Drought and mycotoxin impact on trace minerals

Drought is influencing agricultural production across two-thirds of the United States and is predicted to be the worst in 50 years. There are some factors to consider regarding trace mineral fortification decisions during drought challenges, especially when mycotoxins are present.

Due to limited forage supplies, more poor quality feeds, such as those high in nitrates, lignin, ash, and mycotoxins will be fed. Feeding extra minerals can help mitigate the negative effects of feeding poor quality forages.
Selected field samples tested by several allied industry companies in July indicate that the corn will be high in aflatoxins (and some fumonisins). Recent drought-stress corn from Texas also produced similar mycotoxin profiles. Due to aflatoxins in grains, higher levels will be concentrated in byproducts.
Poultry has a very low tolerance for aflatoxins that can cause weak capillary wall subsequently increasing the incidence of bruising/haemorrhages during processing. Supplementing extra zinc through the diet has shown to drastically decrease the incidence of bruising and haemorrhages.
Aflatoxins can also interact with coccidia to make gut lesions more severe. While e.g. Availa-Zn is not a cure for coccidiosis, it can certainly influence epithelial tissue resulting in less severe lesions and faster healing processes.
Researchers have also reported observations that high inorganic zinc levels in chicken feeds increase the aflatoxin production in the feed. A complexed zinc should prevent further in-feed aflatoxin increases.
With increased mycotoxin concentrations in feedstuffs, inclusion of binders in diets will increase. Some classes of mycotoxin sequestering agents may render some minerals and vitamins unavailable for absorption and metabolism. Therefore, providing a highly bioavailable source of trace minerals in a complexed form is further warranted.
Immunity
The immune response can be impacted during drought through different mechanisms; diet quality, presence of mycotoxins, limited dry matter intake and heat stress. When trace mineral status declines, the first biological function compromised is immunity.
The dynamics of immunity is sensitive to small shifts in trace mineral balance. Once immunecompetency is lowered, subsequent effects are lowered production. Nutrients partitioned to support an activated immune response are no longer available to support growth, m lactation, reproduction or other production parameters.
Complexed minerals consistently influence immunity for all species. Drought-associated stress will influence the magnitude of response observed between organic trace minerals and other ordinary trace mineral sources.

Source:www.allaboutfeed.ne

South Africa's 2013 maize crop forecast seen down on drought

South Africa is likely to cut its forecast for this year's maize crop as dry weather conditions in the main growing areas dashes prospects for better yields, a survey showed on Wednesday. In its first production forecast last month, the South African government said farmers were likely to harvest 12.35 million tonnes of maize in 2013, from 11.83 million tonnes last year. 

But recently dry conditions have hit the provinces of Free State and North West, which together produce more than half of the country's maize crop. An average forecast of five trading houses polled by Reuters showed traders now expect the 2013 crop to come in at 11.5 million tonnes. The estimates ranged between 11.3 million tonnes and 11.8 million tonnes. 

Source: http://www.brecorder.com/

Severe drought has lasting effects on Amazon

The Amazon basin does not readily bounce back after a period of drought, researchers suggest.

Rodrigo Baleia/LatinContent/Getty Images

Hannah Hoag

A study published today in the Proceedings of the National Academy of Sciences¹ sheds light on the long-term effects of drought on the Amazon rainforest — giving clues about how the rainforest might be affected by global warming in the future. The researchers report that the severe drought that hit the rainforest in 2005 had lasting effects on the forest canopy, such that it remained damaged at least four years later.
The effects of the 2005 drought have been debated since 2007, when researchers reported in Science² that photosynthesis within the canopy had increased, leading the Amazon basin to ‘green up’ during the dry period. But in 2010 another group reported that they were unable to reproduce the results using the same data³
“The ‘green-up’ is a short-term response and a bit of a red herring,” says Oliver Phillips, a tropical ecologist at the University of Leeds, UK. But the latest study “transcends that debate”, he says. “The question of the underlying health of the forest is much deeper than the instantaneous response.”

Bare branches

A drawback of the method used in the earlier studies — which used satellite measurements to estimate forest greenness using reflected solar radiation — is that the data can be muddied by clouds and atmospheric aerosols. So for the latest study, Sassan Saatchi, a remote-sensing expert at the California Institute of Technology Jet Propulsion Laboratory in Pasadena, California, studied the forest’s microwave ‘silhouette’, showing its contours instead of its greenness. To look at canopy structure, he and his colleagues used microwave satellite data, which are unaffected by clouds, from a NASA probe. When it passed over lush canopy, the satellite sensor recorded a smooth signal. Bare branches, thinned leaves and missing trees showed more roughness.

Bad timing

“This is the first piece of really strong evidence that the drought has had a negative impact on the forest,” says Greg Asner, an environmental scientist at the Carnegie Institution for Science in Stanford, California.
The latest analysis paints a grim picture for Amazonian rainforests should severe droughts become more frequent. Most Amazonian droughts are driven by warmer surface waters in the eastern Pacific Ocean, but the severe droughts of 2005 and 2010 seem to have been influenced by warmer sea-surface temperatures in the North Atlantic Ocean.
It could change the drought outlook in the next report from the Intergovernmental Panel on Climate Change, due in 2014. The most recent report, released in 2007 and based on climate-modelling experiments done before the droughts, was more “speculative”, says Ranga Myneni, an expert in the remote sensing of vegetation at Boston University in Massachusetts, and a co-author on the latest study.
Saatchi says that he hopes to extend the analysis past the 2010 drought using data from the Indian satellite Oceansat-2. If the droughts continue to occur every 5–10 years, the forest edges could begin to transition to dry forests, he warns. “We’d like to say something about how the Amazonian forest has been doing since 2009,” he says.

Journal name:

Nature

DOI:

doi:10.1038/nature.2012.12129

References

1. Saatchi, S. et al. Proc. Natl. Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1204651110 (2012).
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2. Saleska, S. R., Didan, K., Huete, A. R. & da Rocha, H. R. Science 318, 612 (2007).
   
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3. Samanta, A. et al. Geophys. Res. Lett. 37, L05401 (2010).
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4. Xu, L. et al. Geophys. Res. Lett. 38, L07402 (2011).

Legume Crops | Salinity and Drought Management

By: Hussain N., G. Sarwar, H. Schmeisky, Salim Al-Rawa

The predicted global climatic changes anticipate rise in temperature, cyclones, floods, variability and unpredictability of rainfall, droughts, and melting of ice. Expected desiccation and rise in temperature will be resulting in high evapo-transpiration. The drier regions of the globe may become further drier. Consequently, it will become highly difficult for water scarce countries to face this challenge. Surface water scarcity will divert pressure on utilization of groundwater, the major part of which is not of safe and usablequality. Hence, soil and water salinity/ sodicty may enhance that will negatively affect soil characteristics (chemical and physical) and consequently reduce growth and yield of crops. Legumes are the most sensitive group in this regard and are expected to affect largely.

Therefore, special management practices must be adopted to cope with the global climatic changes. Suitable hydraulic options (leaching and drainage), appropriate agronomic practices like; leveling, deep plowing, rainfall harvesting, application of organic matter, balanced nutrients, suitable sowing methods, mulching and planting geometry and appropriate irrigation technologies; scheduling, modification of irrigation system (shifting from surface irrigation to drip, sprinkler or sub-surface), cyclic use of good quality and brackish water have to be adopted. The changing situations will also require wise decisions like; selection of crop sequences that can withstand salinity stresses and inclusion of legumes in the crop rotations. Understanding of genetic variability with respect to salt tolerance will be necessary. Starting strong breeding programs to achieve this objective supported with modern approaches; Biotechnology, Mutation and Genetic Engineering will necessarily be desired from right now