Combined Use Of Inorganic Fertilizers Research Articles

Influence of 36 years of integrated nutrient management on soil carbon sequestration, environmental footprint and agronomic productivity of wheat under rice-wheat cropping system

A long-term field experiment was conducted to study the effects of different combinations of integrated nutrient management (INM) on carbon sequestration and wheat yield in a rice-wheat cropping system. The experiment consisted of 11 treatments that were replicated three times. The organic manures used in the study included farmyard manure (FYM), wheat straw (WS), and green manure (GM) with Sesbania aculeata. The results of the experiment revealed that the application of 50% of the recommended dose of fertilizers (RDF) along with 50% nitrogen (N) through FYM during rice cultivation, and RDF during wheat cultivation, led to a significant increase in soil organic carbon (SOC). Specifically, the SOC content was enhanced by 46.4% (18.29 Mg ha-1) compared to RDF in rice and wheat, resulting in a C sequestration rate of 0.22 Mg ha-1 year-1. These increases were higher in treatments that combined organic and inorganic inputs. Additionally, the application of 50% RDF and substituting 50% of the nitrogen with FYM during wheat cultivation resulted in a 24.7% increase in grain yield compared to RDF in rice and wheat. The INM treatments, showed significantly (p ≤ 0.05) higher agronomic efficiency (AE) of nitrogen (N), phosphorus (P) and potassium (K), partial factor productivity (PFP) of N, P and K, and carbon pool index (CPI) compared to the application of inorganic fertilizers at the recommended dose. Moreover, the INM treatments also exhibited lower greenhouse gas (GHG) emission intensity. Application of neither chemical fertilizers nor organic manure (T1) resulted in maximum GHG emission intensity (328.1 kg CO2 eq Mg−1 yield). Based on these findings, it can be concluded that the combined use of inorganic fertilizers and organic manures significantly increased crop yield and soil organic carbon sequestration while reducing GHG emissions in a rice-wheat cropping system in the eastern Indo-Gangetic Plains (EIGP) of India.

Soil microbial community structure affected by biochar and fertilizer sources

Use of organic fertilizer or organic amendments can potentially mitigate the deleterious environmental impacts of inorganic fertilizers in agroecosystems, but they can also affect soil microorganisms which have not been well defined. The aim of this research was to evaluate an incorporation of poultry-waste based organic fertilizer in various combinations of inorganic fertilizer and amendment with biochar on soil microbial properties after two growing seasons of serrano chili peppers. Treatments included combinations of inorganic N with different rates (0%, 50%, 75% and 100% of total N supply) of organic N (org-N) and inorganic N with amendment of three rates (10, 30 and 50 t ha−1) of a coconut shell biochar. After two years of application, the amounts of total, arbuscular mycorrhizal fungal (AMF), and Gram positive and Gram negative bacterial phospholipid fatty acid (PLFA) increased significantly at the higher rates of biochar compared to those at lower rates, unfertilized, and non-amended soil. However, significant differences were not observed for fungal PLFA between inorganic N with biochar and those without addition of biochar. Organic N application also increased (with the highest from 75% rate) the amounts of total, Gram positive and Gram negative bacterial and AMF PLFAs compared to unfertilized and inorganic N treatments, but the amounts of fungal PLFA significantly decreased as organic N application rate increased. All the rates of biochar and org-N amendments increased the pepper yield compared to unfertilized and inorganic N treatments in the second year. Results indicate that soil amendment with biochar or incorporation of organic fertilizer for about two years affected microbial community biomass, composition and crop yield. Thus, in conventional farming, the combined use of inorganic fertilizers with org-N source or organic amendment with biochar can improve soil health and crop productivity.

Response of the soil microbial community to different fertilizer inputs in a wheat-maize rotation on a calcareous soil

The combined use of inorganic fertilizers with organic manures has recently attracted increasing interest in China in attempts to mitigate the deleterious environmental impacts of excessive rates of chemical fertilizers in agroecosystems. However, questions remain concerning temporal change and how the soil microbiome responds to different fertilizer inputs in intensively managed crop rotations. Here, we collected soil samples from a wheat–maize system to investigate the response of the soil microbiome to four years of application of inorganic fertilizer only (NPK), NPK plus either cattle manure or straw, NPK plus both manure and straw, or a zero fertilizer control. The soil bacterial and fungal populations and community composition, nitrogen functional genes (amoA) and carbon utilization patterns were assessed. Sampling time had a much greater influence on the soil microbiome than did fertilizer regime, and the effect of fertilization was mostly significant at the wheat harvest. Fertilization increased amoA gene copy numbers but only AOB abundance showed differences among fertilizer treatments. In June the community composition of both bacteria and fungi was clearly separated between the organic matter additions and the zero organic matter treatments. Microbial carbon source utilization was significantly affected by fertilization regime and sampling time. By contrast, at the maize harvest neither microbial populations nor microbial community composition were altered. Our results suggest that the entire soil microbiome is more responsive to organic inputs than to chemical fertilizers in the short term. Temporal shifts in microbial community composition in the crop rotation imply that crop species and environmental conditions need to be carefully integrated into nutrient management strategies.

Effect of integrated nutrient management on seed yield and quality in cowpea

A study was carried out to assess effect of inorganic fertilizers, vermicompost, Vesicular Arbuscular Mycorhizae (VAM) and biofertilizers [Rhizobium and Phosphate solubilizing bacteria (PSB)] inoculation on seed yield and quality of cowpea (Vigna unguiculata). The experiment was conducted in a split plot design for two consecutive cropping season, kharif 2012 and 2013, with two main plot treatments of inorganic fertilizers i.e. 100% and 75% recommended dose of fertilizers (RDF) and nine sub plot integrated nutrient management (INM) treatments including control (No organic fertilizer). Main plot treatments were at par but sub plot INM treatments differed significantly for plant height, seed yield, number of pods/plant, pod length, number of seeds/pod, 1000-seed weight, seed germination and vigour indices. Integrated use of inorganic fertilizers + Vermicompost 2.5 t ha-1 (4.76, 4.16 q ha″1) performed significantly better than the control (3.32, 2.79 q ha″1) for seed yield and its attributes as well as seed quality parameters during Kharif 2012 and 2013, respectively. It was at par with combined use of inorganic fertilizers + biofertilizer inoculation (Rhizobium + PSB) + VAM 10 Kg ha-1 Also, the mean cost benefit ratios (2.04, 1.90) were highest for combination of biofertilizer inoculation (Rhizobium + PSB) + VAM 10 Kg ha-1 +inorganic fertilizers 100% and 75% RDF, respectively.

NUTRIENT AND DROUGHT MANAGEMENT PRACTICES FOR RAINFED SORGHUM UNDER VERTISOL

Field experiments were conducted during north east monsoon seasons of 1994-95 and 1995-96 under vertisol of Tamil Nadu Agricultural University, Coimbatore to evolve suitable nutrient and drought management practices with combined use of inorganic fertilizers and organic manures along with various seed hardening materials in rainfed sorghum (Co 26). The results of the present study revealed that the enriched pig manure @ 875 kg with 40 Kg N ha along with 2 per cent Calotropis leaf extract seed hardening for sorghum recorded higher growth attributes which inturn resulted in higher grain yield as compared to other treatments.

Studies on the substitution of inorganic fertilizers with organic manure and their effect on soil fertility in rice?wheat rotation

Field studies on the substitution of N and P fertilizers with farm yard manure (FYM) and their effect on the fertility status of a loamy sand soil in rice—wheat rotation are reported. The treatments consisted of application of 12 t FYM ha−1 in combination with graded levels of N and P. Application of fertilizer N, FYM and their different combinations increased the rice yield significantly. There was no significant response to P application. The magnitude of response to the application of 12 t FYM and its combined use with each of 40 kg and 80 kg N ha−1 was 0.7, 2.2 and 3.9 t ha−1 respectively. Application of 120 kg N ha−1 alone increased the yield by 3.9 t ha−1, and was comparable to rice yield obtained with 80 kg N and 12 t FYM ha−1. This indicated that 12 t FYM ha−1 could be substituted for 40 kg N as inorganic fertilizer in rice. In addition FYM gave residual effects equivalent to 30 kg N and 13.1 kg P ha−1 in the succeeding wheat. The effect of single or combined use of inorganic fertilizers and FYM was significantly reflected in the build up of available N, P, K and organic carbon contents of the soil. The relationship for predicting rice yield and nutrients uptake were also computed and are discussed.