Effect of different agricultural managements on the reduction of dust damage on wheat yield

In Iran, salinity is a pervasive and limiting Factor of agricultural sustainable production. Plants in saline conditions are exposed to limited absorption of nutrients, water and toxicity of some elements and subsequently, their yield will be affected by salinity. Moreover, dust storms in arid and semi-arid climates are one of the most important environmental and pollution problems, as they directly and indirectly reduced the quality and quantity of agricultural products. Dust occurrence frequency in the country, especially in the western and southwestern regions increased in the last decades. Hence, increased dust occurrence frequency and intensity during the growth period of agricultural crops is one of the most substantial risks in agricultural sustainable production in Khuzestan province. Thus, the aim of the study was to investigate the effects of dust occurrence and farm management practices applied to reduce the effects of this stress on wheat yield indices as a strategic agricultural product in Khuzestan province.

This study was carried out in Khuzestan province in a calcareous and saline soil with clay loam texture under wheat cultivation (Barat cultivar) as a split plat experiment in a randomized complete blocks design with three replications. Two agricultural farm managements included 1) the custom of the farmer (traditional farming) and 2) nutrition management (soil test, soil balanced and complementary nutrition) based on plant phenological growth stages. In each farm management operation, four leaf washing treatments including 1) without leaf washing, 2) leaf washing after the occurrence of dust phenomenon in the tillering stage, 3) leaf washing after the occurrence of dust phenomenon in the booting stage and 4) leaf washing after the occurrence of dust phenomenon in both the tillering and booting stages, in plots with an area of 20 m2 were applied in three replicates. At the end of the growth season, wheat yield indices involved thousand kernel weight, number of grains per spike, biomass weight, grain yield and the number of tillers per square meter in different treatments were determined. SAS v.9.1 statistical software and Duncan's multiple range test were used to compare the means of the studied treatments.

The results showed that the highest wheat grain yield was observed in the treatment of balanced nutrition management and leaf washing after dust occurrence at two wheat growth stages (5180 kg ha-1), while the least wheat grain yield was in the traditional management and no leaf washing treatment (2830 kg ha-1). The interactions of farm management practices and different leaf washing treatments on biomass, grain yield, harvest index, thousand kernel weight and number of tillers per square meter were significant (p< 0.01). In the traditional management of the farmer, using the plant leaves washing at only one wheat growth stage after the occurrence of dust caused about 30% increase in wheat grain yield on average (24 and 35% increase in grain yield as a result of leaf washing after dust, respectively, in the tillering and booting stages). While in the traditional management and leaf washing at both two stages of wheat growth, it increased the wheat grain yield by 43%. In addition, the results showed that by using balanced nutrition management without leaf washing, wheat grain yield and harvest index increased by 10 and 9%, respectively. Application of balanced nutrition and leaf washing after the dust occurrence at both two wheat growth stages (tillering and booting) caused 32, 59, 21 and 11% increase in biomass, grain yield, harvest index and thousand kernel weight of wheat.

Based on the results of this research, it was found that the use of different management operations in the farms, such as balanced nutrition of the crop based on the plant growth phenological stages and the leaves washing after the occurrence of dust, can significantly reduce the damage of wheat yield caused by the occurrence of dust. However, it should be noted that despite the positive and significant effect of washing the plant leaf surface after the occurrence of dust phenomenon on reducing wheat yield damage, the time of leaves washing application is very important. Because if immediately after washing the leaf surface of the plant, the dust phenomenon occurs again, the wetness of the plant leaf surface causes more dust particles to deposit on it and the damage caused by dust on wheat yield indices increases.
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