Effects of Biochar Application in a Sorghum Crop under Greenhouse Conditions: Growth Parameters and Physicochemical Fertility

Abstract

Application of biochar from vine shoots (Vitis vinifera L.) as an organic amendment in the soil is an alternative agricultural management of interest. The behavior of this type of amendment in the soil requires more information to adjust the pyrolysis conditions in order to obtain a high-quality biochar. The aim of this work is determining the influence of the application of this type of biochar on the soil-plant system. For this purpose, an agronomic test was performed in greenhouse pots. A randomized tri-factorial block design was adopted with the following factors: final pyrolysis temperature (400 and 600 °C), application rate (0 wt. % as a control, 1.5 and 3 wt. %) and texture of the growing media (sandy-loam and clay-loam origin). The selected crop was sorghum (Sorghum bicolor L. Moench), the development and production of which was evaluated during two complete growing cycles under greenhouse conditions. Application of biochar produced at 400 °C significantly increased plants roots dry weight in the sandy-loam growing substrate (52% compared to the control). Grain production was also significantly affected by biochar application, showing better results after addition of biochar produced at 400 °C. Water holding capacity and K, Ca, and Mg contents were enhanced by biochar addition, with evident effects of the application ratios for some of these variables. The effect on the pH of substrates in the sandy-loam texture was weak; however, a significant decrease was observed after the addition of biochar produced at 600 °C.

The Effects of Biochar on Indigenous Arbuscular Mycorrhizae Fungi from Agroenvironments

“…However, depending on the experimental conditions and especially on soil-nutrient availability, decreases in AMF root colonization have also been reported [ 18 , 21 ]. In this particular experiment, it was confirmed that biochar had a positive effect on AMF development in the sandy-loam texture (S1); nevertheless, the higher activity of mycorrhized roots or number of AMF spores did not result in any marked increase in the biological crop yield, as reported in a previous publication [ 30 ]. The obtained results in B600 treatment at high doses in the clay-loam substrate, as mentioned above, showed the minimum value of root colonization and the maximum value for the number of AMF spores, which leads to the conclusion that the sporulation strategy by the mycorrhiza prevailed in this treatment over root colonization.…”

“…For the specific results of our experiment, no differences in P content were found on substrates or plant tissue [ 30 ]; however, a positive correlation between AMF activity and Pseudomonas abundance was confirmed for the sandy-loam substrate (see Table S4 ).…”

“…The complete characterization of the two types of biochar produced is detailed in a previous publication [ 30 ]. The results were primarily dependent on pyrolysis operating conditions.…”

“…A randomized factorial block design was adopted with three factors as independent variables, as is detailed in Table 6. The duration of the trial was 13 months in which the crop completed two production cycles as is detailed in a previous publication [30]. Experiment 2.…”

“…For Experiment 1, a detailed report of productive parameters and physicochemical changes in the substrates is collected in a previous publication [30]. Regarding the biological parameters, the following measurements were carried out during the experiment and after the first harvest: AMF root colonization: three measurements of AMF root colonization were done at different dates after sowing (120 days-D 120 , 210 days-D 210 , and 330 days-D 330 ) while the crop was established.…”