Synchronising diagnosis and correction of nitrogen deficiency in barley grown in semi-arid environments

1993 ◽  
Vol 155-156 (1) ◽  
pp. 363-366 ◽  
Author(s):  
D. E. Elliott ◽  
S. D. Pelham ◽  
D. J. Reuter
Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 354
Author(s):  
El-Sayed M. Desoky ◽  
Elsayed Mansour ◽  
Mohamed M. A. Ali ◽  
Mohamed A. T. Yasin ◽  
Mohamed I. E. Abdul-Hamid ◽  
...  

The influence of 24-epibrassinolide (EBR24), applied to leaves at a concentration of 5 μM, on plant physio-biochemistry and its reflection on crop water productivity (CWP) and other agronomic traits of six maize hybrids was field-evaluated under semi-arid conditions. Two levels of irrigation water deficiency (IWD) (moderate and severe droughts; 6000 and 3000 m3 water ha−1, respectively) were applied versus a control (well-watering; 9000 m3 water ha−1). IWD reduced the relative water content, membrane stability index, photosynthetic efficiency, stomatal conductance, and rates of transpiration and net photosynthesis. Conversely, antioxidant enzyme activities and osmolyte contents were significantly increased as a result of the increased malondialdehyde content and electrolyte leakage compared to the control. These negative influences of IWD led to a reduction in CWP and grain yield-related traits. However, EBR24 detoxified the IWD stress effects and enhanced all the above-mentioned parameters. The evaluated hybrids varied in drought tolerance; Giza-168 was the best under moderate drought, while Fine-276 was the best under severe drought. Under IWD, certain physiological traits exhibited a highly positive association with yield and yield-contributing traits or CWP. Thus, exogenously using EBR24 for these hybrids could be an effective approach to improve plant and water productivity under reduced available water in semi-arid environments.


1996 ◽  
Vol 47 (6) ◽  
pp. 829 ◽  
Author(s):  
JB Lowry ◽  
CS McSweeney ◽  
B Palmer

Mammalian metabolism of plant phenolics, initially studied in monogastric animals, gave an emphasis to their toxic and antinutrient effects. Subsequent studies in tropical ruminants and wild herbivores have highlighted the high levels than can occur in some diets and the extensive microbial modification and degradation that can occur in the tract. This paper reviews aspects of plant phenolics as they relate to ruminant nutrition in tropical or semi-arid environments in which some forage plants contain high levels of phenolic compounds. Effects range from occasional acute toxicity of hydrolysable tannins, to acetate-releasing microbial degradations that apparently enable certain phenolics to act as nutrients. The most important and complex effects are those due to tannin-protein interactions. Although these can clearly reduce feed intake, nutrient digestibilities, and protein availability, many of the interactions are still not understood. The diverse effects of plant phenolics on nutrient flow probably result from the balance between adverse effects on some organisms and the rate at which they are degraded or inactivated by other organisms, and improved animal performance can likely be obtained by manipulation of rumen microbial metabolism.


2021 ◽  
Vol 283 ◽  
pp. 110051
Author(s):  
Nompumelelo Thelma Mobe ◽  
Sebinasi Dzikiti ◽  
Timothy Dube ◽  
Dominic Mazvimavi ◽  
Zanele Ntshidi

2016 ◽  
Vol 88 (2) ◽  
pp. 1113-1125 ◽  
Author(s):  
José N.B. Campos ◽  
Iran E. Lima Neto ◽  
Ticiana M.C. Studart ◽  
Luiz S.V. Nascimento

This study investigates the relationships between yield and evaporation as a function of lake morphology in semi-arid Brazil. First, a new methodology was proposed to classify the morphology of 40 reservoirs in the Ceará State, with storage capacities ranging from approximately 5 to 4500 hm3. Then, Monte Carlo simulations were conducted to study the effect of reservoir morphology (including real and simplified conical forms) on the water storage process at different reliability levels. The reservoirs were categorized as convex (60.0%), slightly convex (27.5%) or linear (12.5%). When the conical approximation was used instead of the real lake form, a trade-off occurred between reservoir yield and evaporation losses, with different trends for the convex, slightly convex and linear reservoirs. Using the conical approximation, the water yield prediction errors reached approximately 5% of the mean annual inflow, which is negligible for large reservoirs. However, for smaller reservoirs, this error became important. Therefore, this paper presents a new procedure for correcting the yield-evaporation relationships that were obtained by assuming a conical approximation rather than the real reservoir morphology. The combination of this correction with the Regulation Triangle Diagram is useful for rapidly and objectively predicting reservoir yield and evaporation losses in semi-arid environments.


2008 ◽  
Vol 59 (8) ◽  
pp. 702 ◽  
Author(s):  
P. Annicchiarico ◽  
A. Abdelguerfi ◽  
M. Ben Younes ◽  
H. Bouzerzour ◽  
A. M. Carroni ◽  
...  

Sulla coronaria (L.) Choi & Ohashi (syn. Hedysarum coronarium L.) may become a major forage species in various Mediterranean-climate areas. This study aimed to assess the extent of genotype × environment (GE) interaction in the western Mediterranean region and its implications for breeding programmes. The milestone Italian varieties Grimaldi and Sparacia, one recent Italian variety, and the Tunisian cv. D’Italie (evolved under moderately favourable conditions from Italian germplasm introduced about 40 years ago) were evaluated in three environments of Tunisia (of which two were irrigated), two of Algeria, and one of Sardinia (Italy). Water available over the crop cycle (rainfall + possible irrigation from October 2004 to June 2006), ranging from 881 to 1906 mm, accounted for 85% of the variation among environments and 72% of the GE interaction variation for dry matter yield. The latter was adequately described by one-covariate factorial regression, which was preferable to joint regression and additive main effects and multiplicative interaction modelling. D’Italie was specifically adapted to environments with available water exceeding 1200 mm, Grimaldi was top-ranking between 950 and 1200 mm, and Sparacia below 950 mm. The crossover GE interaction between top-yielding material (P < 0.05) has implications for adaptation targets, genetic resources, selection environments, and opportunities for international co-operation between breeding programmes. It suggests breeding either for rainfed cropping in semi-arid or near semi-arid environments, or for definitely subhumid or irrigated environments.


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