Soil carbon sequestration is a complex process influenced by agricultural practices, climate and soil conditions. Labile organic carbon is sensitive to soil management practices and thus provides ...better management of carbon dynamics than total carbon alone. Thus, an attempt is made here to investigate the Carbon sequestration potential and labile pool of soil organic carbon (SOC) in post kharif-2014 in flooded tropical rice (Oryza sativa L.) under long-term fertilizer experiment started in the year 2005-06 in the central farm of Odisha University of Agriculture and Technology (OUAT) under All India Coordinated Research Project (AICRP) taking rice as a test crop. The experiment was laid out in a Randomized Block Design with quadruplicated treatments. The treatments include no fertilization, 100% N, 100% NP, 100% NPK, 150% NPK and 100% NPK+FYM. The results revealed that cultivation over the years caused a 14% decrease in SOC in unfertilized control over uncultivated soil. The carbon sequestration potential (1.77 Mg ha
−1
) was highest in 100%NPK +FYM treatment. The greater accumulation of microbial biomass C, water and extractable carbon (WEO-C), potassium permanganate oxidizable C (KMnO4-C) was recorded in 100%NPK + FYM treatment. The highest carbon management index (CMI) was computed in 100%NPK with FYM. CMI can be used as a more sensitive indicator of the rate of change of SOC in response to soil management changes. Results suggested that 100% NPK+ FYM are adequate for maintaining SOC stock and this practice may help in maintaining the sustainability of rice-rice cropping system.
Integrated use of inorganic fertilizer N and well decomposed cattle manure (CM) or 30–35 days old
Parthenium (
Parthenium hysterophorus L.), a weed grown off site as green manure (GM) under repeated ...applications of fertilizer P and urea N for eight years in a rice (
Oriza sativa L.)–wheat (
Triticum estivum L.) sequence was studied on transformation of fertilizer P applied to soil at the National Research Center for Weed Science, Jabalpur, India. Based on the results, it appeared that, repeated applications of 52
kg super-phosphate P resulted in a marked increase in Olsen P linearly with time. Conjunctive use of urea fertilizer N with organic manure resulted in a larger increase in Olsen P in the Vertisol. Studies further revealed that the greater accumulation of fertilizer P applied in excess to crop removal occurred in inorganic P in the plots receiving only fertilizer N. However, plots receiving fertilizer N along with organic manures led to P accumulation predominantly in organic forms. The study suggests that these two pools of P acted as a sink when fertilizer P was applied in excess to crop removal and are bio-chemically active. The Olsen P status after 8 cycles of rice–wheat crops revealed that the average amount of fertilizer P required after adjusting for crop uptake to increase Olsen P by 1
mg
kg
−1 soil was 7.2
kg
P
ha
−1 in the plots receiving only fertilizer N. Whereas, application of 5
t FYM or 6
t GM reduced it to 4.6
kg
P
ha
−1. The plots receiving manure always maintained a greater concentration of Olsen P. The application of CM or GM with fertilizer N enriched short-term inorganic P as well as long-term organic P fertility. After eight years, larger concentrations of organic P in the subsurface layer (16–30
cm), compared to initial values, indicates downward movement of P in organic forms.
In an experiment conducted over 8 years at the research farm of the National Research Centre for Weed Sciences, Jabalpur, we investigated the effects of mineral fertilizer and organic manures on K ...balances and non-exchangeable K release kinetics in a Typic Haplustert under a rain-fed rice (
Oryza sativa L.) and irrigated wheat (
Triticum vulgare L.) system. Each year, rice was grown with variable levels of fertilizer N with and without organic manures, while recommended rates of 26
kg
P
ha
−1 and 33
kg
K
ha
−1 were applied to both the crops. Wheat was grown without organic manure but with the same levels of fertilizer N as for rice. The apparent K balance was measured as the difference between total K added and that removed by the crop. Increasing levels of fertilizer N resulted in an increase in the negative K balance from 56
kg
ha
−1
yr
−1 (control) to 103
kg
ha
−1
yr
−1 at 90
kg
N
ha
−1 and 156
kg
ha
−1 at 180
kg
N
ha
−1. Incorporation of farmyard manure (FYM) or green manure (GM) with fertilizer N reduced the negative K balance. Repeated extraction of soil with 0.01
M CaCl
2 revealed that continuous cropping for 8 years either without fertilizer N (control) or with 90
kg
N
ha
−1 reduced the cumulative K release. However, the application of 180
kg
ha
−1 of fertilizer N not only maintained the cumulative K release but also improved it. Incorporation of 5
t
FYM or 6
t
GM
ha
−1 with 90
kg
N
ha
−1 resulted in an increase in K release by 58 and 37
mg
kg
−1 soil, respectively, over the values measured in a soil sample collected at the onset of the experiment. A parabolic diffusion equation described the release rate of the non-exchangeable K. The equation suggested that the application of fertilizer N reduced the release rate of K, whereas the incorporation of manure, with fertilizers, increased it over the values obtained from soil collected at the onset of the experiment. The large cumulative K release at 180
kg
N
ha
−1 was due to the amount of K released initially. Continuous cropping at a fertilizer level of 33
kg
K
ha
−1 may pose a threat to the sustainability of the rice–wheat system. Recycling of crop residue or application of higher levels of fertilizer K may provide long-term sustainability to the system.
•Balanced use of nutrients through STCR based fertilizers with organic manures recorded increasing trend of yield.•Sole use of chemicals or organics could not sustain the yield and system ...productivity of maize- chickpea system.•Long-term integrated use of organic and inorganic sources of nutrients enhanced the system productivity and soil health.
Long-term sustainability concerns are growing in agriculture owing to over and under application of fertilizers and poor management of available resources which are resulting into soil health deterioration and declining crop productivity. Balanced and integrated use of organic and inorganic fertilizers is the most logical concept for managing and sustaining long term soil health and crop productivity. Hence, a long-term field experiment was conducted from 2012 to 2017 to develop integrated nutrient management (INM) practices for sustaining crop productivity and maintaining soil health under maize (Zea mays L.) chickpea (Cicer arietinum L.) cropping system in Vertisols of central India. Twelve treatments that comprised of various combinations of general recommended dose (GRD) of NPK, farmyard manure (FYM), poultry manure (poultry manure), urban compost (UC), maize residue (MR), glyricidia loppings (GL) and soil test crop response (STCR) based NPK with target yield 5.0 and 1.50 Mg ha1 in maize and chickpea, respectively were tested. The experiment was conducted following a Randomized Complete Block Design (RCBD) set up with three replications and Simple Random Sampling (SRS) technique of sampling. The results indicated that the grain yield and system yield were observed to be significantly higher with 75% NPK of STCR + FYM at 5 Mg ha1 treatment and recorded an increase of 20.9% and 13.08% in mean grain yield of maize and chickpea, respectively over GRD. The combined analysis results illustrated significant (P < 0.0001) year x nutrient management interaction effect on grain yield with N input (R2 = 0.80) and N uptake (R2 = 0.91). Stepwise multiple regression model also showed that the N input and N uptake significantly (P < 0.05) influenced the system yield under different INM practices. However, apparent nutrient balance was negative for N and K in all treatments except higher level of FYM treatment (FYM at 20 Mg ha1) while P balance was positive under balanced and complete nutrition through organic and inorganic treatments over the years. A significant increase was observed in the various soil health indicators (physical, chemical and biological) under balanced and integrated use of organic and inorganic fertilizers. FYM, poultry manure and urban compost improved the physical properties of soil like mean weight diameter (MWD), water stable aggregates (WSA), bulk density and porosity. The application of higher level of FYM (20 Mg ha1) significantly increased the soil organic carbon (SOC) (6.30 g kg1), SOC stock (11.8 Mg ha1), carbon sequestration rate (213.1 kg ha1 year1), KMnO4-N (121.7 mg kg–1), Olsen-P (23.8 mg kg–1) and NH4OAc-K (273.5 mg kg–1) concentration in surface soil as compared to GRD and control treatments. The soil enzymes, dehydrogenase (DHA), alkaline phosphates (Alk-P) and fluorescein diacetate (FDA) were enhanced significantly with the application of FYM at 20 Mg ha1 and STCR based 75% NPK + FYM at 5 Mg ha1. The STCR based 75% NPK along with FYM at 5 Mg ha1 treatment recorded highest sustainable yield index (SYI) 0.84 and 0.92 with maximum guaranteed yield of 6.19 and 1.99 Mg ha1 in maize and chickpea, respectively. The results indicate that the chickpea yield was more sustainable as compared to the maize.
Fertilizer use in Indian agriculture is skewed towards nitrogen (N) and phosphorus (P), and farmers generally neglect potassium (K) input ignoring K requirement of crops. We, therefore, studied the ...long-term effect of imbalanced fertilization (i.e. without K) on K supplying capacity of a kaolinitic red soil (Typic Haplustalf) after 42 years of intensive cultivation. Soil samples (0–15 and 15–30 cm) were collected after the completion of 42 cropping cycles from an on-going long-term fertilizer experiment located at Birsa Agricultural University, Ranchi, India, from six treatments, viz. control (unfertilized), fertilizer N, NP, NPK, 150% NPK (1.5 times of NPK) and NPK + FYM (NPK + farmyard manure), along with adjacent uncultivated land. Soil K pools, clay minerals, quantity-intensity relationship and K release kinetics along with grain yield and K uptake of soybean and wheat were studied. Among the treatments, NP treated soils showed the lowest amounts of labile (KL) and non-exchangeable K (Knex). Equilibrium activity ratio (AReK) and non-specifically held K (−ΔK0) were also lowest under NP treatment. The gap between equilibrium exchangeable K (EK0) and minimum exchangeable K (EKmin) was minimum under NP. Cropping and fertilization-induced transformation in clay minerals was noticed wherein continuous neglect of K fertilizer led to a decrease in illite content with a concomitant increase in interstratified minerals. On the other hand, noticeably lower alteration in clay minerals and comparatively less depletion in overall K-supplying capacity of soil were recorded under K addition as compared to imbalanced fertilization (i.e. without K). Soybean showed a significant positive response to K application. The study thus underlined the necessity of adequate K input for the sustenance of soil health, inherent K-supplying capacity and crop productivity.
•We studied long-term effect of cropping with or without K input on soil K-fertility.•Imbalanced fertilization with respect to K caused depletion of soil K pools.•Imbalanced fertilization adversely affected quantity, intensity and K release rate.•Continuous neglect of K addition led to distortion in clay minerals.•Cropping with K addition maintained much better K-supplying capacity of soil.
Long-term application of fertilizer and manure can affect soil properties with implications on the productivity and sustainability of crops. Data from a long-term fertilizer experiment at ...Bhubaneswar, India was used to study the impact of seven treatments viz. control, application of recommended dose of NPK (NPK), 150% NPK (1.5 NPK), NPK + Zn (NPKZn), NPK + FYM (NPKFM), NPK + Zn + B (NPKZnB) and NPK + Zn + S (NPKZnS) on productivity, sustainability (in terms of sustainable yield index (SYI)), soil properties (physical, chemical and biological) and soil organic carbon (SOC) sequestration of rice-rice cropping system. Results revealed that application of NPKFYM improved the average grain yield and SYI of wet and dry season rice and the system by 36.3, 21.6, and 28.3% and 28.8, 17.1, 22.8%, respectively, over NPK alone. Application of NPKFYM improved soil fertility by stimulating microbial activity, improving soil physical health, resisting drop in pH to more acidity and improving CEC and macro- and micro-nutrients levels. NPKFYM also sequestered higher SOC than NPK alone. Therefore, application of NPKFYM can be recommended for sustaining the productivity of the rice-rice system with improvement of soil health under Inceptisols of Eastern India.
Agriculture produces a large amount of greenhouse gases (GHGs), for instance overuse of synthetic fertilizer and pesticides in agriculture may lead to tremendous GHGs emission, which poses a serious ...threat to sustainability of agriculture, environmental quality and human health. Integrated nutrient management (INM) practices have been advised to farmers with the aim to boost agricultural productivity and soil quality. A long-term fertilizer experiment (LTFE) was undertaken from 2012 to 2020 to evaluate the energy budget, carbon footprint (CF) and economic audit under INM modules in maize–chickpea system over organic and inorganic modules for developing cleaner production technology. In this study, twelve organic, inorganic and INM modules that consisted of various combinations of soil test crop response (STCR) based NPK, general recommended dose (GRD) of NPK and organic manures (OM's) viz., farmyard manure (FYM), poultry manure (PM), urban compost (UC), maize residue mulch (MRM) and Gliricidia sepium mulch (GLM) were evaluated in maize–chickpea system. Uniqueness of this research work is that the effect of INM modules on GHGs emission was evaluated along with crop productivity, energy use efficiency (EUE) and carbon footprint (CF) jointly as environment friendly approach for sustainable and safe food grain production. Adoption of STCR based INM module (FYM+75%NPK of STCR) minimized the energy requirement by 14%, cost of cultivation by 6.5% and besides that CF on a spatial scale was 17% lower than GRD. Thus, STCR based INM module enhanced the EUE, energy productivity (EP) and energy profitability (EPF) by 28.5%, 31.5% and 31.8% respectively, over GRD. The CF (CO2-e) was greater in organic module (FYM 20 Mgha-1 every year) (2422 CO2-e kg ha−1) and GRD (2230 CO2-e kg ha−1) than STCR based INM module (2152 CO2-e kg ha−1). The saving of fossil fuels from judicious use of fertilizers/manures, lower input energy and higher crop yields under INM modules were significant. Nitrous oxide (N2O) emission was also increased by integration of OM's, and the higher quantity of organic inputs used, more was the emission. INM module (FYM+75%NPK of STCR) also increased system productivity by 17.0%, carbon efficiency (CE) by 19.3% and carbon sustainability index (CSI) by 21% than GRD. Thus, the study supports and suggests that the STCR based INM module is an economically viable, environmentally secure and clean production technology for improving crop yield and energy use, while decreasing the CFs and production cost of cereal–legume cropping system.
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•Fertilizer based CO2 emission contributes significantly to the global GHGs emission and carbon footprints.•The adoption of INM module increased crop yields with lower carbon footprints.•Balanced fertilization had higher net return and 17% reduced carbon footprints on spatial scale.•INM module increased the energy efficiency and energy productivity by 29% and 32%, respectively.•INM module reduced the carbon footprints by 17% and 14% in fertilizers and N2O emissions and leading to 11% total reduction.
In the present investigation, an attempt was made to determine the direct effects of fertilizers on various soil properties like acidification, organic matter content, the content of essential and ...toxic trace metals in soils and food grains under long term (>25 years) fertilizer experiment. Soil and plant samples were collected from Bengaluru center of All India Coordinated Research Project on Long-Term Fertilizer Experimental site in the sub-regions AESR 8.1 of India, with the treatments e.g. control, 100% N, 100% NP, 100% NPK, 150% NPK, 100% NPK + Lime, 100% NPK+ farmyard manure (FYM) at 0 to 60 cm depth with an interval of 15 cm. Laboratory analysis was conducted to know the vertical distribution of heavy metals and micronutrient cations in soil and plant produce by following the standard method. The DTPA soil Zn remained unchanged with the higher rates of N application, i.e. 100% N. There was very little effect of N, NP, and NPK application on the buildup of DTPA-able Zn, Fe, Mn, and Cu content in both the soils. However, the application of NPK + FYM showed a buildup in comparison to control for Fe 10 mg kg
−1
, Mn 18 mg kg
−1
, Zn 1.23 mg kg
−1
, and Cu 0.84 mg kg
−1
in soil. Continuous fertilizer application contributed a meager amount accumulation of Cd, Pb, Ni, Co, and Cr in the soil under the finger millet - maize cropping sequence. The estimation of heavy metals in food grains, supposed to come from fertilizers, lime materials applied in soil was also of our concern. All the cited heavy metals were present in the maize and finger-millet grains. Risk assessment to human health (Hazard Quotient, HQ) for the intake of heavy metals through consumption of contaminated food grains was computed and observed that the values of 'HQ' for all the crops were far less than unity (<1) and safe for the consumers.
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