The Effects of Soil Microbiomes on Preventing Nematode Damage to Rice Plants

<i>Meloidogyne graminicola</i> (Mg), commonly referred to as rice root-knot nematodes (RKNs), is one of the most prevalent plant parasitic nematodes in rice agroecosystems, and sustainable agricultural practices are still limited. This study aimed to assess the effectiveness of soil microbiotas extracted from different agricultural practices in reducing RKN damage to rice plants. We used conservation agriculture (CA), cover crops with machine tillage (CA), conservation agriculture without tillage (CAU), and conventional agriculture practices (CT). All types of soil microbiotas were isolated from soil samples collected from each rice agricultural practice in the Preah Vihear and Kampong Thom provinces of Cambodia in order to test the effectiveness of the microbiotas against Mg on rice plants (Variety IR64). The experiment was conducted in test tubes, using sterilized sand to grow rice. Then, 250 juveniles (J2) were used to infect each tube and were classified into three treatments: (1) infected 25 mL of microbiota suspensions from non-sterilized soil (M); (2) infected 25 mL of microbiota from sterilized soil (ST); and (3) a control with only J2 (CT). After 3 weeks of infection, rice plants were examined under microscopes to measure the number of nematodes (J2 and eggs). The results showed that the number of nematodes was significantly different under treatment (ST) 230 ± 100.132 compared to treatment (M) 159 ± 64.41, respectively. The data demonstrated that soil microbiotas in CA were effective in reducing Mg damage to rice roots, a method which can be used as a biological control to lower RKN in rice plants. However, further research is required to conduct the assessment of the effects of microbiotas on rice development and yield and determine the taxa of beneficial microbiomes with the most benefit to rice growth.