Crop Land Use Change Research Articles

The socio-ecological implications of shifting patterns of cropland use in northeast China

Globally, mid-latitude Mollisol regions are vital breadbasket areas, but their ecosystems are being exhausted by overproduction. Understanding the evolution of agricultural practices and the associated consequences across different socio-ecological contexts is crucial for planning future crop production. Most studies to date have focused mainly on tropical regions, and have concentrated on fixed effects while overlooking spatiotemporal heterogeneity. We present an important case study from northeast China, using shifting patterns of cropland expansion, intensification and specialization from 2000 to 2019 to demonstrate how agricultural practices have evolved and encroached on natural resources. The locational Gini coefficient, revised universal soil loss equation, modified InVEST models, and geographically and temporally weighted regression model were applied to estimate the underlying socio-ecological implications. The results indicated that, cropland expansion (+44.22 %) and specialization were prominent, with grain cultivation increasing to almost 87 % while crop diversity was drastically reduced. Cropland intensification revealed a homogenizing transition, with an increase in machinery power (+97.25 %) and fertilizer (+28.80 %) applications. In the northern Songnen Plain and Sanjiang Plain, alongside expansion, cropland distributions have changed, with the majority of intensification and specialization indicators being pushed to higher latitudes. For example, maize production has driven soybean production to the Lesser Khingan Mountains, and rice has been transferred from the Liaohe Plain to Sanjiang Plain. During 2000–2019, some social indicators, including rural household income, grain production and inequality of agricultural development, improved, but not necessarily in relation to the changes in cropland use. Cropland expansion was beneficial to grain production, but detrimental to spatial equality. Water stress and pollution were identified as major ecological threats as a result of cropland expansion. Carbon sequestration also experienced an expansion-driven increase, but at the expense of crucial local ecosystems with higher carbon densities. Although the overall quality of natural habitats had improved, these habitats were threatened by most of the changes witnessed on the plains. Soil loss was sensitive to expansion in hilly reclaimed areas, but in Songnen Plain and Liaohe Plain, where conservation tillage has been promoted, intensification and specialization pressures were mitigated. A northwards shift of cropland distribution is currently a primary driver of the intensifying socio-ecological implications, representing the ongoing adaption of farming in marginal areas. The intensification and specialization of agricultural practices in Mollisol regions should be the focus for addressing the necessary future reconciliation of agriculture and nature.

The Impact of Cropland Use Changes on Terrestrial Ecosystem Services Value in Newly Added Cropland Hotspots in China during 2000–2020

The assessment of ecosystem services value is the basis for the realization of integrated management of these services. In recent decades, the hotspots of China’s newly added cropland have shifted to the Xinjiang oasis areas, where the ecological environment is relatively fragile. However, the impact of changes in cropland use on the terrestrial ecosystem services value (TESV) in Xinjiang, China, has not been studied in depth, and it is related to the sustainability of the dynamic balance between China’s cropland and the sustainable management of natural resources in Xinjiang. This study focuses on Xinjiang and employs the benefit transfer method and five phases (2000, 2005, 2010, 2015 and 2020) of high-resolution and finely classified remote sensing monitoring data of land use to evaluate the impact of changes in cropland use on the TESV from 2000 to 2020. The findings suggest the following: (1) The cropland area in Xinjiang grew from 6.5682 million ha in 2000 to 8.9874 million ha in 2020, demonstrating significant expansion, and it has gone through four stages: rapid expansion, steady expansion, rapid expansion and relative stability. (2) A sharp mutual conversion trend is observed between cropland and other types of land use in Xinjiang. Grassland and unused land are the main sources of new cropland, while lost cropland has been mainly converted back into grassland and construction land. (3) During 2000–2020, although the extensive expansion of cropland and conversion of cropland mainly at the expense of ecological land in Xinjiang have significantly enhanced the provision services of the terrestrial ecosystem (539.49 million USD), ecosystem regulation services (−1508.47 million USD), support services (−1084.47 million USD) and cultural services (−565.05 million USD) experienced losses. Consequently, an overall loss in the TESV has ensued. This study provides new insights that help re-examine the sustainability issue of the spatial transfer of cropland in China, and it also offers guidance for the realization of the sustainable management of natural resources in Xinjiang.

Role of land quality in corn acreage response to price and policy changes: evidence from the Western Corn Belt

Land quality influences how farmers allocate croplands in response to market forces. Farmers in the Western Corn Belt (WCB) have historically utilized the highest quality lands for corn cultivation, putting lower quality lands to other uses. This paper questions whether high corn prices influenced expansion of corn cultivation on lower quality lands, and the role played by US biofuel policy in such land use change. Using three decades of data, I estimate that the proportional change in corn acreage to rising corn prices is nearly three times larger in counties with lowest land quality versus those with the highest land quality. This variable response, however, is driven by the changes in cropland use for corn cultivation after 2006, the period following the change in US biofuel policy, and punctuated by two crop price spikes. Marginal agricultural lands and other lower quality lands, such as grasslands used for range or pasture, are therefore prone to conversion into corn cropping disproportionately during high price periods. High price responsiveness of lower quality lands also suggests these lands may cycle in and out of corn cropping opportunistically. This has implications for marginal land availability for bioenergy crops, and poses environmental concerns to the extent lower quality lands are also more environmentally sensitive.

Rural transition in the loess hilly and gully region: From the perspective of “flowing” cropland

The loess hilly and gully region of China supports a fragile ecosystem that has been subject to serious water loss and soil erosion in recent decades. In response, ongoing soil and water conservation and ecological restoration efforts have been conducted. A review of the region's development history indicates that the utilization mode of cropland in rural areas played an important role in the course of soil and water conservation and socioeconomic development. As a representative area, this study evaluated the status of the Yangjuangou catchment of Liqu Town, Baota District, Shaanxi Province. The dynamic processes, driving factors, variation characteristics, and intrinsic mechanisms of changes in cropland use since the 1980s were analyzed using remote sensing and participatory interview survey data. The results showed that changes in cropland use in Yangjuangou catchment occurred in four stages, including slope cropland utilization stage (1985–1998), the Grain for Green Project stage (1999–2007), agricultural structure adjustment stage (2008–2012), and cropland abandonment stage (2013–2017). These changes in cropland use were driven by policy, economic, socio-cultural, and environmental factors and showed certain characteristics. Specifically, cropland exhibited a “core-margin" funnel-shaped pattern in vertical space, with its changes tending to “flow” toward the core; its utilization intensity generally increased, and the area of intensive utilization and intensive elements gradually shifted. In recent years, spatial patterns gradually developed a sustainable “ecology-production" spatial pattern and abandoned cropland exhibited “contagion” spatial patterns. Finally, based on the behavior mechanisms of farmers and government, we found that the driving force for changes in cropland has changed over time. Initially, food demand on farmers and the goal of ecological safety promoted by the government were dominant. But more recently, the drivers have changed to development demand on farmers and the equal government objectives of promoting ecological safety, rural development, and food security. This study provides a microcosmic perspective on understanding the process and rules of changes in cropland use in the loess hilly and gully region. It also helps to understand the rural transition, providing a reference for developing rural development strategies and policies in this region.

Soil capability as a predictor of cropland change in Alberta, Canada from 1988 to 2010

AbstractUnderstanding the mutual influences between cropland use and soil characteristics is important in anticipating and planning for food production, environmental protection and resource sustainability. Numerous studies focus on the relationship between crop rotations and soil characteristics at a microscale, but fewer studies focus on the relationships between soil capability and cropland use and change at a medium scale. We explore how soil capability has influenced cropland changes over 22 yr, using statistical and land use transition analysis. Landsat images from the years 1988, 2002 and 2010 were used to map cropland changes by soil capability class within a pilot site in Alberta, Canada. Between the late 1980s and 2010: (i) the area of annual crops increased substantially while that of forest and summer‐fallow decreased; (ii) changes in cropland use among annual crops, perennial crops and summer‐fallow differed substantially depending on soil capability; and (iii) a transition from annual crops and summer‐fallow to perennial crops was more likely on land of poorer soil capability, whereas the transition from perennial crops and summer‐fallow to annual crops was more likely on land with higher soil capability. The changes in land use practices identified in this study indicate that producers are actively intensifying production on their best land to optimize profitability while simultaneously reducing the intensity of production on poorer land for either financial or environmental reasons, or both.

Looking back to move forward on model validation: insights from a global model of agricultural land use

Global agricultural models are becoming indispensable in the debate over climate change impacts and mitigation policies. Therefore, it is becoming increasingly important to validate these models and identify critical areas for improvement. In this letter, we illustrate both the opportunities and the challenges in undertaking such model validation, using the SIMPLE model of global agriculture. We look back at the long run historical period 1961–2006 and, using a few key historical drivers—population, incomes and total factor productivity—we find that SIMPLE is able to accurately reproduce historical changes in cropland use, crop price, crop production and average crop yields at the global scale. Equally important is our investigation into how the specific assumptions embedded in many agricultural models will likely influence these results. We find that those global models which are largely biophysical—thereby ignoring the price responsiveness of demand and supply—are likely to understate changes in crop production, while failing to capture the changes in cropland use and crop price. Likewise, global models which incorporate economic responses, but do so based on limited time series estimates of these responses, are likely to understate land use change and overstate price changes.

Water Quality Co-Effects of Greenhouse Gas Mitigation in U.S. Agriculture

This study develops first-order estimates of water quality co-effects of terrestrial greenhouse gas (GHG) emission offset strategies in U.S. agriculture by linking a national level agricultural sector model (ASMGHG) to a national level water quality model (NWPCAM). The simulated policy scenario considers GHG mitigation incentive payments of $25 and $50 per tonne, carbon equivalent to landowners for reducing emissions or enhancing the sequestration of GHG through agricultural and land-use practices. ASMGHG projects that these GHG price incentives could induce widespread conversion of agricultural to forested lands, along with alteration of tillage practices, crop mix on land remaining in agriculture, and livestock management. This study focuses on changes in cropland use and management. The results indicate that through agricultural cropland about 60 to 70 million tonnes of carbon equivalent (MMTCE) emissions can be mitigated annually in the U.S. These responses also lead to a 2% increase in aggregate national water quality, with substantial variation across regions. Such GHG mitigation activities are found to reduce annual nitrogen loadings into the Gulf of Mexico by up to one half of the reduction goals established by the national Watershed Nutrient Task Force for addressing the hypoxia problem.