Plants have to have a continuous offer of the nutrient to expand, but nitrogen deficiency within the soil is popular. NPK fertilizers deliver plants with an accessible source of this critical nutrient.??? ???? ??????? ??? ??????? ??? ??????? ??? ????? ????? ?????? ????????? ???????? ??? ???? ????? ????? ?????? ?? ??????? ?????? ??? ??? ????? ?????