Related by context. Frequent words. (Click for all words.) 62 nitrogen fertilizers 58 nitrogen fertilizer 57 nutrient runoff 57 atmospheric nitrogen 57 nitrogen 57 potent greenhouse gas 57 bee pollination 56 synthetic fertilizers 54 Drip irrigation 54 livestock manure 54 glucosinolates 54 chemical fertilizers 54 nitrification 54 artificial fertilizers 54 castor bean plant 53 Soil erosion 53 nitrogen phosphorous 53 nitrogen fixing 52 nitrogen phosphorus 52 herbicides pesticides 52 Anhydrous ammonia 52 atmospheric methane 52 distiller grain 52 cellulosic materials 51 absorbing carbon dioxide 51 crop residues 51 nitrous oxide emissions 51 irrigated crops 51 elemental sulfur 51 pesticides fertilizers 51 terpenes 51 phytate 51 arable crops 51 salination 51 bioenergy crops 51 crop yields 51 manures 51 fertilizers pesticides 51 lignocellulose 51 Methyl bromide 51 cropland 50 photosynthesis 50 adipic acid 50 naturally occurring bacteria 50 soil fertility 50 methane 50 arable land 50 feedstuffs 50 Stormwater runoff 50 forbs 50 nutrient uptake 50 toxic solvents 50 phytoplankton blooms 50 biofuel feedstocks 49 biodiesel feedstock 49 hydrologic cycle 49 microscopic algae 49 Nitrogen oxides 49 nitrous oxides 49 pest insects 49 Carbon sequestration 49 hydroxyl radicals 49 pesticides 49 xylem 49 Nitrogen 49 fertilizer 49 sugar beet crop 49 bollworms 49 oxalic acid 49 triclocarban 49 phytoplankton 49 weedkillers 49 CO -2 49 nutrient absorption 49 chicken manure 49 arable 49 aerosol particles 49 groundwater aquifers 49 nonrenewable resources 49 mycelium 49 irrigated agriculture 49 bee populations 49 nutrient rich 48 nutrient loading 48 biopesticides 48 livestock rearing 48 Genetic modification 48 carbonic acid 48 cereal grains 48 overgrazing 48 monocultures 48 Bt toxin 48 compost heaps 48 nutrient 48 agricultural 48 animal dung 48 fertilizers 48 soils 48 chlorella 48 Genetically modified crops 48 pollinating insects