Measurement and prediction of permethrin persistence in six Malaysian agricultural soils

Soil Research ◽  
2002 ◽  
Vol 40 (5) ◽  
pp. 817 ◽  
Author(s):  
B. S. Ismail ◽  
Kalithasan Kailasam

The effect of soil types, soil temperature, and soil moisture content on the degradation of permethrin was studied under controlled greenhouse conditions. Six soils were used in the study: Soil 1 (Teringkap series), Soil 2 (Ringlet series), Soil 3 (Teringkap 2), Soil 4 (Teringkap 3), Soil 5 (Gunung Berinchang), and Soil 6 (Lating series). Observed data showed that permethrin was more persistent in Soil 1 (23.3 days) and less persistent in Soil 5 (16.7 days). Similarly, the degradation rate coefficient (k) was greater in Soil 5 than Soil 1. The half-life and the dissipation patterns of permethrin between the observed and predicted data were not much different in all 6 soils studied, even though the predicted data were slightly higher. The half-life of permethrin in Soil 6 decreased as the temperature increased from 20°C (36.1 days) to 35°C (13.9 days). The degradation rate coefficient increased as the temperature increased. The predicted data derived from the model showed greater values than the observed data. The half-life of permethrin in Soil 6 decreased as the soil moisture increased from 30% (26.8 days) to 80% (20.1 days). The dissipation rate was not very different between the predicted and the observed data at 80% field capacity and at the temperature of 35°C, and it consequently became closer when the incubation period was prolonged.

2013 ◽  
Vol 742 ◽  
pp. 272-277
Author(s):  
Liang Shan Feng ◽  
Zhan Xiang Sun ◽  
Jia Ming Zheng

In this study, the results showed that water is the most important factor to affect crop yields and optimum soil moisture is lower under the conditions of peanut-and-millet interplanting. Thus, peanut-and-millet interplanting is generally able to fit most of the semi-arid region. In the interaction of various factors, the coupling effect of water and phosphorus was stronger than the coupling effect of fertilizers, following by the coupling effect of water and nitrogen. Among peanuts factors of water, nitrogen, and multi-factorial interaction of water, nitrogen, and phosphorus, water and nitrogen showed a negative effect, whereas the two-factor interactions had a positive effect. There were some differences between peanut and millet in the need for water and fertilizer, in which peanut required more nitrogen and millet needed slightly higher soil moisture and phosphorus. When other factors were in rich level, both of the optimal value for single factors of water, nitrogen, and phosphorus and the optimal value for two-factor interactions of water-nitrogen, water-phosphorus, and nitrogen-phosphorus, were higher than the optimal value for the interaction of water, nitrogen, and phosphorus. The tiny demand difference on moisture in peanut-millet interplanting could be compromised by configuring a reasonable interplanting population structure and the corresponding demand difference on fertilizer could be resolved by uneven crop planting strips. Under the condition of water-nitrogen-phosphorus interaction, the soil moisture content optimal for peanut accounted for 57.3% of the field capacity, and the related appropriate application rates of nitrogen and phosphorus were 0.98 g/pot (81.18 kg/hm2) and 0.39g/pot (32.18 kg/hm2), respectively. Likewise, the soil moisture content optimal for millet was 59.1% of the field capacity, and the counterpart appropriate application rates of nitrogen and phosphorus were 0.57 g/pot (47.03 kg/hm2) and 0.45g / pot (37.13 kg/hm2), respectively.


1965 ◽  
Vol 45 (2) ◽  
pp. 171-176 ◽  
Author(s):  
J. C. Wilcox

Drainage curves following irrigation were determined at six depths in eight soils having unrestricted drainage but varying widely in soil texture. The field capacities were determined under relatively high rates of evapotranspiration. The time after irrigation that it was necessary to wait before sampling the soil, to determine field capacity, was also determined. A high positive correlation was obtained between the log of field capacity in inches and the log of time after irrigation at which to sample the soil. The time varied from about 0.5 day with 1.5 in. field capacity to 4.0 days with 35 in. From the curves of soil moisture content versus time, the errors caused by sampling too soon or too late were determined. The percentage error (i.e. percent of field capacity) increased with an increase in the error in time of sampling; it decreased with an increase in field capacity in inches; and it was greater when sampling was too soon than when it was too late.


Weed Science ◽  
1985 ◽  
Vol 33 (4) ◽  
pp. 558-563 ◽  
Author(s):  
Kausalya Thirunarayanan ◽  
Robert L. Zimdahl ◽  
Darryl E. Smika

Adsorption of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl) amino] carbonyl] benzenesulfonamide} on four soils having different pH values (6.2 to 8.1) was low. Log/log Freundlich isotherms for all soils at 8 and 30 C were linear, the extent of adsorption being greater at 8 than at 30 C. There was an inverse relationship between pH and degradation rate with a half-life of 88.5 days at pH 6.2 and 144 days at pH 8.1 at 20 C. Rapid disappearance was noted during the first 15 days after application. With decreasing moisture and temperature, chlorsulfuron degraded more slowly. The half-life ranged from 229 days at 10 C and moisture content of 75% field capacity to 62.5 days at 40 C and 75% field capacity at pH 7.7.


2018 ◽  
Vol 34 (6) ◽  
pp. 963-971 ◽  
Author(s):  
Tonny José Araújo da Silva ◽  
Edna Maria Bonfim-Silva ◽  
Adriano Bicioni Pacheco ◽  
Thiago Franco Duarte ◽  
Helon Hébano de Freitas Sousa ◽  
...  

Abstract.Accurate measurements of soil moisture content can contribute to resource conservation in irrigated systems. The objective of this study was to evaluate various soil moisture sensors (a porous cup tensiometer, Diviner 2000, PR2, XH300, PM100, and ML3; the mention of model names does not constitute an implied endorsement) used in four different soil types. The experiment was conducted inside a greenhouse using a specially constructed box that contained the soil samples. The soil samples were first saturated and subsequently drained before starting the measurements. The soil moisture content was determined by the oven-drying method. Using the standard deviation of the sensor readings, regression analyses were performed, resulting in calibration equations and coefficient of determination (R2) values for each sensor and soil type combination. The porous cup tensiometer, Diviner 2000, PR2, and ML3 measurements resulted in excellent R2 values that exceeded 0.95 for the four soils. However, measurements with the XH300 and PM100 sensors resulted in R2 values of 0.37 to 0.86 and 0.61 to 0.94, respectively, limiting their scientific applicability for the studied soils. Therefore, the porous cup tensiometer, Diviner 2000, PR2, and ML3 estimated the soil moisture content with greater confidence than did the other sensors and with an error of less than 5%. Keywords: Calibration, Tensiometer, Volumetric water content.


1975 ◽  
Vol 51 (5) ◽  
pp. 196-199 ◽  
Author(s):  
R. J. Day ◽  
G. R. MacGillivray

The root regenerating potential of fall-lifted 2+0 white spruce nursery stock is described after transplanting into soil-maintained at 8, 10 and 15% soil moisture content (SMC) in glass fronted root boxes. At 15% SMC (0.1 bar soil moisture tension), which is close to field capacity, root regeneration began 10 days after transplanting and root elongation continued at a high rate for the remainder of a 40-day study period. At 10% SMC (0.6 bar SMT) root regeneration was delayed until 20 days after transplanting and root elongation was at a slower rate. At 8% SMC (1.5 bars) root regeneration and elongation was negligible. Plant moisture stress measured at 40 days was least when root regeneration was most and vice versa. The results suggest that field planting of white spruce in soils with moisture tensions of over 0.6 bar will be hazardous.


1978 ◽  
Vol 58 (2) ◽  
pp. 347-356
Author(s):  
W. N. BLACK

Irrigation and nitrogen (N) requirements of a natural pasture sward were studied on a Charlottetown sandy loam soil over a 5-yr period. The soil moisture content at the 0-to 15- and 15- to 30-cm depths was determined at from 7- to 10-day intervals, while irrometer soil moisture readings at 15-, 30-, and 45-cm depths were recorded more frequently during the grazing seasons. Soil moisture content in irrigated plots averaged 92 and 94% of field capacity, respectively, at 0- to 15- and 15- to 30-cm sampling depths. In non-irrigated plots, corresponding values were 77 and 82%. N treatments resulted in significant dry matter (DM) increases over untreated plots. Yield differences among plots receiving 56, 84, and 112 kg of N/ha in mid-June and again in mid-August were not significant. Early spring and September applications of N at 56 kg/ha, combined with mid-June and early August supplements of N at 84 kg/ha were superior to all other treatments in prolonging the grazing period. Neither irrigation nor N affected the characteristic yield decline of naturally occurring forage species in mid- and late-season. Mean DM production for the 5-yr period, and for years, showed no significant N treatment × moisture level interaction. While irrigation failed to increase yields significantly, livestock preferred to graze the irrigated plots. As a result of less competition from grasses, volunteer white clover became better established, and constituted a larger percentage of the sward than on non-irrigated plots.


1966 ◽  
Vol 46 (3) ◽  
pp. 213-216 ◽  
Author(s):  
S. J. Bourget ◽  
B. J. Finn ◽  
B. K. Dow

Young seedlings of flax and cereals, grown in a greenhouse, were subjected to 0, 12.5, and 25.0 cm of soil moisture tension for periods of 7, 14, and 21 days The grain, straw, and root yields of all plant species, except barky, increased with increasing soil moisture content was maintained near field capacity during the growth of plants. The yields of oats, winter wheat, and fall rye decreased with increasing duration of flooding, whereas those of barley, flax and spring wheat were variable. Correlation coefficients between yields of tops and roots were positive.


2004 ◽  
Vol 6 (2) ◽  
pp. 46-50
Author(s):  
Kukuh Murtilaksono ◽  
Enny Dwi Wahyuni

This research was conducted to study relationship between soil moisture content and soil physical characteristics that affected the moisture.The soil samples were collected from 22 scattered sites of West Java and Central Java. Analysis of soil physical properties (texture, bulk density, particle density, total porosity and soil moisture retention) and soil chemical property (organic matter) was conducted at the laboratory of Department of Soil Sciences, Faculty of Agriculture, Bogor Agricultural University. Analysis of simple linier regression was applied to know the correlation between soil moisture content and other basic soil physical properties.Availability of soil moisture (pF 4.20 – pF 2.54) significantly correlated with organic matter, total porosity, and micro pores. The higher organic matter content as well as total porosity and micro pores the higher available soil moisture. Soil moisture of field capacity significantly correlated with clay content, sand content, micro and macro pores. The higher clay content and micro pores the higher soil moisture of field capacity. In the contrary, the higher macro pores and sand content the lower the field capacity. Soil moisture of wilting point significantly correlated with clay content and macro pores. The higher clay content the higher the wilting point, while the higher macro pores the lower soil moisture of wilting point. Keywords : Available soil water, field capacity, organic matter, soil pores, wilting point


GEOMATICA ◽  
2019 ◽  
Vol 73 (3) ◽  
pp. 63-73 ◽  
Author(s):  
Mohammad Reza Mobasheri ◽  
Meisam Amani ◽  
Mahin Beikpour ◽  
Sahel Mahdavi

Soil moisture content (SMC) is a crucial component in various environmental studies. Although many models have been proposed for SMC estimation, developing new models for accurate estimation of SMC is still an interesting subject. This study aimed to develop new models for SMC estimation using the water absorption bands in the spectral signatures of three different soil types: loam, silty loam, and sandy loam. Based on the three absorption bands (i.e., 1400, 1900, and 2200 nm) and regression analyses, six approaches were considered. These scenarios were generally based on the reflectance value and its logarithm, as well as the difference between the wet and dry reflectance values for the absorption bands. Finally, 24 models were developed for SMC estimation from the three different soil types, as well as the entire soil samples. The most accurate SMC, as indicated by the lowest root mean squared error (RMSE) and the highest correlation coefficient (r), was obtained from the model developed using the logarithm of the average values reflectance in the three water absorption bands for sandy loam (RMSE = 0.31 g/kg, r = 0.99). Overall, using the spectrometry data derived in the lab, the results of the proposed models were promising and demonstrate great potential for SMC estimation using spectral data collected by satellites in the future studies.


Author(s):  
K. Deka ◽  
P. P. Hazarika ◽  
B. K. Medhi ◽  
Rupjyoti Borah ◽  
G. G. Kandali ◽  
...  

“Biochar” is a relatively new term, yet it is not a new substance. Biochar, product of thermal decomposition or incomplete combustion of biomass or bio-wastes under limited oxygen supply, are fine-grained highly porous charcoal substances that are distinguished from other charcoals in its intended use as soil amendments. The state of Assam produces surplus quantities of biowastes and leaves behind bulk quantity of wastes soon after harvest of the main crop(s) remain unutilized annually and these farm wastes have the potential of further reutilization through production of biochar, which may effectively be used in sustainable production system. Characterization of biochar with respect to physico-chemical properties determines the suitability of biochar to conserve soil moisture, which is again regulated by kind and source of feed stock materials. Keeping these aspects in view, a study on characterization of biochars prepared from four different feed stocks, namely rice straw, rice husk, toria stover, and bamboo leaves was conducted at Assam Agricultural University during 2014-15 and 2015-16 to validate its efficiency to conserve soil moisture for longer time. After determining the physicochemical properties of the four biochars, a set of pot culture experiment in poly house taking toria as test crop was conducted with four biochars. Four hundred gram of soil (preferably light textured) in 500 g capacity of plastic pot replicated thrice was designed statistically (factorial CRD) with four doses of biochars (0, 0.5, 1.0, and 1.5% wt/wt). Initially, a moisture level at field capacity was maintained and periodical volumetric soil moisture content (upto 70 days) was monitored to evaluate their efficiency. Gravimetric soil moisture content decreased significantly with the progress in days of experimentation irrespective of types of biochar used. However, increase in biochar doses increased the soil moisture content significantly over the one where no biochar was applied. Highest efficiency to conserve soil moisture over the days of study period was due to the application of bamboo leaves biochar.


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