3HUNTER A H. Laboratory and greenhouse technique for nutrient survey to detemine the soil amendment required optimum plant growth[M]. Agro Sevices International Inc. USA, 1980.
4DOWDIE S, PORTCH S. Asystemic approach for determining soil nutrient constrains and establishing balanced fertilizer recommendation for sustained high yields[M]. Proceedings of the International Symposium on Balanced Fertilization, 1988:243 - 251.
5HUNTER A H. Laboratory and greenhouse techniques for nutrient survey to determine the soil amendments required for potimun plant gowth[M].Mimeograph. Florida,USA:Agro Service International,1980.