1Department of Agricultural Chemistry and Soil Science, Bidhan Chandra Krishi Viswavidyalaya, Mohanpur, West Bengal-741252
2Department of Soil Science, Punjab Agricultural University, Ludhiana-141004, Punjab
The present field study was conducted to study the effect of long-term poor quality irrigation water and crop residue incorporation on phosphorus (P) content in grain and straw in a rice-wheat cropping system. The long-term experiment had 16 treatment combinations involving four irrigation water qualities: canal water irrigation (SW1), sodic water (SW2), sodic water plus gypsum (SW3) and saline water (SW4) and four crop residue treatments: 6 t wheat straw ha−1 to rice (T1), 6 t rice straw ha−1 to wheat (T2), rice straw to wheat and wheat straw to rice at 6 t ha−1 each (T3) and the unamended control (T4). Irrigation water and crop residue treatments significantly influenced P concentration of grain and straw of wheat as well as rice. Mean value of P content was observed to be the highest under good quality water treatment (SW1) and the least under saline water treatment. Mean P content in wheat grain and straw were in the order of T3 > T2 > T1 >T4. Maximum Cl− and HCO3− contents were observed in saline water treatment that had not received any crop residue amendment (SW4T4) whereas the lowest values of these ions were found in soil treated with good quality water and both rice and wheat straw amendment (SW1T3) in subsequent seasons. The study showed that adverse effect of poor quality irrigation waters on plant uptake of major nutrients can be managed by incorporating crop residues.
Crop residues, Phosphorus, Rice-wheat, Saline water, Sodic water
