Coupling of crop and livestock production can reduce the agricultural GHG emission from smallholder farms.

Ensuring global food security and environmental sustainability is dependent upon the contribution of the world's hundred million smallholder farms, but the contributions of smallholder farms to global agricultural greenhouse gas (GHG) emissions have been understudied. We developed a localized agricultural life cycle assessment (LCA) database to calculate GHG emissions and made the first extensive assessment of the smallholder farms' GHG emission reduction potentials by coupling crop and livestock production (CCLP), a redesign of current practices toward sustainable agriculture in China. CCLP can reduce the GHG emission intensity by 17.67%, with its own feed and manure returning to the field as an essential path. Scenario analysis verified that greater GHG emission reduction (28.09%-41.32%) will be achieved by restructuring CCLP. Therefore, this mixed farming is a mode with broader benefits to provide sustainable agricultural practices for reducing GHG emissions fairly.

Environmental Conservation or the Treadmill of Law: A Case Study of the Post-2014 Husbandry Waste Regulations in China.

As industrialized animal agriculture expanded rapidly in the last decade, the resultant pollution has generated widespread despoliation of natural resources and environmental victimization in rural China. This study examines the formulation and implementation of national environmental regulations from 2014 to 2019 and finds that the juxtaposing ministerial and provincial jurisdictions resulted in conflicting interpretations of the scale and evaluation criteria of the national policy. We argue that the regulations are more than centralized conservation programs designed to reduce environmental pollution caused by the expansion of animal husbandry. Instead, these regulations are fundamentally state-led rural development initiatives that utilize the designations of ecological protection zones to reconfigure land use and promote scale-up production in agricultural structural adjustment initiatives. The enforcement of these environmental regulations, therefore, constitutes a treadmill of law (ToL) that accelerated the geographical specialization and function intensification of the Chinese husbandry sector.

Fertilizer overuse in Chinese smallholders due to lack of fixed inputs.

Fertilizer overuse by smallholder farmers is widespread in China, leading to significant financial losses and threatening the environment. Understanding what mechanism behind this is critical for agricultural and environmental sustainability. By using a fixed effect panel model of over 20,000 rural households in China from 1995 to 2016, we found that the low ratio of fixed inputs such as machinery and knowledge to total inputs is the key factor leading to over-fertilization in smallholder farms. Low fixed input can result in or interact with nutrient-unbalanced fertilization, low agricultural income ratio and more cash crops that further aggravate fertilizer overuse. Smallholders lack fixed inputs, then compensate by over-applying fertilizer to attempt to achieve their yield goals. Thus, improving fixed input via increasing the average farm size to 3.8 ha or advanced service rental could save not only 45% fertilizers but also increase 16% agricultural net profit, benefiting agricultural and environmental sustainability.

Plastic pollution in croplands threatens long-term food security.

Plastic pollution is a global concern given its prevalence in aquatic and terrestrial ecosystems. Studies have been conducted on the distribution and impact of plastic pollution in marine ecosystems, but little is known on terrestrial ecosystems. Plastic mulch has been widely used to increase crop yields worldwide, yet the impact of plastic residues in cropland soils to soil health and crop production in the long term remained unclear. In this paper, using a global meta-analysis, we found that the use of plastic mulch can indeed increase crop yields on average by 25%-42% in the immediate season due to the increase of soil temperature (+8%) and moisture (+17%). However, the unabated accumulation of film residues in the field negatively impacts its physicochemical properties linked to healthy soil and threatens food production in the long term. It has multiple negative impacts on plant growth including crop yield (at the mean rate of -3% for every additional 100 kg/ha of film residue), plant height (-2%) and root weight (-5%), and soil properties including soil water evaporation capacity (-2%), soil water infiltration rate (-8%), soil organic matter (-0.8%) and soil available phosphorus (-5%) based on meta-regression. Using a nationwide field survey of China, the largest user of plastic mulch worldwide, we found that plastic residue accumulation in cropland soils has reached 550,800 tonnes, with an estimated 6%-10% reduction in cotton yield in some polluted sites based on current level of plastic residue content. Immediate actions should be taken to ensure the recovery of plastic film mulch and limit further increase in film residue loading to maintain the sustainability of these croplands.

Mitigating land pollution through pesticide packages - The case of a collection scheme in Rural China.

Pesticide packages that are discarded on agricultural land can contaminate water bodies and pose a threat to the environment and human health. Little is known about how developing countries deal with this kind of land pollution. While in developed countries, packages are collected by professional organizations, the smallholder context in developing countries makes the collection of this waste much more difficult. This paper introduces and analyses a successful Pesticide Package Collection Scheme in one of the poorest regions in China, i.e. Guangxi Province. The purpose of the paper is to analyze and discuss how such a scheme can be established by multiple actors. The paper finds that the underlying success factors for establishing such a scheme are 1.) that a scheme piggy-bags on existing economic structures that reach out to farmers (e.g. associations); 2.) that the scheme itself facilitates actors' exchange of resources to establish a temporary resource equilibrium; 3.) that all stakeholders obtain returns on their investment, even if the quality and time scale of these returns may differ. The initiation of the scheme by a pesticide company however increased both its political and market influence. Caution hence has to be paid to whether the short-term improvement in land pollution happens at the expense of a dependency on and increased use of certain kinds of pesticides.

Nitrogen, Phosphorus, and Potassium Flows through the Manure Management Chain in China.

The largest livestock production and greatest fertilizer use in the world occurs in China. However, quantification of the nutrient flows through the manure management chain and their interactions with management-related measures is lacking. Herein, we present a detailed analysis of the nutrient flows and losses in the "feed intake-excretion-housing-storage-treatment-application" manure chain, while considering differences among livestock production systems. We estimated the environmental loss from the manure chain in 2010 to be up to 78% of the excreted nitrogen and over 50% of the excreted phosphorus and potassium. The greatest losses occurred from housing and storage stages through NH3 emissions (39% of total nitrogen losses) and direct discharge of manure into water bodies or landfill (30-73% of total nutrient losses). There are large differences among animal production systems, where the landless system has the lowest manure recycling. Scenario analyses for the year 2020 suggest that significant reductions of fertilizer use (27-100%) and nutrient losses (27-56%) can be achieved through a combination of prohibiting manure discharge, improving manure collection and storages infrastructures, and improving manure application to cropland. We recommend that current policies and subsidies targeted at the fertilizer industry should shift to reduce the costs of manure storage, transport, and application.