Farming is driving force in drying soil in Northern China

Purdue University News: An important agricultural region in China is drying out, and increased farming may be more to blame than rising temperatures and less rain, according to a study spanning 30 years of data. A research team led by Purdue University and China Agricultural University analyzed soil moisture during the growing season in Northern China and found that it has decreased by 6 percent since 1983.

The optimal soil-moisture level for farmland is typically 40 percent to 85 percent of the water holding capacity, and the region's soil is now less than 40 percent and getting drier. If this trend continues, the soil may not be able to support crops by as early as 2090, said study leader Qianlai Zhuang, Purdue's William F. and Patty J. Miller Professor of Earth, Atmospheric and Planetary Sciences and Agronomy.

"The soil moisture declined by 1.5 to 2.5 percent every decade of the study and, while climate change is still a factor, this water depletion appears to be largely driven by human activities," Zhuang said. "A 10 percent decline in soil moisture over the course of a century would have major implications for agriculture and the fresh water supply in this heavily populated area."

Forty percent of the nation's population resides in Northern China, according to the country's population census office. The region also accounts for 65 percent of the nation's cropland, Zhuang said.

"The drying of soil in Northern China has been well documented, but its causes and the impacts of agricultural intensification in general have been understudied," he said. "This information is critical to improvement of agricultural practices and water resource management. The demand for food and water is increasing, but current practices to meet this demand threaten the future security of water resources. Unfortunately, with the growing world population, more and more regions could face the same circumstances of agricultural intensification for food security."...

This is a map of soil moisture trends in Northern China during the growing seasons from 1983-2012. The shading shows the trend in satellite-observed surface soil moisture, and the circles represent monitoring stations within agricultural plots. A Purdue University-led research team found that farming was more of a driver in the drying of the soil than rising temperatures and declining rainfall. The change in volumetric water content is shown. (Purdue University image/Yaling Liu) 

No-till agriculture may not bring hoped-for boost in global crop yields

A press release from the University of California-Davis: No-till farming, a key conservation agriculture strategy that avoids conventional plowing and otherwise disturbing the soil, may not bring a hoped-for boost in crop yields in much of the world, according to an extensive new meta-analysis by an international team led by the University of California, Davis.

As the core principle of conservation agriculture, no-till has been promoted worldwide in an effort to sustainably meet global food demand. But after examining results from 610 peer-reviewed studies, the researchers found that no-till often leads to yield declines compared to conventional tillage systems. It still shows promise for yield gains in dryland areas, however.

...“The big challenge for agriculture is that we need to further increase yields but greatly reduce our environmental impacts,” said Cameron Pittelkow, who co-authored the study as a postdoctoral scholar at UC Davis and is now on the faculty of the University of Illinois.  “The common assumption that no-till is going to play a large role in the sustainable intensification of agriculture doesn’t necessarily hold true, according to our research findings.”

...The goals of conservation agriculture are to improve long-term productivity, profits and food security, particularly under the threat of climate change. Because conservation agriculture avoids tillage, it is less time-consuming and can be more cost-effective than conventional farming methods. In recent years, however, there has been some disagreement about the impact of no-till farming practices on yield.

...In regions with moist climates and sufficient precipitation, no-till farming actually resulted in yields that were on average 6 to 9 percent lower than with conventional tillage methods. “No one has ever stated that there would be a significant decline like this,” said Chris van Kessel, a professor of plant sciences at UC Davis and co-author of the study. “Our findings suggest that broad implementation of conservation agriculture may not be warranted in all areas, particularly where residue retention and crop rotation practices are hard to implement.” ...

No-till farming, such as used in this Illinois soybean field, shows promise in dry regions but causes lower yields in cold, moist areas like Northern Europe, a new study finds. (Paige Buck/USDA NRCS Illinois photo)

Dryland ecosystems emerge as driver in global carbon cycle

University of Montana News Service: Dryland ecosystems, which include deserts to dry-shrublands, play a more important role in the global carbon cycle than previously thought. In fact, they have emerged as one of its drivers, says Montana State University faculty member Ben Poulter.

Surprised by the discovery, Poulter and his collaborators explained their findings in Nature. At the same time, they urged global ecologists to include the emerging role of dryland ecosystems in their research. Nature is a weekly international journal that publishes peer-reviewed research in all fields of science and technology.

"Our study found that natural events in Australia were largely responsible for this anomaly," Poulter said. "La Nina-driven rainfall during 2010 and 2011, as well as the 30-year greening up of its deserts and other drylands contributed to significant changes across the globe.”

...He realized ... that the world’s land carbon sink in 2011 seemed to be absorbing an unusually large amount of carbon, Poulter said. Carbon dioxide moves constantly between land, oceans, vegetation and the atmosphere. When one of those absorbs more carbon dioxide than it releases, it’s referred to as a carbon sink.

Poulter and his collaborators investigated the phenomena with a variety of data sets and modeling approaches. They eventually discovered surprising interactions between climate extremes and desert greening that increased in importance over the past 30 years.  Further study showed that the dryland systems in the Southern Hemisphere, specifically Australia, had particularly high productivity in response to increased La Nina-phase rainfall.

“What surprised us was that no analogous biosphere response to similar climatic extremes existed in the past 30 years, prompting us to explore whether documented dryland-greening trends were responsible for changes in the carbon cycle dynamics,” said Philippe Ciais, co-author and senior scientist at LSCE.

...“Dryland systems have high rates of carbon turnover compared to other biomes,” Ciais said. “We can expect the carbon to be quickly respired or consumed in wildfires, already partly reflected by the high atmospheric carbon dioxide growth rate in 2012.”...

A kangaroo warning sign on Stuart Highway in Northern Territory, Australia, shot by Jpp, Wikimedia Commons, under Creative Commons 3.0 license

Africa’s first ‘Islamic-compliant’ livestock insurance pays 100 Kenyan herders for drought-related livestock losses

Susan Macmillan in ILRI News: Today, for the first time in Africa, an insurance policy that combines an Islamic-compliant financial instrument with innovative use of satellite imagery is compensating Muslim pastoralists for drought-induced losses suffered in Kenya’s northeastern Wajir County, where livestock are valued at Ksh46 billion (USD550 million).

Thirty women and 71 men in arid and semi-arid Wajir are the first beneficiaries of livestock insurance that conforms to the Islamic concept of takaful, in which risks are shared among a group of participants. Through a contract called tabbaru (donation), participants make contributions to a risk fund. In the case of a payout, which happened today, the fund makes payments commensurate with the contributions received.

The pilot program is paying approximately Ksh500,000 (USD5,800) for losses suffered to their herds of sheep, goat, cattle and camels during the long dry season that typically ends in March. The herds were insured last August by Takaful Insurance of Africa (TIA) with an Index-Based Livestock Insurance (IBLI) product, branded as Index-Based Livestock Takaful (IBLT).

IBLI uses satellite imagery—measuring the conditions of grazing lands—that is fed into an algorithm that predicts livestock loses. Predictions beyond the 15-percent level trigger indemnity payments. Drought conditions in much of Wajir County have surpassed the index trigger and active contract holders in these areas were compensated today.

This payout is critical for building confidence in the concept of insurance for the pastoral, drought-prone regions of East Africa, where life revolves around livestock and droughts can bring disaster,” said Andrew Mude, who leads the IBLI program of the Nairobi-based International Livestock Research Institute (ILRI)....

Wajir from the air, shot by lex Maisuradze, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

What does the future hold for pastoralists in the Sahel?

IRIN: Harsher droughts and rising numbers of conflicts with farmers are threatening the future of pastoralism in the Sahel, but experts say that integrating crop and livestock systems can help sustain the livelihoods of herders and farmers.

Droughts have wrought severe consequences in recent years, including in 2011-2012, when a major drought left some 18 million people in the region at risk of hunger.  Practices such as rotational grazing, land and tree regeneration, intercropping, and agroforestry can help ensure herders continue to feed their animals while avoiding conflict with farmers over shrinking productive lands, experts say.

Nomadic pastoralism remains an essential part of life in the Sahel, where more than 60 percent of the population is involved in livestock farming.  “In the Sahel, pastoralists are first and foremost mobile,” said Jonathan Davies, the Global Drylands Initiative coordinator for the International Union for the Conservation of Nature (IUCN). “So it goes without saying that the thing that defines most pastoralists throughout all of Africa is the herd movements.

“But there’s this huge misunderstanding and prejudice. Many governments and development agencies still see mobility as a problem they need to stop rather than… the most rational management strategy in a highly variable climate,” said Davies.

He explained that moving between areas of good rainfall and vegetation allows pastoralists to manage such variability, particularly in very dry countries like Niger, where land productivity is low.  “For all pastoralists, some sort of crop-agriculture or fodder production is possible, but that is not to say it is desirable,” said Davies. “The scarcer the water, the less you want to waste it on cultivating a tiny oasis.”...

Livestock grazing on an island in the River Niger, seen from a bridge in Niamey, shot by ILRI/Stevie Mann, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Climate change to disrupt soil nutrients in drylands

Jan Piotrowski in SciDev.net: The increased aridity expected this century as a result of climate change may disrupt the balance of key soil nutrients with a knock-on effect on soil fertility threatening livelihoods of more than two billion people, a study finds.

The drop in nitrogen and carbon concentrations that occurs as soils become dryer could have serious effects on ecosystem services such as food production, carbon storage and biodiversity, according to the Nature paper published today.

Loss of nitrogen and carbon, which are the basic building blocks of living organisms, drastically affects land’s productivity, says Fernando T. Maestre, a biologist and geologist from King Juan Carlos University, Spain, and a co-author of the report. “If plant productivity is reduced, the capability of the land to support livestock and crops will be affected and this will have a big impact on people who depend on them,” he tells SciDev.Net.

Drylands make up more than 40 per cent of the world's land area, and host a similar proportion of the world’s population. Many are expected to get drier because of climate change.

The study measured the nitrogen, carbon and phosphorus content of soil at 224 sites across all continents except Antarctica, which together represent a wide range of soil and vegetation types, climates and species diversity. As ecosystems became more arid, it found, both nitrogen and carbon concentrations decreased, which may significantly impair plant and microbial activity, with knock-on effects on organic decomposition and plant growth....

The Spider Rock Overlook at Canyon de Chelly in Arizona, National Park Service

Agricultural research 'key to easing climate-change impacts'

Rasha Dewedar in SciDev.net:  Agricultural research should be a strategic priority of the UN's efforts to lessen the impacts of climate change, according to a report launched at a UN climate change conference in Doha, Qatar.

The report, released by a group of leading international experts in climate change and agriculture last month (30 November), is intended to inform policymakers and agricultural planners about the risks climate change poses to dry areas. It offers practical solutions to reduce these threats and boost the productivity of this type of land.

'Strategies for Combating Climate Change in Drylands Agriculture' was produced by the International Center for Agricultural Research in the Dry Areas (ICARDA) with two CGIAR research programmes — on Dryland Systems and on Climate Change, Agriculture and Food Security (CCAFS) — and the Qatar National Food Security Programme.

Drylands constitute more than 40 per cent of the world's land surface and are home to 2.5 billion people, says the report. Those lands have less than eight per cent of the world's renewable water sources and are vulnerable to temperature extremes, frequent drought, land degradation and desertification, it adds....

A dry field in Chandeni, India, shot by Nitin.i.azam, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Scientists call for investments in dryland forests

Anthony Aisi and Eric Akasa in Africa Science News: Scientists are concerned that despite clear evidence of their benefits – and of the disasters that occur in the wake of their loss – dryland forest protection and restoration is receiving scant attention compared to humid forest preservation. They point out that this disparity is particularly evident within discussions of climate change adaptation and mitigation.

However, the scientists say restoring and preserving the dryland forests and planting more trees to provide food, fodder and fertilizer on small farms are critical steps toward preventing the recurrence of the famine now threatening millions of people in the Horn of Africa.

Across the Horn, drought-induced famine has claimed tens of thousands of lives and swelled refugee camps in Kenya, Ethiopia and elsewhere, with millions of starving people – many of them children. Bearing the brunt of the crisis is Somalia, which not coincidentally is also a country that has lost a significant amount of its forests. Experts say forest destruction and other forms of human-caused land degradation have done far more than the drought to turn vast areas of once grazeable and farmable land into a lunar-like landscape.

“Forests and trees frequently form the basis of livelihood diversification, risk-minimization and coping strategies, especially for the most vulnerable households such as those led by women,” said Frances Seymour, director general of the CGIAR’s Center for International Forestry Research (CIFOR). “However, deforestation and land degradation have hindered capacities to cope with disasters and adapt to climate variability and change in the long-term.”...

Almadow Forest, northern Somalia (area claimed by Somaliland, Puntland and Maakhir); shot by Abdirisak