Investigating the Effect of Wheat and Rice Straw Biochars on Some Strawberry (Fragaria×ananasa) Characteristics

One of the main factors in increasing the quantity and quality of crops is increasing soil organic matter. Biochar is a form of material burned in special conditions and added to soil as organic material, which increases soil organic matter and reduces environmental hazards. The increase in organic matter improves the physical, and chemical properties of the soil, and ultimately increases the absorption of the elements by the plant. Biochar is one of the methods for increasing organic matter in the soil, which is produced by burning in low oxygen conditions. There are many studies that show that the use of coke can be beneficial for plant growth. Fragaria ananasa is an important plant in nutrition of human that cultivated extensive area of the world. The purpose of this study was to investigate the effect of two types of biochar produced from wheat and rice straws on some of the characteristics of strawberry cv. Kurdestan.

This research was conducted as a factorial based on a randomized complete block design with three replications. Each block contained 15 pots and 45 plants were planted in each pot. The treatments included 1.5 and 3% of the two types of straw, wheat and rice residues, along with three levels of chemical fertilizer containing zero, 50 and 70 % of the plant requirements. In order to prepare the biochar, wheat and rice straw separately put in a special container made for this purpose and were placed in an electric furnace at 550 °C for 2-2.5 hours. In this research, yield, fresh weight of the plant, number of fruits were measured by conventional methods. The amount of nitrogen, phosphorus, potassium and iron elements in two parts of the fruit and shoot were measured by Kjeldahl method, spectrophotometry, flame photometric sulfuric acid digestion and atomic absorption spectrometry, respectively.

The results showed that the highest fruit yield was obtained in 70 % of fertilizer application and 3% of wheat straw (83.3 g per plant). Reason of increasing yield was to provide elements and improved conditions of soil. The results showed that the increase in the amount of chemical fertilizer and biochar significantly increased the plant yield. The greatest effect of biochar was observed when the chemical fertilizer has been sufficiently provided. The results showed that in the treatment of 70% of fertilizer requirement, using wheat and rice straws, nitrogen content increased to 0.7 and 0.5 g/100g of dry matter, respectively. The results have shown that the use of biochar has led to an increase in the fresh weight of the aboveground of the strawberry plant. The amount of phosphorus was 0.31 g/100g of fruit in the absence of chemical fertilizer and biochar. By increasing the requirement to 70% of chemical fertilizers plus 3% of rice straw the amount of phosphorus in the fruit reached to 0.37 g/100g . Results showed that the highest amount of iron in the fruit is found in 70% of fertilizer and 3% of biochar, equal to 13.5 mg/100g in the fruit. Also, the highest amount of iron in the aboveground obtained at the same treatment with 14.8 mg/ 100g.

The burning of plant remains naturally induced a lot of damages on the farm, causing soil degradation and reduces plant yield. The results of this study and other researchers show that the use of biochar is an appropriate method for converting plant debris into useful material. The increase in the amount of biochar will improve the absorption of the elements needed by the plant. As a result, providing the nutrients needed for the plant will perform better. In general, the results showed that use of both types of biochar has a very beneficial effect on strawberry plants, and the biochar derived from wheat straw have better effect than rice straw on the plant quality and quantity properties. The fruits have been improved by using biochar and chemical fertilizer. This indicates the basic role of the chemical fertilizers that cannot be completely eliminated and should only reduce their consumption.