R. Ohtomo, S. Morimoto, K. Nagaoka, T. Karasawa, Takuji Nakamura, N. Oka
{"title":"Predicting arbuscular mycorrhizal fungal colonization of soybean in farmers’ fields by using infection unit density","authors":"R. Ohtomo, S. Morimoto, K. Nagaoka, T. Karasawa, Takuji Nakamura, N. Oka","doi":"10.1080/00380768.2022.2153345","DOIUrl":null,"url":null,"abstract":"ABSTRACT Estimating arbuscular mycorrhizal (AM) fungal activity to colonize crop root before cultivation is prerequisite for effective utilization of their functions which enhance growth and yield of the plant especially under low fertilizer input. We have hypothesized that the infection unit (IU) density formed on test plant roots grown for short period (12 days) with soil sampled from soybean production fields would be an effective indicator to predict AM fungal colonization intensity to the plant. In order to test this hypothesis, three-year farmland survey was conducted, in which soil samples before sowing soybean and the plant root samples at third trifoliate (V3) and full bloom (R2) stage were collected from farmers’ fields in two regions in Hokkaido, Iwamizawa and Tokachi. For each sampling spot, IU density was determined by using test plants, and intensity of AM fungal colonization of soybean root was measured. Before pursuing field survey, laboratory experiments were conducted to find out proper soil storage condition that keeps IU density unchanged while handling many soil samples. Our results indicated that IU density was almost comparable to the original value after six-month storage if soil samples were kept in a refrigerator, although storing at ambient temperature significantly decreased the measurement. Air drying also had negative impact on IU density. According to the field survey, IU densities determined using field soil were positively and significantly correlated with AM fungal colonization of soybean roots at both V3 and R2 stages. Differences in climate, soil type, and style of agriculture between Iwamizawa and Tokachi seemed to have little effect on IU density-AM fungal colonization relationship. Other than IU density, soil pH and soil penetration resistance at 10 cm depth were selected as significant explanatory variables for predicting AM fungal colonization by multiple regression analysis. However, IU density was the most influential factor among three. Therefore, IU density is recognized as an effective measure to evaluate AM fungal colonizing activity in field soil.","PeriodicalId":21852,"journal":{"name":"Soil Science and Plant Nutrition","volume":null,"pages":null},"PeriodicalIF":1.9000,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Soil Science and Plant Nutrition","FirstCategoryId":"97","ListUrlMain":"https://doi.org/10.1080/00380768.2022.2153345","RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
引用次数: 0
Abstract
ABSTRACT Estimating arbuscular mycorrhizal (AM) fungal activity to colonize crop root before cultivation is prerequisite for effective utilization of their functions which enhance growth and yield of the plant especially under low fertilizer input. We have hypothesized that the infection unit (IU) density formed on test plant roots grown for short period (12 days) with soil sampled from soybean production fields would be an effective indicator to predict AM fungal colonization intensity to the plant. In order to test this hypothesis, three-year farmland survey was conducted, in which soil samples before sowing soybean and the plant root samples at third trifoliate (V3) and full bloom (R2) stage were collected from farmers’ fields in two regions in Hokkaido, Iwamizawa and Tokachi. For each sampling spot, IU density was determined by using test plants, and intensity of AM fungal colonization of soybean root was measured. Before pursuing field survey, laboratory experiments were conducted to find out proper soil storage condition that keeps IU density unchanged while handling many soil samples. Our results indicated that IU density was almost comparable to the original value after six-month storage if soil samples were kept in a refrigerator, although storing at ambient temperature significantly decreased the measurement. Air drying also had negative impact on IU density. According to the field survey, IU densities determined using field soil were positively and significantly correlated with AM fungal colonization of soybean roots at both V3 and R2 stages. Differences in climate, soil type, and style of agriculture between Iwamizawa and Tokachi seemed to have little effect on IU density-AM fungal colonization relationship. Other than IU density, soil pH and soil penetration resistance at 10 cm depth were selected as significant explanatory variables for predicting AM fungal colonization by multiple regression analysis. However, IU density was the most influential factor among three. Therefore, IU density is recognized as an effective measure to evaluate AM fungal colonizing activity in field soil.
期刊介绍:
Soil Science and Plant Nutrition is the official English journal of the Japanese Society of Soil Science and Plant Nutrition (JSSSPN), and publishes original research and reviews in soil physics, chemistry and mineralogy; soil biology; plant nutrition; soil genesis, classification and survey; soil fertility; fertilizers and soil amendments; environment; socio cultural soil science. The Journal publishes full length papers, short papers, and reviews.