The experiment was conducted at the National Grassland Research Institute, Nishinasuno, Tochigi, Japan during the period from 23 June to 18 September 1999. Two soils, one treated with farmyard manure (FYM) and the other with chemical fertilizers, each for a period of 12 years, were used in this study. The manure treated soil was pH 6.2 and the fertilizer treated soil was pH 5.8. The available contents of N, Zn, B, Cu, Mn, and Fe in the manure supplemented soil were 26.8, 4.8, 0.70, 3.0, 15.5, and 53.7 µgg-1, respectively. The corresponding values of the elements for the fertilized soil were 9.8, 0.96, 0.39, 2.2, 4.91, and 44.2 µgg-1, respectively. A 3-kg sample of soil was weighed into a pot, each pot 16 cm diameter and 19 cm height. There were four treatments consisting of control (no B or Zn), B, Zn and B+ Zn. The rates for B and Zn applications were 2.5 and 5mg kg-21 soil from ZnSO4:7H2O and H3BO3, respectively. The treatments were replicated three times in a randomized complete block design. The test crops were corn (Zea mays L., cv. DK789) and soybean (Glycine max L., cv. Wase-edamame). There were 24 pots for each of soybean and corn (4 treatments 3 replications 2 soils 2 crops). A basal application was made with N, P2O5 and K2O each at the rate of 1.5 g pot-1. Nitrogen was also added to soybean pot since the plant was not inoculated with Bradyrhizobium japonicum. All fertilizers were applied in solutions and were thoroughly mixed with soil. Nine seeds of soybean or corn were placed in each pot. The number of plants in each pot was thinned to five after one week of germination. Watering (deionized water) was done whenever required throughout the experiment. The experiment was conducted in a greenhouse. The crop was harvested after 8 weeks of planting. After drying, the shoot weight of each pot was recorded. Since the roots were spread throughout the pot, the whole soil was considered as rhizosphere sample. The roots were carefully removed during collection of soil samples. The soil samples were analyzed for pH and available N, Zn, B, Cu, Mn, and Fe contents. The inorganic N (NH4-N and NO3-N) content was determined by 2M KCl extraction method. The Zn content in soil was extracted with DTPA, and the soil B content was determined by extraction with 0.01M CaCl2 at 1358C (10). The N concentration in plant was determined by indophenol method after digestion with conc. H2SO4, and the other plant nutrients were determined in HNO3–HF digests. The NH4-N concentration in the soil extract was determined by indophenol method, the NO3-N concentration by sulfanailamide–napthylamine method with a reduction by Cd, and the Zn, Cu, Mn, and Fe contents by atomic absorption spectroscopy (AAS, Z-8100, Hitachi, Japan). Concentrations of K, Ca, and Mg in the plant digest were measured by an atomic absorption spectrophotometer. The B content in both soil and plant, and the Zn, Cu, and Mn concentrations in plant were determined by inductively coupled plasma-mass spectroscopy (ICP-MS).