◽  
Vol 17 (3) ◽  
pp. 148-159
Author(s):  
Samuel Lalronunga ◽  
C. Lalrinchhana

Specimens of a rare rhacophorid frog of the genus Theloderma were collected from Hmuifang, Mizoram, India. Based on their morphology and molecular analysis (16S rRNA), the specimens were identified as Theloderma moloch, a rare species previously recorded only from the Himalayan foothills of India and China. The present record significantly extends the known range of the species and is a first record for the state of Mizoram and Indo-Burma biodiversity hotspot. The uncorrected p-distance between the specimen from Mizoram, NE India and the specimen from Arunachal Pradesh, India (KU169993) and Tibet, China (KU243081) are 0.0% and 1.2% respectively.


1957 ◽  
Vol 5 (2) ◽  
pp. 151 ◽  
Author(s):  
RL Specht

Heath vegetation shows a major flush of growth during the mediterraneantype summer season, a time when calculations of the soil moisture storage by the techniques of Thornthwaite (1948) or Prescott, Collins, and Shirpurkar (1952) indicate that severe drought conditions should oocur. Monthly observations on the moisture status of the Makin sand under heath vegetation and, for comparison, under various pastures are therefore recorded. The problems of obtaining an accurate water balance-sheet for such a heterogeneous vegetation as the heath are discussed. Difficulties in the use of the various techniques for measuring soil moisture in sand, which has a low pF of 1.85 at field capacity, are enumerated. The following relationships were found between the evapotranspiration index (Itr = Etr / Ew0.75) and the available water (W). These data were calculated for 6 ft of sand. (i) Heath vegetation (10–14 years old) log (2.4–Itr) = 0.420–0.0383 W (ii) Heath vegetation (burnt) log (2.4–Itr) = 0.461–0.0380 W (iii) Oenothera odorata Jacq. pasture log (2.4–Itr) = 0.395–0.0269 W (iv) Medicago sativa L. pasture log (2.4–Itr) = 0.390–0.0270 W (v) Ehrharta calycina Sm. pasture log (2.4–Itr) = 0.400–0.0339 W From these equations the mean monthly quantities of rainfall which may be stored in 6 ft of sand under the various treatments described were calculated. Drought conditions are shown to occur in December and January, but are relieved in the later months of summer. Even if the stored moisture below 8 ft is considered, the soil moisture status would be expected to be just sufficient to maintain the vegetation in a "dormant" state, and yet the major growth of the heath vegetation occurs at this time. The calculated mean annual values of Itr range from 0.53 to 0.60 for these perennial communities. Close approximations to the actual soil moisture status can be obtained by substituting these values for K in Prescott's formula for potential evaporation, i.e. Etr = K x Ew0.75. Supplementary data on transpiration, growth, and the root systems of the pastures are also included.


1965 ◽  
Vol 45 (1) ◽  
pp. 33-38 ◽  
Author(s):  
W. S. Ferguson

Mean weekly evapotranspiration by spring wheat at Brandon, Man. (1955–1959) was dependent on the stage of development of the crop. It increased from 0.70 in. per week at the 3-leaf stage to 1.45 in. per week at the flowering stage and decreased to 0.60 in. per week as the crop reached maturity. Evapotranspiration was correlated positively with Bellani-plate evaporation when the soil was moist to the surface and correlated negatively when the surface soil was dry, but total soil moisture was greater than 50% of field capacity. When the soil moisture was less than 50% of field capacity evapotranspiration was not correlated with Bellani-plate evaporation. Evapotranspiration was correlated positively with total soil moisture plus rainfall. This emphasizes the importance of moisture stress in limiting evapotranspiration in a semi-arid region.


Author(s):  
P. R. Anjitha Krishna ◽  
B. Maheshwara Babu ◽  
A. T. Dandekar ◽  
R. H. Rajkumar ◽  
G. Ramesh ◽  
...  

Efficient utilization of available water resources requires appropriate management strategies considering the changing environmental conditions. The present study used a widely adopted crop water requirement estimation model-CROPWAT 8.0 for estimation and scheduling of irrigation requirement for onion crop grown under Vertisol in the Rabi season in the semi-arid region of Raichur district. The soil moisture at the root zone was not allowed to fall below 50% depletion. The irrigation events brought the soil moisture back to the field capacity level. The total water requirement for the 1st and 2nd seasons was 428.77 mm and 399.98 mm respectively at 90% irrigation efficiency. CROPWAT based two days irrigation scheduling scenario was found to be appropriate to maintain optimal soil moisture range within the crop root zone at different crop stages.


MAUSAM ◽  
2021 ◽  
Vol 68 (2) ◽  
pp. 279-286
Author(s):  
N. CHATTOPADHYAY ◽  
S. S. VYAS ◽  
B. K. BHATTACHARYA ◽  
N. S. TIDKE ◽  
N. G. DHANGAR

Under the present study estimation of high resolution soil moisture (SM) under Pan India mode using simple water balance method and from satellite data has been explored. It aims at the simple calculation of soil moisture followed by verification with ground truth data of SM on spatial and temporal scale (WC) as climatic input. The model has been verified for winter (January-February), pre-monsoon (March-May), monsoon (June-September) and post-monsoon (October-December) seasons of year 2013. The comparison of model estimates with the in-situ data from 17 ground stations (for 396 paired datasets) over different seasons produced a better correlation coefficient varying from 0.46 to 0.60. The spatial comparison of SM estimated from model and satellite SM for the monsoon season shows a greater degree of coherence over most parts of India. Model derived weekly gridded SM combined with higher resolution satellite SM could use simple formulation and minimum inputs in conjunction with geographic information system (GIS). The SM is calculated on weekly basis and using gridded rainfall, potential evapotranspiration (PET) and field capacity (FC) and wilting point be used for better accuracy of the proposed block level agrometadvisory services.


1991 ◽  
Vol 27 (3) ◽  
pp. 269-279 ◽  
Author(s):  
J. P. Wright ◽  
J. L. Posner ◽  
J. D. Doll

SummaryThe growing season in the semi-arid region of West Africa is drought prone and of irregular duration. Two experiments were conducted in 1986 and 1987 to test the effects of flat cultivation and tied ridge cultivation (TRC) on the yields of maize and the component crops of a maize and cowpea relay cropping system. The two research sites, with slopes of 0.05% and 3%, were near Sapu, The Gambia, on an Aridic Kandiustalf in the 700 mm rainfall zone.Both growing seasons had above average rainfall. In both years, maize on level sites showed no response to tillage practices. On the sloped site in 1987, soil moisture 10 and 15 days after the last rain was greater with TRC than with flat cultivation and yields of sole cowpea and maize were 25% and 18% greater, respectively. On the level site, TRC had no effect on residual soil moisture or grain yield. When rainfall was well distributed, tied ridging did not appear to be a viable tillage alternative for maize-based systems on flat land in central Gambia but with modest slopes, tied ridges markedly increased soil water reserves in the 0.15 to 0.60 m depth after maize harvest.


2021 ◽  
Vol 13 (1) ◽  
pp. 167-202
Author(s):  
Musa Oladejo Kehinde ◽  
Aliyu Tambuwal Umar

The estimation of soil moisture storage is fundamental to crop production, hydrological and biological processes. This study assessed soil moisture storage in Nigeria using the Climatic Water Budgeting Approach. Mean monthly air temperature and monthly rainfall data were collected from the archives of the Nigerian Meteorological Agency from 27 weather stations in Nigeria. The data were subjected to Climatic Water Budgeting Approach to compute the monthly soil moisture storage at different locations in Nigeria over two years with contrasting moisture conditions (1983 and 2003). The mean monthly air temperature data were used to estimate the monthly potential evapotranspiration (PE) while the PE in conjunction with the mean monthly rainfall and the soil water holding capacity of 250mm were used to calculate the monthly soil moisture storage. The results showed that most locations north of latitude 9°N recorded low soil moisture storage below 10 mm from April to July especially in 1983. The soil moisture storage was high in all the places in January and February due to low potential evapotranspiration and accumulated potential water loss (APWL). Most Places South of latitude 9°N recorded higher soil moisture storage between 20 mm and 100 mm from January to May compared to their counterparts north of latitude 9°N in both 1983 and 2003. The soil moisture storage attained 250 mm (100%) from July-October across Nigeria. This study concluded that the soil moisture varies spatially and temporally in Nigeria decreasing from South to North. A paired sample test revealed a significant difference between the soil moisture storage of 2003 and 1983 in Nigeria (p=.000).


1989 ◽  
Vol 20 (2) ◽  
pp. 109-122 ◽  
Author(s):  
Lotta Andersson

Some commonly used assumptions about climatically induced soil moisture fluxes within years and between different parts of a region were challenged with the help of a conceptual soil moisture model. The model was optimised against neutron probe measurements from forest and grassland sites. Five 10 yrs and one 105 yrs long climatic records, from the province of Östergötland, situated in south-central Sweden, were used as driving variables. It was concluded that some of the tested assumptions should not be taken for granted. Among these were the beliefs that interannual variations of soil moisture contents can be neglected in the beginning of the hydrological year and that soils usually are filled up to field capacity after the autumn recharge. The calculated climatic induced dryness was estimated to be rather insensitive to the choice of climatic stations within the region. Monthly ranges of soil moisture deficits (1883-1987) were shown to be skewed and it is therefore recommended to use medians and standard deviations in statistical analyses of “normal” ranges of soil moisture deficits.


2011 ◽  
Vol 59 (1) ◽  
pp. 13-22
Author(s):  
Z. Varga-Haszonits ◽  
E. Enzsölné Gerencsér ◽  
Z. Lantos ◽  
Z. Varga

The temporal and spatial variability of soil moisture, evapotranspiration and water use were investigated for winter barley. Evaluations were carried out on a database containing meteorological and yield data from 15 stations. The spatial distribution of soil moisture, evapotranspiration and water use efficiency (WUE) was evaluated from 1951 to 2000 and the moisture conditions during the growth period of winter barley were investigated. The water supply was found to be favourable, since the average values of soil moisture remained above the lower limit of favourable water content throughout the growth period, except for September–December and May–June. The actual evapotranspiration tended to be close to the potential evapotranspiration, so the water supplies were favourable throughout the vegetation period. The calculated values of WUE showed an increasing trend from 1960 to 1990, but the lower level of agricultural inputs caused a decline after 1990. The average values of WUE varied between 0.87 and 1.09 g/kg in different counties, with higher values in the northern part of the Great Hungarian Plain. The potential yield of winter barley can be calculated from the maximum value of WUE. Except in the cooler northern and western parts of the country, the potential yield of winter barley, based on the water supply, could exceed 10 t/ha.


Sign in / Sign up

Export Citation Format

Share Document