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1.
Abstract

The carbon (C) budget of managed grassland in a cool-temperate region of Japan was estimated using a combination of eddy covariance and the biometric method for five years, to evaluate the effect of manure application. Chemical fertilizer was applied to the fertilizer (F) plot at a rate of 79 ± 20 kg N ha?1 yr?1. In the manure (M) plot, dairy cattle manure was applied at a rate of 10 Mg fresh matter ha?1 yr?1 (1923 ± 407 kg C ha?1 yr?1, 159 ± 68 kg N ha?1 yr?1). There was no significant difference in seasonal gross primary production (GPP) and harvest between the treatment plots, indicating that both fertilizer and manure can increase the biomass production. Annual net ecosystem production (NEP) and ecosystem respiration (RE) was significantly different between the treatment plots. The difference in RE, and between M and F plots approximates heterotrophic respiration of manure (RHm), which ranged from 0.9 to 1.3 Mg C ha?1 yr?1. Average annual RHm was 1.1 ± 0.4 Mg C ha?1 yr?1, and accounted for 56% of the total amount of applied manure C. The annual net biome production (NBP) in the M plot (from 0.0 to 1.5 Mg C ha?1 yr?1) was significantly higher than in the F plot (?1.4 to 0.5 Mg C ha?1 yr?1). The long-term effect of manure application combined with chemical fertilizer did not reduce grass production compared with chemical fertilizer only; however, manure application decreased the NEP throughout manure decomposition, and long-term manure application enhanced the NBP.  相似文献   

2.
Quantitative measurements of plant growth characteristics, forage production, nitrogen (N) fixation, and soil N accumulation by white clover were determined in a field experiment at the subhumid hilly region of Rawalakot, Azad Jammu and Kashmir (AJK). Three indigenous and two exotic ecotypes of white clover were used in the study. Indigenous ecotypes were collected from three different locations (i.e., Tollipir, Banjosa, and Rawalakot), whereas exotic ecotypes (NuSiral and Irrigation) were collected from New South Wales Agricultural Research and Advisory Station, Australia. Data were collected for two seasons (spring 2004–autumn 2004). Total average values for height, number of stolons, length of stolons, number of leaves, and leaf area were 13–50 cm, 9–20, 2–4 cm, 23–81, and 7–16 cm2, respectively. The morphological characteristics of exotic ecotypes were significantly higher than the indigenous ecotypes, and the percentage increase in different plant characteristics was +6% to 214%. Total herbage dry‐matter yield (DMY) in the indigenous and exotic ecotypes varied between 0.5–2.3 and 3.6–4 Mg ha?1, respectively. All the ecotypes showed substantial nodulation potential, and the number of nodules in plant roots ranged from 65 to 119, confirming the presence of indigenous Rhizobium population in the soil. The N contents of harvested herbage of white clover were 2.3–3.0% compared to 0.85% in the grass, and the estimated rates of N2 fixation were 26 kg N ha?1 in the indigenous to 79 kg N ha?1 in the exotic ecotypes. Amount of N2 fixed was strongly correlated with DMY, suggesting that crop DM can be used as an indicator of N2 fixation in white clover. Protein content of white clover was 14–19%, compared to 5% in the indigenous grass species. Total organic carbon (C) and N in control soil were 8.5 and 0.75 g kg?1, which increased significantly to 13.1 and 0.93 g kg?1 in soil under white clover. It is concluded that white clover has substantial potential for growth and establishment in the subhumid hilly regions and can be used to recuperate degraded soils because of its ability to sustain high level of pasture production and increase the N status of soil. These benefits could be of particular use for small‐scale resource‐poor farmers.  相似文献   

3.
The aim of this study was to assess the changes in soil organic carbon (SOC) stock in relation to the carbon (C) input from nine wheat-based cropping systems and untilled grass. The SOC pool ranged from 32.1 to 49.4 Mg ha?1 at 0–20 cm and from 94 to 171 Mg ha?1 at 0–100 cm for the arable soil, while in untilled grassland, it was higher (54 and 185 Mg C ha?1, respectively). SOC stock was observed to be lower at the unfertilized 2-year rotation and higher at the 4-year rotation with manure and mineral fertilization. The study showed a winter wheat yield decrease of 176.8 kg ha?1 for a 1- Mg ha?1 SOC stock change in the 0–20-cm soil depth. The estimated C input for SOC stock maintenance was from 266 to 340 g C m?2 year?1 for winter wheat and rotations, respectively. Additional C input did not increase the SOC pool, suggesting that arable plots had a limited ability to increase SOC. These results provide guidance for the selection of management practices to improve C sequestration.  相似文献   

4.
ABSTRACT

To identify efficient field management practices for enhanced soil carbon sequestration suited to crop rotation-based Andosol fields in northern Japan, the impacts of a combination of tillage, fertilizer type, and plant residue input on soil carbon sequestration rates were studied in a 4-year field experiment (April 2007 to March 2011). The rates of changes in soil organic carbon over the entire study period were determined by soil carbon stock change and by net ecosystem carbon budget. Across eight field management treatments and two replicates for each treatment, the rates of changes in soil organic carbon determined by net ecosystem carbon budget were positively correlated with the rates determined by soil carbon stock change (r = 0.766, n = 16). The arithmetic means of the rates determined by net ecosystem carbon budget (1.24 Mg C ha?1 year?1) were greater than those determined by soil carbon stock change (?0.18 Mg C ha?1 year?1) because decomposing crop residues and composted cattle manure in soil were included in the calculation of the net ecosystem carbon budget but were excluded in the calculation of soil carbon stock change (decomposing crop residues and composted cattle manure in soil samples were removed by sieving in measuring the soil carbon stock change). Both methods led to the same conclusion that soil carbon sequestration was significantly enhanced by composted cattle manure application and increased input of plant carbon from crop residues and green manure but was not enhanced by reduced tillage. The p values for net ecosystem carbon budget were smaller than those for soil carbon stock change in analysis of variance; therefore, the net ecosystem carbon budget was more sensitive to field management practice than the soil carbon stock change.  相似文献   

5.
Effectively utilizing composts requires that their nitrogen (N) and phosphorus (P) contents be used as fertilizer, but how this is best accomplished is not fully understood. The authors' objective was to quantify N and P availability of a calcareous clay loam soil receiving composts derived from four contrasting beef cattle feedlot feedstocks applied at 50, 150, and 450 mg total P kg?1 and supplemented twice with fertilizer N for a 42-week greenhouse plant bioassay. Three composted manures from beef cattle fed distinct diets and a composted mix of slaughterhouse and construction waste were applied. Inorganically fertilized and non-amended soils were included as controls. Canola (Brassica napus L.) and pea (Pisum sativum L.) were grown in pots containing 1.5 kg air-dried soil for six alternating 7-week cycles. Soils amended with composted manure from beef cattle fed typical finishing diets had the lowest apparent N recovery (31%) and the greatest soil nitrate after 42 weeks (25 mg N kg?1). Phosphorus availability was greater with composted manure from beef cattle fed distillers' dried grains than composted manure from beef cattle fed typical finishing diets and a composted mixture of slaughterhouse and construction waste. Apparent P recovery (66%) was greatest from composted manure of beef cattle fed corn (Zea mays L.) distillers' dried grains applied at 50 mg total P kg?1. Composted manure from beef cattle fed distillers' dried grains had greater P availability than conventional composted beef cattle feedlot manure. Overall, performance of the composted mixture of slaughterhouse and construction waste was similar to the composted beef cattle manures.  相似文献   

6.
Organic amendments recycle nutrients, but N2O emissions are both environmental and agronomic concerns. We conducted a 4-year field experiment to determine no-till barley (Hordeum vulgare L.) yield and nutrient uptake and soil N2O emissions following a single application of six amendment treatments: (1) no amendment (Check); (2) synthetic N fertilizer (Fert); (3) fresh beef cattle feedlot manure (ManureF); (4) beef cattle feedlot manure compost (CompostR); (5) beef cattle feedlot manure composted with cattle mortalities (CompostM); and (6) separated solids from anaerobically digested cattle feedlot manure (ADM). Barley grown in Year 1 (2006), Year 2 (2007), and Year 4 (2009) (with Year 3 (2008) under fallow) had higher grain yields from ManureF (4.73 Mg ha?1) in Year 2 and ADM (6.30 Mg ha?1) in Year 4 (p < 0.05) than other treatments. The grain N and P contents were not affected (p > 0.05), but N uptake over 3 years (112.8 kg N ha?1 yr?1), and P uptake in Year 1 (19.1 kg ha?1 yr?1) and Year 2 (14.3 kg ha?1 yr?1) from ManureF, were higher (p < 0.05×) than other treatments. The cumulative N2O emissions from ManureF in Year 1 (1.488 kg N ha?1) and from ADM in Year 2 (1.072 kg N ha?1) were higher (p < 0.05) than other treatments while the fraction of applied N emitted as N2O was small (0.00 to 0.79%) and not affected by treatment. However, the percentages of applied N emitted as N2O from compost and ADM were similar to synthetic fertilizer and livestock manure.  相似文献   

7.
Abstract

Two Ferralsols (350 and 600 g kg?1 clay) from the Brazilian Cerrado Region were evaluated for long‐term effects (5 and 8 years) of no tillage on carbon (C) stocks in particulate (>53 µm) and mineral‐associated (<53 µm) soil organic matter (SOM) fractions. Carbon stocks in particulate SOM increased under no tillage compared with conventional tillage, and the rate was higher in the clayey soil (0.62 Mg C ha?1 yr?1) than in the sandy clay loam soil (0.31 Mg C ha?1 yr?1). In contrast, the mineral‐associated SOM in the top soil layer (0–20 cm) was not affected by tillage system. Sequestration of atmospheric C in tropical no‐tillage soils seems to be due to accumulation of C in labile SOM fractions, with highest rates in clayey soils probably due to physical protection.  相似文献   

8.
ABSTRACT

Biological nitrogen fixation (BNF) is an important nitrogen source for both N2-fixers and their neighboring plants in natural and managed ecosystems. Biological N fixation can vary considerably depending on soil conditions, yet there is a lack of knowledge on the impact of varying soils on the contribution of N from N2-fixers in mixed swards. In this study, the amount and proportion of BNF from red clover were assessed using three grassland soils. Three soil samples, Hallsworth (HH), Crediton (CN), and Halstow (HW) series, were collected from three grassland sites in Devon, UK. A pot experiment with 15N natural abundance was conducted to estimate BNF from red clover, and the proportion of N transferred from red clover to the non-N2 fixing grass in a grass-clover system. The results showed that BNF in red clover sourced from atmosphere in the HH soil was 2.92 mg N plant?1, which was significantly lower than that of the CN (6.18 mg N plant?1) and HW (8.01 mg N plant?1) soils. Nitrogen in grass sourced from BNF via belowground was 0.46 mg N plant?1 in the HH soil, which was significantly greater than that in CN and HW soils. However, proportionally there were no significant differences in the percentage N content of both red clover and grass sourced from BNF via belowground among soils, at 65%, 67%, 65% and 35%, 27%, 31% in HH, CN, and HW, respectively. Our observations indicate that the amount of BNF by red clover varies among grassland soils, as does the amount of N sourced from BNF that is transferred to neighboring plants, which is linked to biomass production. Proportionally there was no difference among soils in N sourced from BNF in both the red clover plants and transferred to neighboring plants.  相似文献   

9.
A long-term experiment on combined inorganic fertilizers and organic matter in paddy rice (Oryza sativa L.) cultivation began in May 1982 in Yamagata, northeastern Japan. In 2012, after the 31st harvest, soil samples were collected from five fertilizer treatments [(1) PK, (2) NPK, (3) NPK + 6 Mg ha?1 rice straw (RS), (4) NPK + 10 Mg ha?1 rice straw compost (CM1), and (5) NPK + 30 Mg ha?1 rice straw compost (CM3)], at five soil depths (0–5, 5–10, 10–15, 15–20 and 20–25 cm), to assess the changes in soil organic carbon (SOC) content and carbon (C) decomposition potential, total nitrogen (TN) content and nitrogen (N) mineralization potential resulting from long-term organic matter addition. The C decomposition potential was assessed based on the methane (CH4) and carbon dioxide (CO2) produced, while the N mineralization potential was determined from the potassium chloride (KCl)-extractable ammonium-nitrogen (NH4+-N), after 2, 4, 6 and 8 weeks of anaerobic incubation at 30°C in the laboratory. Compared to NPK treatment, SOC in the total 0–25 cm layer increased by 67.3, 21.0 and10.8%, and TN increased by 64.2, 19.7 and 10.6%, in CM3, RS and CM1, respectively, and SOC and TN showed a slight reduction in the PK treatment by 5.2 and 5.7%, respectively. Applying rice straw compost (10 Mg ha?1) instead of rice straw (6 Mg ha?1) to rice paddies reduced methane production by about 19% after the soils were measured under 8 weeks of anaerobic incubation at 30°C. Soil carbon decomposition potential (Co) and nitrogen mineralization potential (No) were highly correlated with the SOC and TN contents. The mean ratio of Co/No was 4.49, lower than the mean ratio of SOC/TN (13.49) for all treatments, which indicated that the easily decomposed organic matter was from soil microbial biomass and soil proteins.  相似文献   

10.
Abstract

Dairy manure increases the yields of dry bean (Phaseolus vulgaris L.) and spring wheat (Triticum aestivum L.) from eroded, furrow‐irrigated soils and may increase corn (Zea mays L.) silage yield from steeper eroded areas under sprinkler irrigation. In a 2‐year field study in southern Idaho on Portneuf silt loam (coarse silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid), the effects of a one‐time, fall application of 29 or 72 Mg ha?1 of dry manure or 22 or 47 Mg ha?1 of dry compost on subsequent silage yield and nitrogen (N) uptake from previously eroded, sprinkler‐irrigated hill slopes were evaluated. In October 1999, stockpiled or composted dairy manure was disked to a depth of 0.15 m into plots with slopes from 0.8 to 4.4%. After planting field corn in 2000 and 2001, a low‐pressure, six‐span traveling lateral sprinkler system was utilized to apply water at 28 mm h?1 in amounts sufficient to satisfy evapotranspiration to 6.4‐×36.6‐m field plots. Yields in 2000 were 27.5 Mg ha?1, similar among all rates of all amendments and a fertilized control. In 2001, compost applied at oven‐dry rates up to 47 Mg ha?1 increased yield compared to controls. Silage yield in 2001 increased initially then decreased with increasing manure applications. Where compost or manure was applied, regardless of rate, 2‐year average N uptake was 15% greater than controls. Regardless of treatment or year, yields decreased linearly as soil slope increased.  相似文献   

11.
Most tropical soils have high acidity and low natural fertility. The appropriate application of lime and cattle manure corrects acidity, improves physical and biological properties, increases soil fertility, and reduces the use of chemical and/or synthetic fertilizers by crops, such as soybean, the main agricultural export product of Brazil. This study aimed to assess the effects of the combination of the application of dolomite limestone (0, 5, and 10 Mg ha?1) and cattle manure (0, 40, and 80 Mg ha?1) on grain yield and the chemical properties of an Oxisol (Red Latosol) cultivated with soybean for two consecutive years. The maximum grain yield was obtained with the application of 10 Mg ha?1 of lime and 80 Mg ha?1 of cattle manure. Liming significantly increased pH index, the concentrations of calcium (Ca2+) and exchangeable magnesium (Mg2+), and cation exchange capacity (CEC) of soil and reduced potential acidity (H+ + Al3+), while the application of cattle manure increased pH level; the concentrations of potassium (K+), Ca2+, and exchangeable Mg2+; and CEC of the soil. During the 2 years of assessment, the greatest grain yields were obtained with saturation of K+, Ca2+, and Mg2+ in CEC at the 4.4, 40.4, and 17.5 levels, respectively. The results indicated that the ratios of soil exchangeable Ca/Mg, Ca/K, K/Mg, and K/(Ca+Mg) can be modified to increase the yield of soybean grains.  相似文献   

12.
《Journal of plant nutrition》2013,36(6):1335-1343
Abstract

Many alternative management systems have been evaluated for corn (Zea mays L.), soybeans (Glycine max L.), and wheat (Triticum aestivum L.) production, however, most have involved rotations from one year to the next. Legume interseeding systems which employ canopy reduction in corn have not been thoroughly evaluated. One such study was initiated in 1994 at the Panhandle Research Station near Goodwell, OK, on a Richfield clay loam soil, to evaluate five legume species interseeded into established corn: yellow sweet clover (Melilotus officinalis L.), subterranean clover (Trifolium subterraneum L.), alfalfa (Medicago sativa L.), arrowleaf clover (Trifolium vesiculosum L.), and crimson clover (Trifolium incarnatum L.). In addition, the effect of removing the corn canopy above the ear (canopy reduction) at physiological maturity was evaluated. Canopy reduction increased light interception beneath the corn thus enhancing legume growth in late summer, early fall, and early spring the following year prior to planting. Forage growth from legumes incorporated prior to planting were expected to lower the amount of inorganic nitrogen (N) fertilizer needed for corn production. Crimson clover appeared to be more shade tolerant than the other species, and interseeding this species resulted in the highest corn grain yields when no N was applied. In the last two years, interseeding crimson clover at physiological maturity, followed by canopy reduction resulted in a 1.32 Mg ha?1 increase in yield compared to conventionally grown corn with no N applied. In 1999, interseeded legumes (except subterranean clover) in conjunction with the application of 56 kg N ha?1 and crimson clover interseeded without the addition of fertilizer N (with and without canopy reduction) resulted in grain N uptake levels equal to the 112 kg N ha?1 treatment.  相似文献   

13.
Abstract

To assess their impacts on net global warming, total greenhouse gas emissions (mainly CO2, N2O and CH4) from agricultural production in arable land cropping systems in the Tokachi region of Hokkaido, Japan, were estimated using life cycle inventory (LCI) analysis. The LCI data included CO2 emissions from on-farm and off-farm fossil fuel consumption, soil CO2 emissions induced by the decomposition of soil organic matter, direct and indirect N2O emissions from arable lands and CH4 uptake by soils, which were then aggregated in CO2-equivalents. Under plow-based conventional tillage (CT) cropping systems for winter wheat, sugar beet, adzuki bean, potato and cabbage, on-farm CO2 emissions from fuel-consuming operations such as tractor-based field operations, truck transportation and mechanical grain drying ranged from 0.424 Mg CO2 ha?1 year?1 for adzuki bean to 0.826 Mg CO2 ha?1 year?1 for winter wheat. Off-farm CO2 emissions resulting from the use of agricultural materials such as chemical fertilizers, biocides (pesticides and herbicides) and agricultural machines were estimated by input–output tables to range from 0.800 Mg CO2 ha?1 year?1 for winter wheat to 1.724 Mg CO2 ha?1 year?1 for sugar beet. Direct N2O emissions previously measured in an Andosol field of this region showed a positive correlation with N fertilizer application rates. These emissions, expressed in CO2-equivalents, ranged from 0.041 Mg CO2 ha?1 year?1 for potato to 0.382 Mg CO2 ha?1 year?1 for cabbage. Indirect N2O emissions resulting from N leaching and surface runoff were estimated to range from 0.069 Mg CO2 ha?1 year?1 for adzuki bean to 0.381 Mg CO2 ha?1 year?1 for cabbage. The rates of CH4 removal from the atmosphere by soil uptake were equivalent to only 0.020–0.042 Mg CO2 ha?1 year?1. From the difference in the total soil C pools (0–20 cm depth) between 1981 and 2001, annual CO2 emissions from the CT and reduced tillage (RT) soils were estimated to be 4.91 and 3.81 Mg CO2 ha?1 year?1, respectively. In total, CO2-equivalent greenhouse gas emissions under CT cropping systems in the Tokachi region of Hokkaido amounted to 6.97, 7.62, 6.44, 6.64 and 7.49 Mg CO2 ha?1 year?1 for winter wheat, sugar beet, adzuki bean, potato and cabbage production, respectively. Overall, soil-derived CO2 emissions accounted for a large proportion (64–76%) of the total greenhouse gas emissions. This illustrates that soil management practices that enhance C sequestration in soil may be an effective means to mitigate large greenhouse gas emissions from arable land cropping systems such as those in the Tokachi region of northern Japan. Under RT cropping systems, plowing after harvesting was omitted, and total greenhouse gas emissions from winter wheat, sugar beet and adzuki bean could be reduced by 18%, 4% and 18%, respectively, mainly as a result of a lower soil organic matter decomposition rate in the RT soil and a saving on the fuels used for plowing.  相似文献   

14.
This study evaluated the petiole uptake of nitrogen, phosphorus, potassium, and sulfur (N, P, K, and S) by the potato from two seed meals, mint compost, and five commercially available organic fertilizers under an irrigated certified organic production system. Available soil nitrate (NO3-N) and ammonium (NH4-N) from each amendment averaged 115 kg N ha?1 at application and 25 kg N ha?1 30 d after planting through harvest, with minor differences between fertilizers. Petiole N declined from an average of 25,000 mg N kg?1, 4 wk after emergence to 3,000 mg N kg?1 prior to harvest. Petiole P and K concentrations were maintained above 4,000 mg P kg?1, 10,000 mg K kg?1, and 2,000 mg S kg?1 tissue, respectively, throughout the growing season in all treatments. Tuber yields were not different between fertilized treatments averaging 53 Mg ha?1. This study provides organic potato growers baseline information on the performance of a diverse array of organic fertilizers and amendments.  相似文献   

15.

Purpose

The objective of this study was to determine the changes in the main soil chemical properties including pH, electrical conductivity (EC), available phosphorus (P), soil organic carbon (SOC) and total nitrogen (TN) stocks after long-term (31 years) additions of two types of organic matters—rice straw and rice straw compost, combined with NPK fertilizers in single rice paddy in a cold temperate region of Japan.

Materials and methods

A long-term experiment on combined inorganic fertilizers and organic matters in paddy rice cultivation began in May 1982 in Yamagata, northeastern Japan. After the 31st harvest, soil samples were collected from five treatments [(1) PK, (2) NPK, (3) NPK + 6 Mg ha?1 rice straw (RS), (4) NPK + 10 Mg ha?1 rice straw compost (CM1), and (5) NPK + 30 Mg ha?1 rice straw compost (CM3)] at five soil depths (0–5, 5–10, 10–15, 15–20, and 20–25 cm). Soil chemical properties of pH, EC, available P, SOC, and TN were analyzed.

Results and discussion

The pH decreased significantly only at the higher compost rate of 30 Mg ha?1, while EC increased in all the organic matter treatments. Available P significantly increased in the CM1 and CM3 treatments by 55.1 and 86.4 %. The amounts of SOC stock increased by 67.2, 21.4, and 8.6 %, and soil TN stock by 64.1, 20.2, and 8.5 % in CM3, RS, and CM1, respectively, compared to NPK treatment.

Conclusions

Significant changes in soil properties were observed after 31 years of organic matter applications with reference to PK- and NPK-fertilized rice paddy soils. A significant decrease in pH was observed with the application of a high rate (30 Mg ha?1) of rice straw compost but not with the conventional rate of 10 Mg ha?1. However, EC increased significantly relative to that of the PK- and NPK-fertilized plots in all the organic matter treatments. Available P significantly increased in the CM1 and CM3 treatments by 55.1 and 86.4 %. The amounts of SOC stock expressed as a percentage of total C applied to the soil were higher from 10 Mg ha?1 compost (28.7 %) than that from 6 Mg ha?1 rice straw (17.4 %), indicating a more effective soil organic C accumulation from rice straw compost than that from original rice straw.
  相似文献   

16.
Abstract

The fragile ecosystem of China's Loess Plateau is being exposed to increasing atmospheric nitrogen deposition but little information about the response of the region's natural vegetation is currently available. We studied the responses of aboveground biomass (AGB) to simulated nitrogen deposition in a field experiment conducted on natural grassland on sunny and shady slopes. Three levels of simulated nitrogen deposition were applied, and two treatments with phosphorus were included to test for secondary phosphorus limitation. For the same level of nitrogen deposition, grass generally grew better on the shady slope than on the sunny slope. Compared to a control treatment with no additional nitrogen, we found: (1) the 2.5 g N m?2 yr?1 treatment significantly increased biomass only on the sunny slope; (2) the total AGB increased significantly in the 5 g N m?2 yr?1 treatment on both the shady slope (by 31%) and the sunny slope (by 25%); and (3) for 10 g N m?2 yr?1, AGB was also significantly increased, however, phosphorus limitation became more apparent, and soil nitrate N levels increased significantly, suggesting nitrogen saturation and the potential for nitrate pollution. The AGB of Stipa bungeana (the dominant grass) was significantly increased by nitrogen, but not by phosphorus. The biomass of the second dominant species Lespedeza davurica Schindl., was not affected by increased nitrogen but addition of phosphorus had some positive impact. Therefore, nitrogen deposition was proven to have effects on plant growth in our study area on the Loess Plateau of China, but high level of nitrogen deposition would result in P limitation. Furthermore, increasing nitrogen deposition is likely to induce diversity change.  相似文献   

17.
Over the years, a scarcity of information on nutrient gains or losses has led to overemphasis being placed on crop yields and economic income as the direct benefits from fertilizer micro-dosing technology. There is increasing concern about the sustainability of this technology in smallholder Sahelian cropping systems. This study was designed in the 2013 and 2014 cropping seasons to establish nutrient balances under fertilizer micro-dosing technology and their implications on soil nutrient stocks. Two fertilizer micro-dosing treatments [2 g hill?1 of diammonium phosphate (DAP) and 6 g hill?1 of compound fertilizer Nitrogen-Phosphorus-Potassium (NPK) (15-15-15)] and three rates of manure (100 g hill?1, 200 g hill?1 and 300 g hill?1) and the relevant control treatments were arranged in a factorial experiment organized in a randomized complete block design with three replications. On average, millet (Pennisetum glaucum (L.) R.Br.) grain yield increased by 39 and 72% for the plots that received the fertilizer micro-dosing of 6 g NPK hill?1 and 2 g DAP hill?1, respectively, in comparison with the unfertilized control plots. The average partial nutrients balances for the two cropping seasons were ?37 kg N ha?1yr?1, ?1 kg P ha?1yr?1 and ?34 kg K ha?1yr?1 in plots that received the application of 2 g DAP hill?1, and ?31 kg N ha?1yr?1, ?1 kg P ha?1yr?1 and ?27 kg K ha?1yr?1 for 6 g NPK hill?1. The transfer of straw yields accounted for 66% N, 55% P and 89% K for removal. The average full nutrient balances for the two cropping seasons in fertilizer micro-dosing treatments were ?47.8 kg N ha?1 yr?1, ?6.8 kg P ha?1 yr?1 and ?21.3 kg K ha?1 yr?1 which represent 7.8, 24.1 and 9.4% of N, P and K stocks, respectively. The nutrient stock to balance ratio (NSB) for N decreased from 13 to 11 and from 15 to 12 for the plots that received the application of 2 g DAP hill?1 and 6 g NPK hill?1, respectively. The average NSB for P did not exceed 5 for the same plots. It was concluded that fertilizer micro-dosing increases the risk of soil nutrient depletion in the Sahelian low-input cropping system. These results have important implications for developing an agro-ecological approach to addressing sustainable food production in the Sahelian smallholder cropping system.  相似文献   

18.
《Journal of plant nutrition》2013,36(8):1561-1580
Abstract

The Magruder plots are the oldest continuous soil fertility wheat research plots in the Great Plains region, and are one of the oldest continuous soil fertility wheat plots in the world. They were initiated in 1892 by Alexander C. Magruder who was interested in the productivity of native prairie soils when sown continuously to winter wheat. This study reports on a simple estimate of nitrogen (N) balance in the Magruder plots, accounting for N applied, N removed in the grain, plant N loss, denitrification, non‐symbiotic N fixation, nitrate (NO3 ?) leaching, N applied in the rainfall, estimated total soil N (0–30 cm) at the beginning of the experiment and that measured in 2001. In the Manure plots, total soil N decreased from 6890 kg N ha?1 in the surface 0–30 cm in 1892, to 3198 kg N ha?1 in 2002. In the Check plots (no nutrients applied for 109 years) only 2411 kg N ha?1 or 35% of the original total soil organic N remains. Nitrogen removed in the grain averaged 38.4 kg N ha?1 yr?1 and N additions (manure, N in rainfall, N via symbiotic N fixation) averaged 44.5 kg N ha?1 yr?1 in the Manure plots. Following 109 years, unaccounted N ranged from 229 to 1395 kg N ha?1. On a by year basis, this would translate into 2–13 kg N ha?1 yr?1 that were unaccounted for, increasing with increased N application. For the Manure plots, the estimate of nitrogen use efficiency (NUE) (N removed in the grain, minus N removed in the grain of the Check plots, divided by the rate of N applied) was 32.8%, similar to the 33% NUE for world cereal production reported in 1999.  相似文献   

19.
Abstract

To determine the relationships between microbial biomass nitrogen (N), nitrate–nitrogen leaching (NO3-N leaching) and N uptake by plants, a field experiment and a soil column experiment were conducted. In the field experiment, microbial biomass N, 0.5 mol L?1 K2SO4 extractable N (extractable N), NO3-N leaching and N uptake by corn were monitored in sawdust compost (SDC: 20 Mg ha?1 containing 158 kg N ha?1 of total N [approximately 50% is easily decomposable organic N]), chemical fertilizer (CF) and no fertilizer (NF) treatments from May 2000 to September 2002. In the soil column experiment, microbial biomass N, extractable N and NO3-N leaching were monitored in soil treated with SDC (20 Mg ha?1) + rice straw (RS) at five different application rates (0, 2.5, 5, 7.5 and 10 Mg ha?1 containing 0, 15, 29, 44 and 59 kg N ha?1) and in soil treated with CF in 2001. Nitrogen was applied as (NH4)2SO4 at rates of 220 kg N ha?1 for SDC and SDC + RS treatments and at a rate of 300 kg N ha?1 for the CF treatment in both experiments. In the field experiment, microbial biomass N in the SDC treatment increased to 147 kg N ha?1 at 7 days after treatment (DAT) and was maintained at 60–70 kg N ha?1 after 30 days. Conversely, microbial biomass N in the CF treatment did not increase significantly. Extractable N in the surface soil increased immediately after treatment, but was found at lower levels in the SDC treatment compared to the CF treatment until 7 DAT. A small amount of NO3-N leaching was observed until 21 DAT and increased markedly from 27 to 42 DAT in the SDC and CF treatments. Cumulative NO3-N leaching in the CF treatment was 146 kg N ha?1, which was equal to half of the applied N, but only 53 kg N ha?1 in the SDC treatment. In contrast, there was no significant difference between N uptake by corn in the SDC and CF treatments. In the soil column experiment, microbial biomass N in the SDC + RS treatment at 7 DAT increased with increased RS application. Conversely, extractable N at 7 DAT and cumulative NO3-N leaching until 42 DAT decreased with increased RS application. In both experiments, microbial biomass N was negatively correlated with extractable N at 7 DAT and cumulative NO3-N leaching until 42 DAT, and extractable N was positively correlated with cumulative NO3-N leaching. We concluded that microbial biomass N formation in the surface soil decreased extractable N and, consequently, contributed to decreasing NO3-N leaching without impacting negatively on N uptake by plants.  相似文献   

20.
A long-term field experiment was conducted for 8 years on a Vertisol in central India to assess quantitatively the direct and residual N effects of soybean inoculation with Bradyrhizobium and wheat inoculation with Azotobacter in a soybean–wheat rotation. After cultivation of soybean each year, its aerial residues were removed before growing wheat in the same plots using four N levels (120, 90, 60 and 30 kg ha?1) and Azotobacter inoculation. Inoculation of soybean increased grain yield by 10.1% (180 kg ha?1), but the increase in wheat yields with inoculation was only marginal (5.6%; 278 kg ha?1). There was always a positive balance of soil N after soybean harvest; an average of +28 kg N ha?1 yr?1 in control (nodulated by native rhizobia) plots compared with +41 kg N ha?1 yr?1 in Rhizobium-inoculated plots. Residual and direct effects of Rhizobium and Azotobacter inoculants caused a fertilizer N credit of 30 kg ha?1 in wheat. Application of fertilizers or microbial inoculation favoured the proliferation of rhizobia in crop rhizosphere due to better plant growth. Additional N uptake by inoculation was 14.9 kg N ha?1 by soybean and 20.9 kg N ha?1 by wheat crop, and a gain of +38.0 kg N ha?1 yr?1 to the 0–15 cm soil layer was measured after harvest of wheat. So, total N contribution to crops and soil due to the inoculants was 73.8 kg N ha?1 yr?1 after one soybean–wheat rotation. There was a total N benefit of 13.8 kg N ha?1 yr?1 to the soil due to regular long-term use of microbial inoculants in soybean–wheat rotation.  相似文献   

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