Results

The different effects on wheat field between conventional fertilizer and new types of fertilizers

To compare the effects of conventional fertilizers and new fertilizers, we selected three treatments for analysis: CK (no nitrogen fertilizer applied), AMS at a specified nitrogen rate combined with biochar, and CCT-BL at the same nitrogen rate. Since the new fertilizers included biochar, we also incorporated a treatment with conventional fertilizers containing biochar for comparison. Our study revealed that regardless of the type of fertilizer used, applying nitrogen fertilizers significantly improved wheat growth compared to the control without nitrogen (Fig. 1). Nitrogen fertilizers increased the stem biomass of wheat (Fig. 1a), resulting in an additional 1014.52 kg/ha of stem biomass. Moreover, the wheat yield with CCT-AS as the nitrogen source increased by 1111.24 kg/ha, suggesting that this novel fertilizer formulation could enhance wheat production (Fig. 1b). However, compared to conventional fertilizers, the application of CCT did not significantly enhance the plant's uptake of elements such as carbon (C), nitrogen (N), and phosphorus (P) (Fig. 1c, d, and e). Interestingly, the use of CCT-AS did influence grain nutrient absorption (Fig. 1f, g, and h), with nitrogen, carbon, and sulfur uptakes in grain increasing by 30.41 mg/kg, 467.61 mg/kg, and 1.36 mg/kg, respectively. These findings highlight the potential of CCT-AS to enhance soil nutrient capacity while positively affecting wheat production and nutrient absorption.

The new type of fertilizer can use biochar more efficiently

This analysis aimed to determine whether applying biochar influences wheat biomass, yield, and nitrogen use efficiency (NUE) and to evaluate how different types of fertilizers affect wheat NUE. Results indicated that conventional fertilizers combined with biochar did not enhance wheat biomass, yield, or NUE (Fig. 2). In contrast, treating the soil with CCT-AS and biochar significantly increased wheat NUE, suggesting that this novel fertilizer formulation, when combined with biochar, enhances nitrogen utilization efficiency. Specifically, the application of CCT-AS with biochar increased biomass, yield, and NUE by 396.90 kg/ha, 506.02 kg/ha, and 18.08%, respectively, compared to conventional fertilizers with biochar. Furthermore, replacing conventional fertilizers containing biochar with innovative fertilizers resulted in even greater improvements, with biomass, yield, and NUE increasing by 1014.52 kg/ha, 1111.24 kg/ha, and 25.49%, respectively. These findings highlight the potential of CCT-AS and biochar to enhance wheat productivity and nitrogen efficiency effectively. 

Fig. 2: The contribution of different types of fertilizers with biochar on the wheat field by ANOVA analysis. (a) the contribution on stem biomass; (b) the contribution on yield; (c) the contribution on NUE. Different colors stand for different treatments. Yellow box stands for AMS @ N-rate treatment; green box stands for AMS @ N-rate + Biochar; blue box stands for CCT-BL @ N-rate. The red dots in the box stand for the mean of the variable. ‘NS’ stands for no significance, and “*” stands for P < 0.05.

We discovered that adding biochar improved the efficiency of CCT-AS (Fig. 2). As a result, we needed to determine what carbon concentration of biochar would serve as a more effective incentive for CTT-AS efficiency. We discovered that if the CCT-AS had more carbon content biochar, the value of the variable increased, implying that CCT-AS combined with high carbon content biochar has a greater influence on the wheat crop (Fig 3). We discovered that CCT-AS with high C content biochar can boost wheat yield, element uptake in grain and NUE.

Fig. 3: The effect of CCT fertilizers adding different carbon content of biochar on wheat fields by unpaired t test. (a). biomass; (b). yield; (c) NUE; (d) N uptake of plant; (e) C uptake of plant; (f) S uptake of plant; (g) N uptake of grain; (h) C uptake of grain; (i) S uptake of grain. Different colours stand for different treatments. The red dot stands for mean of variable. ‘NS’ stands for no significance, “*” stands for P < 0.05, “**” stands for P < 0.01. The units of element uptake are mg/kg.

In different treatments, the application of CCT with low biochar significantly increased the total nitrogen (N) uptake of wheat (P<0.05, Fig. 4a). However, regardless of whether new fertilizers or conventional fertilizers were applied, there were no significant changes in the total sulfur (S) or carbon (C) uptake of wheat (Figs. 4b, 4c).

Fig. 4. The total element uptake of wheat in different treatments

The new type of fertilizer can enhance biomass and yield by increasing crop NUE

     We determined the relationship between biomass and yield, respectively. We found that the stem biomass (R2 = 0.58, P < 0.05) and wheat yield (R2 = 0.86, P < 0.05) increased when the NUE of wheat increased (Fig. 4).

Fig. 4. Linear regression of the relationship between plant NUE and wheat biomass (red) and yield (blue), respectively.

Our study revealed a significant positive correlation between wheat biomass and yield and the element uptake by the plants (P < 0.05). The application of new fertilizers, including biochar, enhanced nutrient uptake, leading to increased biomass and yield (Fig. 5).

Fig. 5. Linear relationship between the total elemental uptake by wheat and its biomass and yield.

In this trial experiment, the fertilizers used in our treatments served as nitrogen (N) fertilizers. We want to know whether there is a synergistic effect between nitrogen uptake by plant organs and the uptake of other elements. After applying novel fertilizers, we found that plant N uptake and grain S uptake had the highest correlation coefficient, which means the positive effect on plant N uptake was mainly from grain S uptake. The grain S uptake and grain N uptake had the highest correlation coefficient, which means the positive effect on grain S uptake was mainly from grain N uptake. The grain N uptake and the grain C uptake had the highest correlation coefficient, which means the positive effect on grain N uptake was mainly from grain C uptake. The grain C uptake and yield had the strongest positive correlation. Plant S uptake and plant C uptake had the strongest positive correlation. The plant C uptake and biomass had the strongest positive correlation (Fig 6).

Fig. 6. Heat map illustrating the correlation between nutrient uptake in wheat plants and grains. The number manes correlation coefficient. N uptake of P stands for nitrogen uptake of plant; C uptake of P stands for carbon uptake of plant; S uptake of P stands for sulfur uptake of plant; N uptake of G stands for nitrogen uptake of grain; C uptake of G stands for carbon uptake of grain; S uptake stands for sulfur of grain. Red color means positive correlation, and blue color means negative correlation