Typic Ustipsamment Research Articles

Moisture Deficits and Grain Sorghum Performance: Drought Stress Conditioning1

AbstractThe exploitation of drought stress conditioning responses in field crops may enable substantial water savings in limited irrigation. We analyzed the effectiveness of stressing grain sorghum [Sorghum bicolor (L.) Moench] to varying degrees prior to the grain‐fill period in inducing a drought stress conditioning response during grain fill. A line source sprinkler system was used to apply two sets of treatments on the three sorghum hybrids in a field study conducted on a sandy soil (Typic Ustipsamment): Gradient irrigation (G) applied throughout all growth stages (GGG), or full irrigation (I) during the vegetative and reproductive periods, followed by gradient irrigation during the grain‐fill period (IIG). Large differences in total dry matter (DM) production and grain yields were observed due to different timings or magnitudes of water stress during grain fill (IIG) or throughout the growing season (GGG). However, the harvest index remained the same regardless of stress treatment. A substantial mobilization of stored assimilates from the stem to the grain was observed (up to 73% of grain weight) on the IIG treatment. The stress adjustment of hybrid RS 626 was significant enough to be of practical importance. Grain yields for the GGG and IIG were the same. Much greater seasonal soil water depletion occurred in the GGG than in the IIG treatment, while soil water extraction during grain fill was similar between the two treatments, although the IIG began this stage with a full profile. Dry matter and grain weight were much less sensitive to seasonal evapotranspiration (ET) deficits in the GGG treatment than in the IIG treatment, but seasonal water‐use efficiency in the GGG treatment was substantially higher. All hybrids had the same water‐use efficiency (WUE) in DM and grain production during the grain fill period. Hybrids, NB 505 and NC + 55X tended to escape the effects of grain fill stress by earlier maturity. Leaf area and canopy temperature comparisons suggest that they were not as physiologically sensitive to drought stress as hybrid RS 626 when stress was imposed with a prior conditioning stress. The results indicate that the magnitude of a drought stress conditioning response may be substantial, but will depend on the genotype used, the phenological timing of the treatment, and the irrigation regimen employed.

Eolian Influence on Development and Weathering of Some Soils of Point Reyes Peninsula, California

AbstractWind‐deposited sands have influenced characteristics of soils on Tomales Point at the northern end of Point Reyes Peninsula in California. The distribution of eolian materials, the interface between eolian and residual granitic parent materials, and mineral weathering were investigated in five pedons along a transect from near the edge of a wave‐cut bluff fronting on the Pacific Ocean to near the crest of a stabilized dune. Based upon distinct textural discontinuities, proportions of rounded and angular sands, organic carbon, and phyllosilicate species in silt and clay fractions, nonconforming zones of eolian materials over granitic residuum were clearly distinguished. The soils along the transect include members of coarseloamy, mixed, isomesic Pachic Haplustolls, coarse‐loamy, mixed, isomesic “Entic” Dystropepts, sandy, mixed, isomesic ustic Dystropepts, and mixed, isomesic Typic Ustipsamment families. A mineral weathering sequence involving the transformation biotite → vermiculite → smectite is evident within the buried granitic residuum along the transect.

Soilscapes, geomorphic processes and soil taxonomic new subgroups identified in the Ghaggar river basin of Haryana and Punjab

Soilscapes of the Ghaggar river basin falling in Haryana and Punjab were interpreted and studied by using the Landsat imagery and aerial photographs. Five major landform units identified and demarcated in the area were : channel courses, levees, flood-plains undulating, basinal floodplains and relict basins. On the basis of sedimentation, nature of the river pattern and soil characteristics, the whole basin was divided into three reaches — upper, middle and lower. Taxonomically the soils were placed under Typic Ustipsamments, Typic Ustorthents and lypic Ustifluvents on channel courses; Aquic Ustifluvents, Typic Ustifluvents and Typic Ustochrepts on levees; Fluventic Ustochrepts, Udic Ustochrepts and lypic Camborthids on floodplains undulating; Typic Ustorthents and Udic Ustochrepts on basinal floodplains; Typic Natrustalfs and Natric Camborthids on relict basins. Two new subgroups were proposed, i.e., Natric within the order of Entisol and Inceptisol, and Aquic-udic within the order of Inceptisol. Two dominant geomorphic processes were observed, i.e., fluvial and aeolian.

Infrared Thermometry for Scheduling Irrigation of Corn1

AbstractIrrigation scheduling is an increasingly important practice in the management of valuable water resources in agricultural regions. The study reported here was conducted to evaluate the feasibility of scheduling irrigation in corn (Zea mays L.) using canopy temperature data obtained with a hand‐held infrared thermometer (IRT).Specific objectives of the study were: 1) to determine whether irrigations can be scheduled from crop canopy temperature data and 2) to evaluate the effectiveness of various canopy temperature irrigation scheduling methods through their effects on some plant responses and the soil water balance.The study was conducted at the Sandhills Agricultural Laboratory located near Tryon, Neb. The soil at the site is classified as a Typic Ustipsamment (Valentine fine sand). The range in temperature of six readings made with an IRT—defined as the canopy temperature variability (CTV)—in a fully irrigated reference plot (WW) was less than 0.7 C. As the temperature difference between a water‐stressed plot and the WW plot increased so did CTV values until a critical stress level was reached beyond which CTV values stabilized. The onset of water stress can, therefore, be signaled when CTV values exceed 0.7 C.Observations of CTV were the basis for one type of irrigation scheduling procedure. Irrigation was initiated when the range of six measurments in a plot exceeded 0.7 C. A second procedure consisted of comparing the difference between the average canopy temperature of the well‐watered plot (WW) with that of the plot to be scheduled. Irrigations were initiated when plot temperatures became either 1.0 (1SMW; SWM = Stressed Minus Well‐watered) or 3.0 C (3SMW) warmer than the well‐watered plot.A total of 283 mm of irrigation water was applied to the WW plot whereas the CTV plot received 127 mm. By the end of the growing season almost all available water had been extracted from the soil in the temperature scheduled plots but the soil profile remained near field capacity in the WW plot. This suggests that during the growing season soil water was most effectively used in the temperature scheduled plots.Grain yields (Y) were reduced in the order of increasing water stress as follows: YWW > YCTV > Y1SMW > Y3SMW > YDL YDL is the yield from a dryland (DL) plot which received no supplemental irrigation. Yields of grain in the CTV treatment were slightly lower than in the WW plot, but not significantly so. This suggests that plants in the CTV plot received adequate water. Grain yields in the other temperature‐scheduled plots were significantly reduced below those of the WW plot. However, only about 50 to 60 mm of irrigation water were applied to these plots.

Relationships between crop temperature, grain yield, evapotranspiration and phenological development in two hybrids of moisture stressed sorghum

Recent studies have shown that the grain yields of corn (Zea mays L.) and wheat (Triticum aestivum L.) are related to the degree of water stress they undergo. The purpose of the study reported here was to establish relationships between crop temperature and the grain yields, phenological development, evapotranspiration rates (ET) and leaf water potential (ψl) of two hybrids of grain sorghum (Sorghum bicolor L. Moench) subjected to varying levels of plant water stress. The study was conducted at the University of Nebraska Sandhills Agricultural Laboratory in 1978 on a Typic Ustipsamment (Valentine fine sand) soil. The sorghum hybrids used were RS 626 and NB 505. Four irrigation treatments were applied in order to subject the crops to varying levels of water stress during each of three major growth stages. Soil moisture was monitored with a neutron probe. ET was estimated with the water balance technique. Crop temperature was measured with an IR thermometer and leaf water potential was measured with a Scholander pressure bomb. Grain yields were reduced by water stress occuring at anytime during the growing season. Yield reductions were largest when stress occurred during only the grainfill period and were least when stress occurred during the entire growing season. The percentage reduction in sorghum grain yield can be described by an index involving the seasonal accumulation of the daily mid-day temperature differences between well-watered and stressed crops (Σ TSD). As Σ TSD values increased, ET decreased. However, the correlation of ET with Σ TSD was relatively low (R2 = 0.60) probably due to the limited amount of data available for analysis and inaccuracies in the soil water balance method used to estimate ET. The mid-day temperature of well-watered rows ranged between 18.0 and 32.8 °C with a mid-day temperature range of about 0.5 °C between the well-watered rows in various plots for several days following an irrigation. However, in certain instances, the mid-day temperature range increased to 1–2 °C for a few days before irrigation. This suggests that certain of the rows experienced water stress and should have been irrigated earlier. Yield data support that conclusion. Range in crop temperature within a field appeared to be a sensitive indicator of crop water stress in sorghum. No significant difference in the phenological development of sorghum resulted from water stress except in one NB 505 plot in which plants were stressed throughout the entire season. In that plot, the stressed plants lagged in development behind non-stressed plants by approximately ten days. The differences in mid-day leaf water potentials (Δψl) and crop temperatures (ΔT) between stressed and non-stressed vegetation were examined. As ΔT increased up to about 4 °C, Δψl, also increased. Beyond that point, Δψl decreased while ΔT continued to increase. This behavior was attributed to stomatal closure which permitted an increase in ψl of the stressed plants (hence reducing Δψl) even as ΔT continued to increase.

MAGNESIUM AND ZINC RELATIONSHIP IN RELATION TO DRY MATTER YIELD AND THE CONCENTRATION AND UPTAKE OF NUTRIENTS IN WHEAT

To obtain information on the magnesium-zinc relationship in wheat, we conducted a greenhouse experiment with four levels each of Zn (0, 5, 10, and 20 ppm) and Mg (0, 15, 30, and 60 ppm) using a Typic Ustipsamment. Response to Zn depended upon the Mg level. High levels of Mg depressed Zn response, which was partly overcome by high levels of Zn. Response to Mg was noted only when it was applied alone, up to 30 or 15 ppm, with low levels of Zn. Application of Mg increased Mg, Cu, and Fe, decreased Zn and K, and did not affect N and Ca concentrations. The concentrations of Mn and P also increased at low levels of Mg, but decreased at high levels of Mg. The uptake of all the nutrients, except Zn, increased with low levels of Mg, but decreased with high levels. The uptake of Zn decreased with increasing levels of Mg. Shoot Zn increased, whereas Fe, Mn, Cu, Mg, and P decreased, and N, Ca, and K concentrations were not affected with increasing levels of Zn. The uptake of P, Mg, Cu, and Mn was not affected, whereas uptake of N, K, and Ca increased at low levels of Mg. In general, Mg and Zn appeared to be antagonistically related.

Plant and air temperatures in differentially-irrigated corn

Studies by Jackson et al. (1977) and Idso et al. (1977) indicate that wheat is not stressed for water unless leaf temperature exceeds air temperature. One objective of the study reported here was to determine relationships between leaf temperature and air temperature within corn canopies as a function of water stress. A second objective was to evaluate the effects of varying levels of plant water stress on crop temperature. A third objective was to establish the relationship between plant water stress and crop temperature in corn ( Zea mays L.) with the aim of providing practical water resource management tools. Meteorological, physiological and phenological measurements were made in nine plots of corn, grown on Valentine fine sand (Typic ustipsamment) at the Sandhills Agricultural Laboratory located near Tryon, Nebraska. Each plot received one of seven different irrigation treatments. Canopy temperatures were measured with an infrared thermometer at midday throughout the growing season. Air and leaf temperature measurements were made on an hourly basis with thermocouples. Physiological and phenological observations were made weekly. The average midday difference in canopy temperature between stressed and non-stressed areas was as large as 7.0°C. In fully-irrigated plots, the standard deviation of midday canopy temperature was about 0.3°C but in non-irrigated areas it reached, at times, 4.2°C. It is concluded that a standard deviation of temperature in a plot exceeding 0.3°C signals that some plants are experiencing water stress. This behaviour can indicate the need for irrigation. Daily profiles of leaf and air temperature in stressed and non-stressed canopies were found to be similar. Profiles tended to be lapse before crop cover was complete and inverted later in the season. At any level within the stressed canopy, plants were warmer than at the same level within the non-stressed canopy. The midday temperature of sunlit leaves of non-stressed and moderately stressed plants was generally 1–2°C below air temperature. The temperature of sunlit leaves in severely stressed plants was as much as 4.6°C above air temperature. It was observed that corn plants may be subject to water stress and still be cooler than air temperature.

Holocene Soils in Eolian Sediments of Bailey County, Texas

AbstractThree Holocene geomorphic surfaces and their associated soils and sediments are recognized in sandhills of Bailey County, Texas. Fairview sediments are related to the activities of man since about 100 years B.P. The Muleshoe (100–4,000 years B.P.) and Longview (4,000–7,000 years B.P.) sediments accumulated as a result of erosion initiated by severe droughts in the Holocene.Typic Ustipsamments and Alfic Ustipsamments are the most common Holocene soils in the study area; Psammentic Haplustalfs also occur, but are less common. The Alfic Ustipsamments have two or more continuous clay bands and the Typic Ustipsamments do not. Clay bands occur sporadically in Muleshoe sediments, but continuously in Longview sediments. Argillic horizons and the Psammentic Haplustalfs occur in some of the Longview sediments and in all of the sediments next older than Longview, which may date from latest Pleistocene or earliest Holocene time. Muleshoe sediments 1‐ to 2‐m thick are underlain by buried argillic horizons in many places, and some soils in these areas have been classified elsewhere as Grossarenic Paleustalfs. Thus, some of the soils so classified actually consist in part of buried soils.Clay in the clay bands is thought to have been deposited from clay in suspension on slowing of downward movement of the wetting front. Some clay apparently moves through the upper bands at times of deeply penetrating moisture and then accumulates in bands beneath as the wetting front slows its downward movement. Lateral movement of soil water is also important in the thickening and lateral spread of some bands. Clay accumulation in the bands gradually decreases soil permeability through time, and clay starts to accumulate between bands as well as in them. Since latest Pleistocene or possibly earliest Holocene time, enough clay has accumulated between some of the bands that they are partially obscured.

Adsorption, Mobility, and Degradation of Cyanazine and Diuron in Soils

In the field, surface applied cyanazine 2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl] amino]-2-methylpropionitrile and diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] did not move below 5 cm in a Monona silty clay loam (Typic Hapludoll) which received 20 cm of water over a 54-day period. In hand-packed soil columns in the laboratory, surface-applied diuron and cyanazine penetrated to depths of 10 and 20 cm, respectively, when leached over a comparable time period and with amounts of water similar to that used in the field. Soil thin layer chromatography and adsorption isotherm studies showed that diuron was adsorbed more strongly than was cyanazine. In general, both compounds were degraded more rapidly at the higher temperatures when incubated at 5, 20, 35, and 50 C over a 20-week period. Degradation was slowest at 5 C in a Valentine loamy fine sand (Typic Ustipsamment). Diuron appeared to break down most readily at 35 C. Cyanazine was usually decomposed by the 10th week at 5 C and the 5th week at higher temperatures.

Soil Crusting and Emergence of Wheat Seedlings1

AbstractSoil crusting is usually referred to be the cause of impaired wheat (Triticum aestivum L.) stands in the Negev region of Israel. The soils in this region vary from mixed hyperthermic, typic Ustipsamment soils to fine loamy, mixed hyperthermic typic Ustorthent soils.The major objective of the work carried out was to estimate and analyze the soil crusting phenomena under field conditions and as a secondary objective to study and analyze wheat seedlings behavior under field and laboratory conditions.Resistance to penetration of natural soil crusts, measured by penetration from underneath the crust, and its dependence on water content and seed bed preparation methods (disking vs. plowing) were determined. These measurements were collected in a field survey carried out during early winter following the first rain that initiated both wheat germination and a sequence of soil slacking and subsequently, as the soil dried out, crusting. It was found that natural crust resistance to penetration was greater for those formed on disked plots than on plowed plots.In laboratory trials, using a sandy silt loam (typic ustipsamment) soil, crusts were formed by simulated rainfall (intensity of 10 mm/hour, rainfall applications of 5, 10, and 30 mm in one or two simulated rainstorms). These crusts were found to be less penetrable than the natural ones for the same soil under natural field conditions at the same water contents.Wheat seedling penetration of soil crusts was evaluated under laboratory conditions, whereas projected penetrability of crusts under field conditions was based on an assumed water potential and subsequent coleoptile thrust in the region of the seedlings. These projected values suggested that crusting in the field may not be the cause for a bad stand, except under extremely adverse conditions. These projections illustrate the urgency of including dynamic considerations of seedling performance in the future studies of small grains germination and emergence under and through crusting soils.