| Currently, the main measure in improving the outputs of agriculture and forestry products was by using chemical fertilizer, which resulted in soil harden, soil degradation, and environment pollution. Up to date, the government has requested for development of green agriculture and protect cultivation soil. The application of green manure might change the development and improvement patterns of agriculture, and indicate the direction for sustainable development of agriculture. In present study, the dominant economic tree in the red soil areas of Southern China, Camellia oleifera Abel, was chosed as the research subject, the potassium-rich species Amaranthus hypochondriacus Linn. was planted for returning green manure. In order to study the decomposition rule of potassium-rich green manure A. hypochondriacus Linn. and understood the effect of green manure application on growth and soil of C.oleifera Abel and to provide the theoretical basis for sustainable management of C.oleifera Abel, an experiment was carried out in Jiangjia forest farm in Wannian Jiangxi China. The main results were as follows:(1) At budding stage, A.hypochondriacus Linn. had high decomposing speed and less residual amount of dry matters, returning on the soil surface or underground the release rate was 68.18% and 71.11% respectively, both had the equivolent decomposing speed of dry matter. A.hypochondriacus Linn. at budding stage had fast releasing of nitrogen(N) and potassium(K), and low speed in phosphorus(P). while at mature stage, the decomposing speed was slowdown with mass of residual dry matters, the fertilizer effect of returing underground was better than that returning on the surface soil, the release rate was 70.66% and 54.05% respectively. The release of N and K was lower than that application at the budding stage, but the release of P was relatively high.(2) Our results showed that the application of A. hypochondriacus Linn. as green manure could increase the soil fertilizer. Either used at budding or mature stage, application of A. hypochondriacus Linn. could significantly increased the contents of available P(p<0.01), soil organic matter(p<0.05) and total N(p<0.05), while no significance in improvement of soil avaiable N and P(p>0.05). Treatment GF1(applied in June and August) showed best perfermence in the improvement of soil nutrients, while the control group GF0 had the lowest soil nutrients. The contents of total N and availabe N in 0~20 cm soil layer and organic matter in 20~40 cm soil layer showed significant difference among the treatments, but the contents of available P have no difference between the 0~20 cm and 20~40 cm soil layers.(3) Application of A. hypochondriacus Linn. could significantly increased the activities of catalase, acid phosphorus and urease in soils but had no improvement on sucrase. The soil enzyme activities of treatment GF1, application of A.hypochondriacus Linn. in Jun and August, were relatively higher than that of other treatments. Except for the soil acid phosphatase, the activities of catalase, surase and urease were higher in the upper layer of soils than that in the dipper layer soils. Correlation analysis indicated that there was a significant positive correlation between the activities of soil enzyme and contents of soil nutrients, while no significant difference between the activities of phosphatase, surase and nutrients of soils, and there was a negative correlation between the activities of surase and the other three enzymes, and between the activities of surase of soil nutrients.(4) The results indicated that application of A. hypochondriacus Linn. could effectively maintain the soil water of C.oleifera Abel. The soil volume moisture in 0~10 cm soil layers in all applications were lower than that in the control treatment, but higher in 10~40 cm soil layer than that in the control group. Among all the treatments, the soil volume moisture of 10~40cm soil layers from high to low ranked as GF1(applied in June and August) >GF0(applied in June) >GF2(applied in August) >G0(control), the soil volume moisture in the application groups were significantly higher than that in the control group.(5) Application of A. hypochondriacus Linn. could increase the soil respiration of Camellia oleifera Abel, and the peak of soil respiration appeared in June and it went down overtime, and no significant difference was observed among these treatments. Meanwhile, the application of A. hypochondriacus Linn. decreased the relationship between soil respiration and soil tempreture, but increased the relationship between soil respiration and soil water content, especially with the water contents at 10~20 cm.(6) Application of A. hypochondriacus Linn. could significantly increase the height, ground diameter and grown width of C.oleifera Abel, but have no obvious effects on leaf area, SPAD, the length of spring shoot and spring shoot diameter. The result of synthetic evaluation by fuzzy membership function showed that treatment GF1(applied in June and August) have the most positive impact on the growth of C. oleifera Abel. In the first year, the application of A. hypochondriacus Linn. had limited improvements on the contents of N and K in leaves; while in the second year, difference of the contents of N and K in leaves were observed, treatment GF1 has the best performance in enrichment of N and K contents in leaves, with increaments of 3.29% and 40.43% than that in the control treatment, respectively; after two year's application, no significant difference of nitrogen and phosphorus in leaves were observed.(7) Application of A. hypochondriacus Linn. could increase the yield of fruit and oil rate of C.oleifera Abel, the kernel and fresh oil rate in the application treatments were higher than that in the control treatment. When compared to the control group, the kernel oil rate of GF0, GF1, GF2 have an increament of 1.49%, 2.54%, 3.86% respectively, and the fresh oil rates increased by 6.17%, 3.31% and 6.89% respectively, but no significant difference of kernel and fresh oil rate. The average yield of GF0 and GF1 relative higher, could increase 31.08% and 8.78% respectively when compared to G0.(8) In conclusion, it's better for A. hypochondriacus Linn. application at both budding and mature stages in the typical red soil region of south China. While in practice, it is better to apply phosphorus fertilizer when application of A. hypochondriacus Linn. as green fertilizer, beacuse the A. hypochondriacus Linn. contains low concentration of phosphorus. |
PDF Full Text Request