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A field study was undertaken to extrapolate the impact of foliar application of potash and its spray schedule on yield and physical and chemical parameters of sweet orange cv. Jaffa at experimental orchard, Department of Horticulture, CCS Haryana Agricultural University, Hisar. The results revealed that foliar application of KNO3 at both the doses (2 and 4%) was found significantly or marginally better than K2SO4 (1.5 and 3.0%) and control (water spray) in increasing the juice content. Peel content, peel thickness and rag content was found to be influenced significantly due to different treatments on K and its spray schedule. Minimum rag content (38.11%) was recorded with foliar application of KNO3 at the rate of 4% and maximum with control. Ascorbic acid and acidity were found maximum with two foliar applications of KNO3 at the rate of 4% in the last week of April and August. Foliar application of KNO3 at the rate of 4% was found most effective in increasing yield of sweet orange over control and other K treatments. Spray of K in the last week of April, May and August was found superior in increasing yield closely followed by two sprays in the last week of April and August. The findings signify the importance of K spray in enhancing yield and quality of sweet orange under semi-arid north western conditions of India. [ABSTRACT FROM AUTHOR]

Wild blueberry ( Vaccinium angustifolium Ait.) fields in the north east Canada are naturally grown in a course textured thin layer of soil and below this layer is a soilless layer of gravel. The root zone depth of this crop varies from 10 to 15 cm. Investigating the depth to the gravel layer below the course textured soil is advantageous, as it affects the water holding capacity of the root zone. Water and nutrient management are the two primary determinants of crop yield and the amount of leaching. The objective of this study was to estimate the depth to the gravel layer using DualEM-2 instrument. A C++ program written in Visual Studio 2010 was used to develop mathematical models for estimating the depth to the gravel layer from the outputs of DualEM-2 sensor. Two wild blueberry fields were selected in central Nova Scotia, Canada to evaluate the performance of DualEM-2 instrument in estimating the rootzone depth above the gravel layer. The mid points of squares created by grid lines were used as the sampling points at each experimental site. The actual depth to the interface was measured manually at selected grid points ( n = 50). The apparent ground conductivity (EC) values of DualEM-2 were recorded and the depth to the interface was estimated for the same sampling points within the selected fields. The fruit yield samples were also collected from the same grid points to identify the impact of the depth to the gravel layer on crop yield. After calibrations, comprehensive surveys were conducted and the actual and estimated depths to the interface were established. The interpolated maps of fruit yield, and the actual (z) and estimated ( $$ {\text{z}}_{\text{in}}^{*} $$ ) depths to the interface were created in ArcGIS 10 software. Results indicated that the z was significantly correlated with $$ {\text{z}}_{\text{in}}^{*} $$ for the North River ( R = 0.73; RMSE = 0.27 m) and the Carmel ( R = 0.45; RMSE = 0.20 m) sites. Results revealed that the areas with shallow depth to the gravel layer were low yielding, indicating that the variation in the depth to the gravel layer can have an impact on crop productivity. Non-destructive estimations of the depth to the gravel layer can be used to develop erosion control strategies, which will result in an increased crop production. [ABSTRACT FROM AUTHOR]