BORON – ITS IMPORTANCE IN CROP PRODUCTION, STATUS IN INDIAN SOILS AND CROP RESPONSES TO ITS APPLICATION.

Boron (B) is unique, not only in its chemical properties, but also in its role in biology. Since boron discovery as essential plant nutrient, the importance of B element as an agricultural chemical has grown very rapidly and its availability in soil and irrigation water is an important determinant of agricultural production. Boron deficiency is the most common and widespread micronutrient deficiency problem, which impairs plant growth and reduces yield. Normal healthy plant growth requires a continuous supply of B, once it is taken up and used in the plant; it is not translocated from old to new tissue. That is why, deficiency symptoms starts with the youngest growing tissues. Therefore, adequate B supply is necessary for obtaining high yields and good quality of agriculture crops. Boron deficient soils include those which are inherently low in B, calcareous and coarse textured soils and those high in clay. Among micronutrients, boron deficiency is one of the most crucial constraint limiting nutrient use efficiency and crop yields. Boron toxicity in plants has been reported from many parts of the world but is mostly associated with the use of high- B contaminated water. In view of B deficiency and toxicity in soils and crops, delineation of critical B deficiency and toxicity levels or concentrations is very important. As B is emerging as second most deficient micronutrient in Indian soils, monitoring of its spatial and vertical distribution is very important in order to sustain the crop yields. Application of B at different rates in different crops have shown the positive influence on yield and other agronomic parameters of different crops reflecting the significance of B in enhancing the yield of different crops. In order to maintain an optimum level of B in soils, B fertilisation should form a part of fertiliser schedule for the predominant crops and cropping systems.