Impacts of climate change;

Increased heat stress can affect milk yield and herd fertility of dairy animals, soil erosion by wind and water represents an economic cost to agriculture, severe rainfall can lead to surface runoff, trees can reduce soil and water movement;

Erosion reduces the long term fertility of the soil;

Drought and water conservation;

The last fifty years has seen increasing average temperature, and decreasing rainfall in many places in the world, the consequences are spreading out of droughts, which lead to reduction in pasture and crop yields, as the result water is over abstracted in large areas, whilst climate change scenarios predict this will get worse.

Rising temperature will increase heat stress to livestock, and periods of drought during the growing season could lead to poor crop germination, reduced growth rates of pasture and low yields, even where irrigation is available, pressure to maintain domestic water supplies should be restricted; therefore such irrigation water that is available will need to be used efficiently.

Crop selection, plant breeding, good husbandry and improved irrigation systems will all play a part in addressing the problems caused by increasing frequency of drought, but shelter for pasture and crops can also be an important factor.

Despite the predicted drop in total seasonal rainfall, it is tending to come in heavier downpours, which always make great impact on surface water flooding, soil erosion, nutrient loss and subsequently for pollution of water courses and the risk of flash floods.

Drought and water conservation:

Water is lost from pasture and crops through a combination of evaporation from the soil surface and transpiration, as water vapor is lost from plants through leaf surface.

When evapotranspiration occurs, humidity levels increase around the soil or leaf surface, as the air becomes saturated the process slows down, unless water vapor is removed.

Faster wind speeds will transfer larger amounts of dry air over the soil or leaf surface and therefore remove saturated air more quickly, increasing evapotranspiration rates.

When levels of available soil water drop below a certain value the crop becomes water stressed, and the lack of water results in a reduction in transpiration and ultimately yield. See Blepharis linariifolia Pers plant.

Shelter and shed for livestock:

Farm animals are vulnerable to increased temperatures, for livestock solar radiation affects feed intake, reproductive performance and susceptibility to disease.

Increased heat stress can affect milk yield and herd fertility of dairy animals, there is number of strategies that can be used to reduce the impact high temperatures on animals, including sprinkler systems and provision of shade.

Shade can be provided by planting native deciduous trees in field or in hedgerows that will protect animals from solar radiation, and also the trees reduce the ambient air temperature beneath the canopy as a result of the evaporation through the leaf surfaces, shelter also is an important factor in reducing the impact of cold weather.

Effects of shelter:

Shelterbelts modify the microclimate by reducing wind speeds and increasing daytime temperatures, lower wind speeds, increase the level of humidity around the plant surface, slowing evapotranspiration water loss.

Pasture and crops protected by shelter will have increased photosynthesis rates and increased water use efficiency.

Soil erosion, water quality and flooding:

Soil erosion by wind and water represents an economic cost to agriculture; soil type, slope, and farming practice all of this impact on the risk of soil erosion.

Climate change and predicted increase in frequency of severe weather events is likely to magnify the impact on the soil.

Erosion can reduce the long term fertility of the soil by removing nutrient rich topsoil and organic matter, and can affect water infiltration and increase runoff, as well leading to loss of seeds, fertilizers and pesticides.

Runoff:

Severe rainfall can lead to surface runoff, as well as the impact on the farm; this leads to sedimentation and contamination of stream, and other water bodies, damaging fisheries and wildlife, increasing water treatment costs.

Timing and type of cultivations, crop selection, siting of cattle feeders and water troughs, and location of manure heaps can affect the likelihood of runoff and contamination of water courses.

Trees can reduce soil and water movement by increasing water infiltration rates and slowing the flow of transported sediments, and by trapping pollutants bound to soil particles, trees can help reduce water pollution, acting as nutrient sinks.

Wind erosion:

Wind erosion tends to affect more limited areas and happen less frequently than water erosion, but when it does occur it can be severe.

On vulnerable soils, wind erosion can cause loss of topsoil, seeds, fertilizers, and agrochemicals, and cause damage to ditches and water courses, and drier parts of the country are particularly susceptible. 

Because of droughts

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