Global animal production and nitrogen and phosphorus flows

Soil Research ◽  
2017 ◽  
Vol 55 (6) ◽  
pp. 451 ◽  
Author(s):  
Qian Liu ◽  
Jingmeng Wang ◽  
Zhaohai Bai ◽  
Lin Ma ◽  
Oene Oenema

Animal production systems provide nutritious food for humans, income and survivability for numerous smallholder farms and transform residues to valuable products. However, animal production is implicated in human health issues (diet-related diseases, zoonosis, antimicrobial resistance) and environmental burdens (ammonia and greenhouse gas emissions, eutrophication of surface waters, biodiversity loss). This paper reviews changes in global animal production and associated nitrogen (N) and phosphorus (P) flows over the past 50 years, during which time total animal production roughly tripled. Cattle still dominate the world in terms of animal biomass, but the number and total production of pigs and poultry have increased faster. Animal production systems are highly diverse and respond to changes in markets. Specialised systems have become more dominant, especially in developed and rapidly developing countries. The annual production of N and P in manure is similar to the amounts of N and P in synthetic fertiliser produced annually, but manure nutrients are often not recycled effectively and used efficiently by plants. Nutrient losses greatly depend on the system, management and regulations. Nitrogen and P use efficiency (NUE and PUE respectively) at the animal level is in the range 5–45%, depending on animal category, feeding and management. NUE of mixed crop-animal systems may range from 5% to 65% depending on NUE at the animal level, and the utilisation of manure nitrogen and new nitrogen inputs. Potentially, values for PUE are higher than those for NUE. Solutions for improving NUE and PUE in animal production are based on a coherent set of activities in the whole chain of ‘feed production–animal production–manure management’. A high efficiency at the system level is achieved through combination of high NUE and PUE at the animal level and effective recycling and utilisation of manure N and P in crop production. Specific regional regulations (low-emission manure storage and application, proper application limits and timing) greatly contribute to high efficiency at a system level.

2004 ◽  
Vol 49 (5-6) ◽  
pp. 7-13 ◽  
Author(s):  
R.W. Howarth

Human activity has greatly altered the nitrogen cycle on Earth over the past few decades, with major effects on both human health and the ecological functioning of natural ecosystems, particularly coastal marine systems where nitrogen is now the largest pollution problem. Agriculture is the largest driver of this change, with pollution from fossil-fuel combustion being a smaller but still significant driver globally. Much of the nitrogen pollution from agriculture derives from animal-production systems, both as a direct result of nitrogen leakage to the atmosphere and waters from these systems, and from the demand for increased crop production that these animal-production systems demand. Wastewater from urban centers is also a significant component of the nitrogen problem, contributing 12% of the nitrogen pollution in rivers in the US, 25% in Europe, and 33% in China. Wastewater sources dominate the inputs of nitrogen to some coastal ecosystems, but globally and in most regions the non-point sources are larger. Many technical solutions to reducing nitrogen pollution exist, so to some extent the current problem reflects policy and political failures. Nonetheless, further technical solutions can and should be developed. These should recognize the significantly greater mobility of nitrogen than phosphorus in the environment.


Animals ◽  
2017 ◽  
Vol 7 (12) ◽  
pp. 75 ◽  
Author(s):  
Maria Yunes ◽  
Marina von Keyserlingk ◽  
Maria Hötzel

2006 ◽  
Vol 63 (2) ◽  
pp. 194-209 ◽  
Author(s):  
Francirose Shigaki ◽  
Andrew Sharpley ◽  
Luís Ignácio Prochnow

Eutrophication has become a major threat to water quality in the U.S., Europe, and Australasia. In most cases, freshwater eutrophication is accelerated by increased inputs of phosphorus (P), of which agricultural runoff is now a major contributor, due to intensification of crop and animal production systems since the early 1990s'. Once little information is available on the impacts of Brazilian agriculture in water quality, recent changes in crop and animal production systems in Brazil were evaluated in the context of probable implications of the fate of P in agriculture. Between 1993 and 2003, there was 33% increase in the number of housed animals (i.e., beef, dairy cows, swine, and poultry), most in the South Region (i.e., Paraná, Rio Grande do Sul, and Santa Catarina States), where 43 and 49% of Brazil's swine and poultry production is located, respectively. Although grazing-based beef production is the major animal production system in Brazil, it is an extensive system, where manure is deposited over grazed pastures; confined swine and poultry are intensive systems, producing large amounts of manure in small areas, which can be considered a manageable resource. This discussion will focus on swine and poultry farming. Based on average swine (100 kg) and poultry weights (1.3 kg), daily manure production (4.90 and 0.055 kg per swine and poultry animal unit, respectively), and manure P content (40 and 24 g kg-1 for swine and poultry, respectively), an estimated 2.5 million tones of P in swine and poultry manure were produced in 2003. Mostly in the South and Southeast regions of Brazil (62%), which represent only 18% of the country's land area. In the context of crop P requirements, there was 2.6 times more P produced in manure (1.08 million tones) than applied as fertilizer (0.42 million tonnes) in South Brazil in 2003. If it is assumed that fertilizer P use represents P added to meet crop needs and accounts for P sorbed by soil in unavailable forms each year, if swine and poultry manure were to replace fertilizer, there would be an annual P surplus of 0.66 million tonnes in the South region alone. These approximations and estimates highlight that, similarly to other parts of the world, there is a potential for surplus P to quickly accumulate in certain regions of Brazil. Unless measures are developed and implemented to utilize manure P, repeated annual surpluses will create an increasingly difficult problem to solve. These measures can be grouped as source and transport management. Source management attempts to decrease dietary P, use feed additives, manure treatment and composting, as well as careful management of the rate, timing, and method of manure applications. Transport management attempts to control the loss of P in runoff from soil to sensitive waters via use of conservation tillage, buffer or riparian zones, cover crops, and trapping ponds or wetlands. These measures are discussed in the contest of Brazil's climate, topography, and land use, and how successful remediation programs may be implemented at farm and watershed level.


2020 ◽  
Vol 8 (3) ◽  
pp. 328 ◽  
Author(s):  
Antonio Castellano-Hinojosa ◽  
Sarah L. Strauss

Increased concerns associated with interactions between herbicides, inorganic fertilizers, soil nutrient availability, and plant phytotoxicity in perennial tree crop production systems have renewed interest in the use of cover crops in the inter-row middles or between trees as an alternative sustainable management strategy for these systems. Although interactions between the soil microbiome and cover crops have been examined for annual cropping systems, there are critical differences in management and growth in perennial cropping systems that can influence the soil microbiome and, therefore, the response to cover crops. Here, we discuss the importance of cover crops in tree cropping systems using multispecies cover crop mixtures and minimum tillage and no-tillage to not only enhance the soil microbiome but also carbon, nitrogen, and phosphorus cycling compared to monocropping, conventional tillage, and inorganic fertilization. We also identify potentially important taxa and research gaps that need to be addressed to facilitate assessments of the relationships between cover crops, soil microbes, and the health of tree crops. Additional evaluations of the interactions between the soil microbiome, cover crops, nutrient cycling, and tree performance will allow for more effective and sustainable management of perennial cropping systems.


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