Improving maize yield and drought tolerance in field conditions through activated biochar application

Abstract

Amidst depleting water resources, rising crop water needs, changing climates, and soil fertility decline from inorganic modifications of soil, the need for sustainable agricultural solutions has been more pressing. The experimental work aimed to inspect the potential of organically activated biochar in improving soil physicochemical and nutrient status as well as improving biochemical and physiological processes, and optimizing yield-related attributes under optimal and deficit irrigation conditions. Biochar enhances soil structure, water retention, and nutrient availability, while improving plant nutrient uptake and drought resilience. The field experiment with maize crop was conducted in Hardaas Pur (32°38.37'N, 74°9.00'E), Gujrat, Pakistan. The experiment involved the use of DK-9108, DK-6321, and Sarhaab maize hybrid seeds, with five moisture levels of evapotranspiration (100% ETC, 80% ETC, 70% ETC, 60% ETC, and 50% ETC) maintained throughout the crop seasons. Furthermore, activated biochar was applied at three levels: 0 tons/ha (no biochar), 5 tons per hectare, and 10 tons per hectare. The study's findings revealed significant improvements in soil organic matter, bulk density, nutrient profile and total porosity with biochar supplementation in soil. Maize plants grown under lower levels of ETC in biochar supplemented soil had enhanced membrane stability index (1.6 times higher) increased protein content (1.4 times higher), reduced malondialdehyde levels (0.7 times lower), improved antioxidant enzyme activity (1.3 times more SOD and POD activity, and 1.2 times more CAT activity), improved relative growth (1.05 times more) and enhanced yield parameters (26% more grain and stover yield, 16% more 1000-seed weight, 29% more total seed weight, 33% more apparent water productivity) than control. Additionally, among the two biochar application levels tested, the 5 tons/ha dose demonstrated superior efficiency compared to the 10 tons/ha biochar dose.

Keywords: Crop evapotranspiration; Drought tolerance; Penman-Monteith equation; Soil health; Water use efficiency.

Fig. 1

SEM & EDX analysis of 0 tons/ ha, 5 tons/ha, and 10 tons/ha biochar supplemented soil showing particles, porosity and elemental composition.

Fig. 2

Weather data comparison of experimental site during the maize seasons (2023 and 2024) obtained from Earth Observing System and Data Analytics (EOSDA) satellite-based precision agriculture platform (a) Wind Speed (b) Average sun hours per day (c) Mean daily temperature (d) Mean daily humidity (e) Total rainfall.

Fig. 3

(a) Estimation of Soil Water Retention Curve fitted by van Genuchten model parameters adjustments (b) Unsaturated hydraulic conductivity curve fitted by using the Mualem-van Genuchten Model.

Fig. 4

Visualization of maize crop water dynamics during the crop growing seasons by using data from the EOSDA crop monitoring platform (a) Season 2023 (23rd March to 25th June), (b) Season 2024 (15th March to 17th June).

Fig. 5

Impact of activated acacia biochar amendment on (a) thousand seed weight and (b) total seed weight in maize hybrids under varied moisture conditions. Note: Different letters on bars represent significant variations among the treatments, as determined by Tukey Pairwise Comparison of ETC × Amendment × Variety at 95% confidence interval.

Fig. 6

Impact of activated acacia biochar amendment on (a) grain yield and (b) stover yield in maize hybrids under varied moisture conditions. Note: Different letters on bars represent significant variations among the treatments, as determined by Tukey Pairwise Comparison of ETC × Amendment × Variety at 95% confidence interval.

Fig. 7

Impact of activated acacia biochar amendment on apparent water productivity in maize hybrids under varied moisture conditions. Note: Different letters on bars represent significant variations among the treatments, as determined by Tukey Pairwise Comparison of ETC × Amendment × Variety at 95% confidence interval.

Fig. 8

Biplot of principal component analysis showing the various physiological and biochemical attributes of maize hybrids grown in biochar amended and non-amended soil under different moisture levels of ETC. Abbreviations: rfw: root fresh weight, rdw: root dry weight, sfw: shoot fresh weight, sdw: shoot dry weight, lfw: leaf fresh weight, ldw: leaf dry weight, la: leaf area, nar: net assimilation rate, rgr: relative growth rate, v_msi: vegetative membrane stability, r_msi: reproductive membrane stability, v_mda: vegetative malondialdehyde content, r_mda: reproductive malondialdehyde content, v_pc: vegetative protein content, r_pc: reproductive protein content, v_sod: vegetative superoxidase dismutase activity, r_sod: reproductive superoxidase dismutase activity, v_pod: vegetative peroxidase activity, r_pod: reproductive peroxidase activity, v_cat: vegetative catalase activity, r_cat: reproductive catalase activity, tsw: total seeds weight, thsw: thousand seed weight, gy: grain yield, sy: stover yield, awp: apparent water productivity.

Fig. 9

Heatmap showing the relation of maize hybrids, biochar amendments and plants growth attributes at vegetative, reproductive and maturity stages. Abbreviations: rfw: root fresh weight, rdw: root dry weight, sfw: shoot fresh weight, sdw: shoot dry weight, lfw: leaf fresh weight, ldw: leaf dry weight, la: leaf area, nar: net assimilation rate, rgr: relative growth rate, v_msi: vegetative membrane stability, r_msi: reproductive membrane stability, v_mda: vegetative malondialdehyde content, r_mda: reproductive malondialdehyde content, v_pc: vegetative protein content, r_pc: reproductive protein content, v_sod: vegetative superoxidase dismutase activity, r_sod: reproductive superoxidase dismutase activity, v_pod: vegetative peroxidase activity, r_pod: reproductive peroxidase activity, v_cat: vegetative catalase activity, r_cat: reproductive catalase activity, tsw: total seeds weight, thsw: thousand seed weight, gy: grain yield, sy: stover yield, awp: apparent water productivity.