| Rapeseed-rice rotation is one of the dominant cropping systems in the Hubei province. In recent years, as the breeding, the ameliorating and the applicating of quality varieties making the yields of rapeseed and rice increase, the original fertilization system could not meet the needs of the development of the current production level, therefore, the research of hign fertilization model of crops under the current level of productivity will be of great significance to increase the continued yield of rapeseed and rice, maintain soil fertility and ameliorat soil. This paper studied the effects of application of N, P, K, B, Zn fertilizer on the yield and economic profit of rapeseed and rice, and the effects of N application on the nutrient accumulation and distribution, soil fertility and nutrient balance in rapeseed-rice rotation by the way of field experiment. On this basis, we had studied the nutrient accumulation regularity of rapeseed and rice and the Changing Charateristics of soil nutrient. By the way of combination of field and pot experiments, the research investigated the effects of combined application of N, P, Zn on rice yield and quality, and the physiological mechanisms which were closely related to yield effect. The main results were as follows:1. Effects of N, P, K, B, Zn on crop yield in experiment areaIn this experiment, in rape growth reason, the application of N, P, K, B significantly increased rapeseed yield, when fertilizing N 90～360 kg/hm, P2O5 90 kg/hm2, K2O 120 kg /hm2, Borax 15 kg/hm2, rapeseed yield would increase as 875～2051 kg/hm2,788～1288 kg/hm2,250～612 kg/hm2,475～650 kg/hm2 respectively, while the application of Zn reduced rapeseed yield, when fertilizing ZnSO4·7H2O 30 kg/hm2, the rapeseed yield would decrease as 51～347 kg/hm2. In rice growth reason, the application of N, P, K, Zn significantly increased rice yield, when appling N 90～360 kg/hm2, P2O5 45 kg/hm2, K2O 60 kg/hm2, ZnSO4·7H2O 45～90 kg/hm2, rice yield would increase as 1000～2251 kg/hm2,1376 kg/hm2,1626 kg/hm2,376～1376 kg/hm2 respectively.2. The average nutrient requirements of production of rapeseed and rice per 100kgIn this experiment, the rapeseed yield with fertilizing N 180 kg, P2O5 90 kg, K2O 120 kg, Borax 15 kg per hectare and the rice yield with N 180 kg, P2O5 90 kg, K2O 120 kg, ZnSO4·7H2O 45 kg per hectare were the highest among all treatments in rapeseed-rice rotation, compared with the FFP fertilizing treatments, the rapeseed and rice yield averagely increased 413 kg/hm2,1125 kg/hm2 respectively. At this time, the average nutrient requirement of production of rapeseed per 100 kg:N 4.73 kg, P2O5 2.29 kg, K2O 12.68 kg, CaO 4.82 kg, MgO 0.87 kg, Fe 35.55 g, Mn 7.78 g, Cu 2.87 g, Zn 6.86 g; rice per 100 kg:N 1.17 kg, P2O5 0.77 kg, K2O 3.85 kg, CaO 0.42 kg, MgO 0.41 kg, Fe 19.48 g, Mn 68.57 g, Cu 4.24 g, Zn 9.27 g.3. The dynamic changes of dry matter and nutrient accumulation under different N fertilization in rapeseed-rice rotation systemThe result showed that the concentration of rapeseed N, P, K with N application appeared rising trend from overwintering to bud period, then showed sharply decreased trend after bud period until the end of maturing period in which the content of N, P, K reach minimum value. The concentration of rice N, P, K showed fluctuant descend trend in the whole rice growing period. The accumulation amount of dry matter and nutrient increased with the crop growing. The rapeseed dry matter and nutrient in seeding stage accumulated quite gently, which accumulated rising rapidly after bolting, the accumulation amount of N, K, Ca, Mg, Fe, Mn presented downward trend after fiower period, while the dry matter and P, Cu, Zn showed rising trend until the end of maturing period. The accumulation of rapeseed dry matter and N, P, K mainly concentrated in peduncle growing- flowering preiod, in which the accumulation amount of dry matter, N, P and K accounted for 41.17%～46.01%,42.19%～77.18%,48.22%～74.39%,60. 15%～87.32% of total accumulation amount respectively. The dry matter and nutrient accumulation amount of rice presented rising trend from seeding stage to heading stage, in the grouting strong period, the N, Ca, Mg, Fe accumulation amount had downward trend, while dry matter, P, K, Cu, Zn accumulation amount kept rising trend until the end of maturing period. The accumulation of rice dry matter and N, P mainly concentrated in jointing-heading preiod, in which the accumulation amount of dry matter, N, P accounted for 50.99%～61.75%,53.73%～61.73%,50.40%～69.29% of total accumulation amount respectively, while K concentrated in seeding stage and tillering stage, in which the K accumulation amount accounted for 43.51%～55.51% of total. In the whole growth period, the accumulation amounts of dry matter and nutrient with N application were more than the control.4. The distribution of crop nutrient after maturity under situation of rapeseed-rice rotationN 41%～76% and P 59.87%～73.05% of rapeseed, N 67.93%～76.07%, P 78. 00%～93.31% of rice mainly distributed in the seed, K 49.49%～53.99% of rapeseed and K 80.13%～84.47% of rice mainly distributed in the stems, in addition, the accumulation amounts of rapeseed Mg, Mn, Zn and Cu of rice mainly distributed in the seed, Fe accumulation of rapeseed and Ca, Mg, Fe, Mn, Zn of rice mainly distributed in the stem, while Ca, Mg accumulation of rice mainly distributed in the pod. The results in maturity showed N application enhanced the content and accumulation of every part of rapeseed and rice and influenced the distribution of nutrients.5. The changing characteristics and balance of soil nutrients in rapeseed-rice rotationIn the whole rapeseed-rice rotation, whether appling nitrogen or not, the contents of soil nutrient showed a fluctuating change process. After rapeseed season, compared with the foundation soil, the contents of total nitrogen(TN) and alkali-hydro nitrogen(AN) increased 16.96%～34.74%,17.53%～47.63% respectively, the available potassium (Ak) content decreased 17.57%～33.97%, in addition, the contents of soil available Ca, Mg, Zn increased, while the available Mn, Cu decreased. Compared with the control, N application increased the content of soil TN 12.79%, AN 68.35%, reduced AK 7.57%, which also increased the contents of available Fe, Mn, but reduced the contents of available Cu, Zn. After rice season, compared with foundation soil, the contents of soil TN, AN with N application increased 7.86%～17.54%,4.81%～16.84% respectively, AK reduced 12.30%～24.60%, moreover, the contents of available Cu, Fe, Zn of all treatments increased, while available Mn reduced. N application increased the contents of soil AN, TN and available Mn, available Fe, available Cu, but reduced the contents of soil available K, available Mn, available Zn.From the balance of soil nutrients in the whole rapeseed-rice rotation perspectives, the farmland soil N elements with N application were in the surplus state, which the surplus quantities increased with the increases of N fertilizer application. The soil P elements with fertilizing N 0～180 kg/hm2 were in the surplus state, but with fertilizing N 270～360 kg/hm2 were in the deficit state, The soil K elements of all treatments were in the deficit state, which the deficit quantities were increasing with the increases of N fertilizer application. In all, reasonably increasing nitrogen application could make the soil N surplus, P basic balance, K deficiency.6. Effects of combined application of N, P, Zn on rice yield and quality under field trial in rapeseed-rice rotationThe result indicated that combining application of any two or three of N, P, Zn could increase the yield, the contents of protein and amylose in some extent. Among the three fertilizers of N, P, Zn, the effects on the yield, the contents of protein and amylase could be in the order of N>Zn>P. Appling N, P feitilizers properly and improving the zinc fertilizer increased rice yield and improved grain quality. In this experiment, fertilizing N 180～270 kg, P2O5 60 kg, ZnSO4·7H2O 120 kg per hectare can significantly improve rice yield, increase the contents of rice protein and amylase.7. In post experiment, effects of combined application of N, P, Zn on rice physiological and biochemical index in rapeseed-rice rotationThe results indicated NR activity (R2=0.8178**), CA activity (R2=0.8685**), the content of chlorophyⅡ(R2=0.7658**) of rice leaves, the root acyivity (R2=0.7683**) and the rice yields of different treatments showed a well significantly positive correlation, but the SOD activity (R2=0.6935*) showed a significantly negative correlation. Combining application of N, P, Z fertilizer properly not only improve the rice CA activity, root activity, but also promote rice to mature early to some extent, which make rice product higher yield. |
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