Research on synergistic substances that increase root surface area by 80% and improve phosphorus use efficiency by 45%, published on JCR

June 11, 2020, Dr. Min Zhang and his group from China National Engineering Laboratory for Efficient Utilization of Soil and Fertilizer Resources in Shandong Agricultural University, studied the effectiveness of conventional diammonium phosphate (DAP), controlled-release diammonium phosphate (CDAP), conventional diammonium phosphate with ZNC (DAPZ), and controlled-release diammonium phosphate with ZNC (CDAPZ) on Maize. The results were published on JCR section 1 journal Field Crop Research, entitled “Maize yield and root morphological characteristics affected by controlled-release diammonium phosphate and Paecilomyces variotii extracts”.

3-year (2016-2018) field research showed that conventional diammonium phosphate applied with ZNC can promote maize root growth, root activities, yield and economic returns. 

Research results

1. Great ability to promote rooting

The researchers found that conventional diammonium phosphate combined with ZNC (DAPZ) significantly increased the total root length, root surface area and root activities of maize. The results showed that the total root length and root surface area increased by 6.8% and 80.4% respectively when treated with DAPZ compared to DAP. At the mature stage, the growth of maize root stopped and the total root length treated with DAPZ increased by 36.6% compared with DAP; the flow rate of stem injury increased by 32.5% at jointing stage and 24.8% at maturity stage.

Root length, volume, surface area, average diameter for different treatments at the soil depths of 0-20, 20-30 and 30-40 cm in maize field at jointing stage (A1, A2, A3, A4) and mature stage (B1, B2, B3, B4).

Bleeding sap rate of maize at jointing (A) and mature (B) stage in 2018 growing season.

2. Content of available P in soil improved

The researchers found that the soil available P increased after it was treated with DAPZ, and the soil available P increased by 45.9% (0-40cm in depth) during the whole growth period compared with DAP.

Available P in the depths of 0-20 cm (A) and 20-40 cm (B) during the 2018 growing seasons.

3. Crop yield improved with great economic returns

The researchers found that DAPZ increased corn yield by 3.6% on average in three years. In this experiment, the use concentration of ZNC was set at 100mg/mu, which was extremely low in dosage and low in use cost, and had certain potential to increase yield, as well as provide good economic benefits.

New discoveries from the research and new ideas

The researchers provided a new model of biogenic hormone combined with fertilizer and exemplified a method of field crop root observation in situ.

After the application of controlled release phosphate fertilizer combined with ZNC in field experiments, it was found that controlled release diammonium phosphate could significantly increase the yield of maize and the yield was consistant compared with conventional diammonium phosphate.

The combination of conventional diammonium phosphate with ZNC showed an increase in yield, which significantly promoted the growth of corn root system and had good potential for increase in yield and economic benefits.

However, there was no superposition of efficacy after the controlled release diammonium phosphate was applied with ZNC.

The field trials showed that both conventional diammonium phosphate and diammonium phosphate with ZNC could significantly promote root growth. 

According to the researchers, for the next step, the synchronous precision release for ZNC and coated diammonium phosphate will be an important part of the research on controlled release diammonium phosphate applied with ZNC. Further research also include ZNC reducing phosphate fertilizer use without decreasing yield, and reducing the fertilizer impact on the environment.

The researchers also pointed out that, more ZNC dosage did not guarantee a higher yield. In a later study, 12.5 mg/mu could provide great potential for yield growth, and further study could be conducted with this dosage.