|
|
:
|
Wheat is the most important strategic crop and meets the main food needs in different countries of the world. Balanced nutrition of wheat increases yield and plant resistance to biotic and abiotic environmental stresses. Different methods are used to identify the nutritional status of crops. The method of Component Nutrient Diagnosis (CND) has an advantage over other methods of assessing plant nutritional status such as deviation from optimum percentage (DOP) due to the consideration of nutrients interactions. Because of the importance of diagnosis the nutritional status of wheat, the project was implemented for two years in wheat fields of six provinces (Kurdistan, Fars, Khorasan Razavi, Alborz, Golestan and Khuzestan) of the Iran country for two years. Each year, 20 to 40 farms were selected for sampling the wheat flag leaves and in the collected samples concentration of macronutrients and micronutrients were measured. Data from laboratory analysis were used to interpret nutritional status of wheat with CND and DOP methods. To calculate the optimum ranges and norms of elements with CND method, yield cutoff values for Alborz, Khorasan Razavi, Fars, Golestan, Khuzestan and Kurdistan provinces were 5.1, 7.6, 6.9, 3.5, 6 and 1.7 t/ha, respectively. To calculate norms of elements with DOP method, yield cutoff values for Alborz, Khorasan Razavi, Fars, Golestan, Khuzestan and Kurdistan provinces were 7.1, 9.4, 8.4, 5.4, 6.7 and 2.9 t/ha, respectively.
Examining the norms and indexes of wheat nutrients with both CND and DOP nutritional status diagnosis methods in the low-yielding group showed that there is an excess or deficiency and generally an imbalance of nutrients in the wheat fields of the study areas.
The average CND indices for nutrients in the low yield group from the most negative index were Mg > Mn > N = Cu > K > Fe > P > S > Zn in Alborz, P > Cu > Mn > N > Ca in Fars, P > Cu > Zn in Khorasan Razavi, N > P in Golestan, the nutritional imbalance of N, P and K elements in Khuzestan and N in the dry lands of Kurdistan, respectively. According to the DOP method, the priority of wheat nutrition in was B > Mn > N Alborz, Cu > Mn > P > Ca > N > Fe > K > Mg in Fars, Ca > Mg > Mn in Khorasan Razavi, excess of N in Golestan, P in Khuzestan and N > P in Kurdistan. The fertilization priorities of CND and DOP methods did not match with each other. The fertilization priorities of CND method for Khorasan Razavi province and DOP method for Khuzestan and Kurdistan provinces were relatively consistent with soil testing results. The wheat yields were higher correlated with the nutritional balance indexes of DOP than CND in most of the studied provinces. Therefore, it seems that in this study, the DOP method performed better than the CND method in diagnosing the nutrition status of wheat. However, in both DOP and CND methods, the fertilization priorities obtained in most provinces did not match with the soil testing results. The reasons for this inconsistency can be a small statistical population (small number of selected farms), the high diversity of climatic and soil conditions of the study areas, and the genetic difference of wheat cultivars in terms of nutrient uptake and yield. Therefore, for future studies, the above items must be taken into account, especially selecting a large statistical population, so that logical and usable results can be obtained.
|