Impact of long-term phosphorous fertilization on Olsen-P and grain yields in maize–wheat cropping sequence

• Published in: Nutrient cycling in agroecosystems 2016-11, Vol.106 (2), p.157-168
• Main Authors: Singh, Jagdeep, Brar, Babu S., Sekhon, Bharpoor S., Mavi, Manpreet S., Singh, Gurbir, Kaur, Gurpreet
• Format: Article
• Language: English
• Subjects: Agricultural ecosystems; Agricultural production; Agriculture; Biomedical and Life Sciences; Cereal crops; Corn; Crop growth; Crop yield; Cropping sequence; Cropping systems; Crops; Cultivated lands; Economics; Fertilization; Fertilizers; Graphical methods; Life Sciences; Mathematical models; Nutrient cycles; Original Article; Phosphorus; Profitability; Soils; Statistical analysis; Statistical methods; Statistical models; Triticum aestivum; Wheat; Zea mays
• ISSN: 1385-1314; 1573-0867
• DOI: 10.1007/s10705-016-9796-8

Due to generally low phosphorus (P) recovery efficiency in maize–wheat cropping systems in northwest India, farmers have over-applied P fertilizers over many decades to improve crop growth and increase profitability. This practice caused a considerable part of cultivated land to have ‘very high’ (>50.0 kg P ha −1 ) Olsen-P values in soil. This study was aimed at finding critical concentrations of Olsen-P for maize ( Zea mays L.) and wheat ( Triticum aestivum L.) sequence for effective utilization of buildup P and optimal P rates for maintaining critical Olsen-P in soil in this region by utilizing one long-term (11 years) and 2 short-term (3 years) trials. Long-term studies in high Olsen-P soils showed increased P buildup with present recommended fertilizer P application rates of 26 kg ha −1 to both crops. With no P application, Olsen-P values in soils decline at rate of 3.0 kg P ha −1  year −1 . For sustaining maize and wheat yields, critical concentrations of Olsen-P obtained from different statistical models (linear plateau, quadratic plateau and exponential) range from 36.7 to 50.0 kg P ha −1 for maize and 39.4–57.1 kg P ha −1 for wheat and 38 kg P ha −1 for both crops using Cate and Nelson split method. The use of Mitscherlich equation for determining the ‘effective’ P and Olsen-P requirement for getting higher yields was found to be a better method compared to above-mentioned statistical and graphical methods. Mitscherlich equation estimates the amount of P applied to achieve the desired Olsen-P levels in soil.