scholarly journals Long-term research needed to avoid spurious and misleading trends in sustainability attributes of no-till

2019 ◽  
Author(s):  
Sarah Cusser ◽  
Christie Bahlai ◽  
Scott M. Swinton ◽  
G. Philip Robertson ◽  
Nick M. Haddad
Keyword(s):  
Soil Moisture ◽  
Crop Yield ◽  
Agricultural Management ◽  
List Type ◽  
Moving Window ◽  
Short Term ◽  
Profitability Analysis ◽  
No Till ◽  
Relative Profitability

ABSTRACTAgricultural management recommendations based on short-term studies can produce findings inconsistent with long-term reality. Here, we test the long-term relative profitability and environmental sustainability of continuous no-till agriculture practices on crop yield, soil moisture, and N2O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no-till as compared to conventional till agriculture over a 29-year period at a site in the upper Midwest, U.S. We find that over a decade is needed to detect the consistent benefits of no-till on important attributes at this site. Both crop yield and soil moisture required periods 15 years or longer to generate patterns consistent with 29-year trends. Only marginally significant trends for N2O fluxes appeared in this period. Importantly, significant but misleading short-term trends appeared in more than 20% of the periods examined. Relative profitability analysis suggests that 10 years after initial implementation, 86% of periods recuperated the initial expense of no-till implementation, with the probability of higher relative profit increasing with longevity. Results underscore the essential importance of decade and longer studies for revealing the long-term dynamics and emergent outcomes of agricultural practices for different sustainability attributes and are consistent with recommendations to support the long-term adoption of no-till management.GRAPHICAL ABSTRACTHIGHLIGHTSWe test long-term effects of no-till on yield, soil moisture, and N2O fluxesWe examine 29 years of data with a moving window and relative profitability methodIt takes at least a decade to detect consistent benefits of no-tillShorter studies can produce significant but misleading findingsLong studies are essential to reveal the dynamics of agricultural management

scholarly journals Effects of Short-term Tillage of a Long-term No-Till Land on Crop Yield and Nutrient Uptake in Two Contrasting Soil Types

2016 ◽  
Vol 5 (3) ◽  
pp. 32 ◽  
Author(s):  
Miles Dyck ◽  
Sukhdev S. Malhi ◽  
Marvin Nyborg ◽  
Dyck Puurveen
Keyword(s):  
Nutrient Uptake ◽  
Crop Yield ◽  
Crop Production ◽  
N Uptake ◽  
P Uptake ◽  
N Fertilization ◽  
Short Term ◽  
Plant Yield ◽  
No Till

<p>Pre-seeding tillage of long-term no-till (NT) land may alter crop production by changing the availability of some nutrients in soil. Effects of short-term (4 years) tillage (hereafter called reverse tillage [RT]) of land previously under long-term (29 or 30 years) NT, with straw management (straw removed [SRem] and straw retained [SRet]) and N fertilizer rate (0, 50 and 100 kg N ha<sup>-1</sup> in SRet, and 0 kg N ha<sup>-1</sup> in SRem plots), were determined on plant yield (seed + straw, or harvested as forage/silage at soft dough stage), and N and P uptake in growing seasons from 2010 to 2013 at Breton (Gray Luvisol [Typic Cryoboralf] loam) and from 2009 to 2012 at Ellerslie (Black Chernozem [Albic Argicryoll] loam), Alberta, Canada. Plant yield, N uptake and P uptake tended to be greater with RT compared to NT in most cases at both sites, although significant in a few cases only at Ellerslie. On average over both sites, RT produced greater plant yield by 560 kg ha<sup>-1</sup> yr<sup>-1</sup>, N uptake by 5.8 kg N ha<sup>-1</sup> yr<sup>-1</sup>, and P uptake by 1.8 kg P ha<sup>-1</sup> yr<sup>-1</sup> than NT. There was no consistent beneficial effect of straw retention on plant yield, N uptake and P uptake in different years. Plant yield, N uptake and P uptake increased with N fertilization at both sites, with up to the maximum rate of applied N at 100 kg N ha<sup>-1</sup> in 3 of 4 years at Breton and in 2 of 4 years at Ellerslie. In conclusion, our findings suggested some beneficial impact of occasional tillage of long-term NT soil on crop yield and nutrient uptake.</p>

Techniques to Predict Agricultural Droughts

2005 ◽  
Author(s):  
Zekai Şen
Keyword(s):  
Crop Yield ◽  
Satellite Data ◽  
Wheat Yield ◽  
Weather Variables ◽  
Short Term ◽  
Yield Model ◽  
Regression Techniques ◽  
The Difference ◽  
Effects Of Drought

In general, the techniques to predict drought include statistical regression, time series, stochastic (or probabilistic), and, lately, pattern recognition techniques. All of these techniques require that a quantitative variable be identified to define drought, with which to begin the process of prediction. In the case of agricultural drought, such a variable can be the yield (production per unit area) of the major crop in a region (Kumar, 1998; Boken, 2000). The crop yield in a year can be compared with its long-term average, and drought intensity can be classified as nil, mild, moderate, severe, or disastrous, based on the difference between the current yield and the average yield. Regression techniques estimate crop yields using yield-affecting variables. A comprehensive list of possible variables that affect yield is provided in chapter 1. Usually, the weather variables routinely available for a historical period that significantly affect the yield are included in a regression analysis. Regression techniques using weather data during a growing season produce short-term estimates (e.g., Sakamoto, 1978; Idso et al., 1979; Slabbers and Dunin, 1981; Diaz et al., 1983; Cordery and Graham, 1989; Walker, 1989; Toure et al., 1995; Kumar, 1998). Various researchers in different parts of the world (see other chapters) have developed drought indices that can also be included along with the weather variables to estimate crop yield. For example, Boken and Shaykewich (2002) modifed the Western Canada Wheat Yield Model (Walker, 1989) drought index using daily temperature and precipitation data and advanced very high resolution radiometer (AVHRR) satellite data. The modified model improved the predictive power of the wheat yield model significantly. Some satellite data-based variables that can be used to predict crop yield are described in chapters 5, 6, 9, 13, 19, and 28. The short-term estimates are available just before or around harvest time. But many times long-term estimates are required to predict drought for next year, so that long-term planning for dealing with the effects of drought can be initiated in time.

scholarly journals Soil carbon release responses to long-term versus short-term climatic warming in an arid ecosystem

2020 ◽  
Vol 17 (3) ◽  
pp. 781-792 ◽  
Author(s):  
Hongying Yu ◽  
Zhenzhu Xu ◽  
Guangsheng Zhou ◽  
Yaohui Shi
Keyword(s):  
Soil Moisture ◽  
Soil Carbon ◽  
Field Experiments ◽  
Sigmoid Function ◽  
Desert Grassland ◽  
Climatic Warming ◽  
Short Term ◽  
Exponential Relationship ◽  
Carbon Release

Abstract. Climate change severely impacts the grassland carbon cycling by altering rates of litter decomposition and soil respiration (Rs), especially in arid areas. However, little is known about the Rs responses to different warming magnitudes and watering pulses in situ in desert steppes. To examine their effects on Rs, we conducted long-term moderate warming (4 years, ∼3 ∘C), short-term acute warming (1 year, ∼4 ∘C) and watering field experiments in a desert grassland of northern China. While experimental warming significantly reduced average Rs by 32.5 % and 40.8 % under long-term moderate and short-term acute warming regimes, respectively, watering pulses (fully irrigating the soil to field capacity) stimulated it substantially. This indicates that climatic warming constrains soil carbon release, which is controlled mainly by decreased soil moisture, consequently influencing soil carbon dynamics. Warming did not change the exponential relationship between Rs and soil temperature, whereas the relationship between Rs and soil moisture was better fitted to a sigmoid function. The belowground biomass, soil nutrition, and microbial biomass were not significantly affected by either long-term or short-term warming regimes, respectively. The results of this study highlight the great dependence of soil carbon emission on warming regimes of different durations and the important role of precipitation pulses during the growing season in assessing the terrestrial ecosystem carbon balance and cycle.

scholarly journals Short-Term and Long-Term Surface Soil Moisture Memory Time Scales Are Spatially Anticorrelated at Global Scales

2019 ◽  
Vol 20 (6) ◽  
pp. 1165-1182 ◽  
Author(s):  
Kaighin A. McColl ◽  
Qing He ◽  
Hui Lu ◽  
Dara Entekhabi
Keyword(s):  
Soil Moisture ◽  
Time Scales ◽  
Time Scale ◽  
Surface Soil ◽  
Satellite Observations ◽  
Surface Soil Moisture ◽  
Short Term ◽  
Term Memory ◽  
Memory Time

Abstract Land–atmosphere feedbacks occurring on daily to weekly time scales can magnify the intensity and duration of extreme weather events, such as droughts, heat waves, and convective storms. For such feedbacks to occur, the coupled land–atmosphere system must exhibit sufficient memory of soil moisture anomalies associated with the extreme event. The soil moisture autocorrelation e-folding time scale has been used previously to estimate soil moisture memory. However, the theoretical basis for this metric (i.e., that the land water budget is reasonably approximated by a red noise process) does not apply at finer spatial and temporal resolutions relevant to modern satellite observations and models. In this study, two memory time scale metrics are introduced that are relevant to modern satellite observations and models: the “long-term memory” τL and the “short-term memory” τS. Short- and long-term surface soil moisture (SSM) memory time scales are spatially anticorrelated at global scales in both a model and satellite observations, suggesting hot spots of land–atmosphere coupling will be located in different regions, depending on the time scale of the feedback. Furthermore, the spatial anticorrelation between τS and τL demonstrates the importance of characterizing these memory time scales separately, rather than mixing them as in previous studies.

scholarly journals The Influence of Atlantic Tropical Cyclones on Drought over the Eastern United States (1980–2007)

2013 ◽  
Vol 26 (10) ◽  
pp. 3067-3086 ◽  
Author(s):  
Jonghun Kam ◽  
Justin Sheffield ◽  
Xing Yuan ◽  
Eric F. Wood
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Tropical Cyclones ◽  
Land Surface ◽  
Hydrologic Model ◽  
Eastern United States ◽  
Short Term ◽  
Drought Duration ◽  
Study Region

Abstract To assess the influence of Atlantic tropical cyclones (TCs) on the eastern U.S. drought regime, the Variable Infiltration Capacity (VIC) land surface hydrologic model was run over the eastern United States forced by the North American Land Data Assimilation System phase 2 (NLDAS-2) analysis with and without TC-related precipitation for the period 1980–2007. A drought was defined in terms of soil moisture as a prolonged period below a percentile threshold. Different duration droughts were analyzed—short term (longer than 30 days) and long term (longer than 90 days)—as well as different drought severities corresponding to the 10th, 15th, and 20th percentiles of soil moisture depth. With TCs, droughts are shorter in duration and of a lesser spatial extent. Tropical cyclones variously impact soil moisture droughts via late drought initiation, weakened drought intensity, and early drought recovery. At regional scales, TCs decreased the average duration of moderately severe short-term and long-term droughts by less than 4 (10% of average drought duration per year) and more than 5 (15%) days yr−1, respectively. Also, they removed at least two short-term and one long-term drought events over 50% of the study region. Despite the damage inflicted directly by TCs, they play a crucial role in the alleviation and removal of drought for some years and seasons, with important implications for water resources and agriculture.

scholarly journals Photosynthetic acclimation and sensitivity to short- and long-term environmental changes

2021 ◽  
Author(s):  
Leonie Schönbeck ◽  
Charlotte Grossiord ◽  
Arthur Gessler ◽  
Jonas Gisler ◽  
Katrin Meusburger ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Gas Exchange ◽  
Environmental Changes ◽  
Leaf Gas Exchange ◽  
Soil Drought ◽  
List Type ◽  
Evaporative Demand ◽  
Leaf Level ◽  
Short And Long Term

SummaryThe future climate will be characterized by an increase in frequency and duration of drought and warming that exacerbates atmospheric evaporative demand. How trees acclimate to long-term soil moisture changes and whether these long-term changes alter trees’ sensitivity to short-term (day to months) variations of vapor pressure deficit (VPD) and soil moisture is largely unknown.Leaf gas exchange measurements were performed within a long-term (17 years) irrigation experiment in a Scots pine-dominated forest in one of Switzerland’s driest areas on trees in naturally dry (control), irrigated, and‘irrigation-stop’ (after 11 years of irrigation) conditions.Seventeen years of irrigation increased photosynthesis (A) and stomatal conductance (gs) and reduced the gs sensitivity to increasing VPD but not to soil drying. Following irrigation-stop, gas exchange did not decrease immediately, but after three years, had decreased significantly in irrigation-stop trees. Vcmax and Jmax recovered after five years.These results suggest that long-term release of soil drought reduces the sensitivity to atmospheric evaporative demand and that atmospheric constraints may play an increasingly important role in combination with soil drought. In addition, they suggest that structural adjustments lead to an attenuation of initially strong leaf-level acclimation to strong multiple-year drought.

Short-term false memories vary as a function of list type

2019 ◽  
Vol 72 (12) ◽  
pp. 2726-2741 ◽  
Author(s):  
Dawn M McBride ◽  
Jennifer H Coane ◽  
Shuofeng Xu ◽  
Yi Feng ◽  
Zhichun Yu
Keyword(s):  
False Memory ◽  
False Memories ◽  
Additive Effect ◽  
False Alarms ◽  
List Type ◽  
Short Term ◽  
Type Experiment ◽  
Trace Theory ◽  
Fuzzy Trace Theory

False memories have primarily been investigated at long-term delays in the Deese–Roediger–McDermott (DRM) procedure, but a few studies have reported meaning-based false memories at delays as short as 1–4 s. The current study further investigated the processes that contribute to short-term false memories with semantic and phonological lists (Experiment 1) and hybrid lists containing items of each type (Experiment 2). In Experiment 1, more false memories were found for phonological than for semantic lists. In Experiment 2, an asymmetrical hyper-additive effect was found such that including one or two phonological associates in pure semantic lists yielded a robust increase in false alarms, whereas including semantic associates in pure phonological lists did not affect false alarms. These results are more consistent with the activation–monitoring account of false memory creation than with fuzzy trace theory that has not typically been referenced when describing phonological false memories.

scholarly journals The effect of short-term vs. long-term soil moisture stress on the physiological response of three cocoa (Theobroma cacao L.) cultivars

2020 ◽  
Vol 92 (2) ◽  
pp. 295-306 ◽  
Author(s):  
Wiebke Niether ◽  
Alexandra Glawe ◽  
Katharina Pfohl ◽  
Noah Adamtey ◽  
Monika Schneider ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Theobroma Cacao ◽  
Moisture Stress ◽  
Biochemical Response ◽  
P Value ◽  
Severe Drought ◽  
Seedling Mortality ◽  
Short Term ◽  
Soil Moisture Stress

Abstract Understanding water stress signaling mechanisms and screening for tolerant cocoa cultivars are major challenges when facing prolonged dry and rainy seasons in cocoa-producing areas. While abscisic acid (ABA) and proline are supposed to enhance drought tolerance in cocoa, the role of polyamines remains unclear. The aim of this study was to investigate the biochemical response and phenological adaptation of cocoa (Theobroma cacao) on different soil moisture conditions, with a focus on short-term (20 days) and long-term (89 days) stress conditions, and to compare the performance of three cocoa cultivars. In a split plot design with four blocks, cocoa seedlings of an international high-yielding cultivar (TSH-565) and two locally selected cultivars (IIa-22 and III-06) from the drought-exposed Alto Beni region, Bolivia, were arranged in pots under a roof shelter (cultivar: three levels). The seedlings were exposed to strong (VERY DRY) and moderate (DRY) soil moisture deficits, water logging (WET) and regular irrigation (MOIST) that served as a control (moisture: four levels). We examined the growth performance and the levels of ABA, proline, and polyamines in the leaves. Growth was reduced already at a moderate drought, while severe drought enhanced seedling mortality. Severe drought increased the levels of ABA by 453% and of proline by 935%, inducing a short-term stress response; both compounds were degraded over the long-term period. The polyamine concentration was unrelated to soil moisture. The cocoa cultivars did not differ in their biochemical response to soil moisture stress (proline: p-value = 0.5, ABA: p-value = 0.3), but the local cultivar III-06 showed a stronger height growth increment than the international cultivar TSH-565 (237%, p-value = 0.002) under drought conditions.

At a Glance …

2012 ◽  
Vol 220 ◽  
pp. F2-F2
Keyword(s):  
Euro Area ◽  
List Type ◽  
Short Term ◽  
Structural Problems ◽  
The Us ◽  
Successful Resolution ◽  
Fiscal Austerity ◽  
The Uk ◽  
Global Growth

Our baseline forecast is for global growth of 3.7 per cent in 2012. Growth will accelerate to 4 per cent in 2013. These forecasts are little changed from our previous forecast.As in our previous forecast, we assume a delayed but ultimately successful resolution of the Euro Area crisis. Nevertheless, we expect a mild recession in the Euro Area as a whole, as well as in the UK. Downside risks to the Euro Area remain high. Fiscal austerity will weigh on growth in the short term, while medium to long term structural problems remain unresolved.We forecast growth of about 2 per cent in the US this year, while China and India, although slowing, will continue to drive world growth.

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