scholarly journals Cyanogenic glucoside production in cassava: The comparable influences of varieties, soil moisture content and nutrient supply

2019 ◽  
Author(s):  
Matema L.E. Imakumbili ◽  
Ernest Semu ◽  
Johnson M.R. Semoka ◽  
Adebayo Abass ◽  
Geoffrey Mkamilo
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Fertility ◽  
Soil Moisture Content ◽  
Soil Nutrient ◽  
Moisture Stress ◽  
Nutrient Supply ◽  
Cyanogenic Glucoside ◽  
Moisture Conditions ◽  
Cassava Varieties

AbstractVarieties and soil moisture content are the two agronomic factors mostly pointed out as influencers of cyanogenic glucoside production in cassava. The role of soil nutrient supply is however often overlooked or minimised, despite its known influence on cyanogenic glucoside production. A pot experiment was hence carried out to determine whether soil nutrient supply had an equal influence on cyanogenic glucoside production in cassava, as varieties and soil moisture content. The cassava varieties, Kiroba (a sweet cassava variety) and Salanga (a bitter cassava variety), were used in the experiment, together with three soil moisture treatments that respectively induced severe moisture stress, moderate moisture stress and no moisture stress (optimal soil moisture conditions where plants were kept well-watered). The soil nutrient treatments used depicted conditions of low (no fertiliser), moderate (25 N mg, 5 P mg, 25 K mg /kg) and high (25 N mg, 5 P mg, 25 K mg /kg) nutrient supply. A sole K treatment was also included (25 K mg/kg). Total hydrogen cyanide (HCN) levels in cassava leaves were used to indicate the effects of the three factors on cyanogenic glucoside production. The results of the study showed that nutrient supply had a significantly (p < 0.001) equal influence on cyanogenic glucoside production, as varieties (p < 0.001) and soil moisture content (p < 0.001). Cyanogenic glucoside production was however found to be differently influenced by soil moisture content (M) and nutrient supply (N) in both Salanga (M×N, p = 0.002) and Kiroba (M×N, p < 0.001). Leaf HCN levels of unfertilised Salanga and Kiroba were respectively increased by 1.8 times and 2.7 times their levels under optimal soil moisture conditions. Thus, under severe moisture stress, low soil fertility was found to have an increasing effect on leaf HCN levels in both varieties. A high supply of N, P and K, however also had an increasing effect on leaf HCN in both varieties regardless of soil moisture conditions. Leaf HCN levels in Salanga ranged from 95.5 mg/kg to 334.5 mg/kg and in Kiroba they ranged from 39.3 mg/kg to 161.5 mg/kg, on a fresh weight basis. The study managed to demonstrate that soil fertility had an equally important influence on cyanogenic glucoside production, just like varieties and soil moisture content. The study also showed that the effects of nutrient supply on cyanogenic glucoside production in various cassava varieties is dependent on changes in soil moisture content and vice versa.

Responses of Lucerne to Different Soil Moisture Regimes

1967 ◽  
Vol 3 (1) ◽  
pp. 21-28 ◽  
Author(s):  
J. J. Landsberg
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Ground Cover ◽  
Moisture Stress ◽  
Early Morning ◽  
Moisture Regimes ◽  
Sampling Programme ◽  
Daily Evaporation ◽  
Moisture Conditions

SummaryAn experiment in which irrigation intervals for lucerne were dictated by four factors applied to daily evaporation from a Class A pan has been reported by Landsberg (1966). This paper discusses data from a number of subsidiary measurements made during that experiment. An extensive soil sampling programme yielded data on the effects of treatments on soil moisture content, and plant height and per cent ground cover measurements enabled detailed evaluations to be made of crop responses. Both height and ground cover were decreased by soil moisture stress. Relative turgidity was closely related to soil moisture content in the early morning, dry treatments showing more rapid recovery of turgor than those where water was kept at more adequate levels. Radiation utilization by the crop was affected by soil moisture conditions, and also apparently by temperature.

Aboveground Biomass of Reaumuria soongorica Shrub Effect on Soil Moisture and Nutrient Spatial Distribution in Arid and Semi-Arid Region

2013 ◽  
Vol 726-731 ◽  
pp. 3803-3806
Author(s):  
Bing Ru Liu ◽  
Jun Long Yang
Keyword(s):  
Spatial Distribution ◽  
Soil Moisture ◽  
Moisture Content ◽  
Aboveground Biomass ◽  
Soil Moisture Content ◽  
Plant Biomass ◽  
Soil Layer ◽  
Soil Nutrient ◽  
Desert Plant ◽  
Important Species

In order to revel aboveground biomass of R. soongorica shrub effect on soil moisture and nutrients spatial distribution, and explore mechanism of the changes of soil moisture and nutrients, soil moisture content, pH, soil organic carbon (SOC) and total nitrogen (TN) at three soil layers (0-10cm,10-20cm, and 20-40cm) along five plant biomass gradients of R. soongorica were investigated. The results showed that soil moisture content increased with depth under the same plant biomass, and increased with plant biomass. Soil nutrient properties were evidently influenced with plant biomass, while decreased with depth. SOC and TN were highest in the top soil layer (0-10 cm), but TN of 10-20cm layer has no significant differences (P < 0.05). Moreover, soil nutrient contents were accumulated very slowly. These suggests that the requirement to soil organic matter is not so high and could be adapted well to the desert and barren soil, and the desert plant R. soongorica could be acted as an important species to restore vegetation and ameliorate the eco-environment.

scholarly journals Spatial and temporal variation of methane emissions in drained eutrophic peat agro-ecosystems: drainage ditches as emission hotspots

2008 ◽  
Vol 5 (2) ◽  
pp. 1237-1261 ◽  
Author(s):  
A. P. Schrier-Uijl ◽  
E. M. Veenendaal ◽  
P. A. Leffelaar ◽  
J. C. van Huissteden ◽  
F. Berendse
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Water Table ◽  
Soil Moisture Content ◽  
Explanatory Variable ◽  
Spatial And Temporal Variation ◽  
Spatial And Temporal Variability ◽  
Ch4 Emissions ◽  
Intensively Managed ◽  
Moisture Conditions

Abstract. Our research investigates the spatial and temporal variability of methane (CH4) emissions in two drained eutrophic peat areas (one intensively managed and the other less intensively managed) and the correlation between CH4 emissions and soil temperature, air temperature, soil moisture content and water table. We stratified the landscape into landscape elements that represent different conditions in terms of topography and therefore differ in moisture conditions. There was great spatial variability in the fluxes in both areas; the ditches and ditch edges (together 27% of the landscape) were methane hotspots whereas the dry fields had the smallest fluxes. In the intensively managed site the fluxes were significantly higher by comparison with the less intensively managed site. In all the landscape element elements the best explanatory variable for CH4 emission was temperature. Neither soil moisture content nor water table correlated significantly with CH4 emissions, except in April, where soil moisture was the best explanatory variable.

scholarly journals Root Regeneration of Fall-Lifted White Spruce Nursery Stock in Relation to Soil Moisture Content

1975 ◽  
Vol 51 (5) ◽  
pp. 196-199 ◽  
Author(s):  
R. J. Day ◽  
G. R. MacGillivray
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Root Elongation ◽  
Soil Moisture Content ◽  
Field Capacity ◽  
White Spruce ◽  
Moisture Stress ◽  
High Rate ◽  
Root Regeneration ◽  
Nursery Stock

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.

scholarly journals Effects of soil‐moisture content on shallow‐seismic data

Geophysics ◽  
1998 ◽  
Vol 63 (4) ◽  
pp. 1357-1362 ◽  
Author(s):  
Robert D. Jefferson ◽  
Don W. Steeples ◽  
Ross A. Black ◽  
Tim Carr
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Seismic Data ◽  
Soil Moisture Content ◽  
Soil Conditions ◽  
Near Surface ◽  
Surface Moisture ◽  
Shallow Seismic ◽  
Unconsolidated Material ◽  
Moisture Conditions

Repeated shallow‐seismic experiments were conducted at a site on days with different near‐surface moisture conditions in unconsolidated material. Experimental field parameters remained constant to ensure comparability of results. Variations in the seismic data are attributed to the changes in soil‐moisture content of the unconsolidated material. Higher amplitudes of reflections and refractions were obtained under wetter near‐surface conditions. An increase in amplitude of 21 dB in the 100–300 Hz frequency range was observed when the moisture content increased from 18% to 36% in the upper 0.15 m (0.5 ft) of the subsurface. In the time‐domain records, highly saturated soil conditions caused large‐amplitude ringy wavelets that interfered with and degraded the appearance of some of the reflection information in the raw field data. This may indicate that an intermediate near‐surface moisture content is most conducive to the recording of high‐quality shallow‐seismic reflection data at this site. This study illustrates the drastic changes that can occur in shallow‐seismic data due to variations in near‐surface moisture conditions. These conditions may need to be considered to optimize the acquisition timing and parameters prior to collection of data.

Diffusion of Iodine and Technetium-99 Through Waste Encasement Concrete and Unsaturated Soil Fill Material

2004 ◽  
Vol 824 ◽  
Author(s):  
Shas V. Mattigod ◽  
Greg A. Whyatt ◽  
J. R. Serne ◽  
Marcus I. Wood
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Unsaturated Soil ◽  
Soil Moisture Content ◽  
Highly Sensitive ◽  
Order Of Magnitude ◽  
Moisture Conditions ◽  
Long Term Performance ◽  
Term Performance

AbstractAn assessment of long-term performance of low level waste-enclosing cement grouts requires diffusivity data for radionuclide species such as, 129I and 99Tc. The diffusivity of radionuclides in soil and concrete media was collected by conducting soil-soil and concrete-soil half-cell experiments. The soil diffusivity coefficients for iodide were 7.03 × 10−8 cm2/s and 2.42 × 10−7cm2/s for soils at 4% and 7% moisture contents, respectively. Iodide diffusivity in soil is a function of moisture content and is about an order of magnitude slower at lower moisture content. The soil diffusivity coefficients for 99Tc were 5.89±0.80 × 10−8 cm2/s (4% moisture content) and 2.04±0.57 × 10−7 cm2/s (7% moisture content), respectively. The soil diffusivity of iodide and 99Tc were similar in magnitude at both water contents, indicating that these ions have similar diffusion mechanisms in unsaturated coarse-textured Hanford soil. The diffusivity of iodide in concrete ranged from 2.07 × 10−14 cm2/s (4% soil moisture content) to 1.31 × 10−12 cm2/s (7% soil moisture content), indicating that under unsaturated soil moisture conditions, iodide diffusivity is highly sensitive to changing soil moisture conditions. Depending on the soil moisture content, the diffusivity of 99Tc in concrete ranged from 4.54 × 10−13 cm2/s to 8.02 × 10−12 cm2/s. At 4% soil moisture content, iodide diffused about 20 times more slowly than 99Tc, and at 7% soil moisture content, iodide in concrete diffused about 6 times slower than 99Tc.

Soil water relations and relative turgidity on leaves in the wheat crop

1966 ◽  
Vol 17 (3) ◽  
pp. 269 ◽  
Author(s):  
RA Fischer ◽  
GD Kohn
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Root Zone ◽  
Moisture Stress ◽  
Flowering Plant ◽  
Wheat Crop ◽  
Stage Of Development ◽  
South Wales ◽  
Plant Moisture

Trials were conducted in 1961 and 1962 at Wagga in southern New South Wales to investigate the yield physiology of the wheat crop. Various cultural treatments were applied to a single variety (Heron). The increases in evapotranspiration and associated reductions in total soil moisture content caused by early sowing, by heavier fertilizer applications, and to a lesser extent by a heavier rate of sowing were reflected in an increased plant moisture stress (reduced leaf relative turgidity) at a given time in the spring. At a given stage of development, however, relative turgidity was not much affected by time of sowing, and in fact post-flowering plant moisture stress increased with later sowing. There were only small treatment effects on the estimated depth and density of rooting. Relatively little water was extracted by crops from below 40 in.; dense crops reduced the soil moisture content throughout the root zone to less than the –15 bar value. Leaf relative turgidity at sunrise showed a consistent inverse relationship to soil moisture content in the root zone. Leaf turgidity (sunrise) was maintained at 100% until root zone moisture levels approached the –15 bar value.

scholarly journals The Agronomic Respons of Three Cassava Varieties at Various Level of Soil Moisture Content

2018 ◽  
Vol 23 (1) ◽  
pp. 44-51
Author(s):  
. Suwarto ◽  
◽  
Eko Sulistyono ◽  
Giansar Prastowo ◽  
◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Cassava Varieties

Study on the Dynamic Variation Law of Highway Slope's Soil Moisture

2014 ◽  
Vol 608-609 ◽  
pp. 1089-1093
Author(s):  
Jia Tian ◽  
Bing Cao ◽  
Li Hua Song ◽  
Ping Zhang
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Lower Layer ◽  
Observation Point ◽  
Variation Coefficient ◽  
Rapid Variation ◽  
Dynamic Variation ◽  
Key Factor ◽  
Moisture Conditions

[Objective] Soil moisture is the key factor of highway greening. To maintain the steady and sustainable development of highway greening, the problem of soil moisture should be primarily solved. [Method] In this paper, the dynamic variation law of highway slope’s soil moisture was studied by the continuous observation of the soil moisture (0~40cm) and rainfall in all points (sunny slope, shade slope, ground, and the central partition belt) of China’s Langfang—Zhuozhou Highway from April to November 2009. [Result] From April to May, the soil moisture content declined continuously. From May to August, the soil moisture content increased rapidly and also was kept at a higher level. From August to October, the soil moisture content declined gradually. From October to November, the soil moisture content increased steadily. The soil moisture in the surface (0~10cm) and the lower layer (10cm~20cm) fluctuated greatly, and the variation coefficient was 28.39% and 24.85% respectively; the change of the soil moisture content in the deep layer (20cm~40 cm) decreased significantly, and the variation coefficient was 19.41%. [Conclusion] The seasonal dynamic variation law of highway slope’s soil moisture is significant, and also keeps consistent with the dynamic rainfall, plant transpiration, and soil evaporation laws. The soil moisture conditions from May to August are the best. The spatial variation of the soil moisture can be divided into two layers: the rapid-variation layer (0~20 cm) and the active layer (20cm~40 cm). In each observation point, the soil moisture conditions are the best in the central partition belt, secondary in the sunny and shade slopes, and the worst in ground.

scholarly journals Comparing the Normalized Difference Infrared Index (NDII) with root zone storage in a lumped conceptual model

2016 ◽  
Vol 20 (8) ◽  
pp. 3361-3377 ◽  
Author(s):  
Nutchanart Sriwongsitanon ◽  
Hongkai Gao ◽  
Hubert H. G. Savenije ◽  
Ekkarin Maekan ◽  
Sirikanya Saengsawang ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Conceptual Model ◽  
Soil Moisture Content ◽  
Root Zone ◽  
Moisture Stress ◽  
Hydrological Models ◽  
Wet Season ◽  
Catchment Scale ◽  
Moisture Deficit

Abstract. With remote sensing we can readily observe the Earth's surface, but direct observation of the sub-surface remains a challenge. In hydrology, but also in related disciplines such as agricultural and atmospheric sciences, knowledge of the dynamics of soil moisture in the root zone of vegetation is essential, as this part of the vadose zone is the core component controlling the partitioning of water into evaporative fluxes, drainage, recharge, and runoff. In this paper, we compared the catchment-scale soil moisture content in the root zone of vegetation, computed by a lumped conceptual model, with the remotely sensed Normalized Difference Infrared Index (NDII) in the Upper Ping River basin (UPRB) in northern Thailand. The NDII is widely used to monitor the equivalent water thickness (EWT) of leaves and canopy. Satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) were used to determine the NDII over an 8-day period, covering the study area from 2001 to 2013. The results show that NDII values decrease sharply at the end of the wet season in October and reach lowest values near the end of the dry season in March. The values then increase abruptly after rains have started, but vary in an insignificant manner from the middle to the late rainy season. This paper investigates if the NDII can be used as a proxy for moisture deficit and hence for the amount of moisture stored in the root zone of vegetation, which is a crucial component of hydrological models. During periods of moisture stress, the 8-day average NDII values were found to correlate well with the 8-day average soil moisture content (Su) simulated by the lumped conceptual hydrological rainfall–runoff model FLEX for eight sub-catchments in the Upper Ping basin. Even the deseasonalized Su and NDII (after subtracting the dominant seasonal signal) showed good correlation during periods of moisture stress. The results illustrate the potential of the NDII as a proxy for catchment-scale root zone moisture deficit and as a potentially valuable constraint for the internal dynamics of hydrological models. In dry periods, when plants are exposed to water stress, the EWT (reflecting leaf water deficit) decreases steadily, as moisture stress in the leaves is connected to moisture deficits in the root zone. Subsequently, when the soil moisture is replenished as a result of rainfall, the EWT increases without delay. Once leaf water is close to saturation – mostly during the heart of the wet season – leaf characteristics and NDII values are not well correlated. However, for both hydrological modelling and water management, the stress periods are most important, which is why this product has the potential of becoming a highly efficient model constraint, particularly in ungauged basins.

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