Effect of zinc sulphate application and the cyclic incorporation of cereal straw on yields, the tissue concentration and uptake of Zn by crops and availability of Zn in soil under rice–wheat rotation
Rama Dwivedi
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Prakash Chandra Srivastva
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R. Dwivedi (&) P. C. Srivastva Department of Soil Science, College of Agriculture, G. B. Pant University of Agriculture and Technology
, Pantnagar 263145, Uttarakhand,
India
Background Soil incorporation of cereal straw to avoid burning and air pollution may influence the availability of Zn, a critical micronutrient in cereal production. Field experiment was carried out to evaluate the effect of zinc sulphate application and the cyclic incorporation of cereal straw on the yields, tissue concentration and uptake of Zn by rice and wheat crops and availability of Zn in soil. Results Application of 25 kg ZnSO4 ha-1 to I year rice crop increased the grain yields of rice by 24.3 and 56.3 % over control during I and II year, respectively. Application of 25 kg ZnSO4 ha-1 to I year rice crop ? cyclic incorporation of 1.5 t straw ha-1 increased the grain yields of rice by 21.4 and 87.4 % over control during I and II year, respectively. In I year, the grain yield of wheat crop was not significantly influenced by the different treatments while in II year the highest wheat grain yield was recorded with 25 kg ZnSO4 ha-1 to I year rice crop ? cyclic incorporation of 6.0 t cereal straw ha-1. Application of 25 kg ZnSO4 ha-1 to I year rice ? cyclic incorporation of 1.5 t straw ha-1 resulted in a significant increase in the concentration of Zn in the plant tissues of both rice and wheat crops. The cyclic incorporation of 1.5-3.0 t cereal straw ha-1 maintained better availability of ZnSO4 applied to I year rice crop to the subsequently grown crops. Conclusion Soil application of 25 kg ZnSO4 along with incorporation of 1.5 t cereal straw ha-1 prior to I year rice transplanting followed by cyclic incorporation of cereal straw in subsequent crops ensures higher availability of Zn in soil and higher yields in rice-wheat rotation.
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Zinc deficiency is a worldwide problem in crop production
and a serious problem, especially in rice croplands of Asia
(Tisdale et al. 1997). Usually, soil application of 25.050.0
zinc sulphate heptahydrate ha-1 is done to correct the
deficiency; however, the availability of soil applied Zn is very
poor and declines with time (Srivastava et al. 2008). It has
been reported that application of 510 t organic manure ha-1
to ricewheat rotation adds useful organic matter to the soil
(Meelu and Morris 1988) and reduces the requirement of Zn
fertilizers by 50 % (Sakal et al. 1985). However, owing to
increasing mechanization in agriculture the population of
farm cattle has declined and the availability of organic
manures to the farmers in Asia is very poor. A major issue for the
sustainability of agricultural systems in the developing
countries is the management of soil organic matter through the
rational use of organic inputs such as animal manures,
industrial wastes, green manures, and crop residues (Singh
et al. 1986; Powlson 1994). The use of industrial wastes as a
substitute of organic manure is also limited due to the possible
presence of toxic organic and inorganic constituents in these
materials. This leaves recycling of crop residues as one of the
easiest option to ensure the conservation of soil organic matter
and help reducing the dependence on chemical fertilizers.
Ricewheat cropping system is one of the most widely
practiced system covering about 12 million ha area in India alone
(Prasad et al. 2000). A considerable area under rice and wheat
is now mechanically harvested using combine harvesters. The
crop residues left in the field after the harvesting are generally
burnt by the farmers to facilitate the seedbed preparation and
seeding of the subsequent crop. This leads to twin problems of
the loss of useful plant nutrients and the pollution of air
(Hanafi et al. 2012). Application of chemical fertilizers
supplying only N, P and K to ricewheat rotation has undoubtedly
increased the production of food grain in the past decades in
many Asian countries, but simultaneously it has also led to the
emergence of some additional nutrient deficiencies
particularly, of micronutrients like Zn in soils. With the recycling of
crop residues in ricewheat rotation, a part of Zn taken up by
the previous crop could be recycled back to the soil to partly
reduce the dependence on chemical zinc fertilizer. Besides
this, the organic acids produced during the decomposition of
incorporated cereal residues might also improve the
availability of Zn in the soil. The present investigation was
conducted to study the effect of zinc sulphate application with or
without cyclic incorporation of cereal straw on the yields, Zn
concentration and uptake by crops and the contents of
DTPAextractable Zn in the soil under ricewheat rotation.
Materials and methods
Field experiments
A field experiment was conducted during 20052007 at
Crop Research Centre, Govind Ballabh Pant University of
Agriculture and Technology, Pantnagar, District Udham
Singh Nagar, India, situated at 29 N latitude, 79.3 E
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