一項研究發現，不同國家和地區的農耕土壤的磷濃度的影響有很大的差異，磷在一些地區過剩，而在另一些地區不足。在理想情況下，由化肥進入土壤的磷與農作物從土壤中吸收的磷是平衡的，但是Graham K. MacDonald及其同事報告說，這種平衡常常被打破。
這組作者使用詳細的農業地圖評估了2000年全世界各個地區的種植100多種農作物的栽培用土壤的磷濃度的平衡。儘管最廣泛的嚴重缺磷存在於南美、美國北部和東歐的一些地區，磷大量過剩的地區主要在東亞大部分地區、美國沿海地區以及西歐和南歐的一部分。儘管化肥在很大程度上對磷過剩有貢獻，在大量從事牲畜生產的地區——那裡也常用糞肥——的磷濃度也過量。此外，缺磷的地區大致上也是種植飼料作物（用於飼養牲畜的作物）的地區。過多的磷可能進入水體，威脅淡水生態系統；相反，缺磷可能限制作物產量。因此，這些發現提示，需要謹慎地使用含磷化肥從而確保在不傷害水質的情況下的可持續的農業生產力。（生物谷Bioon.com）
生物谷推薦英文摘要：
PNAS doi: 10.1073/pnas.1010808108
Agronomic phosphorus imbalances across the world's croplands
Graham K. MacDonalda,1, Elena M. Bennetta,b, Philip A. Potterc, and Navin Ramankuttyd
Increased phosphorus (P) fertilizer use and livestock production has fundamentally altered the global P cycle. We calculated spatially explicit P balances for cropland soils at 0.5° resolution based on the principal agronomic P inputs and outputs associated with production of 123 crops globally for the year 2000. Although agronomic inputs of P fertilizer (14.2 Tg of P·y−1) and manure (9.6 Tg of P·y−1) collectively exceeded P removal by harvested crops (12.3 Tg of P·y−1) at the global scale, P deficits covered almost 30% of the global cropland area. There was massive variation in the magnitudes of these P imbalances across most regions, particularly Europe and South America. High P fertilizer application relative to crop P use resulted in a greater proportion of the intense P surpluses (>13 kg of P·ha−1·y−1) globally than manure P application. High P fertilizer application was also typically associated with areas of relatively low P-use efficiency. Although manure was an important driver of P surpluses in some locations with high livestock densities, P deficits were common in areas producing forage crops used as livestock feed. Resolving agronomic P imbalances may be possible with more efficient use of P fertilizers and more effective recycling of manure P. Such reforms are needed to increase global agricultural productivity while maintaining or improving freshwater quality.