[Difference of several major nutrients accumulation in vegetable and cereal crop soils]

Investigation and determination of several major nutrients in different types of vegetable and cereal crop soils were carried out in the Guanzhong Plain in Shaanxi Province. The results showed that organic matter, nitrogen, phosphorus and potassium accumulated more in the 0-200 cm profile of vegetable soils than in that of cereal crop soils. However, the accumulation degrees were different with different nutrient forms. The total amount of nitrate-N in the soil profile of plastic greenhouse and usual vegetable field was 1520.9 kg.hm-2 and 1358.8 kg.hm-2, being 5.2 and 4.5 times higher than that in the cereal crop fields respectively. The total amount of available-P was respectively 978.1 kg.hm-2 and 503.3 kg.hm-2 in the two vegetable soils, and 136.2 kg.hm-2 in cereal crop soils, and the former two were 6.2 and 2.7 times higher than the latter. For other nutrients, organic matter in cereal crop soil was 249.4 Mg.hm-2, and that in plastic greenhouse and usual vegetable soil was 280.5 Mg.hm-2 and 269.3 Mg.hm-2, respectively, which were only 12.5% and 8.0% higher than that in cereal crop soils. The total-N in plastic greenhouse and usual vegetable soils was 37.5 Mg.hm-2 and 32.7 Mg.hm-2, which was 36.2% and 18.6% higher than that (27.5 Mg.hm-2) in cereal crop soils, respectively. The ammonium-N was 211.5 kg.hm-2 and 197.8 kg.hm-2, which was 29.6% and 21.2% higher than that (163.2 kg.hm-2) in cereal crop soils. The available-K was 6567.8 kg.hm-2 and 5523.6 kg.hm-2, which was 30.6% and 9.8% higher than that (5029.7 kg.hm-2) in cereal crop soils. Furthermore, serious nutrient leaching occurred in vegetable soil profiles due to over-fertilization and irrigation.