Nitrogen fertilizers Fertilizers and other Amendments 3 Nitrogen 3 Plant Production 3 Crop production 2 Nutrient availability 2 Nutrient deficiencies 2 Nutrient uptake 2 Phosphorus 2 Plant Nutrition 2 Plant nutrition 2 Pollution and Degradation 2 Soil Chemistry and Mineralogy 2 Soil Fertility 2 Soil Physics 2 Agriculture 1 Air pollutants 1 Air pollution 1 Animal Wastes 1 Application date 1 Application methods 1 Application rates 1 Arable land 1 Atmosphere 1 Beta vulgaris 1 Beta vulgaris var. saccharifera 1 Boron 1 Boron fertilizers 1 Calcium 1 Calcium fertilizers 1