臺灣水稻田施肥與稻穀增產關係圖解

Graphical Studies of Rice-Fertilizer-Yield Relations in Taiwan

黃達河(T. H. Huang)

《中華農業研究》 1卷3期 (1950/09) Pp. 13-23

https://doi.org/10.29951/JARC.195009.0002

摘要

1．本文以圖解方式分析臺灣水稻田肥料要素施用率與稻殼施肥增產值及可得各級增產值水稻田百分比的關係，製成有關曲線圖4幅，並另製一圖說明肥料換殼比何與肥料要素含量及肥料要素臨界增產值的關係。
2．從圖表分析得知臺灣各地水稻田施肥效應差異很大，施用肥料要素有減低稻穀產量可能，此可能性施N時最小，施P2O5或K2O時較大。
3．第一明作N的增產效應最大，P2O5的較小，K2O的更小；第二期作增產效應亦以N爲最大，但不及第一玥作時，P2O5和K2O的效應卡分接近，然皆不及第一明作P2O5效應。
4．文中五圖可以配合應用；可用以估計在若干已知條件之下，什麼是合理的肥料要素施用率？有若干稻田可以施肥？肥料換穀比例多少才算合理？全省稻田一共需要多少化學肥料？除此以外，尚可用以解答某種情形之下其他未知數值。

並列摘要

1. In light of the results of rice fertilizer experiments in Taiwan, graphical studies ars made of the response of rice to added plant food at different levels of plant food addition and also the relation of fertilizer-rice barter ratio to fertilizer grade and ”critical” yield increment of rice. The later term is defined as the cost of each kg. of plant food, expressed as number of kg. of hulled rice.
2. The experiments were carried out in the period 1930-1942 in 118 localities distributed throughout the entire Island. The time of experimentation varied from one to four years. In all the experiments, the farming practice of the local farmers was followed closely. Fertilizers used were ammonium sulfate, calcium superphosphate and potassium sulfate. Rates of plant food addition studied, in kg. per hectare, were 40, 80, 120 and 160 for N and 40, 80 and 120 for P205 and K00. Rice response to one of these essential elements was studied, while 80 kg, per hectare of each of the other two elements had been added.
3. Available data are reca'culated to show the response of rice to added plant food, expressed as .increase of hulled rice in kg. per kg. of N, P2O5 or K2O added. Curves are plotted for different rates of plant food application to show the percentages of localities investigated (data of which are available) giving various levels of minimum yield increment of hulled rice. These curves are replotted to show the relation between the rate of plant food application and the level of minimum yield increment, for different percentages of the localities studied (data availab'e), which. vary in steps of 10%.
4. These curves show that there is a significant difference in rice response to added plant food between the localities studied. The curves also show that plant food addition might bring about decrease in yie1.d of rice; such probability is least with N, but comparatively higher with P2O5 and K2O. For the first rice crop, N gives the highest response, that of P2O5 comes next, and that of K2O is the lowest. For the second rice crop, N still gives the highest response, but not as high as that for the first rice crop; responses of P2O5 and K2O are close to each other, but less than that of P2O5 for the first rice crop.
5. The ”critical” yield increments of hulled rice are plotted vs. 100 times the reciprocals of fertilizer grades (% N, P2O5 or K2O) for various fertilizer-hulled rice barter ratios (or price of 1 ton fertilizer expressed as tons of hulled rice). A set of straight lines results.
6. With the help of the five diagrams presented, it is feasible to estimate that under certain known conditions:
(1). What should be the rates of plant food application for the first and second rice crops?
(2). How much rice fields might be fertilized?
(3). What should be the correct fertilizer-hulled rice barter ratio?
(4). How much fertilizers ars needed for the first and second rice crops?