03 Nov 2011

Nutrient Balance Assessments in Crop Production

IPNI sees on-going assessment of nutrient balance and nutrient use efficiency in crop production as one of its responsibilities. This page lists materials and/or tools developed by IPNI on assessments of nutrient balance in crop production in different parts of the world.

The Nutrient Use Geographic Information System (NuGIS) has two objectives to: (a) continually assess nutrient balance and nutrient use efficiency and (b) identify weaknesses in the process of doing that assessment with the hope that all involved in the process will collectively strive for improvements.

The Nutrient Use Geographic Information System (NuGIS) for India estimates nutrient use balances in India. Data was compiled from state-level spreadsheets of district-level data to create one database of nutrient use (application to the land and fixation by crops) and removal by plants. Balance and ratio calculations were then re-created within a relational database and the resulting balance and ratio estimates, along with the original input data, were joined to maps of the states and districts of India. These maps are now available via an interactive map viewer on this website.

Please login, or request a login, to view the interactive maps, download tabular data, or learn more about this project.

NuGIS-U.S. integrates multiple tabular and spatial datasets to create county-level and watershed-level estimates of N, P and K applied to the soil in fertilizer and livestock manure, and nutrients removed by harvested agricultural crops. Geospatial techniques were used to estimate balances for 8-digit hydrologic units using the county-level data. The current version makes estimates for five years, coinciding with the USDA Census of Agriculture, from 1987 - 2007. A version that can be updated annually for non-Census years is under development. Results are viewable through an interactive color map or exportable as tabular data. A pdf file of a short article providiing a summary of the methods used in NuGIS is attached (see 'Additional Resources').

In-depth methods are provided on the website to offer complete transparency into how the balance estimates are made and displayed. Interpretation of the results, other than a few summary bullets, is not done here. Future focused publications will emphasize interpretation. Please submit comments or suggestions for improvement to nugis@ipni.net

Crop Nutrient Balances for Canada (1973-2013)
The crop nutrient balance—the comparison of nutrients applied to cropland in relation to those removed by crops—is an important indicator of the sustainability performance of crop production. Deficits in the nutrient balance can limit crop yields and deplete soil fertility, and surpluses can cause economic waste and increase the risk of harm to water and air.

The crop nutrient balances for Canada were estimated from 1973-2013. Manure was estimated based on Statistics Canada inventory of cattle, hogs, and poultry and coefficients for excretion and recoverability. Fertilizer nutrient applications were calculated from industry data on shipments to agricultural markets. Legume fixation of nitrogen was assumed proportional to the nitrogen removed by the major legume crops, mainly forage legumes and soybeans. Crop removal of nutrients was estimated by applying coefficients to crop production data from Statistics Canada.

In general, crop removals are increasing over time, owing to yield increases in the major crops. Nutrient balances have seen dramatic changes over the past seven years (2007-2013) in response to both weather and price changes for fertilizers and crops.

Regional Nutrient Budgets for Australia
The 2001 Australian Natural Resource audit took account to the nutrient balances for different regions in Australia, based on data from 1994 to 1996. The methods used in that audit have been repeated for the years 2007-08 and 2009-10 using production data from each natural resource management region, fertilizer inputs from farm surveys, and expected nutrient densities.

The amounts of N, P, K and S applied as fertilizers and removed as agricultural commodities were calculated using Australian Bureau of Statistics (ABS) data for 2007-08 and 2009-10 for all Australian Natural Resource Management (NRM) regions.