Leptosphaeria maculans. [Descriptions of Fungi and Bacteria].

1972 ◽  
Author(s):  
E. Punithalingam
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Brassica Oleracea ◽  
Geographical Distribution ◽  
Seed Treatment ◽  
Leptosphaeria Maculans ◽  
Severe Infection ◽  
Perfect State ◽  
Dry Rot ◽  
The Republic

Abstract A description is provided for Leptosphaeria maculans. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: On Brassica spp. ; Brassica oleracea, B. rapa and B. napobrassica and other Cruciferae. DISEASE: Variously known as canker, dry rot and black leg, mainly of Brassica oleracea, B. rapa and B. napobrassica. Several cruciferous genera are attacked. The first symptoms are seen on seedlings as pale lesions on the stem, cotyledons and first true leaves. These become greyish with the pycnidia developing in their centres. On older plants in the field lesions on the leaves and other above-ground parts often have purplish margins. The stem, root and bulb are attacked causing necrotic, girdling cankers and transverse splits; severe infection of stem or root leads to wilt or the plant toppling over. Pycnidia develop abundantly on all infected areas. The perfect state has been reported from Australia, Canada, England and the Republic of Ireland (44, 65; 45, 1568; 48, 51). GEOGRAPHICAL DISTRIBUTION: Widespread but mostly in temperate regions (CMI Map 73 ed. 3, 1969). Records not yet mapped are: Australia (NT), Brazil, Costa Rica, Salvador, USSR (Ukraine). TRANSMISSION: The seed is invaded, dormant mycelium forming beneath the seed coat (11: 489; 19: 58). A recent survey in Denmark (48, 2641) showed seed of B. oleracea var. capitata to be most frequently infected and a longevity of 3 yr 8 months reported. From New Zealand a longevity of 14 months was found (39: 200). Seed treatment for control of conidial infection has led to the recognition that the disease may also be introduced by air-borne ascospores from host debris (42: 62; 49, 1822; 50, 2027). A persistence of 3 yr in soil organic matter can occur (9: 218; 29: 448).

The effect of alfalfa age on the accumulation of total and soil organic matter when rotating grain crops

2021 ◽  
pp. 26-29
Author(s):  
А.А. Гусейнов ◽  
Г.Н. Гасанов ◽  
М.А. Арсланов ◽  
Х.М. Мирзаева
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Winter Wheat ◽  
Soil Layer ◽  
Organic Mass ◽  
Post Harvest ◽  
Trial Field ◽  
Grain Crop ◽  
The Republic ◽  
Top Mass

Исследования проведены в 2013–2015 годах в ООО «Вымпел 2002» в Хасавюртовском районе Республики Дагестан. Почва экспериментального участка содержит в пахотном слое гумуса 2,77%, Р2О5 — 2,21 мг, К2О — 32,8 мг/100 г почвы, плотность в пахотном слое — 1,24 г/см3, наименьшая влагоёмкость слоя 0–0,6 м — 29,2%. Целью наших исследований являлось выявление влияния возраста люцерны на накопление общей и неотчуждаемой из почвы органической массы в зернокормовом севообороте в условиях Западного Прикаспия. Рассмотрено два севооборота (с двухлетней и трёхлетней люцерной), по пласту и обороту пласта выращивали озимую пшеницу, после уборки которой в пожнивный период с помощью провокационного полива формировали пожнивный естественней фитоценоз (ПЕФ). Степень насыщения севооборотов люцерной составляла соответственно 50 и 60,0%, озимой пшеницей + ПЕФ — 60,0 и 40%. Установлено, что увеличение срока использования люцерны в зернотравяных севооборотах с 2 до 3 лет и доли её в структуре посевных площадей с 50 до 60% способствовало увеличению сборов сена с 1 га севооборотной площади на 2,57 т/га (на 19,0%), зерна озимой пшеницы по пласту — на 7,9%, по обороту пласта — на 6,5%, надземной массы ПЕФ — на 5,3 и 5,1% соответственно. Одновременно увеличивалось и количество накапливаемой растительной массы с 71,56 до 92,66 т/га севооборотной площади. Но в том случае, когда люцерна в севообороте использовалась 2 года, а доля озимой пшеницы с последующим использованием пожнивного периода под ПЕФ увеличивалась с 40 до 50% севооборотной площади, неотчуждаемой из почвы растительной массы накапливалось больше на 20,2%. Заслуживает уточнения в методическом плане вопрос об отнесении части урожая сена люцерны, произведённого в хозяйстве, к неотчуждаемой из почвы продукции подобно тому, как это делается в отношении соломы, только 60% которой считается экосистемной. The investigation took place at the OOO “Vympel 2002” in the Khasavyurt district of the Republic of Dagestan in 2013–2015. Soil of the trial field contained 2.77% of humus, Р2О5 — 2.21 mg, К2О — 32.8 mg/100 g of soil, layer density — 1.24 g/cm3, the lowest moisture content of the 0–0.6 m layer — 29.2%. The aim was to test the effect of alfalfa age on the accumulation of total and soil organic mass in grain crop rotation in the Western Caspian region. Two crop rotations were studied (two- and three-year old alfalfa). After harvesting winter wheat the plot was irrigated to form post-harvest natural phytocenosis. Alfalfa proportion amounted to 50 and 60%, winter wheat + post-harvest natural phytocenosis — 60 and 40%. Cultivation of alfalfa for 3 years instead of 2 and increase in its proportion from 50 to 60% improved hay yield by 2.57 t ha-1 (19%), wheat grain yield — by 7.9 and 6.5%, top mass of post-harvest natural phytocenosis — by 5.3 and 5.1%, respectively. Plant mass increased from 71.56 to 92.66 t ha-1. When alfalfa was cultivated for 2 years and winter wheat proportion raised from 40 to 50%, accumulation of soil organic matter improved by 20.2%. Attributing part of alfalfa hay to soil organic matter was performed the same way as for straw, only 60% of which belonged to an ecosystem.

Pythium spinosum. [Descriptions of Fungi and Bacteria].

2004 ◽  
Author(s):  
M. A. Spencer
Keyword(s):  
South Africa ◽  
Organic Matter ◽  
New Zealand ◽  
Great Britain ◽  
Soil Organic Matter ◽  
North America ◽  
South America ◽  
Geographical Distribution ◽  
Damping Off ◽  
Wide Range

Abstract A description is provided for Pythium spinosum. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. DISEASES: Seedling damping-off. HOSTS: Wide range of plant hosts. GEOGRAPHICAL DISTRIBUTION: AFRICA: South Africa. NORTH AMERICA: Canada, USA (Florida, Hawaii, Iowa). SOUTH AMERICA: Argentina. ASIA: China (Zhejiang), India, Japan, Korea, Taiwan. AUSTRALASIA: Australia (Queensland), New Zealand. EUROPE: France, Germany, Great Britain, Italy, Netherlands. TRANSMISSION: Contaminated soil, organic matter (oospores) and water (sporangia).

Soil Organic Matter

1962 ◽  
Vol 54 (5) ◽  
pp. 470-470
Author(s):  
T. M. McCalla
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter

Soil Organic Matter Fractions under Managed Pine Plantations of the Southeastern USA

2004 ◽  
Vol 68 (3) ◽  
pp. 950 ◽  
Author(s):  
Marietta E. Echeverría ◽  
Daniel Markewitz ◽  
Lawrence A. Morris ◽  
Ronald L. Hendrick
Keyword(s):  
Organic Matter ◽  
Soil Organic Matter ◽  
Pine Plantations ◽  
Southeastern Usa ◽  
Soil Organic Matter Fractions ◽  
Organic Matter Fractions
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