Introduction
Windbreaks act as natural or artificial barriers that, by reducing wind speed, prevent soil erosion, reduce humidity, and damage to agricultural products, and increase crop efficiency. Due to the specific climatic conditions of Fars Province, where drought and inappropriate temporal and spatial distribution of rainfall are undeniable realities, it can be said that irrigation water is the most important input for agricultural production, and any sustainable food production and agriculture depends on the correct and rational use of the province's limited resources. A review of research conducted at the national level shows that despite the increase in the efficiency and productivity of irrigation water in the field in recent years, for various reasons, including disregard for climate potential and water resources and unplanned development of agricultural lands to meet the food needs of the country's growing population, excessive extraction of groundwater resources and the destruction of aquifers have been witnessed. The aim of this study was to investigate the effect of density and distance from windbreak on the production of wheat and dry fodder, as well as soil moisture retention at a depth of 10 cm. This study was conducted in the 1401-1402 crop year on four homogeneous and uniform wheat plots with identical varieties, planting dates, planting distances, soil characteristics, and irrigation and fertilization conditions in the Shahed area of the Faculty of Agriculture of Shiraz.
Material and Methods
This research was conducted in the 1401-1402 crop year in four homogeneous and uniform wheat crop plots at the Shiraz University of Agriculture farm (crop area about 547 hectares). For this study, three plots with different densities of tree windbreaks (density above 90%, between 40 and 90% and also less than 40%) and one plot without windbreaks were used. To investigate the effect of distance from windbreaks on soil moisture storage parameters and crop yield, distances of 1, 5, 10 and 15 times the height of the windbreak (average height 12 m) were determined in lands with high, medium and low density and without windbreaks, and soil samples and crop yield were collected in three replications from each distance based on a completely randomized block design. To measure the moisture content after sample collection and transfer to the laboratory, the samples were first weighed, then placed in an oven for 24 hours and weighed again. Also, to measure the yield after harvesting a plot (one square meter) of wheat in completely random replications and at specific intervals from different treatments, samples were collected separately and kept in the environment for four days until the moisture in their forage was completely dried. First, the harvested crop was weighed, then the wheat was separated from the forage, and the net weight of wheat and the weight of dry forage were weighed.
Results and discution
The parameters studied were analyzed using SPSS software at a significant level of 5% using Duncan's test. The results of comparing the average percentage of soil moisture retention in three densities, high, medium and low, showed a similar trend with respect to height, such that the lowest moisture loss was at a distance of one height from the windbreak and in the plot of land with a density above 90%. The plot of land with a density below 40% at a distance of 10 meters from the windbreak had a similar performance to the land without a windbreak and did not show an effect in reducing moisture loss. In relation to the amount of crop production, the density above 90% has a more significant difference with other densities, so that the average crop production at different distances (1, 5, 10 and 15 times the height of the windbreak) was 2.24 kg/m2, which decreased to 2.13 kg/m2 at medium density, 1.97 kg/m2 at low density, and 1.94 kg/m2 in the plot of land without a windbreak. In other words, under the same agricultural conditions, the amount of crop produced in the plot of land with medium density was 4.9%, in the plot of land with low density was 12.05%, and in the plot of land without a windbreak was 13.4% less than the plot of land with high density. In the plot of land with low density at all distances from the windbreak, the amount of crop produced in the measured area behaved similarly to the plot of land without a windbreak and did not differ significantly from each other.
Conclusion
The present study investigated the effect of density and distance from windbreaks on the production of wheat and dry fodder, as well as the maintenance of soil moisture at a depth of 10 cm from the soil surface. Windbreaks can reduce water evaporation from the soil and plant surface by reducing wind speed in the areas around them. Therefore, soil moisture is maintained more in lands with windbreaks, which will benefit plant growth and crop production efficiency. As shown in the results, the production and moisture from the soil surface are a function of the height of the distance from the windbreak, and the maximum production was at a distance of five times the height of the windbreak. It is suggested that in studies related to this subject, a plot of land without wheat cultivation and only to examine the soil moisture at different distances from the windbreak should be investigated. Also, for the construction of windbreaks around Shiraz farms, educational and promotional programs should be provided for farmers on the benefits of windbreaks and how to construct them; cultivated fields should be identified, parceled, and prioritized; Also, multipurpose and economically suitable native species for creating windbreaks should be identified and introduced. It is worth noting that creating financial and advisory facilities while encouraging farmers can help accelerate the implementation of this strategy. |
