Effect of 46 years' application of fertilizers,FYM and lime on physical,chemical and biological properties of soil under maize–wheat system in an acid Alfisol of northwest Himalayas

Imbalanced fertilizer use with intensive cropping has threatened the sustainability of agroecosystems, especially on acid soils. An understanding of the long-term effects of fertilizers and amendments on soil health is essential for sustaining high crop yields. The effects of application of fertilizers, and amendments for 46 years on soil properties and maize yield in an acid Alfisol were investigated in this study. Ten fertilizer treatments comprising different amounts of NPK fertilizers, farmyard manure (FYM) and lime, and one control, were replicated three times in a randomized block design. At 0–15 cm soil depth, bulk density was least (1.20 t/m³), porosity (49.8%) and water holding capacity (61.7%) were greatest in 100% NPK + FYM, corresponding to the largest organic carbon content (13.93 g/kg). Microbial biomass C and dehydrogenase activity in 100% NPK + FYM were 42% and 13.7% greater than 100% NPK, respectively. Available nutrients were significantly more with 100% NPK + FYM and 100% NPK + lime than control and other fertilizer treatments. At 15–30 cm depth, the effect of various treatments was comparable to the surface layer. Grain yield declined by 55% and 53% in 100% NPK(-S) and 100% NP, respectively, compared with 100% NPK, whereas 100% N as urea alone eventually led to crop failure. Soil porosity recorded the greatest positive correlation (r = .933**), whereas bulk density recorded a negative significant correlation (r = −.942**) with grain yield. The results suggest that integrated use of FYM/lime with chemical fertilizers is a sustainable practice in terms of crop yield and soil health, whereas continuous application of urea alone is detrimental to the soil health.     

Effect of Continuous Application of Fertilizers,Farmyard Manure and Lime on Soil Fertility and Productivity of the Maize-Wheat System in an Acid Alfisol

A study on the long-term effect of fertilizers and amendments on crop productivity and changes in soil fertility in maize-wheat cropping system in an acid Alfisol was carried out in randomized block design (RBD) with 11 treatments. Continuous application of chemical fertilizers along with farmyard manure (FYM) or lime significantly influenced the grain and straw/stover yield and the uptake of nutrients by wheat and maize crops significantly. The organic carbon content increased from 7.9 to 12.1 g kg^?1, cation exchange capacity (CEC) from 12.1 to 14.6 cmol (p⁺) kg^?1 and available phosphorus from 21.9 to 75.2 kg ha^?1 through the integrated use of organic and fertilizers for the last 42 years while the status of available nitrogen (N) and potassium (K) declined over the years in all the treatments. Continuous application of urea alone resulted in a drastic decline in soil pH at both depths. Imbalanced use of fertilizers led to a significant reduction in the productivity of both crops and depleted the soil fertility.     

Effect of a four-decade long application of fertilizers,farmyard manure and lime,on forms of soil acidity and their relationship with yield of wheat and maize in an acid Alfisol

The present investigation was undertaken in the on-going long-term fertilizer experiment initiated during 1972 at experimental farm of Department of Soil Science, Himachal Pradesh Agricultural University, Palampur, India. Continuous application of fertilizers either alone or in combination with farmyard manure (FYM)/lime affected different forms of soil acidity (total acidity, total potential acidity, pH dependent acidity, extractable acidity, exchangeable acidity, and non-exchangeable acidity) significantly, in surface and sub-surface layers. Continuous cropping with the application of lime and optimal doses of fertilizers decreased different forms of soil acidity at all the depths, significantly. Highest productivity of wheat and maize was recorded in 100% (nitrogen, phosphorus, potassium) NPK + FYM, which was at par with 100% NPK + lime. Different forms of soil acidity were found to be negatively correlated with wheat and maize yield. Grain and straw/stover yield of wheat and maize showed the highest negative correlation values with non-exchangeable acidity.     

Effect of a decade-long chemical fertilizers and amendments application on potassium fractions and yield of maize​–wheat in an acid Alfisol

Effect of long-term addition of chemical fertilizers with or without amendments was studied on different forms of potassium and the yield of maize and wheat. Continuous application of chemical fertilizers and amendments for 40 years influenced different fractions of potassium significantly. Integrated use of a balanced dose of chemical fertilizer, with farmyard manure (FYM) or lime, sustained higher yields of maize and wheat in comparison to inorganic fertilizers alone. Application of urea (100%) N alone for 40 years resulted in zero yield level. Continuous application of chemical fertilizers either alone or in combination with FYM or lime influenced different fractions of potassium significantly. Continuous cropping without fertilization resulted in depletion to the order of 21.5%, 16.6%, 11.7%, and 5.5% in water-soluble, exchangeable, 0.5 N HCl extractable, and non-exchangeable K, respectively. Different fractions of potassium were found to be positively and significantly correlated with grain and stover/straw yield of maize and wheat.