nn valuenarrow row plantingnatric horizonnatural erosionnatural leveeneocutanneoformationnet primary productionneutralneutral soilneutralismneutron probenichenitrate reductionnitric phosphatesnitrificationnitrogen cyclenitrogen fixationnitrogenaseno tillage systemnodulenodule bacterianon capillary porositynon limiting water rangenonlimiting range waternonpoint pollutionnonpressure solutionnonrenewable natural resourcesnonsaline alkali soilnormal erosionnose slopenppnutrient antagonismnutrient balancenutrient capitalnutrient concentration vs contentnutrient deficiencynutrient efficient plantnutrient interactionnutrient loadingnutrient stressnutrient supplying power of soilnutrient toxicitynutrient use efficiency