Spatial Variability Of Soil Water Content And Soil Properties And Its Effects On Yield And Quality Within A Vineyard Of Arid Region In Northwest China

The Shiyang River Basin belongs to a typical arid inland basin with water shortage. This region has abundant light resource which is highly suitable for planting wine grapevine. In recent years, wine grapevine becomes one of most important local cash crops. However, for a long time the traditional extensive field management resulted in low production and water use efficiency. With the development of agricultural automatization and "3S" technology, precision agriculture would be one of the best selections to improve production and water use efficiency. Therefore, study on spatial variability of grape yield and quality and its possible association with soil properties have important theoretical and practical significance for applying precision agriculture.The study was carried out at huangtai vineyard at the Wuwei Experimental Station of Crop Water Use, Ministry of Agriculture, located in Gansu Province of northwest China from2012to2013. Grape yield, quality, topography and some soil properties were measured with the geo-referenced points, which were located on a regular grid of25m×25m, and their spatial variability were analyzed using classical statistics and geostatistical methods with related sofftware(i.e., Arcgis10.0、GS+9.0、SAS9.0and SPSS20.0). The main results are as follows:(1) The coefficient of variation (CV) of spatial soil water content ranged from14.45%to31.8%and decreased with higher spatial mean soil water content, and data on the CV and mean soil water content were fitted with the exponential model. Soil water content was significantly and consistently correlated with soil texture and bulk density, while correlations with topography were mostly insignificant. The spatial structure of soil water content was found to be similar at different periods of irrigation cycles, and structure variation explained about80%of total variation.(2) The mean grape yield for2012and2013were1.32and1.28kg/vine. The spatial structure of yield was similar between two years, but spatial structure of quality parameters was instability between years. Yield was significantly negative correlated with surface soil water content, and its correlation coefficient decreased with soil depth increasing, there was no correlation between them below60cm depth.(3) The maximum change of soil water content (△θ) in2012and2013were all at flowering+berry development stage, and their maximum diary values were all at veraison stage, respectively. Under the standardized△θ(01] condition, parameters associated with soil water movement for0-20cm and soil fertility parameters for20-40cm were significantly different between low and high yield zones, but under the standardized△θ[-2-1] condition soil properties were almost no significant different between high and low zones in both years.(4) Most part of total yield spatial variability could not be explained by soil properties. In the explainable part, nonspatial soil variation explained more total yield spatial variability than others, and spatial variation not shared by soil variables explained very less total yield spatial variability at high yield zone, increased at medium yield zone, and the largest at low yield zone.