| Mineral nutrient elements nitrogen, phosphorus and potassium are important components of plant and the foundation nourishment in food chain for life and plant growth. They are correlative with protein, grease, nucleic acid and vitamin and so on. At the same time, they are important for keeping balance of nutrition resources in ecosystem, increasing yield, improving quality of farm production, reducing pollution and improving human nutrition. Seven-year-old'RED GLOBE'grape tree, capsicum (Capsicum annuum Linn.) and potato were used as experiment materials. Roots distribution, biomass, elements content and accumulation in different organs in different periods were studied in grape tree. Effect of balanced fertilization on yield, quality and nutrients accumulation of capsicum and potato was also studied. The main results were showed as follows:1. Study on the dynamics of biomass and roots distribution in grape treeTo find out the nitrogen absorption, utilization and accumulation in grape tree, and to provide a reasonable fertilizer rate and application periods, field experiments were conducted in Fu Feng county, Shaanxi Province for analyzing yearly biomass, nitrogen content and its accumulation at different parts of grape trees (Red globe) which are cultivated about 7 years. The results showed that biomass increment of stem, trunk, leaves, fruits and new shoots were 2481 kg/ha,1939 kg/ha,2357 kg/ha,4866 kg/ha,6118 kg/ha, respectively. Biomass of plant and the parts above ground increased quickly from June 30 to August 20. In the main growing period, biomass of roots fluctuated between 2303～4132 kg/ha, net increase was 1830 kg/ha, about 14.8% of gross. The biomass of whole plant increased 12369 kg/ha. About 86.7% roots distributed in the 0～40 cm soil depth, the deep of soil the less of roots. Roots in 40～60 cm soil depth accounted for 7.4% of the whole roots,60～80 cm only 3.6%, and 80～100cm just 2.3%. Biomass of roots in 0～20 cm soil depth developed more quickly from May 10 to June 30, cortex vegetated 34.7%; and xylem vegetated 25.7%. From August 20 to September 30, biomass of soil cortex in 0～20 cm soil depth also increased rapidly from 0.095 kg/plant to 0.109 kg/plant, rate of increase about 15.2%. Biomass of roots xylem below 40 cm increased less.2. Study on nitrogen absorption, utilization and accumulation in grape tree Grape yield of this orchard was 18 t/ha. Total nitrogen absorption rate was 97.13 kg/ha in one year of the growing period.39% of that was absorbed during the new shoots flourishing period, and 30.5% was absorbed during the fruit growing period. To achieve 1000 kg economic fruits yield,5.4 kg N was taken up by grape trees from soil. Nitrogen content order in the organs was:leaves>fruits> new branches> roots> branches>stems. Nitrogen content in cortex was larger than that in xylem. N accumulation in plant above-ground and roots were 94.49 kg/ha and 2.64 kg/ha, about 97% and 3% of the gross, respectively. Nitrogen move away by leaves and fruits were 35.09 kg/ha and 32.27 kg/ha. New shoots absorbed 23 kg/ha nitrogen, and 5.11 kg/ha nitrogen was carried off by pruned branches, account for 5% of the gross. Nitrogen loss carried away by leaves, fruits and pruned branches should be applied by fertilization. The total nitrogen application rate was 129.5 kg/ha (yield 18 t/ha) recommended, while 39.4 kg/ha of nitrogen was applied as base fertilizer in forced dormancy period of plant, and 50.7 kg/ha was used during new shoots flourishing period, and remaining 39.4 kg/ha was applied as topdressing in the rapid growing phase of fruit.3. Study on phosphorus absorption, utilization and accumulation in grape treeTotal 33.1 kg/ha phosphorus was absorbed by grape tree in a year, about 3.1 kg/ha absorbed by leaves, and 11.9 kg/ha by fruits. New shoots, stem and trunk absorbed phosphorus 9.1 kg/ha,3.5 kg/ha,1.6 kg/ha, respectively.3.8 kg/ha phosphorus was absorbed by roots. Among 33.1 kg/ha phosphorus,15.4 kg/ha was absorbed during the fruit growing period, about 47% of total uptake. In early time, grape trees mainly use reserved phosphorus to construct organs. Phosphorus assignment diverted along with the shift of growth center. In same phenophase, potassium content in cortex and xylem was: roots>branches>stem. To attain 1000 kg economic yield, grape tree should uptake P2O5 1.84 kg. The yearly suggested total phosphorus application amount was 55.1 kg/ha (yield 18 t/ha), while 29.2 kg/ha of nitrogen was applied as base fertilizer in forced dormancy period of plant, and 25.9 kg/ha was applied as topdressing in the rapid growing phase of fruit.4. Annual change of potassium content, accumulation in grape treePotassium content in new organs (leaves, shoots and fruits) during early spring was higher than that at later time. In same phenophase, potassium content in new organs was higher than that in old organs (branch, trunk and roots). Potassium content in roots almost had no remarkable change in one year. Total 140.52 kg/ha potassium was absorbed in a year, among 17.24 kg/ha absorbed by leaves, and 64.29 kg/ha by fruits. New shoots, stem and trunk absorbed phosphorus 31.63 kg/ha,8.43 kg/ha,7.06 kg/ha, respectively.11.87 kg/ha phosphorus was absorbed by roots. Among the new shoots flourishing period and the fruit growing period, grape tree need more potassium, about 38.59 kg/ha absorbed during the new shoots flourishing period, and 64.29 kg/ha during the fruit growing period,27.5% and 45.8% of the total uptake. To attain 1000 kg economic yield, grape tree should uptake potassium 7.8 kg. The total potassium application rate was 175.6 kg/ha (yield 18 t/ha) recommended, while 46.9 kg/ha of potassium was applied as base fertilizer in forced dormancy period of plant, and 48.3 kg/ha was used during new shoots flourishing period, and the rest of 80.4 kg/ha was also applied as topdressing in the rapid growing phase of fruit.5. Effect of balanced fertilization on yield, quality and nutrients accumulation of capsicumA field experiment was carried out in Feng Xiang from 2007-2008, and effects of different fertilizer treatments on Capsicum yield, quality and nutrient accumulation were studied. Treatment was NPK, PK, NK, NP, and CK. The results indicated that capsicum yield could reach up to 22001 kg/ha by using balanced fertilization techniques. Compared with NPK, yield of PK, NK, NP decreased by 12%,7.5% and 15%.1 kg N, P2O5, K2O could increase the capsicum yield by 11 kg,10 kg, and 17 kg, respectively. NO3--N and vitamin C content of PK decreased by 2.3 mg/kg and 223 mg/kg. Vitamin C content of NK was lower than NPK, decreased by 51 mg/kg. NO3--N content of NP increased by 9.6 mg/kg, while vitamin C content decreased by 279 mg/kg. Fertilizer efficiency was:nitrogenous fertilizer 38.4%, phosphate fertilizer 17.6%, and potash fertilizer 37.4%. To attain 100 kg economic yield, plant should absorb nutrient:N 1.87 kg, P2O5 0.42 kg, K2O 1.42 kg. Nutrients accumulation in NPK treatment was highest: N 410 kg/ha, P2O5 93 kg/ha, K2O 311 kg/ha. The optimum ratio of N:P2O5:K2O was 1:0.59:0.82, and the suitable application amount of N, P2O5, K2O was 262 kg/ha,155 kg/ha,213.6 kg/ha, respectively. Only the balanced application of N, P and K can have the best of the Capsicum yield, quality and benefit.6. Effect of balanced fertilization on the yield and nutrients content, accumulation of potatoField experiments were carried out in Hua county and Mi Zhi county in one year. There were 6 treatments, NPK, PK, NK, NP, FP and CK, respectively. Rate of fertilizer application in the two experiments was distinct. Due to the difference of soil and climate, the influence of N, P, K nutrients on the yield of potato were not the same. Hua county showed as:N>K>P,1 kg N, P2O5, K2O could increase the potato yield by 32.6 kg,4.3 kg,24.7 kg, respectively. By using balanced fertilization techniques, potato yield could reach up to 47916 kg/ha in Hua county, and Mi Zhi county was 26527 kg/ha. In Mi Zhi County,1 kg N, P2O5; K2O could increase the potato yield by 16.8 kg,4.7 kg, and 21.6 kg, respectively. With application of balanced fertilization, farmers could save fertilizer inputs, and have the best of benefit. In same phenophase, the order of nutrient content in above-ground plant showed as:K>N>P. Nutrients accumulation of NPK treatment in Hua county was:N 232.7 kg/ha, P2O5 46.4 kg/ha, K2O 210.8 kg/ha, while in Mi Zhi was:N 170.4 kg/ha, P2O5 32.4 kg/ha, K2O 162.8 kg/ha. The total N, P2O5,K2O application rate in Hua County was 363,86,301 kg/ha recommended, while N, P2O5, K2O application rate in Mi Zhi County was 258,82,258 kg/ha.7. Evaluation of fertilization situation for grape and capsicum in Shaanxi provinceThe source, the rate of manure and chemical fertilizer in grape and capsicum fields were studied by using the investigation data (n=94) in Rougu, Heyang and Fengxiang county of Shaanxi Province in November,2008. The fertilization situation of grape and capsicum had been revealed and evaluated. The results were as follows:(1) Among 94 investigated households for grape, the ratio of N application was very high by 71.4%(>350 kg/ha); amount of P application was very high by 61.9%(>184 kg/ha); very low of K application was by 55.7%(<140 kg/ha). (2) The same as grape, input of chemical fertilizer was unbalanced badly in capsicum. The ratio of N application was higher by 40%, suitable by 44%, lower by 16%; amount of P application was higher by 93%, suitable by 6%, lower by 1%; K application rate was higher by 4%, suitable by 63%, lower by 33%. (3) There were remarkable differences of nutrient input among the households, and the rate of fertilizer application was also unbalanced. (4) The farmers usually use fertilizer with conventional experience. (5) The rate of manure was low. The farmer should decrease the N, P application rate, while increase K application rate.
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