Ploughing and tilling on hilly slopes is causing farm soils to thin and threatens future crop yields, 发表在《药物》杂志上的一项新研究发现.
研究背后的科学家, 来自葡京直营和奥格斯堡(德国)大学, 除非农民停止在山坡上耕作, over the long-term the soils on hillsides could thin to the point where growth of food crops is severely threatened.
几个世纪以来, farmers have tilled the soil in their fields to provide seed beds in order to produce crops. 曾经使用传统的动物拉犁, as farming has mechanised within the last century the tilling process has shifted to heavier and faster tractors.
耕作土壤, 其中包括耕作, is known to move significant amounts of soil down slopes and adds to erosion caused by weather. 倾斜的土地上, tillage causes soils to move down off 凹的部分 of hills, 并沉积在谷底.
如斜坡上的土壤变薄, 底土中的物质与表土混合, reducing its growing quality because of inferior nutrients, 生物活性和减少蓄水.
约翰·昆顿教授, of 葡京直营 and one of two Principal Investigators of the study, said: “The role of tillage in reducing soil depth remains an under-recognised threat to plant production. While we have known that tillage moves significant amounts of soil down slopes, often exceeding the amount moved by water and wind erosion, we have known little about how the resulting thinning of the soils affects crop yields, 直到现在.”
Professor Peter Fiener of University of Augsburg and second Principal Investigator said: “As machines continue to grow and climate change increases the frequency of droughts the impact of erosion of soils by tillage on crop production in rolling topography is likely to become more severe across many parts of the world.”
The researchers looked at wheat and maize crops grown in the northern German region of Uckermark, which is a highly mechanised and very productive agricultural region in Europe. Although agricultural production has been possible in Uckermark for at least 1,000年, the researchers’ modelling predicts that over the next fifty years wheat and maize yields are likely to decline as modern mechanised agriculture accelerates erosion caused by tillage on slopes.
The researchers used published information of crop thinning on crop yields and applied soil redistribution and crop growth models to examine the effects of tillage at a regional landscape scale.
This enabled them to determine whether the yield gains in the parts of the landscape that gained soil from erosion, 凹的部分, 超过了山坡上土壤变薄所造成的损失.
Their calculations show that by continuing along a business as usual approach to tilling on slopes, farmers across the Uckermark region will see combined declines of winter wheat yields of up to 7.1 per cent within 50 years and up to 10 per cent over a century (in normal to dry years).
For maize, the researchers predict yields to reduce by up to 4 per cent over fifty years, and 5.超过100年(正常至干燥年份)的9%.
The effects of thinning soils will be most pronounced in times of drought as thinning soils are less able to hold on to moisture and nutrients. 湿润的年, 虽然不像正常和干燥年份那么明显, 50年到100年的收益率也会下降吗.
These reductions equate to thousands of tonnes of lost food production from the Uckermark region alone. The researchers believe reductions in crop yields due to soil erosion are likely to apply across the world where tilling takes place on slopes.
They argue that this projected increase highlights the need for urgent action to reduce soil thinning caused by tilling.
Professor Quinton said: “Our modelling shows that if we keep tilling our soils then we will see declines of crop yields at a regional scale – this will be worse during periods of droughts as thinner soils are less able to retain water for plants.
Professor Fiener said: “We show that the business as usual approach will depress crop yields in the long term. Farmers could look at mitigations such adapting tillage speeds depending on slope position and overall reducing tillage depths to slow the erosion process, but really farmers need to be looking at moving away from tilling on slopes to protect their soils and future yields.”
Although the researchers did not model the effects of climate change, they believe that the pressure of tillage erosion will likely be amplified as climate change increases the frequencies of dry spells during crop growing seasons.
研究结果在论文中有所概述。”Tillage exacerbates the vulnerability of cereal crops to drought，这篇文章已经在《药物》杂志上发表.
The paper’s authors are J Quinton of 葡京直营; JL Ottl and P Fiener of University Augsburg.
John Quinton and Peter Fiener were joint principal investigators.