Effects of Trichoderma seedling treatment with System of Rice Intensification management and with conventional management of transplanted rice.

Ram B Khadka,Norman Uphoff

doi:10.7717/peerj.5877

Abstract

Many benefits of Trichoderma inoculation for improving crop production have been documented, including growth and yield enhancement and the alleviation of biotic and abiotic stresses. However, because rice is usually cultivated under continuous flooding that creates anaerobic soil conditions, this limits the benefits of these beneficial fungi. Cultivating rice with the methods of the System of Rice Intensification (SRI) provides rice plants with a more favorable environment for their colonization by beneficial microbes in the soil because the soil is more aerobic under SRI management and contains more organic matter. This study evaluated the effects of Trichoderma inoculation of rice plants under SRI management compared with transplanted and flooded rice plants, considering also the effects of different means of fertilization and different varieties in rice. Experiments were conducted in 2015 and 2016 under the tropical climate of Nepal’s western terai (plains) during both the rainy season (July to November) and the dry season (March to July). The results indicated significantly better performance (P = 0.01) associated with Trichoderma inoculation for both seasons and for both systems of crop management in terms of grain yield and other growth-contributing factors, compared to non-inoculated rice cropping. Relatively higher effects on grain yield were recorded also with organic compared to inorganic fertilization; for unimproved (heirloom) varieties compared with improved varieties; and from SRI vs. conventional flooded crop management. The yield increase with Trichoderma treatments across all trials was 31% higher than in untreated plots (4.9 vs 4.5 mt ha−1). With Trichoderma treatment, yields compared with non-treated plots were 24% higher with organic SRI (6.38 vs 5.13 mt ha−1) and 52% higher with non-organic SRI (6.38 vs 3.53 mt ha−1). With regard to varietal differences, under SRI management Trichoderma inoculation of the improved variety Sukhadhan-3 led to 26% higher yield (6.35 vs 5.04 mt ha−1), and with the heirloom variety Tilkidhan, yield was 41% higher (6.29 vs 4.45 mt ha−1). Economic analysis indicated that expanding the organic cultivation of local landraces under SRI management should be profitable for farmers where such rice has a good market price due to its premium quality and high demand and when SRI enhances yield. These varieties’ present low yields can be significantly increased by integrating Trichoderma bio-inoculation with SRI cultural methods. Other recent research has shown that such inoculation can be managed profitably by farmers themselves.

Highlights

Microorganisms are a vital but unseen constituent of farming systems
Effect of Trichoderma seedling treatment with different rice cultivation methods Measures of grain yield, grain test weight, and number of panicles hill−1 averaged across the three different methods of crop establishment showed significantly better crop performance with Trichoderma seedling treatment
The values of these three parameters comparing bioinoculated vs. non-inoculated plants in their respective plots were, respectively, 5.9 vs. 4.7 tonnes ha−1 for yield; 20.6 vs. 19.5 grams for 1000-grain weight; and 11.8 vs. 10.7 for panicles hill−1

Summary

Introduction

Microorganisms are a vital but unseen constituent of farming systems. Many free-living microorganisms establish beneficial biological relationships with crop plants by living in the rhizosphere around the roots and by colonizing plants’ roots, an effect not limited to leguminous crops. Some microorganisms inhabit tissues and cells within plants’ aboveground organs as well as in their roots, living inside the plants as symbiotic endophytes (Uphoff et al, 2013). While many microorganisms are predatory or parasitic, the majority live harmoniously and even beneficially with their plant hosts (Parmar & Dadarwal, 1999). They have capability to influence plants’ physiological processes, enhance their growth and development, and make plants more tolerant of biotic and abiotic stresses (Dardanelli et al, 2010; Berendsen, Pieterse & Bakker, 2012). Has the concept of holobionts, which refers to the composite entities where microbiota are living symbiotically with their host plants (Margulis & Fester, 1991)

Methods

Results

Discussion

Conclusion