Spatial and temporal variability of soil fertility for crop management under calcareous soil conditions [electronic resource].

Includes references.

the uniformity trial was conducted during winter wheat season at El-Hangar area (El-Tanmeya Village) to study the effect of several combinations and rates on NPS fertilizer applications to calcareous soils on field spatial and temporal variability of nutrients level and yield. Descriptive statistical analysis showed that the variance values of available and uptake of phosphorus and iron in tillering and heading stages and grain yield represent the highest vatiance among different variables under study. Semi-variogram and the best fitting were exponential and spherical models for soil pH and soil salinity (ED, dS/m) values fitted Gaussian and exponential models in tillering and heading stages. Data showed that the nugget variance values of pH and EC were 4.62, 7.62 and 3.60, 4.42 m, respectively, which reflects medium to strong spatial dependence and inherited variability.. Semi-variogram were Gaussian and exponential models for the available phosphorus (P) and iron (Fe) values fitted Gaussian and' spherical models in tillering and heading . stages. Data reveal that the nugget variance values of available P were 39.60 and 25.87 m which reflects strong spatial dependence, while available Fe values were 0.64 and 0.18 m. Its values indicated their weak spatial dependence and low inherited variability. P uptake and Fe uptake fitted to exponential model in heading stage. Data showed that nugget variance values of P uptake and Fe uptake were 45.4 m and 3.6 m, which indicated its strong to medium spatial dependence and high inherited variability. Gaussian model for the measured wheat grain and straw yield. Data showed that the nugget variance value of grain yield was 3.93 m, which reflects medium to strong spatial dependence and inherited variability. Moreover, its value of straw yield was 0.16 m, indicating its weak spatial dependence. The kriging maps were drawn to indicate the inherited spatial micro-variability distribution of pH, EC, available and uptake of phosphorus and iron, grain and straw yield. Data were tested for spatial correlation using autocorrelation function. The data showed the autocorrelation values of grain yield gradually decreased from 0.76 to -0.09 with increasing the distance (log). While, the cross autocorrelation values of grain and straw yield increased with distance indicating that spatial correlation in experimental exists between plots even at large separation distance.

Summary in Arabic.

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