長期連用同樣肥料對於土壤化學性質與稻谷收量之影響

Effects of Some Long-Term Fertilizer Treatments on the Chemical Properties of Soil and Yield of Rice

林家棻(C.F. Lin) ； 李子純(T.S. Lee Wang) ； 張愛莘(A.H. Chang) ； 陳卿英(C.Y. Cheng)

《中華農業研究》 22卷4期 (1973/12) Pp. 241-262

https://doi.org/10.29951/JARC.197312.0001

摘要

本文之目的在探討長期施用同樣肥料對於稻田土壤化學性之變異，肥料要素在土壤之消長與位移，以及對於稻谷收量之影響。土壤樣本乃探自本所圃場自民國13年(1924)以來舉辦之長期肥料試驗。其中設12種不同配合之肥料處理，包括硫酸錏、過磷酸鈣、硫酸鉀、石灰、大豆粕、堆肥及綠肥等。48年來共施硫酸錏、過磷酸鈣、硫酸鉀、石灰以N, P, K．及Ca計算時，各爲8,370, 3,657, 6,952及35,241 kg/ha,堆肥、綠肥、大豆粕各以N計時，則各爲8,370 kg/ha。所得結果扼要報告如下：
(1)以三要素與無肥區比較時，在48年來施下肥料中，被水稻移去之N爲施用量的25~28%, P爲18%，K爲40%, Ca爲5%。蓄積於土壤中者，氮爲施用量的4.3%， P爲55%，K爲0.4%，及Ca爲1.4%（以三要素加石灰區與三要素區比較者）。
(2)底土中所含全磷、Fe-P、全鉀、固定鉀、交換性鈣、鎂以及游離鐵與有效矽酸等均顯然高於表土。顯示在稻田強烈淋滲之下，肥料向底土位移，或位移於底土以下，即使磷肥亦不例外。
(3)長期施用硫醉錏對於表土之pH與鹽基飽和度與無肥區比較時，差異仍不顯著。顯示在稻田情形之下，鹽基之淋失雖然甚烈，但土壤礦物之風化可能亦甚速，淋失的鹽基容易獲得補充而達到平衡。
(4)從稻谷收量顯示稻田不宜偏施硫酸錏、過磷酸鈣、或硫酸鉀等單質肥料，必須施用三要素完全肥料；但化學肥料只能維持地力，欲求高產，增進肥力，更須兼施堆肥，因堆肥可增加表土中氮可礦物化能量(N mineralization Potential)，及礦物化速率(Rate of N mineralization)，同時並可增加表土有效矽釀含量；堆肥與過磷釀鈣併施，復可顯著地提高土壞的陽離子交換能量及磷的釋放速率，藉以減少鹽基的淋失與磷的被固定作用。

並列摘要

A 48-year field trial with lowland rice has been conducted since 1924 on an acid alluvial to evaluate the effects of fertilizer treatments on the soil chemical properties, nutrient accumulation, nutrient movement, nutrient removal, and yield of rice. The twelve fertilizer treatments involved in the experiment are : (1) complete inorganic fertilizer, (2) ammonium sulphate, (3) calcium superphosphate, (4) potassium sulphate, (5) farmyard manure, (6) green manure, (7) soybean cake and superphosphate, (8) farmyard manure and superphosphate, (9) green manure and superphosphate, (10) green manure and lime, (11) complete inorganic fertilizer and lime, and (12) check, without fertilizer or manure.
This experiment was suspended during 1943-1945, and resumed in 1946. Soil samples were taken just after the harvest of the first crop of 1972. The total amounts of P, K, and Ca added as calcium superphosphate, potassium sulphate, and lime plus superphosphate in the 48 years are 3.66, 6.95, and 35.24 tons/ha, respectively. While the amount of ammonium sulphate, soybean cake, green manure and farmyard manure calculated on the basis of N is 8.37 tons/ha for each of them. The results may be summarized as follows
1. By comparing the nutrient uptake between NPK-plot and check plot, the removals of N, P, K, and Ca by rice crop as the percentage of those added in the past 48 years are 25-29%, 18%, 40% and 5%, respectively.
2. The nutrients accumulated in the 35-cm depth of soil profile including surface and subsoil as percentage of those added are 4.3% for N, 58% for P, 0.4% for K, and 1.4% for Ca.
3. The contents of total P, Fe-P, total K, fixed K, exchangeable Ca and Mg, free iron oxide, and available silica in the subsoil are unanimously higher than those in the surface soil. It indicates that the build-up of fertility status in the soil profile through application of fertilizers is very difficult under flooded condition. Even superphosphate tends to move downwards. On the contrary, the degree of base saturation and pH of the soil do not decrease appreciably even by long-term application of ammonium sulphate alone It may be due to the supply of soil bases under flooded condition better than those in the upland soil through quicker weathering of soil minerals.
4. So far as the yield of rice is concerned, single application of ammonium sulphate/ calcium superphosphate/potassium sulphate gives yield significantly lower than complete inorganic fertilizer. Addition of lime to complete inorganic fertilizer does not cause great increase in yield especially in the later period (1946-1971). Addition of lime to green manure shows the same effect. It is interested to note that the best yield has been given by farmyard manure with superphosphate throughout the 43 years. It is due probably to the fact that farmyard manure has shown favorable effects on soil N mineralization potential, rate of N mineralization, liberation of soil phosphate and availability of soil silica. In addition, the cation exchange capacity has also been significantly increased by the combined application of farmyard manure and superphosphate. It is, thus, concluded that the addition of farmyard manure with complete inorganic fertilizer is indispensable for increasing productivity of paddy soil.