Direct effect of boron and zinc on productivity, quality and nutrient uptake by Indian mustard (Brassica juncea) and their residual effect on succeeding pearl millet (Pennisetum glaucum) in mustard-pearl millet crop sequence

A field experiment was conducted at Research farm of Raja Balwant Singh College, Bichpuri, Agra to study the effect of boron and zinc on productivity, nutrient uptake and quality of Indian mustard [Brassica juncea (L.) Czernj and coss.) in mustard-pearl millet [Pennisetum glaucum (L.) R. Br.] cropping sequece during 2015-16 and 2016-17. Boron and zinc levels alone and in different combinations were applied to mustard crop during 2015 and 2016 and their residual effect was studied in succeeding pearl millet crop. Higher levels of B and Zn along with RDF recorded higher growth and yield attributes at harvest, viz. plant height, branches/plant, siliquae/plant, seeds/siliqua and test weight of mustard crop than recommended dose of fertilizers and other treatments. Highest seed and stover yield of mustard crop was recorded with the combined application of 2 kg B + 8 kg Zn/ha along with recommended dose of NPK fertilizers (RDF) which was at par with RDF + 1 kg B + 8 kg Zn/ha, RDF + 1 kg B + 4 kg Zn/ha and RDF + 2kg B + 4 kg Zn/ha, and significantly superior to RDF only and other treatments. The uptake of B and Zn by both seed and stover of mustard crop also increased with increasing levels of both these elements and was superior to RDF as well as RDF along with sole application of B or Zn. Oil and protein contents also followed the same increasing trend. The residual effect of combined application of 2 kg B and 8 kg Zn/ha on the grain and stover yields of succeeding pearl millet crop was also significant; the increases were 18.9 and 20.3% for grain and stover yield, respectively over RDF. Protein content in grain and stover of pearl millet also increased significantly with residual effect of 2 kg B + 8 kg Zn/ha. Boron and zinc uptake by pearl millet crop also showed an increasing trend which was statistically significant over RDF alone and other treatments. The status of B and Zn in post harvest soil also improved with their application.