Abstract
Avoidance of intensive rice cultivation (IRC) and soil amendments are potential practices to enhance soil properties. There is only limited information on the effects of reduced IRC and its mixture with compost or silicate fertilizer (Si) on the soil nematode community in salt–affected soils. This study aimed to assess the shifts of soil nematode community by reducing a rice crop from triple rice system (RRR) to a double rice system and mixed with compost or Si in paddy fields in acid sulfate soil (ASS) and alluvial soil (AL) in the Mekong Delta, Vietnam. Field experiments were designed with four treatments in four replicates, including RRR and a proposed system of double–rice followed by a fallow (FRR) and with 3 Mg ha–1 crop−1 compost or 100 kg ha–1 crop−1 Si. Soils were collected at harvest after the 2 year experiment, reflecting the fifth and third consecutive rice crop in RRR and FRR system, respectively. Results showed that reduced IRC gave a significant reduction in abundance of plant–parasitic nematodes (PPN), dominated by Hirschmanniella and increased abundance bacterivorous nematodes when mixed to compost and silicate fertilizer in ASS. In addition, reduced IRC increased nematode biodiversity Hill’s indices and reduced herbivorous footprint in ASS. Proposed system having compost or Si had strongly increased in bacterivorous and omnivorous footprints. Particularly, reduced IRC mixture with Si increased abundance of Rhabdolaimus, Mesodorylaimus and Aquatides, metabolic footprints (structure footprint, bacterivorous, omnivorous and predator) and diversity Hill’s N1 index in ASS. Our results highlighted that reduced IRC was a beneficial practice for decreasing abundance of PPN in salt-affected soils and increasing abundance of FLN in ASS. IRC mixture with compost or Si had potential in structuring the nematode communities with increasing biodiversity, trophic structure, and metabolic footprints.
Highlights
The Vietnamese Mekong Delta (VMD) region predominantly grows rice and has a long history of extremely intensive cultivation of rice in irrigated paddy fields
Our study suggests that keeping fallow conditions during dry season in a double rice cropping system may reduce the number of plant– parasitic nematodes (PPN) in soil of subsequent crops
The use of reduced intensive rice cropping alone resulted in a significant reduction in the abundance of PPN, dominated by Hirschmanniella, in salt-affected soils, and increased the abundance of Free-living nematodes (FLN), in particular bacterivorous (Rhabdolaimus) nematodes, in acid sulfate soil (ASS)
Summary
The Vietnamese Mekong Delta (VMD) region predominantly grows rice and has a long history of extremely intensive cultivation of rice in irrigated paddy fields. The consecutive growth of three rice crops in the same field per year (called triple–rice cropping system) is a usual cropping system in the VMD, it is not popular in the rest of the world In this system, the soil is irrigated and flooded frequently during rice cultivation periods, and this process has been repeated every crop and year. Salinity water intrusion into agricultural lands is becoming a severe problem in this area due to climate changes, in the dry season from February to May [7]. This problem occurs annually, causing many difficulties in growing rice and damage to farmers’ income [1]. Soriano and Reversal [23] recommended that rotating one or two consecutive crops of cowpea in rice field or including a fallow period before a rice crop reduced PPN populations and improved rice yield by 30–80%
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
