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1.
Dinesh Kumar Benbi Amardeep Singh Toor Gayatri Verma 《Communications in Soil Science and Plant Analysis》2016,47(15):1828-1844
The study was conducted to investigate the aggregate stability and distribution of organic carbon (C) in different-sized aggregates and mineral fractions in a loamy soil under rice-wheat system with continuous application of fertilizer nitrogen, phosphorus and potassium (NPK), farmyard manure (FYM), N+FYM and NPK+FYM, compared with unfertilized control. Macro-aggregates comprised 37.1–49.3% of the total water-stable aggregates (WSAs), compared with 23.3–30.3% as micro-aggregates. Application of inorganic fertilizers and FYM significantly increased the proportion of macro-aggregates, which were linearly related to total organic C (TOC). Organic C concentration in coarse macro-aggregates (CMacA) was higher than the micro-aggregates (CMicA). Application of FYM significantly increased the concentration of organic C in different-sized aggregates and mineral fraction, compared with the unfertilized control. Averaged across treatments, mineral-associated C comprised 26% of TOC. Macro-aggregates, on an average, constituted 66–68% of C preservation capacity of WSA. The amount of TOC sequestered was higher when NPK+FYM was applied together. 相似文献
2.
Phosphorus (P) in soil exists both in organic and inorganic forms and their relative abundance could determine P supplying capacity of soil. Differential input of exogenous and plant-mediated phosphorus and carbon in soil under different land-uses could influence P availability and fertilizer P management. While the effect of land-use on soil organic carbon (SOC) is fairly well-documented, its effect on soil P fractions is relatively less known. We investigated the effect of different land-uses including rice–wheat, maize–wheat, cotton–wheat cropping systems and poplar-based agroforestry systems on soil P fractions and organic carbon accrual in soils. Total P concentration was the highest under agroforestry (569 mg P kg?1) and the lowest under maize–wheat (449 mg P kg?1) cropping systems. On the contrary, soils under rice–wheat had significantly higher available P concentration than the agroforestry systems, probably because of higher fertilizer P application in rice–wheat and prevailing wetland conditions during rice growth. In soils under sole cropping systems viz. rice–wheat, maize–wheat and cotton–wheat, inorganic P was the dominant fraction and accounted for 92.2–94.6% of total P. However, the soils under agroforestry had smaller proportion (73%) of total P existing as inorganic P. Among soil P fractions, water soluble inorganic P (0.13–0.26%) represented the smallest proportion inorganic P in soils under different land-uses. Agroforestry showed significantly (p < 0.05) higher concentrations of SOC than the other land-uses. Soil organic C was significantly correlated with soil P fractions. It was concluded that poplar-based agroforestry systems besides leading to C accrual in soil result in build-up of organic P and the P supplying capacity of soil. 相似文献
3.
Dhram Prakash D. K. Benbi G. S. Saroa 《Communications in Soil Science and Plant Analysis》2017,48(1):92-106
Information on phosphorus (P) release kinetics and sorption–desorption in soils is important for understanding how quickly reaction approaches equilibrium and replenishes the depleted soil solution. Laboratory experiments were conducted to study the P release and sorption–desorption kinetics in soils differing in clay, soil organic carbon (SOC), available P, and calcium carbonate (CaCO3) contents. Phosphorus release from soils proceeded in two phases: initially faster phase followed by a slower phase as equilibration progressed. Elovich equation (R2 ≥ 0.97**) described well the P release versus time data. P release coefficients for power function were significantly correlated with available P and SOC. Freundlich sorption constants increased with increase in clay and CaCO3 content. With increase in SOC and available P concentration in soils, substantial reduction in sorption constants was observed. It was concluded that for efficient P management, it is important to take into account soil texture, the existing soil P level, SOC content, and soil calcareousness. 相似文献
4.
D. K. Benbi H. S. Thind Shivani Sharma Kiranvir Brar A. S. Toor 《Communications in Soil Science and Plant Analysis》2017,48(15):1822-1833
Disposal of ashes from agro-industrial waste has become an important issue that can cause serious environmental problems. These materials may be used in agriculture for soil fertility improvement and carbon sequestration. The effect of applying bagasse ash (BA), rice husk ash (RHA), and RHA mixed with fly ash (MA) to wheat was evaluated on soil organic carbon (SOC) and microbial activity in a loamy sand soil after four years of wheat-rice cropping. BA application resulted in C accrual at 525 kg ha?1 y?1 in soil, whereas RHA and MA did not have a significant effect. BA increased coarse particulate (cPOC) and mineral-associated organic matter (MinOC) and extractable C pools viz. hot water soluble, potassium permanganate (KMnO4)-oxidizable, easily oxidizable, non-oxidizable, and microbial biomass C. BA application also improved overall microbial and oxidative activity and stimulated fluorescein diacetate (FDA), dehydrogenase, and cellulase enzyme activities in soil. Application of RHA though did not lead to net C sequestration, yet it increased dehydrogenase and cellulase activities. Compared to unamended soil, MA application increased MinOC and FDA activity in soil. After 4 years of their application, none of the ashes adversely influenced soil biological activity expressed in terms of enzyme activities suggesting that these ashes can be disposed to agricultural soils. However, effects of their long-term application on soil biological processes need to be further investigated. 相似文献
5.
Dinesh K. Benbi 《Communications in Soil Science and Plant Analysis》2018,49(17):2103-2112
Precise measurement of soil organic carbon (SOC) is essential for constructing regional inventories, developing best agricultural management practices, and modeling purposes. Currently, the automated dry combustion method is considered standard, but the method is both costly and time-consuming. There is a need for a simple, easy to use and cost-effective method of organic C determination in soil. A simple method of total organic carbon (TOC) determination in soil that involved wet digestion of K2Cr2O7-H2SO4-soil mixture in a commercial microwave oven followed by spectrophotomteric measurement of Cr (III) was evaluated. The method was compared with automated dry combustion and two other wet digestion methods. The method showed close agreement with dry combustion method (R2 = 0.90; root mean square error = 0.70) and the TOC measured with the two methods did not differ for a range of soils drawn from lowland and upland land-uses and varying in pH (6.2–9.3), TOC (2.8–14 g kg?1), and calcium carbonate content (0–6.7%). The recovery of the added organic C by the microwave method was 98.6 ± 4.2%. The results suggested that microwave-spectrophotometric method could be easily adopted in routine soil analysis as it is not only precise, rapid, and cost-effective but also produced small volume of reagent waste. 相似文献
6.
Influence of farmyard manure, inorganic fertilizers and weed control practices on some soil physical properties in a long-term experiment 总被引：4，自引：0，他引：4
Abstract. In a long-term experiment, soil physical properties were studied after 20 annual cycles of maize-wheat-fodder cowpea cropping with annual application of inorganic fertilizers and farmyard manure (FYM). Weeds were controlled by hand or by the use of herbicides. The hand weeding treatment resulted in a lowering of the bulk density of the surface layer (0-15 cm) and a significant increase in the subsurface (15–30 cm) density. Application of FYM significantly increased the soil organic carbon (OC), infiltration rate, water retention, aggregation and aggregate stability in water. Application of inorganic fertilizers had small but statistically significant effect in increasing soil OC. 相似文献
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8.
Saroj Kumar Yadav Dinesh Kumar Benbi Amardeep Singh Toor 《Archives of Agronomy and Soil Science》2019,65(3):374-384
Knowledge of K-dynamics in soils can help devise practices for efficient K management in intensive rice-wheat systems. We studied the effect of long-term application of rice straw, farmyard manure (FYM) and inorganic fertilizer on total K and its distribution among different forms in 60-cm soil profile after 14 years of rice-wheat cropping. The exchangeable, the non-exchangeable and the lattice K respectively comprised 1%, 3–10% and 89–95% of total K in surface soil under different treatments. Application of rice straw and FYM positively impacted total K status of soil and its distribution among different forms. The greatest concentrations of total K, lattice K, exchangeable K and NH4OAc-extractable K were observed in plots receiving both rice straw and FYM together and the lowest in inorganic fertilizer treated plots. On the contrary, the non-exchangeable K was the highest in inorganically fertilized plots and the lowest in rice straw amended plots. The exchangeable, the water soluble and the NH4OAc-extractable K decreased with soil depth and did not indicate K movement beyond the rooting zone of the crops. The results showed that incorporation of rice residue in soil, instead of burning, besides reducing environmental pollution led to improved K-fertility of soils. 相似文献
9.
Microbial biomass in arable soils of Germany during the growth period of annual crops 总被引：1，自引：0，他引：1
Results from several field studies involving numerous measurements were used to describe the change of soil microbial biomass C (Cmic) and N (Nmic) during the growth period of annual crops (years 1988–1992, 1994, 1995) under the temperate climatic conditions of central Europe. The data were taken from our own investigations as well as from the literature. Only studies with at least eight measurements on one plot during the growth period were used. The total number of farms (cash crop–production farms) was 7, that of experimental plots was 15. The evaluation of these results through regression analysis demonstrated that Cmic and Nmic from the beginning of a year increased only slightly until summer and subsequently decreased until autumn to their initial levels. This increase on an average corresponded to a C assimilation of approx. 100 kg ha–1 and an N immobilization of approx. 20 kg ha–1 (30 cm)–1. The increase in Nmic alone could not explain N immobilization rates frequently observed in different studies using 15N‐labeled fertilizers. Most of the labeled N that was immobilized (>50 kg N ha–1) might have accumulated in the matrix of soil organic matter (SOM). Therefore, the changes in microbial biomass may be of less importance for changes in soil N storage as frequently assumed. 相似文献
10.
Agricultural management practices are known to influence soil organic C. While changes in total organic C (TOC) are relatively less discernible over short to medium-term, some extractable pools of TOC are considered early indicators of changes in TOC. Therefore, to devise nutrient management practices that can lead to C sequestration, it is important to study their effect on soil organic C pools that may respond rapidly to management. We studied the impact of balanced (NPK) and imbalanced (N, NP, NK and PK) application of fertilizer nutrients without and with farmyard manure (FYM) on total and labile pools of organic C viz. water soluble (WEOC), potassium permanganate oxidizable (KMnO4-C), microbial biomass (MBC) and fractions of decreasing oxidizability after 5-cycles of rice-wheat cropping. Integrated use of NPK and FYM significantly increased TOC and extractable C pools in both surface (0–7.5 cm) and sub-surface (7.5–15 cm) soil. Majority of TOC (72%) was stabilized in less labile and recalcitrant fractions; the magnitude being higher under balanced (NPK+FYM) than imbalanced nutrient management (N+FYM). The results showed that balanced fertilizer application conjointly with FYM besides enlarging TOC pool favorably impacts soil organic matter composition under rice-wheat system. 相似文献