農業と科学　2021/11

本号の内容

§ブロッコリー栽培におけるマイクロロングトータルのセル苗施用効果
Chiba Prefectural Agriculture and Forestry Research Center
水稲畑地園芸研究所 東総野菜研究室
竹内　大造
(Currently: Kaeso Agricultural Office, Extension Division)
§先人が築いた坂井農場（第１回）
〜120 Years of History - A Look Back at the Transition of Varieties, Fertilizers, etc. as Reflected in the Transcripts
JA福井県 坂井農場
前 農場長　長谷川　彰
§土のはなし−第６回
よい土の条件　化学的性質−その１
土の酸性度（pH）
Jcam Agri Co.
北海道支店 技術顧問
松中　照夫

　

　

Effects of cell seedling application of Micro Long Total in broccoli cultivation.

Chiba Prefectural Agriculture and Forestry Research Center
水稲畑地園芸研究所 東総野菜研究室
竹内　大造
(Currently: Kaeso Agricultural Office, Extension Division)

Introduction.

　In Chiba Prefecture, the cultivation of autumn-winter broccoli, which is harvested from November to February, is spreading due to the relatively mild winters in the Kanto region, and there are examples of cultivation not only in the fields but also in the mid-mountainous areas, such as backcropping in paddy fields.
　However, the planting period of cell-molded seedlings is short due to root clogging and lack of nutrients because of the limited capacity of the culture medium for cell-molded seedlings. On the other hand, in the fall/winter broccoli crop, planting is often delayed due to unseasonable weather conditions in addition to competition with rice harvesting. This has led to the extension of the seedling growing period and the planting of seedlings past the optimum time for planting, which has caused problems such as shortening of the seedlings due to additional fertilization to restore vigor and poor establishment due to over-formation of the root pots.
　In order to expand the planting time of cellular seedlings, we conducted a test on the promotion of seedling growth by box application of a coated fertilizer (Micro Long Total).

About Super Cell Seedlings

　The following is an introduction to supercellular seedlings, the premise for the tests conducted by the author. There are a variety of knowledge on broccoli cultivation trials, and in particular, the "supercellular seedling" technique developed by Tokushima Prefecture has been proven to be useful in many areas. Supercell seedlings are cell-molded seedlings that have been grown for a long period of time (more than 40 days) using only water, instead of the usual 30 days or so, and not only can they be prevented from growing tall, but they also have improved drought resistance, disease resistance, and insect resistance (Photo 1). On the other hand, there are reports that the seedlings take longer to become established, and that their growth is inferior to that of seedlings planted at the appropriate time within about 10 days after planting.

Post-planting growth promotion using Micro Long Total

　千葉県農林総合研究センター水稲・畑地園芸研究所東総野菜室の場内露地圃場（淡色黒ボク土)において試験を行った。供試品種は「むつみ」(㈱ブロリード）で，平成29年7月25日及び8月15日に播種し，それぞれ育苗52日と31日にあたる9月15日に定植した。52日間育苗した苗は育苗期間中水のみで育苗し，定植前日に「くみあい微量要素入り被覆燐硝安加里肥料マイクロロングトータル280−40」を箱施用した（写真２) 。試験区は60g/セルトレイを施用した52日ML区と定植直前にも肥料の施用を行わない52日区を設けた（表１) 。また，31日間育苗した苗についても同様に31日ML区と31日区を設けた。

Results and Discussion

(1) Growth at and after planting

　The growth of seedlings at planting was surveyed in two replications of 10 seedlings per day on seedling boxes prior to planting. The results showed that seedlings with longer seedling days had higher plant height and leaf number (Table 2). One week after planting, regardless of the number of days of seedling growth, seedlings in the test area where MicroLong Total was applied tended to have higher grass height and more leaves than those in the test area where liquid fertilizer was applied. In addition, in 2009, Typhoon No. 21 caused tidal and wind damage, which could not be avoided in this trial.

(2) Growth at harvest

　平成29年は台風21号による潮風害が発生し，当試験においても影響が大きく，塩害による欠株が多発した。また，一時的に生育が停滞したため収穫開始日の遅れや収量の低下が予想された（写真３) 。

　収穫時の生育を表３に示す。52日ML区の収穫開始日は1月10日と最も早く，31日ML区と31日区が1月24日，52日区は2月7日であった。
　The 31-day ML crop was heavier than the 52-day ML crop, and the 31-day ML crop had the largest flower bud diameter. On the other hand, the number of harvested plants, which seemed to be greatly affected by the typhoon, was the highest in the 52-day ML (4,280 plants/10a).
　The percentage of plants harvested in each test plot by standard is also shown in Fig. 1).

　規格別割合では，L規格（花蕾径11cm以上）の花蕾が最も多かったのは52日ML区であった。また，育苗日数が同じ試験区で比較するとマイクロロングトータルを施用した区で販売不可となる株が少なく，収量が多い傾向であった。販売不可の初期生育が優れ，潮風害にあっても収量を維持でき，収穫日の遅れが軽減されることが示唆された。また，育苗期間中水だけで育苗した苗において大きな効果があることが推察された。
　This is thought to be due to the fact that the fertilizer content of Micro Long Total applied to the cell trays leached out around the root zone, allowing even supercellular seedlings with fully rotated rootpots to absorb the fertilizer content immediately after planting. In addition, when the seedlings were exposed to wind and tide damage, growth stagnated due to leaf damage and root wetness, but because MicroLong Total was applied, the fertilizer content leached out around the roots, which were less susceptible to moisture damage, at the base of the plants, and growth recovered quickly.

Conclusion

　In the study presented here, it was shown that the application of MicroLong Total to the seedling boxes of supercellular seedlings and their planting had a growth-promoting effect. It should be noted that the seedlings responded immediately to the elution of MicroLong Total and showed a tendency to grow taller, so the advantage of supercellular seedlings was lost if the seedlings were not planted immediately after application (Photo 4). However, since many of the seedlings did not adhere well to the soil surface and spilled out, 60 to 120 g/box was considered to be appropriate.

　In addition, as mentioned earlier, in 2017, the year in which this study was conducted, there was sufficient precipitation due to a typhoon that caused significant damage, and the temperatures after September 15, when the plants were planted, were near normal, presumably providing sufficient conditions for the elution of microlong total. It should be noted that the leaching rate would be different in a colder planting season or a drought year, so careful consideration should be given to how broccoli would be affected.

　

　

Sakai Farm built by our predecessors (Part 1)
〜120 Years of History - A Look Back at the Transition of Varieties, Fertilizers, etc. as Reflected in the Transcripts

JA福井県 坂井農場
前 農場長　長谷川　彰

　坂井農場の書庫には，明治35年1月発刊（第２報）以来，大正・昭和・平成・令和５代にわたる75冊の試験成績書が残されています。残念なことに激動の昭和時はかなり散失しているものの，福井県の農業技術，歴史の推移が窺える貴重な資料です。　　
　そして，この褐色に変色した成績書からは，農家が直面した課題に真正面から取り組んだ農場や先人・指導者の姿が浮んできます。
　発足以来，一貫しての取り組みは，県農会との連携による有望と思われる品種を実際に栽培し，良し悪しを検討した品種比較試験と肥料試験でした。ここでは，時代とともに坂井農場が取り組んだ内容と農業の流れについて紹介します。

History of Sakai Farm

　坂井農場は，県農会長・帝国農会長を務めた山田斂氏により坂井郡農会試験場として明治33年に開設されて以来，令和2年で120年目を迎えました。｢農家のための農場づくり」という山田氏の教えのもと，地域の指導農場として，当初から県農会農事試験場と連携した優良品種の確保や肥料効果試験等を行ってきました。
　大正時代には，より農家に密着した農場として，試験内容や技術指導について視察会を開催し，現在は農場参観デーとして継続されています。
　In 1933, His Imperial Highness Prince Takamatsu visited the farm and encouraged the farmers to increase food production. Later, during the postwar agricultural policy reform, the Agricultural Improvement and Promotion Law was enacted in 1948, and the prefecture was given the main responsibility for technological development in agriculture, and prefectural agricultural experiment stations were established and the experiment stations of agricultural associations in various regions were abolished. However, due to the strong enthusiasm of farmers, heads of agricultural cooperatives, and mayors of towns and villages, the farm was decided to be continued, and was transferred from the Agricultural Association to the Sakai-gun Agricultural Cooperative Liaison Council, followed by the Prefectural Agricultural Cooperative Central Association, the Economic Federation, JA Hanasaki Fukui, and since 2020 JA Fukui Prefecture has been in charge of its operation.

I. The Meiji Era The Meiji Era: Sakai County Agricultural Society Agricultural Experiment Station Period (1900-1945)

　明治時代前半（16年〜32年）の全国平均収量は210kg/10aと極めて低く，収量向上は正に緊急の課題でした。
　明治35年1月の成績書から，農場では，水稲，大豆，麦，小豆，油菜などが栽培され，いずれも品種試験が主体となっていることがわかります。明治35年と明治42年の水稲の取組みは，表１に示すとおり，品種に加え肥料試験が中心で，大陸からの大豆粕や北海道からの鰊粕など魚粕，人糞尿は，苗代に使用されていたことなど現在では考えられないような試験，有機農業が実践されています。人造肥料試験では日本肥料１号，日ノ出肥料，多木九重肥料など９品目が使用されています。
　明治37年2月に発行された成績書表紙の裏面には，日露開戦に伴う農業者に対する農商務大臣の演説要旨が記載され，当時の世相が偲ばれます。ここに，その要旨をほぼ原文に近い形で紹介します。

The biggest caution for farmers regarding the start of the war between Japan and Russia.

　The export of agricultural products accounts for 431 TP3T of total exports and 521 TP3T of total imports, and since exports are exclusively to Europe and the U.S., the impact of the outbreak of war has been enormous.
　○米麥（米麦）については，特に注意を。人類馬匹に欠かせない必須品。殊に戦時に在って供給が重要。然るには明治30年は虫害のため外国米を購入。明治35年は天候不順により300万石の減収のみならず翌36年産の麥も平年に比べ大きく減収。両年を通じ6975石の外国米を輸入。平時にありては輸入米の価格1000萬円を超えざるに，１年凶作あれば7000萬円の正貨が流出。明治36年においては4600萬石の豊作で今日の状態を保って今年にて若し凶作となると幾千万の正金が海外に流出するのは明らか。よって農民を鼓舞し以て豊収を得ざるべし。麥は，平年1900万石なるに不幸にして，明治36年は稀なる凶作に依り麥粉の輸入が増加。これに加え現今馬糧不足にして，大麥１石に付き５割以上騰貴をみる。昨冬は幸いにして，麦作を害すべき天候でなく今後は人力を尽くし平年を超える収穫を得んと望む。農産の増収を計らざるに幾多障碍の前程に横たわるものあり，即ち本年は豊作の翌年にして，田地の養分平常より欠乏せること其の一，廉価にて多効ある大豆粕肥料の供給一時中絶せんとすること其の二，北海道鯡粕，肥料等の運搬分配上，遷延の恐れあること其の三，壮丁の徴募は為に労力の減少を來すこと其の四なりとす故に，内にありて生産に従事する者は十二分の勤勉を以って当たること。最も注意すべき事項は，第一害虫の豫防駆除にして本年は貴重の穀物一粒も浸食せらざるの用意あるべく，第二肥料については，田畑の麥間に大豆，豌豆等の豆科植物を蒔き青刈りして緑肥に今秋至っては紫雲英などを普及し堆肥の製造を増加改良し肥料の供給を豊富ならしむべき，第三麥作収穫の時期を誤らず乾燥を完良ならしむべし，其他先般本大臣の農会に論達せし事項は励行を期せらるべし。
　The speech outlines the following issues: (1) the eradication of pests and diseases, (2) the increase of fertilizer supply by sowing legumes, green manure, and Chinese beans, (3) the timely harvesting and drying of wheat, in order to improve self-sufficiency in rice and wheat, amid concerns about the decline in soil fertility due to the previous year's bumper harvest, the interruption of soybean meal fertilizer supply from the continent, the uncertainty of fish meal supply from Hokkaido, and labor shortages due to the draft. (3) Ensuring and improving yields through timely harvesting and drying of wheat.

(1) Outline of variety testing, etc. (mainly local native species)

　In the paddy rice variety trials in 1902, 14 varieties were cultivated, including "Machiya," "Omi," "Sekitori," and "Ishiuzu," which were collected from Ishikawa, Toyama, Niigata, Shiga, and other prefectures in addition to varieties grown in the region.
　At that time, the transplanting period (June 8) and maturity period (September 29-October 20) yielded 345-420 kg/10a in variety trials. At the end of the Meiji period (1868-1912), 15 promising native varieties from inside and outside of the prefecture, such as "Oba," "Ishiuzu," "Nabeshima," "Shioda," and "Ecchu Boshu," were planted, and seeds for wheat and soybeans were ordered from various regions of Japan. 15 wheat and 20 soybean varieties were also planted, in search of better varieties. In 1911, the main varieties grown in Fukui Prefecture were "Shirachinji" (61 TP3T of the total area planted), "Oba" (51 TP3T), and "Ippon" (51 TP3T), and many other varieties.

(2) Outline of fertilizers (mainly soybean meal and kernels)

　Looking at the paddy rice application standards in 1902, superphosphate lime was widely distributed as nursery fertilizer (straw ash, human manure) and main field fertilizer (soybean meal, kurikiri), and in 1909, nursery fertilizer (straw charcoal, seed meal, ammonium sulfate) and main field fertilizer (soybean meal, compost, superphosphate lime). The prices of the various materials listed in the report indicate that the fertilizer cost as a percentage of rice income was 321 TP3T, which was quite high. Incidentally, in 1902, the cost of fertilizers per 1 tan was 1.90 yen for 10 kan of soybean meal and 3.10 yen for 10 kan of kiri, for a total of 5 yen, and the price of rice was 4.96 yen per bale.
　In 1911, with the development of the chemical industry, ammonium sulfate was introduced and used as a supplementary fertilizer for seedlings.

II. Taisho Period (1912-1926)

　明治33年から明治44年までの10a当たりの全国平均収量は246kgと，懸命な努力にもかかわらず停滞気味でした。低収の原因は，肥料面から考えると，Ｎ成分の殆んどが有機肥料で天候に左右されやすく，肥効が不安定であることに加え，肥料が高価なため基準量が守られていなかったのではないかと考えられます。
　大正2年にも明治時代同様，水稲，大豆，麦等が栽培され，品種試験が主体となっていましたが，水稲では，優良種子を確保・供給するための採種田試験を新たに実施しています。肥料試験では，過燐酸石灰・石灰窒素・硫安などの単肥が出回り始め，元肥・追肥・穂肥などきめ細かく幅広い内容となっています。
　大正13年には，人口の急激な増加など社会的背景から麦，大豆の試験は実施せず，水稲への収量確保・向上に対する緊迫性，意気込みが感じられる内容に移りつつありました。また，経済合理性が重視されてきて，肥料試験においては，玄米代金より肥料価格を差引し経済的有利性を検証しています。
　Around 1921, the price of rice soared, causing rice riots in Toyama Prefecture and other parts of Japan. Rice was freely traded until the first half of the Taisho era (1912-1926), but to stabilize the rice market after World War I, the Rice Law was enacted, under which the government directly controlled a portion of the rice market.

(1) Outline of varieties, etc. (Consolidation of local native species)

　本時代の前半も，県内で栽培されている品種に加え，北陸地域や滋賀県から種子を取り寄せ試験をおこなっています。主な品種は『大場』『高砂』『鍋島』『神力雄町』など15品種で，移植時期（6月2, 3日）成熟期（9月15日〜10月21日）となっています。収量（270〜440kg/10a）は品種間でかなりのバラツキがあり，移植時期は早まっています。
　大正13年頃の種子は，主に福井県立農事試験場をはじめ県内各地から，また県外の種場産地富山県種田村からも取り寄せています。品種は『福井大場１号』『富山銀坊主』『銀坊主６号』『中生珍子45号』『赤珍子』など19品種が栽培され，『富山銀坊主』『赤珍子』などは，400kgを超えています。
　The main varieties in Fukui Prefecture in 1918 were "Oba" (241 TP3T of the total area planted), "Chinko" (171 TP3T), "Shioda" (91 TP3T), "Aikoku" (41 TP3T), and "Koso-ishiu" (31 TP3T), showing that the varieties were much more uniform than during the Meiji Period, when many varieties were grown.

(2) Outline of fertilizers (mainly soybean meal, widely distributed ammonium sulfate)

　According to the application standards in 1913, the standards were applied to nursery fertilizers (soybean meal, straw ash, and ammonium sulfate) and rice field fertilizers (soybean meal and straw ash). Soybean meal has been the main ingredient, and ammonium sulfate has been widely distributed. In addition, application standards for early, middle, and late maturity have been established, and more detailed guidance has been provided.
　The price of rice in 1924 was 15.30 yen per bale, nearly three times higher than in the Meiji era, and the cost of fertilizer (medium raw material) was 10.32 yen per 1 tan with 32 kan of soybean meal. The fertilizer cost as a percentage of rice income was estimated to be 14%, which was about half of that in 1902.

　

　

No Soil - Part 6
よい土の条件　化学的性質−その１
土の酸性度（pH）

Jcam Agri Co.
北海道支店 技術顧問
松中　照夫

　I believe that good soil for crop production is soil that meets the four conditions that I presented in the first article of this series (May issue). Of these four conditions, I have discussed two that relate to the physical properties of the soil. From this month, I would like to move on to the two conditions related to the chemical properties of soil. This month, I will discuss one of them, acidity (pH).

1. what is pH?

　First, let's talk about the term pH. pH indicates the strength of acidity or alkalinity. pH ranges from 0 to 14, with neutral being pH 7. A pH value less than 7 is acidic, while a pH value greater than 7 is alkaline. Originally, pH was calculated from the concentration of hydrogen ions dissolved in water (strictly speaking, the degree of activity). The higher the hydrogen ion concentration, the more acidic the water is, and the lower the pH value. Conversely, the lower the hydrogen ion concentration, the greater the pH value, and the less acidic (more alkaline) the water. This is a little different from common sense, so it is easy to get confused.
　For example, the difference between pH 5 and 6 is 1. The difference between pH 4 and 6 is only 2, but the hydrogen ion concentration is 100 times higher at pH 4.

2. pH conditions suitable for crop production

　In Japan, the optimum pH condition for good soil for crop production is in the range of 5.5 to 6.5, which is slightly on the acidic side. Of course, even within this range, the optimum pH varies slightly depending on the crop. For example, spinach, lettuce, chrysanthemum, and tomatoes prefer a pH closer to 6.5. On the other hand, balayasho (Japanese radish) prefers a pH closer to 5.5 for healthy growth, and radish and turnip are also tolerant of acidic conditions. Why is it that the optimal pH of soil in Japan is within this range? The reason is that Japanese soil tends to become acidic when left to nature.

3. factors causing acidification of Japanese soil

　So why does Japanese soil become acidic when left to nature? Two factors are mainly responsible: (1) rainwater and (2) chemical fertilizers, which are indispensable for crop cultivation. The two main factors are (1) rainwater and (2) chemical fertilizers, which are indispensable for crop cultivation.

(1) Acidification by rainwater

　Rainwater is not neutral at pH 7. In the process of falling from the sky, it dissolves carbon dioxide (CO2) from the atmosphere and becomes natural carbonated water. Its pH is about 5.6. Japan has more precipitation than any other country in the world, and this acidic water washes away the soil, causing it to tend toward the acidic side.
　However, rainwater is naturally carbonated water when it falls in ideal, clean, unpolluted air. In areas with severe air pollution, various air pollutants are present in the atmosphere, such as sulfur oxides, nitrogen oxides, and chlorides from the oceans. These substances are also dissolved in rainwater and chemically transformed into strongly acidic substances such as sulfuric acid, nitric acid, and hydrochloric acid, respectively. This results in rainfall with a pH lower than the ideal pH of rainwater (carbonated water) of 5.6. This is acid rain (snow and fog also become acidic through the same mechanism as rain). Even ordinary rainwater, when washed away from the soil over a long period of time, causes acidification of the soil. Needless to say, acid rain (snow and fog) accelerates soil acidification.

(2) Acidification by chemical fertilizers

　The second soil acidifying factor is chemical fertilizers. Chemical fertilizers are chemically manufactured crop nutrients. While they themselves may provide nutrients to crops, they do not have any specific detrimental effects on crops. However, if chemical fertilizers are not used properly, they can have a variety of negative effects. Acidification is one of them.
　However, not all chemical fertilizers acidify the soil to the same degree. Urea, for example, is decomposed by microorganisms in the soil and then converted to ammonia for use by plants. Therefore, it acidifies the soil to a lesser degree than other fertilizers. Ammonium nitrate (ammonium nitrate) and ammonium phosphate (ammonium phosphate) are also members of this class of fertilizers.

4. why soil acidification is bad for crop growth

　The activity of soil microorganisms and the availability of nutrients to crops are greatly affected by soil pH (Figure 1). Table 1 summarizes the effects of soil acidification (low pH) on crop growth. Basically, soil acidification has a negative effect on crops. The most serious problem is that acidification causes aluminum, iron, manganese, and other elements to dissolve into the water in the soil (soil solution), which in turn damages crops.

　アルミニウムは，通常，土の中の粘土鉱物の結晶を構成して存在している。ところが土の酸性化によって増えた水素イオンは粘土鉱物の結晶を破壊し，結晶を構成しているアルミニウムを土壌溶液に溶けている各種の陽イオンと入れ替わることができる形態（交換性アルミニウム）に変化させる。このため，pHが5程度より低下すると，急速に土壌溶液中のアルミニウム濃度が高まる（図１) 。土壌溶液の高アルミニウム濃度は，作物の根の細胞に直接障害を与え，養分吸収を阻害する。アルミニウムだけでなく，土の中に多く含まれている鉄やマンガンも，酸性化すると急に土壌溶液に溶け出していく（図１) 。鉄やマンガンは，アルミニウムとちがって作物の必須養分である。しかし，土が酸性になって過剰に溶け出すと，作物に過剰吸収害を与え生育に悪影響を与える。
　Even more inconvenient is the fact that aluminum and iron are strongly bound to phosphorus, and the combined aluminum and iron phosphates are almost insoluble in water. This makes it difficult to absorb the phosphorus that is fed as fertilizer, and crops are prone to phosphorus deficiency.

5. proper acid amendment of soil as well.

　You cannot tell its pH just by looking at the soil. It is practical to have the soil analyzed by soil diagnosis. If the analysis shows that the pH is lower than the optimum pH, the amount of alkaline material (calcium carbonate, etc.) needed to improve the pH to the optimum level is suggested. The acidity can be improved by giving the appropriate amount to the field and thoroughly mixing it with the soil. Conditions related to the chemical properties of the soil are relatively easy to improve, unlike the physical properties.