Heat Stress, Plant-Available Soil Moisture, and Corn Yields in Iowa: A Short- and Long-Term View

jpa ◽  
1990 ◽  
Vol 3 (3) ◽  
pp. 293-297 ◽  
Author(s):  
Richard E. Carlson
2021 ◽  
pp. 102876
Author(s):  
Maria Emilia Fernandez ◽  
Maria Carla Labaque ◽  
Gabriel Orso ◽  
Raúl Hector Marin ◽  
Jackelyn Melissa Kembro

1990 ◽  
Vol 70 (2) ◽  
pp. 125-136 ◽  
Author(s):  
C. CHANG ◽  
T. G. SOMMERFELDT ◽  
T. ENTZ ◽  
D. R. STALKER

Nineteen years of soil moisture content data at Lethbridge and two locations near Turin (Turin 1 and Turin 2) in southern Alberta were examined to evaluate the efficiency of follow for conserving moisture, and to calculate the long-term mean amount of water recharge during growing and nongrowing seasons under a fallow-cereal, 2-yr rotation and a continuous cropping system. Soil samples were taken annually from 1969 to 1987 to a depth of 120 cm in 30-cm intervals in the spring (early May) and fall (late September). A method for testing differences of means between nonstandard data using localized uncertainty associated with sliding polynomial smoothing was used to test for differences in the soil moisture contents due to cultural practices. The available soil moisture content of the soil to 120-cm depth was at least 50% of available water-holding capacity (AWHC) of the profile for the fallow treatment at Lethbridge and Turin 2, and, except in some years, at Turin 1. At seeding time, there was an average of 69 mm more available water (AW) in the fallow field than in the continuous cropping field at Lethbridge and 30, 35 and 27 mm more AW in the fallow field than in the fresh stubble field of a fallow-cereal, 2-yr rotation for Lethbridge, Turin 1 and Turin 2, respectively. The overall mean precipitation conserved as soil moisture for the fallow-cereal rotation practice was 23, 29 and 23% for Lethbridge, Turin 1 and Turin 2, respectively. The significantly higher soil water content at the 90- to 120-cm depth for the fallow field than for other fields during various periods of time indicates that the soil water recharge from precipitation might be deeper in the fallow field than in continuous cropping and fresh stubble of fallow-cereal rotation fields. The deeper soil water recharge could increase the available soil moisture for crop production and it could also contribute to ground water recharge. Key words: Soil water, available water content, continuous cropping, summerfallow


2021 ◽  
Author(s):  
Leonie Schönbeck ◽  
Charlotte Grossiord ◽  
Arthur Gessler ◽  
Jonas Gisler ◽  
Katrin Meusburger ◽  
...  

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.


2021 ◽  
Author(s):  
Santanu Kumar Bal ◽  
H. S. Shivaramu ◽  
P. Vijaya Kumar ◽  
H. Lingaraj ◽  
V. M. Sandeep ◽  
...  

Abstract Assessment of soil moisture availability and timely declaration of drought are keys for exemplary relief assistance in water stressed regions. Percent available soil moisture (PASM) is one among several drought declaration indices, needs evaluation with respect to individual crop and cropping system, as the amount of water requirement varies with respect to crop and its growth stage. Analysis of yield variability due to PASM was carried out by employing correlation and linear regression analyses based on long term observations in experiments conducted at different dry farming locations of the peninsular India. The range of available soil moisture in order to obtain at least 50 per cent of optimum yield in cereals (maize: 26 and finger millet: 52.9 PASM), pulses (pigeonpea: 37.2 PASM), oilseeds (soybean: 26.8 to 30.5, groundnut: 53.8 to 61.7 PASM) and commercial crops (cotton: 26.3 PASM) was 26 to 61 per cent. Establishment of these regression models helped in timely drought declaration / precise identification of drought hit areas and assuring feasible relief assistance. The outcomes of the study may be used for amending the existing drought norms (0–50; severe, 50–75; mild and 75–100; no drought) for provision of proportionate compensations to the farmers.


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