Water Requirement and Precipitation Suitability of Apple Planting in Northern China

Abstract

Precipitation is the main water source of apple production in northern China. Under the background of climate change, it is of great significance for apple planning to study the apple water requirement and precipitation suitability. Based on daily meteorological data and 1 km resolution digital elevation data of 210 meteorological stations in the study area and its surrounding area, the minimum humidity method is used to estimate the daily crop coefficient (Kc), and the spatial interpolation software ANUSPLIN based on spline function interpolation theory is applied. Then the water requirement and precipitation suitability of apple are calculated. According to the geographical distribution of the main planting area and percentile method, the threshold value range of precipitation suitability and optimal critical value of precipitation suitability are determined respectively. Using geographic information system (GIS) software ArcGIS, coefficient of variation, climate tendency rate and other related mathematical statistical methods, the spatial and temporal variation characteristics of apple water requirement and precipitation suitability in the study area are analyzed, and the precipitation suitability index model of apple in whole growth period is constructed to evaluate the precipitation suitability. Results show that, the average annual water requirement in most areas is 500-800 mm, accounting for 87.1% of the study area. The average water requirement in the main planting areas is basically 500-800 mm.The ratios of the average water requirement in the germination and young fruit stage, fruit expanding stage and coloring and maturity stage to the annual average water demand are 0.186-0.282, 0.392-0.562 and 0.159-0.282, respectively. The threshold ranges of precipitation suitability of apple in the annual, germination and young fruit stage, fruit expanding stage and coloring and maturity stage are 0.49-2.07, 0.25-1.70, 0.54-2.25 and 0.46-2.65, respectively. The optimal threshold values are 0.71, 0.55, 0.82 and 0.56, respectively. Therefore 85.4%, 87.4%, 85.6% and 84.9% of the study area are suitable during each stage. The area from the most suitable critical value to the balance of water supply and demand account for 39.8%, 36.9%, 20.4% and 47.1% of the study area. The most suitable, sub suitable and unsuitable areas in the whole growth stage of apple account for 31.9%, 50.6% and 17.5% of the study area, respectively.

Keywords

• crop coefficient
• key growth stage
• apple
• water requirement
• precipitation suitability