不同施肥管理對經八年水旱田輪作系統的玉米與水稻產量及養分吸收的影響

Abstract

本研究目的在於探討經八年長期玉米－水稻輪作系統下之土壤，施用不同量與不同種類氮肥對不同生長時期玉米與水稻生長及養分吸收，和土壤中養分有效性的影響。試驗共有七種處理，分別為，1. 對照區 (CK)，2. 化學氮肥區 (Chem-N)，3. 堆肥區 (Comp)，4. 堆肥額外添加化學氮肥區之化學氮肥量之三分之一(Comp + 1/3 N)，5. 堆肥額外添加化學氮肥區之化學氮肥量之三分之二 (Comp + 2/3 N)，6. 綠肥額外添加化學氮肥區之化學氮肥量之三分之一(GM + 1/3 N)，7. 泥炭額外添加化學氮肥區之化學氮肥量之三分之一 (Peat + 1/3 N)。除對照組外，其餘處理皆施相同量的磷肥與鉀肥。每處理四重複，採逢機完全區集排列。分別採玉米膝高期、雄穗抽出期、成熟期及水稻分蘗盛期、幼穗形成期、開花期、成熟期的植株，分析植體中總氮、硝酸態氮、銨態氮、不溶性氮、磷、鉀、鈣、鎂、鐵、錳、銅、鋅含量，和土壤基本理化性質。 結果顯示，玉米成熟期乾物質產量以Comp + 2/3 N處理者最高，水稻則以Chem-N處理者之乾物質產量最高。玉米及水稻的氮吸收量皆以Chem-N與Comp + 2/3 N處理者顯著高於其他處理者。與Chem-N處理比較，種植玉米添加有機資材的施肥處理，在成熟期皆增加作物對磷的吸收量，其中以Comp + 1/3 N處理者最高，可能是因添加堆肥使得土壤中的有效磷含量增加。在成熟期水稻磷的吸收量則是以Chem-N處理者最多，除了對照組外，其餘各處理間差異不顯著。在施加堆肥的不同化學氮肥處理下，隨化學氮肥增加，玉米的鉀吸收量也增加，而水稻則在生長後期之效應較顯著。一般而言，不同處理對於玉米及水稻不同生長時期之鈣、鎂、鐵、錳、銅與鋅吸收量的影響，在統計上並不顯著。 關鍵字：玉米、水稻、輪作系統。

The purpose of this study was to study the effects of nitrogen (N) fertilization management on the growth and nutrient uptake of rice and corn plants under corn-rice rotation system for eight years. There were seven treatments, which included: 1. check (CK); 2. chemical nitrogen fertilizer treated-plot (Chem-N); 3. compost treated-plot (Comp); 4. compost combined with additional one-third amount of N fertilizer as Chem-N treatment (Comp + 1/3 N); 5. compost combined with additional two-thirds amount of N fertilizer as Chem-N treatment (Comp + 2/3 N); 6. green manure combined with additional one-third amount of N fertilizer as Chem-N treatment (GM + 1/3 N); 7. peat combined with additional one-third amount of N fertilizer as Chem-N treatment (Comp + 1/3 N). The application rates of chemical fertilizer treated plot for corn and rice plants, were 140-80-80 kg ha-1 and 120-60-60 kg ha-1 for N, P2O5, and K2O, respectively. The same amount of superphosphate and potassium chloride as Chem-N plot were applied in all organic fertilizer treated plots. The treatments were replicated four time and arranged in randomized complete block design. Corn plants were sampled at knee high, tasseling, and maturity stage and rice plants were harvested at the most active tillering, primordial initiation, heading, and ripening stages, respectively. The concentrations of total N, ammonium N, nitrate N (for corn plants), insoluble N, phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), manganese (Mn), copper (Cu), and zinc (Zn) in the various parts of the plants were determined. Some selected soil chemical properties before and after the harvest of the plants were also determined. The results showed that the dry matter yield of corn plants at maturity stage of the Comp + 2/3 N treatment was the highest among the all treatments. However, the dry matter yield of rice plants of Chem-N treatment was the highest at maturity stage. The amount of N absorption of Chem-N and Comp + 2/3 N treatments for both corn and rice plants were higher than that of the other treatments. Owing to the higher rate of P was applied in organic fertilizer treated plots, the absorption of P of these plots was higher in corn plants at maturity stage as compared with the Chem-N treatment and the highest amount of P uptake occurred in Comp + 1/3 N treatment. The Chem-N treated rice plant had the highest amount of P uptake at maturity stage. There was no significant difference in P uptake among the fertilized rice plants. The K uptake of corn plant increased with the rate of N applied in the compost treated plots. This also occurred in rice plant significantly at the maturity stage. In general, the effect of treatments on the uptake of Ca, Mg, Fe, Mn, Cu, and Zn was not statistically significant for both corn and rice plant at different growth stages. Key words: corn, rice, rotation system.