Monitoring changes in soil organic carbon pools, nitrogen, phosphorus, and sulfur under different agricultural management practices in the tropics

Abstract

Soil organic matter not only affects sustainability of agricultural ecosystems, but also extremely important in maintaining overall quality of environment as soil contains a significant part of global carbon stock. Hence, we attempted to assess the influence of different tillage and nutrient management practices on various stabilized and active soil organic carbon pools, and their contribution to the extractable nitrogen phosphorus and sulfur. Our study confined to the assessment of impact of agricultural management practices on the soil organic carbon pools and extractable nutrients under three important cropping systems, viz. soybean-wheat, maize-wheat, and rice-wheat. Results indicated that there was marginal improvement in Walkley and Black content in soil under integrated and organic nutrient management treatments in soybean-wheat, maize-wheat, and rice-wheat after completion of four cropping cycles. Improvement in stabilized pools of soil organic carbon (SOC) was not proportional to the applied amount of organic manures. While, labile pools of SOC were increased with the increase in amount of added manures. Apparently, green manure (Sesbania) was more effective in enhancing the lability of SOC as compared to farmyard manure and crop residues. The KMnO(4)-oxidizable SOC proved to be more sensitive and consistent as an index of labile pool of SOC compared to microbial biomass carbon. Under different cropping sequences, labile fractions of soil organic carbon exerted consistent positive effect on the extractable nitrogen, phosphorus, and sulfur in soil.

Effects of contrasting soil management regimes on total and labile soil organic carbon fractions in a loess soil in China

“…This is consistent with observations by Blair et al (2006) and Rudrappa et al (2006). Similar concentrations of KMnO 4 C following manure and straw amendments have also been reported under wheat-maize and rice-wheat systems by Verma et al (2010), and are probably related to the similar amounts of lignin supplied in the SNPK and MNPK treatments because the KMnO 4 C content of organic materials (straw and manure) do not correlate with their total C contents but significantly correlate with their lignin contents (Tirol-Padre and Ladha, 2004). In addition, Blair et al (2006) observed similar KMnO 4 C contents in chemically fertilized and unfertilized soils.…”

Site Specific Nutrient Management of an Intensively Cultivated Farm Using Geostatistical Approach

“…4D) due to accumulation of phosphorus in the crop field for longer period of cultivation. High level of available P was also reported by Verma et al [29] for soils of IARI farm. The delineated map showed presence of medium level (4.5-11.2 mg kg -1 ) of available P in the south and south-eastern corner of IARI farm.…”

Long‐Term Effects of Soil Fertility Management on Carbon Sequestration in a Rice–Lentil Cropping System of the Indo‐Gangetic Plains

“…Sustainable yield index reflects the stability of yield with different management practices withstanding variations of rainfall and other climatic conditions. A balanced application of plant nutrients, organic amendments, and inclusion of legumes can enhance and sustain SOC concentration and stock (Majumder et al, 2007; Mandal et al, 2008; Verma et al, 2010; Srinivasarao et al, 2011).…”