Elmer Wade H, LaMondia James A
The Connecticut Agricultural Experiment Station, New Haven 06504.
The Connecticut Agricultural Experiment Station, Valley Laboratory, Windsor 06095.
Plant Dis. 1999 Feb;83(2):119-123. doi: 10.1094/PDIS.1999.83.2.119.
The combined effects of rotation crops and nitrogen fertilizers were examined on the strawberry black root rot disease complex. In July 1995, microplots were filled with soil that had a history of strawberry black root rot and seeded with two types of oats (Avena strigosa 'Saia oats' or A. sativa 'Garry oats') or with sorgho-sudangrass (Sorghum bicolor × S. sudanense 'Triple S'). Microplots planted with 1-year-old 'Honeoye' strawberry crowns served as the controls. In May 1996, the crops were chopped and incorporated into the soil. The soil was re-planted with 1-year-old strawberry 'Honeoye' crowns and then fertilized with (NH)SO or Ca(NO) at equivalent rates of N. Two months later, (NH)SO-treated plants had 36% more leaf area and 41% more runners than strawberries treated with Ca(NO) Strawberries that had been pre- cropped with 'Saia' oats had 135% more runners and 38% more early fruit yield than strawberries grown in control microplots. Total fruit yield was not affected by the treatments. Compared to Ca(NO), the (NH)SO treatment reduced the percentage of blackened roots. The influence of the cover crops on growth and disease was stronger with (NH)SO fertilization than with Ca(NO) fertilization. Combining 'Saia' oats or sorgho-sudangrass rotation with (NH)SO fertilization reduced lesion nematode (Pratylenchus penetrans) numbers in subsequent strawberry roots when compared to controls. Also, the combination of 'Saia' or 'Garry' oats as a pre-crop with applications of (NH)SO reduced black root rot severity when compared to controls. Only the 'Garry' oat rotation reduced strawberry root colonization by Rhizoctonia fragariae when compared to controls. Other effects were associated with using (NH)SO. The (NH)SO treatment lowered the rhizosphere soil pH by 0.2 units, reduced the numbers of fluorescent pseudomonads in the rhizosphere by 10- to 15-fold, and produced leaves that had more N, K, S, Mn, and Zn content than plants treated with Ca(NO). Rotation with 'Saia' oats combined with (NH)SO fertilization may suppress strawberry black root rot and increase yields through multiple effects on the host, pathogens, and associated microflora.
研究了轮作作物和氮肥对草莓黑根腐病复合病害的综合影响。1995年7月，在曾发生过草莓黑根腐病的土壤中设置微型小区，播种两种燕麦（Avena strigosa的‘赛亚燕麦’或A. sativa的‘加里燕麦’）或高粱-苏丹草（Sorghum bicolor×S. sudanense的‘三S’品种）。种植1年生‘哈尼耶’草莓植株的微型小区作为对照。1996年5月，将作物切碎后翻入土中。在土壤中重新种植1年生草莓‘哈尼耶’植株，然后分别施用等量氮素的(NH₄)₂SO₄或Ca(NO₃)₂进行施肥。两个月后，与施用Ca(NO₃)₂的草莓相比，施用(NH₄)₂SO₄的植株叶面积多36%，匍匐茎多41%。预先种植‘赛亚’燕麦的草莓比对照微型小区种植的草莓匍匐茎多135%，早期果实产量高38%。各处理对总产量没有影响。与Ca(NO₃)₂相比，(NH₄)₂SO₄处理降低了根变黑的比例。与Ca(NO₃)₂施肥相比，(NH₄)₂SO₄施肥时覆盖作物对生长和病害的影响更强。与对照相比，将‘赛亚’燕麦或高粱-苏丹草轮作与(NH₄)₂SO₄施肥相结合，可减少后续草莓根中病变线虫（穿刺短体线虫Pratylenchus penetrans）的数量。此外，与对照相比，将‘赛亚’或‘加里’燕麦作为前作并施用(NH₄)₂SO₄可降低黑根腐病的严重程度。与对照相比，只有‘加里’燕麦轮作减少了草莓根被草莓丝核菌（Rhizoctonia fragariae）的定殖。其他影响与施用(NH₄)₂SO₄有关。(NH₄)₂SO₄处理使根际土壤pH值降低0.2个单位，根际荧光假单胞菌数量减少10至15倍，且叶片中的氮、钾、硫、锰和锌含量高于施用Ca(NO₃)₂的植株。将‘赛亚’燕麦轮作与(NH₄)₂SO₄施肥相结合，可能通过对寄主、病原体和相关微生物群落的多种作用来抑制草莓黑根腐病并提高产量。
