Rotational Sequences Research Articles

Liming acidic soils creates profits, land use options but often more emissions

Context Soil acidity constrains crop production in Australia. The practice of liming can reduce soil acidity but produces greenhouse gas emissions. Aims By examining land use sequences over three decades at a range of locations in Western Australia, this study aims to identify firstly where and when liming might boost farm profits and secondly, what emissions and land use management flexibilities are generated by liming. Methods Bioeconomic simulation modelling is used to identify the gross margins and emissions associated with liming in land use sequences at 14 locations in Western Australia. Three intensities of cropping and three different rotational sequences are considered. The simulations account for price and weather–year variations across a 30-year period of analysis. Key results Liming is profitable at almost all locations and across all rotation sequences examined. Where problematic soil acidity is a feature or is poised to soon become a problem at a location, liming is a profitable ameliorative practice that enables greater diversity in land use. For most situations assessed, liming increases emissions. The exceptions are at locations where liming prevents a switch away from a crop-dominant system, due to soil acidity reducing crop yields, into additional sheep production that increases emissions. Conclusions Liming is profitable in most acidic soil situations and preserves land use flexibility, although additional greenhouse gas emissions are often generated. Implications Liming acidic soils bolsters land use profitability and helps sustain biologically diverse land use sequences, despite often increasing greenhouse gas emissions.

A Variational Optical Flow Model for Accurate Motion Estimation from Rotational Image Sequences

A Variational Optical Flow Model for Accurate Motion Estimation from Rotational Image Sequences

Tillage and Crop Residue Management on Weed Dynamics and Productivity of Direct Seeded Rice

A field experiment was conducted during 2019 and 2020 to evaluate the effect of tillage and residue management on weed dynamics and productivity of direct seeded rice with four tillage systems; Conventional tillage in rice and wheat, Zero tillage in rice and wheat and two rotational tillage sequences that alternated between Conventional tillage and Zero tillage whereas four residue management practices; residue applied in both season, residue applied in kharif season only, residue applied in rabi season only and without residue in both season. The experiment was carried out at research farm of Birsa Agricultural University, Ranchi, Jharkhand. Results revealed that in direct seeded rice having highest grain yield (10%), straw yield (8%) and yield attributes (10-15%) as well as lesser weed density and weed dry matter found under Conventional tillage during both the seasons of experiment but performance of zero tillage was slightly better (3-4%) in second year as compared to all treatments. Whereas surface retention of residue @5 tonne/ha was significantly more effective in controlling different category of weeds, it decreased up to 60-75% weed population, resulting increment in grain yield up to 19% and 23% during first and second year, respectively, as compared to plot receiving no residue.

Subtle Responses of Soil Bacterial Communities to Corn-Soybean-Wheat Rotation

Crop rotational diversity can improve crop productivity and soil health, and boost soil microbial diversity. This research hypothesized that a 3-year rotation of corn-soybean-wheat (CSW), compared with a 2-year corn-soybean (CS) rotation, would result in a more diverse and more complex soil bacterial community, together with a greater abundance of beneficial bacteria. This was evaluated in a replicated experiment established in 2013 at two locations in Ohio (United States). The soil bacterial communities under soybean were compared between CS and CSW at both studied sites in 2018 and 2019, through 16S ribosomal DNA amplicon metabarcoding. Experimental site was the main driver of bacterial richness and evenness. Significant effects on bacterial community composition were observed in response to the interaction between site, rotational sequence, and year of study. Eight bacterial amplicon sequence variants were identified within all CSW treatments and were not present in CS. Several taxa were differentially abundant between rotation treatments, including the genera Ralstonia being more abundant in CS. Co-occurrence networks, including hub taxa, were generally different between rotation treatments and year, with more structure observed in CSW networks for one of the studied sites. Few bacterial genera were consistently identified as hubs across all networks, including an unidentified member of order Acidobacteriales, while other hubs were unique for CSW networks, including members of the family Gemmatimonadaceae. Finally, the composition of the bacterial communities at the northwestern site positively correlated with plant biomass and active carbon, whereas more recalcitrant pools (total carbon and organic water) correlated with the bacterial communities at the western site.

ACCURATE MOTION ESTIMATION FOR ROTATIONAL IMAGE SEQUENCES

Complex motion patterns, non-rigid deformations, occlusions, and illumination changes largely affect rotational image sequences. This makes accurate motion estimation a challenging task. To address this issue, we propose an optical flow model to accurately estimate motion in rotational image sequences. Our model uses an additional constraint in the objective weighted with an edge-stopping function which allows non-zero curl specifically in the regions where rotation is involved. Our implementation of the model relies upon the robust Chambolle-Pock algorithm. We discuss the effects of the model parameters and the primal-dual parameters in the convergence of the algorithm. To further validate the effectiveness of our model, we combine our algorithm with some of the sophisticated implementation approaches with weighted median filtering. Our results on some of the rotational sequences from the Middlebury benchmark datasets show that our method achieves the best average angular and end-point errors when compared with some of the well-known models in the literature.

A Search for Stellar Siblings of the ∼200 Myr TOI-251 b Planetary System

Young planets (<1 Gyr) are helpful for studying the physical processes occurring at the early stage of planet evolution. TOI-251 b is a recently discovered sub-Neptune orbiting a young G dwarf, which has an imprecise age estimation of 40–320 Myr. We select TOI-251 sibling candidates based on kinematics and spatial proximity to TOI-251 and further use the color–magnitude diagram to refine the list and to compare to multiple open clusters. We report the stellar rotational period for 321 sibling candidates in a 50 pc radius around TOI-251 by analyzing their stellar light curves and find a color–rotational period sequence that lies in between the Group X (300 Myr) and Pleiades (120 Myr) members, suggesting an age ∼ 200 Myr. A quantitative age analysis using gyrochronology relations gives 204 ± 45 Myr, consistent with the average Li age of selected siblings (238 ± 38 Myr) and the Gaia variability age (193 Myr). The detection fraction of comoving candidates that have a short rotational period is 68.1%, much higher than the typical value in the field (14%–16% from Kepler). The overdensity of young stars and consistency in age of stellar siblings suggest a potential young association candidate in the Phoenix–Grus constellation. Though TOI-251 b has a radius larger than most of its field-age counterparts, we are uncertain whether TOI-251 is inflated, due to a lack of knowledge on the planet’s mass.

A frame orientation optimisation method for consistent interpretation of kinematic signals

In clinical movement biomechanics, kinematic data are often depicted as waveforms (i.e. signals), characterising the motion of articulating joints. Clinically meaningful interpretations of the underlying joint kinematics, however, require an objective understanding of whether two different kinematic signals actually represent two different underlying physical movement patterns of the joint or not. Previously, the accuracy of IMU-based knee joint angles was assessed using a six-degrees-of-freedom joint simulator guided by fluoroscopy-based signals. Despite implementation of sensor-to-segment corrections, observed errors were clearly indicative of cross-talk, and thus inconsistent reference frame orientations. Here, we address these limitations by exploring how minimisation of dedicated cost functions can harmonise differences in frame orientations, ultimately facilitating consistent interpretation of articulating joint kinematic signals. In this study, we present and investigate a frame orientation optimisation method (FOOM) that aligns reference frames and corrects for cross-talk errors, hence yielding a consistent interpretation of the underlying movement patterns. By executing optimised rotational sequences, thus producing angular corrections around each axis, we enable a reproducible frame definition and hence an approach for reliable comparison of kinematic data. Using this approach, root-mean-square errors between the previously collected (1) IMU-based data using functional joint axes, and (2) simulated fluoroscopy-based data relying on geometrical axes were almost entirely eliminated from an initial range of 0.7°–5.1° to a mere 0.1°–0.8°. Our results confirm that different local segment frames can yield different kinematic patterns, despite following the same rotation convention, and that appropriate alignment of reference frame orientation can successfully enable consistent kinematic interpretation.

Modeling the development of cortical responses in primate dorsal ("where") pathway to optic flow using hierarchical neural field models.

Although there is a plethora of modeling literature dedicated to the object recognition processes of the ventral ("what") pathway of primate visual systems, modeling studies on the motion-sensitive regions like the Medial superior temporal area (MST) of the dorsal ("where") pathway are relatively scarce. Neurons in the MST area of the macaque monkey respond selectively to different types of optic flow sequences such as radial and rotational flows. We present three models that are designed to simulate the computation of optic flow performed by the MST neurons. Model-1 and model-2 each composed of three stages: Direction Selective Mosaic Network (DSMN), Cell Plane Network (CPNW) or the Hebbian Network (HBNW), and the Optic flow network (OF). The three stages roughly correspond to V1-MT-MST areas, respectively, in the primate motion pathway. Both these models are trained stage by stage using a biologically plausible variation of Hebbian rule. The simulation results show that, neurons in model-1 and model-2 (that are trained on translational, radial, and rotational sequences) develop responses that could account for MSTd cell properties found neurobiologically. On the other hand, model-3 consists of the Velocity Selective Mosaic Network (VSMN) followed by a convolutional neural network (CNN) which is trained on radial and rotational sequences using a supervised backpropagation algorithm. The quantitative comparison of response similarity matrices (RSMs), made out of convolution layer and last hidden layer responses, show that model-3 neuron responses are consistent with the idea of functional hierarchy in the macaque motion pathway. These results also suggest that the deep learning models could offer a computationally elegant and biologically plausible solution to simulate the development of cortical responses of the primate motion pathway.

A multifield loads evaluation method for offshore wind turbines considering multivariate coherence effect

The structural design and reliability assessment of offshore wind turbine systems for maximally exploring the renewable energy resources significantly rely on the actual marine environmental loads. The major challenges arising from the estimation of offshore wind turbine loads are the effects of rotating blades on wind velocity and the interactions among multiple components such as wind, waves and the structure. These factors make the environmental loads more complex and multivariately correlated. To address such issues, a multivariate coherence effect (MCE)-based evaluation method has been proposed to analyze the rotational effect on the wind velocity by discovering the perturbation mechanism of wind spectrum. Furthermore, analytical formulations in the form of the blade speed and wind spectrum have been developed to construct the MCE-based joint power spectrum matrix for the load redistribution via intercorrelations among multiple domains representing the ambient environment of offshore wind turbines. Results show that the MCE-based method has the ability to retain the characteristic multiple rotational frequencies of rotational blades and enables the simultaneous reconstructions of the stationary-state wind field, rotational wind field and wave height sequences for accurate load redistributions by decomposing the MCE-based joint power spectrum matrix. As compared with the traditional techniques, a more cost-effective approach can be further developed for the reliable estimation of the blade flapwise deflection using the proposed method. Summarily, the present work provides analytical formations for the accurate load configuration and dynamic analysis of offshore wind turbines subject to harsh marine environments.

A 4 Gyr M-dwarf Gyrochrone from CFHT/MegaPrime Monitoring of the Open Cluster M67

We present stellar rotation periods for late K- and early M-dwarf members of the 4 Gyr old open cluster M67 as calibrators for gyrochronology and tests of stellar spin-down models. Using Gaia EDR3 astrometry for cluster membership and Pan-STARRS (PS1) photometry for binary identification, we build this set of rotation periods from a campaign of monitoring M67 with the Canada–France–Hawaii Telescope’s MegaPrime wide-field imager. We identify 1807 members of M67, of which 294 are candidate single members with significant rotation period detections. Moreover, we fit a polynomial to the period versus color-derived effective temperature sequence observed in our data. We find that the rotation of very cool dwarfs can be explained by simple solid-body spin-down between 2.7 and 4 Gyr. We compare this rotational sequence to the predictions of gyrochronological models and find that the best match is Skumanich-like spin-down, P rot ∝ t 0.62, applied to the sequence of Ruprecht 147. This suggests that, for spectral types K7–M0 with near-solar metallicity, once a star resumes spinning down, a simple Skumanich-like relation is sufficient to describe their rotation evolution, at least through the age of M67. Additionally, for stars in the range M1–M3, our data show that spin-down must have resumed prior to the age of M67, in conflict with the predictions of the latest spin-down models.

Impact of Rotational Sequence Selection on Weed Seedbank Composition in Australian Broadacre Crops

The use of competitive crops in successional rotations has been shown to reduce the growth and establishment of annual weeds by the depletion of the weed seedbank in broadacre cropping systems. However, the impact of specific crop rotational sequences contributing to weed seedbank density has not been quantified in the Riverina region of southern Australia. Trials were established in two locations in 2014–2018 to quantify the impact of selected annual rotations featuring grain, pulse, and pasture crops on weed infestation and seedbank dynamics with a focus on winter and summer annual weeds. The weed seedbank dynamics were evaluated by a twice-annual soil sampling regime (at planting and harvest), followed by soil sample screening for weed propagule germination and seedling establishment in a subsequent controlled-environment screening performed from 2014–2020. The weed seedling density decreased in the cereal rotations in years experiencing average to above-average rainfall, as crops established a dense canopy leading to reduced weed establishment and fecundity. Several rotational treatments were effective in suppressing the weed propagule numbers over time, including those using dual-purpose cereals only or a canola break-crop along with the cereals. Rotational selection can be an important and cost-effective tool in integrated weed management systems when applied over multiple growing seasons.

Double echo symmetry-based REDOR and RESPDOR pulse sequences for proton detected measurements of heteronuclear dipolar coupling constants

1H{X} symmetry-based rotational echo double resonance pulse sequences (S-REDOR) and symmetry-based rotational echo saturation pulse double resonance (S-RESPDOR) solid-state NMR experiments have found widespread application for 1H detected measurements of difference NMR spectra, dipolar coupling constants, and internuclear distances under conditions of fast magic angle spinning (MAS). In these experiments the supercycled R412 (SR412) symmetry-based recoupling pulse sequence is typically applied to the 1H spins to reintroduce heteronuclear dipolar couplings. However, the timing of SR412 and other symmetry-based pulse sequences must be precisely synchronized with the rotation of the sample, otherwise, the evolution of 1H CSA and other interactions will not be properly refocused. For this reason, significant distortions are often observed in experimental dipolar dephasing difference curves obtained with S-REDOR or S-RESPDOR pulse sequences. Here we introduce a family of double echo (DE) S-REDOR/S-RESPDOR pulse sequences that function in an analogous manner to the recently introduced t1-noise eliminated (TONE) family of dipolar heteronuclear multiple quantum coherence (D-HMQC) pulse sequences. Through numerical simulations and experiments the DE S-REDOR/S-RESPDOR sequences are shown to provide dephasing difference curves similar to those obtained with S-REDOR/S-RESPDOR. However, the DE sequences are more robust to the deviations of the MAS frequency from the ideal value that occurs during typical solid-state NMR experiments. The DE sequences are shown to provide more reliable 1H detected dipolar dephasing difference curves for nuclei such as 15N (with isotopic labelling), 183W and 35Cl. The double echo sequences are therefore recommended to be used in place of conventional S-REDOR/S-RESPDOR sequences for measurement of weak dipolar coupling constants and long-range distances.

Stellar Rotation in the Gaia Era: Revised Open Clusters’ Sequences

Abstract The period versus mass diagrams (i.e., rotational sequences) of open clusters provide crucial constraints for angular momentum evolution studies. However, their memberships are often heavily contaminated by field stars, which could potentially bias the interpretations. In this paper, we use data from Gaia DR2 to reassess the memberships of seven open clusters with ground- and space-based rotational data, and present an updated view of stellar rotation as a function of mass and age. We use the Gaia astrometry to identify the cluster members in phase space, and the photometry to derive revised ages and place the stars on a consistent mass scale. Applying our membership analysis to the rotational sequences reveals that: (1) the contamination in clusters observed from the ground can reach up to ∼35%; (2) the overall fraction of rotational outliers decreases substantially when the field contaminants are removed, but some outliers persist; (3) there is a sharp upper edge in the rotation periods at young ages; (4) at young ages, stars in the 1.0–0.6M ⊙ range inhabit a global maximum of rotation periods, potentially providing an optimal window for habitable planets. Additionally, we see clear evidence for a strongly mass-dependent spin-down process. In the regime where rapid rotators are leaving the saturated domain, the rotational distributions broaden (in contradiction with popular models), which we interpret as evidence that the torque must be lower for rapid rotators than for intermediate ones. The cleaned rotational sequences from ground-based observations can be as constraining as those obtained from space.

Managing the functional diversity of arbuscular mycorrhizal fungi for the sustainable intensification of crop production

Societal Impact StatementThe need to increase food production with reduced use of resources and environmental impact demands innovative rethinking and evolution of cropping systems. The essential changes required are consistent with sustaining arbuscular mycorrhiza, which, together with their associated microorganisms, could be managed to play an important role, especially in the protection of crops against abiotic and biotic stresses. Mycorrhiza should be included in agronomic decision processes, where chemical options to protect crops are limited or require the use of large applications. Defining rotational plant sequence or using cover crops and adopting reduced or no‐till techniques are key components of a strategy for a consistent and predictable way of manipulating the native inoculum to capitalize on the manifold benefits potentially provided by arbuscular mycorrhizal fungi through their functional diversity.SummaryDespite the wide range of benefits arbuscular mycorrhiza can confer, they are not usually considered in large‐scale farming systems because the potential improvements in crop yields through the enhanced uptake of nutrients is a matter of debate and the advantages from the bio‐protection afforded against biotic and abiotic stresses have not been adequately recognised. Research carried out by our group over the last 20 years has allowed the development of a strategy based on the intentional use of selected host plants (Developer plants), to develop an extensive extraradical mycelium which, when kept intact by the adoption of appropriate tillage techniques, acts as preferential source of inoculum for the following crop, leading to earlier and faster colonization by AM fungi. Depending on the particular host plant chosen as Developer, this strategy can also be used as a tool to manage AMF functional diversity. Using this approach, we have achieved effective protection against abiotic (Mn soil toxicity) and biotic (Fusarium oxysporum and Magnaporthiopsis maydis) stresses in different crops. The strategy can easily be applied at field scale, both in low and high input cropping systems. It only requires small changes to the cropping system, such as employing no‐till and altered crop rotation or cover crops, that are simple to adopt and can realistically be implemented at the field level. This represents an important breakthrough as it allows intentional and predictable manipulation of the native soil mycorrhizal population over a range of different soils and circumstances.

ON THE EVOLUTION OF ANGULAR MOMENTUM, MAGNETIC ACTIVITY AND MASS LOSS RATE OF LATE TYPE MAIN SEQUENCE STARS

With the best data, I find that nearly all 0.5 to 1.2 M main sequence stars converge to a single rotational mass-dependent sequence after 750 Myr; when M &gt; 0.8 M_, most of them converge in ≈ 120 Myr. If stars rotate as rigid bodies, most have angular momenta within clear bounds. The lower bound defines a terminal main sequence rotational isochrone, the upper one coincides with slow rotators from the Pleiades; stars from Praesepe delineate a third one. Mass dependent exponential relationships between angular momentum and age are determined. Age estimates based on the angular momentum are acceptable for stars older than 750 Myr and with M &gt; 0.6− 0.7 M_⨀. The Rossby number indicates that the Parker dynamo may cease early on in stars with M/M_≥ 1.1. An empirical formula and a model for the torque, and a relation between rotational period and magnetic field, lead to a formula for the evolution of the mass loss rate; the present solar rate is near a minimum and was about five times larger when life on Earth started.

Litter stock and quality in Eucalyptus grandis in Northern Rio de Janeiro State, Brazil

Abstract Litter decomposition restores part of the elements absorbed by the plant back into the soil, acting as a regulator of the biogeochemical cycling of nutrients. This study aimed to evaluate the litter quantity and quality of Eucalyptus grandis in Northern Fluminense region, RJ. Three rotational sequences were studied, the first after 8 years (FR8), the second after 1.5 years (SR2), and a 5year old regrowth (R5). Leaf litter was divided into whole leaves (WL), fragmented pieces (FP), twigs/branches (TB), reproductive structures (RS) and bark (B). The total litter in FR8 was 9.56 Mg ha-1, in SR2, 13.85, and in R5, 22.97 Mg ha-1, corresponding to 83, 163 and 75 kg ha-1 of N, respectively. FP represented 38%, 48% and 55% of N, respectively, in SR2, R5 and FR8. The WL and FP fractions have high recycling potential of organic matter and nutrients due to their lower C/N and Lig/N quality index values.

Nutrient Cycling in Organic Field Crops in Canada and the United States

Organic farmers have identified soil fertility and weed management as the two highest research priority areas. No review exists of research on soil nutrient management in organic field crop systems. We conducted a comprehensive review to identify the principles and factors governing nutrient management, knowledge gaps, and future research needs in organic grain and other field crop systems in Canada and the United States. We compared results from research conducted in different climates, soils, and crop rotational sequences. Results indicate that (i) dual‐use cover/green manure crops and/or animal manure are the most common sources of plant available N and other nutrients in organic field crop systems; (ii) soil nutrient deficiencies can develop through sole reliance on cover/green manure crops; (iii) dependence on animal manure can lead to N and P excesses; (iv) conventional soil testing procedures may not accurately predict crop nutrient needs; (v) greater knowledge of microbial processes governing nutrient cycling is needed; and (vi) better understanding of the impact of weeds on soil fertility may create weed and nutrient management synergies. Knowledge gaps include a lack in understanding of how the soil and plant biomes influence nutrient‐use efficiency and how crop diversity and rotations impact soil fertility, sustainability, and resilience in organic field crop systems. Likewise, interactions between weeds, crops, soil fertility, and weed management strategies are poorly understood.Core Ideas Soil, climate, fertility sources, and land use impact organic nutrient management strategies. Cover/green manure crops and animal manures are used to maintain soil fertility on organic farms. Conventional soil testing may not be ideally suited to organic systems. Tracking soil nutrient temporal changes can improve comprehensive nutrient management plans. More research of how weeds and soil microbial community structure/function impact nutrient cycling and crop production is needed.

Importance of multicranked configuration mixing for angular-momentum-projection calculations: Study of superdeformed rotational bands in Dy152 and Hg194

Recently we investigated an effective method of multicranked configuration mixing for angular-momentum-projection calculations, where several cranked mean-field states are coupled after projection: The basic idea was originally proposed by Peierls and Thouless more than fifty years ago. With this method a good description of the rotational band has been achieved in a fully microscopic manner. In the present work, we apply the method to the high-spin superdeformed band, for which a long rotational sequence is observed, and study how a good description is obtained for the rotational spectrum as well as the ${\mathcal{J}}^{(1)}$ and ${\mathcal{J}}^{(2)}$ moments of inertia as functions of angular momentum. The Gogny D1S force is employed as an effective interaction, and the yrast superdeformed bands in $^{152}\mathrm{Dy}$ and $^{194}\mathrm{Hg}$ are taken as typical examples in the $A\ensuremath{\approx}150$ and $A\ensuremath{\approx}190$ regions, respectively. The effect of pairing correlations is examined by the method of variation after particle-number projection to understand the different behaviors of ${\mathcal{J}}^{(2)}$ moments of inertia observed in these two nuclei. The particle-number projection on top of the angular-momentum projection has been performed for the first time with the multicranked configuration mixing.

Adaptive Segmentation and Feature Acquisition of Test Sequence for Momentum Wheel

In aerospace engineering, the telemetry sequence is a vital reference for evaluating the performance of each component. The segmentation algorithm is an effective method for processing telemetry sequence, which lays a solid foundation for obtaining feature indicators. For the Momentum Wheel, rotational speed stability and acceleration characteristic are two crucial feature indicators. This paper presents a novel method of Adaptive Segmentation and Feature Extraction (ASFE) for processing the rotational speed sequence of the Momentum Wheel, which can realize the requirements of online testing and automatic acquisition of these two indicators. Firstly, based on the two different working modes of constant speed and adjusting speed, the rotational speed sequence of Momentum Wheel is identified as smooth and transitional. Secondly, the improved Adaptive Piecewise Constant Approximation (APCA) algorithm is proposed to identify the smooth segmentation, and the feature extraction sub-algorithm with online processing capability is also proposed to obtain the indicator of rotational speed stability. Thirdly, the fitting method based on slope threshold is used for the data of the transition segmentation, and the indicator of acceleration characteristic is extracted. The experiment results with the X Momentum Wheel shows that the accuracy of the data measurement processing is not less than 0.96 of the theoretical true value. This indicates that ASFE can significantly improve the test efficiency and meet the requirements of the Momentum Wheel test.

Soil Water Extraction for Several Dryland Crops

Core Ideas Crops differ in depth of soil water extraction. Crops did not differ in lower limit of water availability. Wheat ends the growing season with a drier soil profile. Proso millet ends the growing season with a wetter soil profile. Extractable available soil water may aid in designing successful rotational sequences. Dryland cropping decisions would benefit from information about soil water extraction by various candidate crops. The objectives of this experiment were to: (i) quantify average soil water extraction by depth in the soil profile for winter wheat (Triticum aestivum L.), corn (Zea mays L.), proso millet (Panicum milliaceum L.) , and dry pea (Pisum sativum L.), and (ii) verify previously published values of drained upper limit (DUL) and lower limit (LL) of water extraction for each crop grown on a silt loam soil in northeastern Colorado. Soil water contents at planting and physiological maturity were measured over a 21‐yr period. Average ending soil water was least at all measurement depths for wheat and greatest for millet. The greatest total profile water extraction was seen for wheat (141 mm) and the least for pea (46 mm). Soil water extraction occurred, on average, from the 0‐ to 180‐cm profile for wheat, 0‐ to 150‐cm profile for corn, 0‐ to 120‐cm profile for millet, and 0‐ to 90‐cm profile for pea. When soil water was plentiful at planting and followed by dry growing season conditions, millet extracted soil water from the entire 0‐ to 180‐cm profile. Crop rotational sequences utilizing shallow rooted crops (such as millet and pea) that do not fully extract soil water at lower depths will allow for greater soil water availability to subsequent crops such as wheat and corn that are able to explore the lower soil profile more effectively for soil water.