Effects of soil zinc availability, nitrogen fertilizer rate and zinc fertilizer application method on zinc biofortification of rice

Abstract

SUMMARYRice (Oryza sativa L.) is one of the most important cereal crops in the world and a potentially important source of zinc (Zn) in the diet. The improvement of Zn content of rice is a global challenge with implications for both rice production and human health. The objective of the present study was to identify the effects of nitrogen (N) fertilizer rates and Zn application methods on Zn content of rice by evaluating rice production on native soils with different Zn availabilities in 2010/11. The results indicated that Zn application increased rice grain yield and Zn content in grains compared with the control; however, this effect was also affected by the native soil Zn availability, N fertilizer rate and Zn fertilizer application method. The native soil Zn status was the dominant factor influencing grain yield and grain Zn content in response to Zn fertilizer application. Grain Zn content ranged from 19·74 to 26·93 mg/kg under the different Zn statuses. The results also indicated that Zn application method has a significant influence on grain yield. Application of Zn fertilizer to the soil was more effective than the foliar spray on rice grain yield; however, the foliar spray resulted in a greater increase in grain Zn content when compared with soil application. Grain Zn content was affected by application method and displayed the following general trend: soil application + foliar spray > foliar spray > soil application. The experiments investigating the effect of N fertilizer rate combined with Zn application method showed a clear increase in both grain yield and Zn content as the N fertilizer level increased from 200 to 300 kg/ha. In addition, the results also indicated that N content and accumulation increased in all plant tissues, which suggests that Zn application might influence the uptake and translocation of N in rice plants. These results suggest that soil application in addition to a foliar spray of Zn should be considered as an important strategy to increase grain yield and grain Zn content of rice grown in soils with low background levels of Zn-associated diethylene triamine pentaacetate acid. Moreover, this process could be further strengthened by a high N application rate. In conclusion, these results demonstrate the potential of optimizing nutrient management using Zn fertilizer to obtain higher grain yields and higher grain Zn content in fields with low native Zn status.

Combined zinc and nitrogen fertilization in different bread wheat genotypes grown under mediterranean conditions

“…This might be related to the low DTPA-Zn levels in soil, indicating that Zn deficiency was a growth-limiting factor on the experimental soils as Cakmak et al (2010) and Gomez-Coronado et al (2016) found in soils with less of 0.3 mg DTPA-Zn kg -1 . Foliar Zn application had not any positive effect on grain yield, in contrast of Karim et al (2012) who found an improvement on growth and antioxidative defence mechanisms of plants against drought-induced oxidative cell damage under drought conditions with foliar Zn sprays but according with Cakmak et al (2010), Gomez-Coronado et al (2016) and Guo et al (2016). The higher grain yield found in both Soil + Foliar treatments and in some cultivars could produce a possible dilution effect.…”

Zinc application in conjunction with urea as a fertilization strategy for improving both nitrogen use efficiency and the zinc biofortification of barley

“…This effect could be due to the fact that Zn acts as a co‐factor for numerous enzymes involved in the metabolism of carbohydrates, proteins and auxins, in membrane integrity, and in flowering and seed production . Various authors have reported increases in the yields of different crops, such as wheat, maize, safflower and rice, with Zn fertilization. In a field experiment using barley as the test plant, Arora and Singh obtained the highest grain and straw yields with the application of 7.5 kg Zn ha −1 and 90 kg N ha −1 ; these yields were not, however, significantly different from those obtained with the application of 7.5 kg Zn ha −1 and 60 kg N ha −1 .…”

“…In addition, the application of Zn to soils can serve as a tool of the agronomic biofortification of crops . Increasing the Zn concentration in grain is therefore a challenge with significant implications for barley production and the nutritional quality of grain …”

Effects of zinc application strategy on zinc content and productivity of chickpea grown under zinc deficient soils

“…Each method has the potential to influence the extent of micronutrient concentration both in the treated plant directly and indirectly through enrichment of the seeds by micronutrient treatment of the parent (Johnson et al, 2005). Much of the research on crop responses to foliar fertilization was done on soybean (Glycine max L.), wheat (Triticum aestivum L.) (Fageria et al, 2009) and rice (Oryza sativa L.) (Guo et al, 2016) with only limited studies on chickpea. Foliar Zn application increased grain and straw Zn concentration in chickpea (Pathak et al, 2012).…”