scholarly journals Water requirements of avocado in Israel. I. Tree and soil parameters

1977 ◽  
Vol 28 (5) ◽  
pp. 859 ◽  
Author(s):  
D Kalmar ◽  
E Lahav
Keyword(s):  
Coastal Plain ◽  
Irrigation Schedule ◽  
Soil Layer ◽  
The Other ◽  
Soil Parameters ◽  
Irrigation Season ◽  
Salt Accumulation ◽  
Water Requirements ◽  
Neutron Probe ◽  
Annual Water

The effect of different irrigation intervals on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The objectives of this experiment were: (a) to make measurements of soil and plant parameters to help understand mechanisms of response to irrigation; and (b) to establish the most suitable irrigation schedule for highest yields of export quality fruit. The trial consisted of four irrigation treatments, at intervals of 7, 14, 21 and 28 days; the respective average annual water applications were 8890, 7450, 6680, and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. Soil moisture consumption was estimated by using a neutron probe and tensiometers. Most of the water consumption was from the upper 60-cm soil layer. With the 7-day interval, the calculated daily loss from the soil profile was greater throughout the whole irrigation season than with the other intervals. The least salt accumulation occurred under the long interval treatments since the large amounts of water supplied at each irrigation leached the salts continuously. Reduced intervals between irrigations resulted in increased trunk growth and increased tree size. It is concluded that with a 21-day interval the vegetative growth of producing trees was restricted and therefore relatively smaller trees with easier fruit picking and delayed orchard thinning were obtained.

Water requirements of avocado in Israel. II.* Influence on yield, fruit growth and oil content

1977 ◽  
Vol 28 (5) ◽  
pp. 869 ◽  
Author(s):  
E Lahav ◽  
D Kalmar
Keyword(s):  
Growth Rate ◽  
Coastal Plain ◽  
Oil Content ◽  
Economic Importance ◽  
Harvest Date ◽  
Irrigation Frequency ◽  
Water Requirements ◽  
Experimental Conditions ◽  
Oil Percentage ◽  
Annual Water

The effect of four different irrigation intervals, 7, 14, 21 and 28 days, on the avocado tree was tested during the years 1968–1974 in the northern coastal plain of Israel. The respective average annual water applications were 8890, 7450, 6680 and 5940 m3/ha. The cultivars Ettinger, Fuerte and Hass were tested in five replications in randomized blocks. After 6 years no significant reduction in yield was observed with Ettinger or Fuerte trees irrigated once in 21 or 28 days. With the Hass cultivar the 28-day interval gave lower yields than with the three other intervals tested. Shortening of irrigation intervals increased the growth rate and size of individual fruits, which may be of economic importance for cv. Hass, where overproduction leads to small fruits unsuitable for export. Shortening of irrigation intervals tended to increase the oil percentage of the fruit, which may advance the harvest date. In view of the equal yields obtained and the predominance of cv. Hass in avocado plantations, it was concluded that the 21-day interval was the optimum irrigation frequency under the experimental conditions. __________________ *Part I, Aust. J. Agric. Res., 28: 859 (1977).

Uncertainties in the measurement of soil water content caused by abrupt soil layer changes, when using a neutron probe

Soil Research ◽  
1988 ◽  
Vol 26 (1) ◽  
pp. 87 ◽  
Author(s):  
DJ Wilson
Keyword(s):  
Neutron Source ◽  
Thermal Flux ◽  
Soil Layer ◽  
Soil Parameters ◽  
Soil Systems ◽  
Neutron Probe ◽  
Detector Geometry ◽  
Real Value ◽  
Measured Water ◽  
Relative Count Rate

Multigroup diffusion code calculations have been made to model the changes in the thermal flux distribution as a fast neutron source passes through an interface between two soil systems. By integrating this flux over the volume of a detector attached to the source, a relative count rate can be determined for different source positions with respect to the interface. Water densities determined from these count rates and calibration curves can be seriously in error near the interface. The magnitude of these errors depends upon the soil parameters, the detector geometry, and the proximity of the soil strata to the neutron source and detector. Unless the soil structure is well known, it would be unwise to rely on water measurements closer than about 25 cm to a soil discontinuity. It two soils merge over 30-40 cm, it is likely that the measured water density will not deviate far from the real value.

scholarly journals The Relationship between Soil Electrical Parameters and Compaction of Sandy Clay Loam Soil

Agriculture ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 114
Author(s):  
Katarzyna Pentoś ◽  
Krzysztof Pieczarka ◽  
Kamil Serwata
Keyword(s):  
Electrical Conductivity ◽  
Magnetic Susceptibility ◽  
Precision Agriculture ◽  
Soil Compaction ◽  
Soil Layer ◽  
Soil Parameters ◽  
Soil Electrical Conductivity ◽  
Electrical Parameters ◽  
Management Zones ◽  
Additional Information

Soil spatial variability mapping allows the delimitation of the number of soil samples investigated to describe agricultural areas; it is crucial in precision agriculture. Electrical soil parameters are promising factors for the delimitation of management zones. One of the soil parameters that affects yield is soil compaction. The objective of this work was to indicate electrical parameters useful for the delimitation of management zones connected with soil compaction. For this purpose, the measurement of apparent soil electrical conductivity and magnetic susceptibility was conducted at two depths: 0.5 and 1 m. Soil compaction was measured for a soil layer at 0–0.5 m. Relationships between electrical soil parameters and soil compaction were modelled with the use of two types of neural networks—multilayer perceptron (MLP) and radial basis function (RBF). Better prediction quality was observed for RBF models. It can be stated that in the mathematical model, the apparent soil electrical conductivity affects soil compaction significantly more than magnetic susceptibility. However, magnetic susceptibility gives additional information about soil properties, and therefore, both electrical parameters should be used simultaneously for the delimitation of management zones.

scholarly journals Effects of different biomass materials as a salt-isolation layer on water and salt migration in coastal saline soil

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11766
Author(s):  
Mao Yang ◽  
Runya Yang ◽  
Yanni Li ◽  
Yinghua Pan ◽  
Junna Sun ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Salt Concentration ◽  
Saline Soil ◽  
Soil Depth ◽  
Soil Layer ◽  
Thick Layer ◽  
Peat Layer ◽  
Salt Accumulation

The aim of this study was to find a material suited for the prevention of evaporative water loss and salt accumulation in coastal saline soils. One-dimensional vertical water infiltration and phreatic evaporation experiments were conducted using a silty loam saline soil. A 3-cm-thick layer of corn straw, biochar, and peat was buried at the soil depth of 20 cm, and a 6-cm-thick layer of peat was also buried at the same soil depth for comparison. The presence of the biochar layer increased the upper soil water content, but its ability to inhibit salt accumulation was poor, leading to a high salt concentration in the surface soil. The 3-cm-thick straw and 6-cm-thick peat layers were most effective to inhibit salt accumulation, which reduced the upper soil salt concentration by 96% and 93%, respectively. However, the straw layer strongly inhibited phreatic evaporation and resulted in low water content in the upper soil layer. Compared with the straw layer, the peat layer increased the upper soil water content. Thus, burying a 6-cm-thick peat layer in the coastal saline soil is the optimal strategy to retain water in the upper soil layer and intercept salt in the deeper soil layer.

scholarly journals Rooting patterns of Rumex species under drained conditions

1987 ◽  
Vol 65 (8) ◽  
pp. 1638-1642 ◽  
Author(s):  
L. A. C. J. Voesenek ◽  
C. W. P. M. Blom
Keyword(s):  
Growth Rate ◽  
Root Distribution ◽  
Soil Layer ◽  
The Other ◽  
Rumex Acetosa ◽  
Soil System ◽  
Relative Growth ◽  
Soil Layers ◽  
Vertical Root Distribution ◽  
Rooting Patterns

Root development and architecture were studied in three Rumex species growing in a perforated soil system in the greenhouse. Distinct differences in vertical root distribution under drained conditions were found among the three species. Rumex acetosa and R. palustris had a relatively superficial root pattern, whereas in R. crispus much of the root growth was concentrated in lower soil layers. In the upper soil layer the relative growth rate of the roots of R. palustris was significantly larger than that of the other species. A relation between the characteristic rooting patterns under drained conditions and the Rumex zonation in the field is discussed.

Aspects of Economic Dualism in Oman 1830–1930

1989 ◽  
Vol 21 (4) ◽  
pp. 495-515 ◽  
Author(s):  
Mark Speece
Keyword(s):  
Coastal Plain ◽  
18Th Century ◽  
The Other ◽  
Recent History ◽  
Port Cities ◽  
History Of ◽  
Head Of Government ◽  
The Ideal

The history of Oman is largely a story of competition, and often conflict, between two very different entities. This duality was even symbolized by the name of the country, “Sultanate of Muscat and Oman,” until 1970. The sultanate was formed from the fusion of the Batina coastal plain and its port cities, symbolically Muscat, and the interior of the country, Oman. During most periods in the recent history of the country, only the coast has been ruled by the sultan. Even before the institution of the sultanate emerged in the 18th century, however, the coast had usually been under separate, often foreign, rule. In the interior, the ideal head of government from very early times was that of an imam, even though the office often remained vacant. At many times during Omani history, of course, one part of the country or the other imposed its control and Oman was temporarily united, but the differences between the two sections of Omani society eventually split the country into two separate states again. Even within the last decade, one of the major problems in Oman's efforts to develop has been “the traditional antithesis between the sultan residing on the coast and the inwardly oriented tribes.”

scholarly journals Intercropping cover crops with a poplar short rotation coppice: Effects on nutrient uptake and biomass production

2018 ◽  
pp. 126-133 ◽  
Author(s):  
Nicola Silvestri ◽  
Vittoria Giannini ◽  
Daniele Antichi
Keyword(s):  
Water Content ◽  
Cover Crops ◽  
Dry Matter ◽  
Soil Cover ◽  
Plant Cover ◽  
Central Italy ◽  
Research Work ◽  
Soil Layer ◽  
Soil Parameters ◽  
Short Rotation

The risks of soil erosion and nutrient leaching can be considered appreciable in short rotation coppices especially in the first growth phases because of the absence of any plant cover. The temporary intercropping with legumes or grasses used as cover crops can help to overcome these environmental issues. The present research work aims to evaluate the effects of the introduction of cover crops in a short rotation poplar (Populus deltoides W. Bartram ex Marshall) with two-year harvest cycle. The plantation was located in a Typic Xerofluvent, silty-loam soil of the coastal Central Italy. Two different species of cover crops, Trifolium subterraneum L. (TS) and Lolium perenne L. (LP), were compared along with an untreated control, colonised by spontaneous vegetation (CO). Several plant and soil parameters were evaluated: the above ground biomass and nutrient accumulation for the three different soil cover types, the nitrate and water content in two soil layers (0.00-0.30 and 0.30-0.60 m), the poplar yield and nutrient content in branches and leaves. TS returned to the soil about 70 kg ha–1 of nitrogen at the end of its biological cycle, thanks to the high N content (over 2%) and to the noticeable amount of dry matter produced (3.46 t ha–1 of dry matter). This value was considerably higher than those of the LP (23 kg ha–1 of N) or CO (10 kg ha–1). The different amount of nitrogen returned to the soil affected both nitrate concentration in topsoil (0.00-0.30 m) and accumulation of nitrogen in poplar organs. Concerning phosphorous, the differences among treatments were less evident and the amount of P returned to the soil ranged from 2 (CO) to 10 (TS) kg ha–1. However, the effect of soil cover type on P uptake in poplar was still appreciable. Generally, the soil water content was slightly affected by the soil cover types. Indeed, the differences between the cover crops and the control became significant only in the shallowest soil layer and over the summer season. In the first year, LP induced a significant decrease in poplar yield (10.1 t ha–1 of dry matter) in comparison with TS (14.7 t ha–1) and CO (13.4 t ha–1), whereas in the second year there were no significant differences among treatments due to the weak regrowth of cover crops. These results show how to make it feasible a long lasting coexistence between cover crops and SRC, a clever design of agro-forestry systems is therefore needed.

Assessing irrigation requirements in the Ord Sugar Industry using a simulation modelling approach

1998 ◽  
Vol 38 (4) ◽  
pp. 345 ◽  
Author(s):  
R. C. Muchow ◽  
B. A. Keating
Keyword(s):  
Soil Water ◽  
Sugar Industry ◽  
Irrigation Schedule ◽  
Climatic Data ◽  
Irrigation Water Requirement ◽  
Irrigation Requirement ◽  
Management Options ◽  
Water Requirements ◽  
Irrigation Requirements ◽  
Modelling Approach

Summary. Sustainable irrigation guidelines that maximise profitability and minimise water losses and accession to the watertable are required for the new Ord Sugar Industry. In addition, knowledge on crop water requirements is needed to guide water allocation and costing policies for the expanding Ord Irrigation Area where sugarcane is likely to be a dominant crop. Field data indicating water requirements for sugar in the Ord Irrigation Area are few and this paper deploys a modelling approach to extrapolate from knowledge of water requirements in other parts of the world. The approach links long-term climatic data with soil water characteristics of the main soil type, with a cropping systems model, to develop indicative estimates of irrigation water requirement and yield consequences for different management options for sugarcane production in the Ord. Analyses of the growth of 12-month old ratoon crops were conducted using the APSIM–Sugarcane model with historical climatic data from 1960 to 1985 and either a deep (188 mm available water to 160 cm depth) or shallow (144 mm of water to 120 cm depth) Cununurra clay soil. Under maximum attainable growth conditions where crops were irrigated after half the soil water supply was depleted, average sucrose yield ranged from 26.7 to 29.0 t/ha, and the irrigation requirement (assuming 100% application efficiency) ranged from 22.7 to 23.8 ML/ha depending on ratooning date. Soil water holding capacity had a major effect on the number of irrigations and the interval between irrigation for a given irrigation schedule but little effect on yield or irrigation requirement. Varying the irrigation schedule by changing the level of soil water depletion before irrigation and thus the irrigation frequency, showed the tradeoff between yield and irrigation requirement with the most profitable irrigation schedule depending on the price of sucrose and the cost of irrigation relative to other costs. Most of the year-to-year variation in irrigation water requirement could be explained by the highly variable effectiveness in soil storage of rainfall which ranged from 44 to 93%. This study has provided insight and indicative estimates of the yield and irrigation requirements for different irrigation management options for use in the establishment of an Ord River sugar industry. These estimates will be further refined as field data become available.

Some detailed water balance studies of research catchments

1978 ◽  
Vol 363 (1712) ◽  
pp. 21-42 ◽  
Keyword(s):  
Land Use ◽  
Water Balance ◽  
Coniferous Forest ◽  
The Other ◽  
Potential Evaporation ◽  
East Anglia ◽  
Drought Period ◽  
Mean Values ◽  
Neutron Probe ◽  
Future Management

Aspects of the water balance during the drought period 1975–76 are reported for the Institute of Hydrology’s experimental catchments in Cumbria, East Anglia, the Thames Valley and upland Wales. Summer (April–September) and winter (October–March) totals of precipitation, streamflow and potential evaporation during the drought were compared with mean values for seasons preceding it; where soil moisture was measured by neutron probe, losses from actual evaporation were also compared. Yield dropped proportionately less in relation to rainfall where catchments contained appreciable storage, such as the Cam catchment in East Anglia with its chalk–glacial drift aquifer, or the Wye and Severn catchments in upland Wales which contain storage areas of peat underlain with glacial drift. The stream draining the Oxford clay of the Ray catchment in the Thames valley, on the other hand, dried up entirely in the second summer of the drought. The paper suggests that the comparison of water yields from the Wye and Severn catchments, which are under hill pasture and coniferous forest respectively, gives results which have considerable bearing on the future management of water resources from upland areas when the aim of management is to maintain supplies of water even during periods of drought as extreme as the years 1975–76. The effect on reservoir opera­tion of neglecting to allow for change in land use is illustrated by a hypothetical example using an artificial 30 year streamflow sequence containing a drought year with very long return period.

scholarly journals Soil moisture monitoring at the field scale using neutron probe

2014 ◽  
Vol 51 (3) ◽  
pp. 332-345 ◽  
Author(s):  
J. Kodikara ◽  
P. Rajeev ◽  
D. Chan ◽  
C. Gallage
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Layer ◽  
Calibration Method ◽  
Flow Equation ◽  
Wetting Front ◽  
Wet Season ◽  
Buried Structures ◽  
Neutron Probe ◽  
Moisture Variation

Measurement of the moisture variation in soils is required for geotechnical design and research because soil properties and behavior can vary as moisture content changes. The neutron probe, which was developed more than 40 years ago, is commonly used to monitor soil moisture variation in the field. This study reports a full-scale field monitoring of soil moisture using a neutron moisture probe for a period of more than 2 years in the Melbourne (Australia) region. On the basis of soil types available in the Melbourne region, 23 sites were chosen for moisture monitoring down to a depth of 1500 mm. The field calibration method was used to develop correlations relating the volumetric moisture content and neutron counts. Observed results showed that the deepest “wetting front” during the wet season was limited to the top 800 to 1000 mm of soil whilst the top soil layer down to about 550 mm responded almost immediately to the rainfall events. At greater depths (550 to 800 mm and below 800 mm), the moisture variations were relatively low and displayed predominantly periodic fluctuations. This periodic nature was captured with Fourier analysis to develop a cyclic moisture model on the basis of an analytical solution of a one-dimensional moisture flow equation for homogeneous soils. It is argued that the model developed can be used to predict the soil moisture variations as applicable to buried structures such as pipes.

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