Effect of soil moisture on transpiration.

1953 ◽  
Vol 4 (3) ◽  
pp. 326 ◽  
Author(s):  
ES West ◽  
O Perkman

The march of soil moisture content in an experimental citrus grove was determined by successive soil sampling. Following an irrigation the soil moisture content progressively falls owing to withdrawal of water by the plants. It was found that the soil moisture content could be expressed as an exponential function of the accumulated evaporation from a free water surface since the last irrigation. Curves of this type were constructed for the three kinds of cultural treatment studied. The rate of water withdrawal is a function of the soil moisture content.

1998 ◽  
Vol 2 (1) ◽  
pp. 129-136 ◽  
Author(s):  
J. W. Finch ◽  
R. J. Harding

Abstract. This paper compares direct measurements of evaporation with the values predicted for reference transpiration. The measurements of actual evaporation were made using an eddy correlation device on a grass field adjacent to the river Thames. Measurements of soil moisture and the driving meteorological variables were also made. The results showed that, during a period with minimal rainfall but no water stress, the cumulative values of reference transpiration compared very well with the cumulative measured evaporation and changes in soil moisture content. However, the values on specific days did not compare well. Following significant rainfall, the measured evaporation increased for a few days, probably due to evaporation of free water from the canopy or soil. Reference transpiration fell consistently below the measured evaporation once the soil moisture deficits exceeded 140 to 150 mm.


1958 ◽  
Vol 9 (6) ◽  
pp. 717 ◽  
Author(s):  
SA Waring ◽  
WE Fox ◽  
LJH Teakle

The effects on wheat yields of available soil moisture at planting, rainfall during the growing period, and evapo-transpiration were examined for the years 1951-1954. The relation between free water surface evaporation, available soil moisture, and evapo-transpiration was examined for the years 1951 and 1952. Wheat yields were found to be correlated with available soil moisture at planting for the four years combined, the two drier years combined (1951 and l953), and the two wetter years combined (1952 and 1954). The relationship for the four years combined was sufficiently strong to suggest that available moisture at planting could be successfully used for yield prediction. Yield was correlated with evapo-transpiration only for the dry year 1953. The ratio of yield to evapo-transpiration was found to be lower for the years of high rainfall during the growing period, the mean values for the wet and dry years being 2.1 and 3.5 bus./in. respectively. Growing-perlod rainfall was correlated with yield only for the month of August for the two dry years of 1951 and 1953 combined. Evapotranspiration (Etr) was found to be correlated with free water surface evaporation (Ew) and Ew0.75 in the monthly data, the value for C in the relationship Etr = CEw0.75 being calculated as 0.53. Available soil moisture was correlated with evapo-transpiration using data from the beginning and end of the season in 1953, but was not correlated using monthly data. The method of calculating monthly available soil moisture is shown to be important in this correlation. A method of calculating available soil moisture over a monthly period, based on a mean daily figure for the month, is described.


2014 ◽  
Vol 955-959 ◽  
pp. 3540-3543
Author(s):  
Ying Dui He ◽  
Xi Ding ◽  
Rui Mei Li ◽  
Yong Xia Liu ◽  
Bi Zun Wang

Soil moisture content and soil porosity were measured in banana plantation under three tillage practices, including deep-tillage (DT), no-tillage (NT), and no-tillage plus straw cover (NTSC). In the experiments, the top layer soil was separated into three depth including 0~15 cm, 15~30 cm and 30 ~ 45 cm. The soil sampling were performed at four plant growth periods, including the stage of banana seedling (SBS), metaphase of banana (MB), the stage of pregnancy (SP) and pumping stage (PS). The results showed that: Among three depth of top layers, soil moisture content in 0~15 cm at four plant growth periods was lower than that in other two depth by three tillage practices. In 0~15 cm top layer soil, all the soil moisture at four plant periods by NTSC practice were highest. And all the soil moisture in soil treated by three tillage practices were increased with the plant growth. The soil porosity in this layer at SBS and MB stages by DT practice was significantly higher than that by NT and NTSC practices. In 15~30 cm layer soil, the soil moisture content and soil porosity at SBS stage was highest in the soil treated by DT practice compared to the that in soil treated by other two tillage practices. In 30~45 cm layer, the soil porosity at SBS stage by DT and NTSC practices were significantly lower than that by NT practice. At MB stage by DT practice it was significantly higher than that by other practices.


2016 ◽  
Vol 4 (1) ◽  
Author(s):  
Muhammad Irvan Nurliansyah

ABSTRAK Limbah cair tahu merupakan limbah cair yang berasal dari proses pembuatan tahu. Limbah cair tahu mengandung senyawa organik yang tinggi. Pembuangan limbah cair tahu secara langsung ke badan air tanpa dilakukan pengolahan dapat mempengaruhi dan mencemari lingkungan. Suatu cara untuk menanggulangi permasalahan tersebut adalah melakukan pengolahan limbah cair tahu. Salah satu alternatif pengolahan limbah cair tahu yang dapat digunakan adalah fitoremediasi menggunakan tanaman genjer. Penelitian ini bertujuan untuk mengetahui efisiensi pengolahan dan efektivitas waktu tinggal pengolahan limbah cair tahu menggunakan tanaman genjer dalam menurunkan BOD dan COD effluen hasil proses pengolahan anaerob limbah cair tahu. Metode yang digunakan dalam penelitian ini adalah fitoremediasi menggunakan tanaman genjer pada sistem lahan basah buatan Free Water Surface flow dengan waktu tinggal 3 hari, 5 hari dan 7 hari. Hasil penelitian menunjukkan bahwa efisiensi pengolahan secara fitoremediasi pada hari ke 3 untuk BOD dan COD berturut-turut sebesar 21,28% dan 16,13%. Pada hari ke 5 efisiensi pengolahan yang diperoleh untuk BOD dan COD berturut-turut sebesar 52,60% dan 45,93% sedangkan efisiensi pengolahan pada hari ke 7 untuk BOD dan COD berturut-turut sebesar 76,42% dan 70,74%. Waktu tinggal efektif yang diperoleh pada penelitian ini adalah  7 hari dengan nilai BOD dan COD telah berada dibawah baku mutu yaitu berturut-turut sebesar 72,72 mg/l dan 213,33 mg/l.   Kata kunci : limbah cair tahu, fitoremediasi, tanaman genjer, efisiensi pengolahan, waktu tinggal


2011 ◽  
Vol 28 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Run-chun LI ◽  
Xiu-zhi ZHANG ◽  
Li-hua WANG ◽  
Xin-yan LV ◽  
Yuan GAO

2001 ◽  
Vol 66 ◽  
Author(s):  
M. Aslanidou ◽  
P. Smiris

This  study deals with the soil moisture distribution and its effect on the  potential growth and    adaptation of the over-story species in north-east Chalkidiki. These  species are: Quercus    dalechampii Ten, Quercus  conferta Kit, Quercus  pubescens Willd, Castanea  sativa Mill, Fagus    moesiaca Maly-Domin and also Taxus baccata L. in mixed stands  with Fagus moesiaca.    Samples of soil, 1-2 kg per 20cm depth, were taken and the moisture content  of each sample    was measured in order to determine soil moisture distribution and its  contribution to the growth    of the forest species. The most important results are: i) available water  is influenced by the soil    depth. During the summer, at a soil depth of 10 cm a significant  restriction was observed. ii) the    large duration of the dry period in the deep soil layers has less adverse  effect on stands growth than in the case of the soil surface layers, due to the fact that the root system mainly spreads out    at a soil depth of 40 cm iii) in the beginning of the growing season, the  soil moisture content is    greater than 30 % at a soil depth of 60 cm, in beech and mixed beech-yew  stands, is 10-15 % in    the Q. pubescens  stands and it's more than 30 % at a soil depth of 60 cm in Q. dalechampii    stands.


2011 ◽  
Vol 33 (1) ◽  
pp. 71-86
Author(s):  
Doorce S. Batubara ◽  
Donald Dean Adrian

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