Maina Samuel, Karuri Hannah, Ng'endo Rossa Nyoike
Department of Biological Sciences, University of Embu, P.O. Box 6-60100, Embu, Kenya.
J Nematol. 2021 Apr 1;53. doi: 10.21307/jofnem-2021-038. eCollection 2021.
Return of plant residues to the soil is a sustainable way of enhancing plant growth, health, and levels of soil quality. In Kenya, maize plant residues are the most commonly returned plant material in many agro-ecosystems. For any plant material to release nutrients into the soil, it must undergo a decomposition process that is usually affected by various organisms, especially nematodes. Despite their great contribution to the breakdown of plant organic matter, there is a dearth of information on the interaction between maize residues and free-living nematodes (FLN) in Kenya. In this respect, this study aimed to assess the influence of decomposing maize residues on FLN dynamics and the soil food web in Mwea, Kenya. The experimental plots were set up in a randomized complete block design, comprising of decomposition plots (incorporated with maize residue to a depth of 30 cm at a rate of 5 tons/hectare), while the plots unincorporated with maize residues were used as the control. Each treatment consisted of four replicates. In all, 30 FLN genera were recovered from the field trials, whereby was significantly abundant in decomposition plots in both seasons. We subsequently found that maize residues reduced the abundance of enrichment opportunist bacterivores (cp-1) relative to general opportunist (cp-2) bacterivores and fungivores. Notably, the results of the channel index showed that the decomposition of maize residues was dominated by fungal energy channels throughout the study in the two seasons. These results suggest that maize residues need to be coupled with a suitable labile organic matter. This would lead to sustainable, active, and reliable turn-over of maize residues into the soil food web ecosystems. The application of labile materials can also help to improve the population of enrichment bacterivores that are essential in the decomposition process. This study shows that the decomposition of maize residues influenced FLN composition, mainly the enrichment opportunist bacterivores whose abundance was lower.
将植物残体归还土壤是促进植物生长、健康以及提高土壤质量水平的一种可持续方式。在肯尼亚，玉米植株残体是许多农业生态系统中最常归还的植物材料。任何植物材料要向土壤中释放养分，都必须经历一个分解过程，而这个过程通常会受到各种生物的影响，尤其是线虫。尽管它们对植物有机物的分解有很大贡献，但在肯尼亚，关于玉米残体与自由生活线虫（FLN）之间相互作用的信息却很匮乏。在这方面，本研究旨在评估分解中的玉米残体对肯尼亚姆韦亚地区自由生活线虫动态和土壤食物网的影响。试验小区采用随机完全区组设计，包括分解小区（以5吨/公顷的速率将玉米残体掺入30厘米深的土壤中），而未掺入玉米残体的小区用作对照。每个处理有四个重复。总共从田间试验中发现了30个自由生活线虫属，其中 在两个季节的分解小区中都显著丰富。我们随后发现，相对于一般机会主义者（cp - 2）食细菌线虫和食真菌线虫，玉米残体降低了富集机会主义食细菌线虫（cp - 1）的丰度。值得注意的是，通道指数结果表明，在两个季节的整个研究过程中，玉米残体的分解主要由真菌能量通道主导。这些结果表明，玉米残体需要与合适的易分解有机物质相结合。这将导致玉米残体可持续、活跃且可靠地转化为土壤食物网生态系统。施用易分解物质还有助于增加分解过程中必不可少的富集食细菌线虫的数量。本研究表明，玉米残体的分解影响了自由生活线虫的组成，主要是丰度较低的富集机会主义食细菌线虫。
