Sugarcane and Pine Biochar as Amendments for Greenhouse Growing Media for the Production of Bean (Phaseolus vulgaris L.) Seedlings

Abstract

Louisiana sugarcane farmers in 2016 harvested 11.7 million Mg of millable sugarcane from 163,000 ha, producing 1.47 million Mg of raw sugar and an estimated 3.5 million Mg of bagasse. Even though Louisiana sugar mills use 80% to 90% of the bagasse for fuel production, another 350,000 to 700,000 Mg of bagasse accumulates each year. The conversion of the excess bagasse into biochar is one solution to reduce the excess supply. Research was conducted to determine the impact of sugarcane biochar as an amendment to soilless planting media for the production of green bean (Phaseolus vulgaris L.) seedlings. Sugarcane bagasse biochar (SBB) and pine biochar (PB) were each combined by volume with a commercial certified organic soilless growing media into 5 combinations (0%:100%, 25%:75%, 50%:50%, 75%:25%, and 100%:0%, biochars and growing media, respectively). Green bean variety ‘Bowie’ seeds were planted in each of the different planting mixtures. The particle size distribution for the two biochars are in stark contrast to each other with the PB particle median, mean, geometric mean, and mode much greater than those of the SBB. As amendments to the soilless greenhouse growing media, the biochars (SBB and PB) functioned very well, especially at the 25% and 75% levels. The 100% SBB performed as well as the 100% commercial soilless growing media and slightly better than the 100% PB when comparing seedling fresh and dry weights. The 100% PB is not recommended as a soilless growing media even with the supplemental fertilizer used in these experiments. These results indicate that the volume of a standard soilless greenhouse growing media can be successfully extended by adding 25% to 75% SBB and PB without reducing bean seedling growth. Future research is needed to evaluate these biochars for the production of additional plant species.

Evaluation of Biochar and Compost Mixes as Substitutes to a Commercial Propagation Mix

“…Similarly, the FWs and DWs of green bean var. 'Bowie' seedlings in mixes of 75% (by volume) sugarcane bagasse BC or pine BC with the rest being commercial growing media were similar to the control [20]. Sáez et al [41] also showed that mixes of 60% or 80% (by volume) holm oak BC (with the rest being pig slurry compost) had similar or higher shoot DWs compared to the mixes with 60% or 80% coir (the resting being pig slurry compost), respectively.…”

“…Similarly, the FWs and DWs of green bean var. 'Bowie' seedlings in mixes of 75% (by volume) sugarcane bagasse BC or pine BC with the rest being commercial growing media were similar to the control [20]. Sáez et al [41] also showed that mixes of…”

“…Margenot et al [23] also showed that the substrate with 70% (by volume) softwood BC and 30% perlite without pH adjustment had no negative effect on the germination rate of marigold seeds compared to the 70:30 peat:perlite mixture. Webber III et al [20] concluded that the percentage of seedling establishment for green beans (Phaseolus vulgaris var. 'Bowie') in mixes of 75% sugarcane bagasse BC or pine BC, with the rest being commercial growing media, was similar to that of the control.…”

“…2019, 9, 4394 2 of 11 production adds extra value to the bioenergy process [19]. Research has shown the potential of BC to be used in seed propagation substrate for agricultural production [20]. It was shown that coconut shell BC (5%, 10%, 20%, or 40%, by volume) could be mixed with an adapted cornell seed germination mix and did not affect final germination percentages [21].…”

Mixed Hardwood and Sugarcane Bagasse Biochar as Potting Mix Components for Container Tomato and Basil Seedling Production

“…Sugarcane bagasse biochar had a pH of 5.9 and HB had a pH of 10.1. The electrical conductivity (EC) of the two biochars were 753 µS/cm (SBB) and 1,058 µS/cm (HB), respectively [31]. Because SBB had a similar pH to PM (SBB 5.9, PM 5.0, Table 1) and the SBB particle size was smaller (mean 0.17mm, resulting in low air space (AS)) [31], when formulating mixes with SBB, 30% P was incorporated to increase the pH of the AS and the mix.…”