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1.
Field experiments were conducted with four nitrogen fertilizer treatments to study the effects of controlled-release urea combined with conventional urea on the nitrogen uptake, root yield, and contents of protein, soluble sugar, saponin, zinc (Zn), iron (Fe), magnesium (Mg), and copper (Cu) in Platycodon grandiflorum. Field experiments were conducted with four nitrogen (N) fertilizer treatments: no N fertilization; conventional urea with N rate of 175 kg N ha?1; conventional urea with N rate of 160 kg N ha?1; controlled-release urea combined with conventional urea with N rate of 160 kg N ha?1; controlled-release urea combined with conventional urea with N rate of 135 kg N ha?1. The results showed that nitrogen application significantly increased the yield of P. grandiflorum compared with the control. Treatment with controlled-release urea combined with conventional urea at 160 kg N ha?1 provided the highest yield of 7329.58 kg ha?1. Nitrogen application also increased the contents of soluble sugar, total saponin, protein, Zn, Fe, and Mg but decreased Cu content. Protein, saponin, and Zn contents were significantly higher, but Cu content was lower in P. grandiflorum fertilized with controlled-release urea combined with conventional urea than those fertilized with conventional urea alone. The combination of controlled-release urea with conventional urea at 160 kg N ha?1 was the optimal treatment under the experimental condition investigated in this study.  相似文献   

2.
To determine nitrogen (N) fate and environmental impact of applying anaerobic digestion slurry (ADS) to rice paddy (Oryza sativa L.), a field experiment was established using three treatments based on contrasting N application rate. The ADS (with ammonium-N accounting for >80 % of total N) treatment at a conventional application rate of 270 kg N?ha?1 was compared to a negative control (no N fertilizer) and a positive control of urea applied at 270 kg N?ha?1. The N budget showed the following distribution of applied N from ADS and urea: 41.3?±?5.1 % for ADS and 36.6?±?4.4 % for urea recovered by the rice plant (including straw, grain, and root), 16.4?±?3.7 % for ADS and 7.4?±?1.8 % for urea lost via ammonia volatilization, 0.26?±?0.15 % for ADS and 0.15?±?0.12 % for urea lost by direct N2O emission, 1.9?±?0.5 % for ADS and 2.3?±?0.8 % for urea leached downward, 0.70?±?0.15 % for ADS and 0.67?±?0.12 % for urea discharged with floodwater drainage, and 39.4?±?8.4 % for ADS and 53.0?±?9.1 % for urea retained by soil or lost by N2 emission. Compared to urea application, ADS application impacts the environment mainly through gaseous N losses rather than water N losses. ADS application had a positive impact on rice grain yield and reduced chemical fertilizer use. Considering the wide distribution of paddy fields and the ever-increasing quantities of ADS, ADS may serve as a valuable N source for rice cultivation, although mitigating ammonia and N2O losses should be further investigated.  相似文献   

3.
A study was conducted to assess fertilizer effect on pearl millet–wheat yield and plant-soil nutrients with the following treatments: T1, control; T2, 100% nitrogen (N); T3, 100% nitrogen and phosphorus (NP); T4, 100% nitrogen, phosphorus and potassium (NPK); T5, 100% NPK + zinc sulfate (ZnSO4) at 25 kg ha?1; T6, 100% NPK + farmyard manure (FYM) at 10 t ha?1; T7, 100% NPK+ verimcompost (VC) at 2.5 tha?1; T8, 100% NPK + sulfur (S) at 25 kg ha?1; T9, FYM at 10 t ha?1; T10, VC at 2.5 t ha?1; T11, 100% NPK + FYM at 10 t ha?1 + 25 kg S ha?1 + ZnSO4 at 25 kg ha?1; and T12, 150% NPK treatments. Treatments differed significantly in influencing soil-plant nutrients and grain and straw yields of both crops. Grain yield had significant correlation with soil-plant N, P, K, S, and zinc (Zn) nutrients. The study indicated superiority of T11 for attaining maximum pearl millet grain yield (2885 kg ha?1) and straw yield (7185 kg ha?1); amounts of N (48.9 kg ha?1), P (8.8 kg ha?1), K (26.3 kg ha?1), S (20.6 kg ha?1), and Zn (0.09 kg ha?1) taken up; and amounts of soil N (187.7 kg ha?1), P (13.7 kg ha?1), K (242.5 kg ha?1), S (10.1 kg ha?1), and Zn (0.70 kg ha?1). It was superior for wheat with grain yield (5215 kg ha?1) and straw yield (7220 kg ha?1); amounts of N (120.7 kg ha?1), P (13.8 kg ha?1), K (30 kg ha?1), S (14.6 kg ha?1), and Zn (0.18 kg ha?1) taken up; and maintaining soil N (185.7 kg ha?1), P (14.5 kg ha?1), K (250.5 kg ha?1), S (10.6 kg ha?1), and Zn (0.73 kg ha?1). Based on the study, 100% NPK + FYM at 10 tha?1 + Zn at 25 kg ha?1 + S at 25 kg ha?1 could be recommended for attaining maximum returns of pearl millet–wheat under semi-arid Inceptisols.  相似文献   

4.
Controlled-release urea (CRU) and its placement method in rice production were investigated during 2007 and 2008 seasons. Controlled-release urea was applied at 62.5, 125, and 187.5 kg nitrogen (N) ha?1, and the urea was 187.5 kg N ha?1. All the CRU treatments were applied to the nursery beds once, and they were brought into the paddy field during transplanting, while the urea treatment was split into three applications from the plowing to the harvest. The results showed that rice seedlings with CRUs germinated and grow well and there was no salt damage at the nursery stage. The CRU treatment with 125 kg N ha?1 had 33% less N than urea treatment (187.50 kg N ha?1), but it produced significantly higher grain and straw yields, higher total N uptake and total apparent N uptake efficiency. In addition, all the CRU treatments effectively decreased floodwater ammonium (NH4 +)-N and nitrate (NO3 ?)-N concentrations, pH, and N runoff.  相似文献   

5.
A study was conducted to evaluate the effect of nitrogen (N) application, through an easily available and cheap source urea, on potassium (K) displacement and its availability in K-deficient maize-growing soils of rainfed subtropics. The greatest amount of K was displaced (11.22 kg ha?1) by N application at the rate of 80 kg N ha?1 (treatment T4). Amount of N fixed to displace K (11.10 kg ha?1) was also greatest in the same treatment. Displaced K was positively related to nonexchangeable potassium (NEK) release. Nitrogen application through urea at 80 kg ha?1 helped not only in meeting N requirement of maize crop in these N-deficient soils but can also satisfy the K requirements (as these soils are low in K) of these soils. Potassium displacement also increased the production efficiency of the maize crop by promoting its relative production efficiency index (RPEI) from suitability class V to class III.  相似文献   

6.
Based on experiments conducted during 1988–2009 on rainfed pearl millet/sorghum with 9 treatments in Vertisols, an efficient treatment for sustainable productivity is identified. Twenty kg of nitrogen (N) from farmyard manure (FYM) + 20 kg N (urea) + 10 kg phosphorus (P) ha?1 in pearl millet and 40 kg N (urea) + 20 kg P + 25 kg zinc sulfate (ZnSO4) ha?1 in sorghum gave maximum yield and rainwater-use efficiency, whereas 20 kg N (FYM) + 20 kg (urea) + 10 kg P ha?1 in pearl millet and 40 kg (urea) + 20 kg P ha?1 in sorghum and gave maximum soil N, P, and potassium (K) over years. The regression model of 20 kg N (crop residue) + 20 kg N (urea) + 10 kg P ha?1 gave maximum R2 for predicting sorghum equivalent yield separately through precipitation and soil variables, whereas 20 kg N (FYM) + 20 kg N (urea) + 10 kg P ha?1 gave maximum R2 under combined model of both variables. Treatment of 20 kg N (FYM) + 20 kg N (urea) + 10 kg P ha?1 was superior for attaining maximum sorghum equivalent yield of 1062 kg ha?1, net returns of Rs. 4805 ha?1, benefit/cost (BC) ratio of 1.50, and 127 kg ha?1 of soil N, 10.3 kg ha?1 of soil P, and 386 kg ha?1 of soil K over years.  相似文献   

7.
It was hypothesized that the application of eucalyptus biochar enhances nutrient use efficiencies of simultaneously supplied fertilizer, as well as provides additional nutrients (i.e., Ca, P, and K), to support crop performance and residual effects on subsequent crops in a degraded sandy soil. To test this hypothesis, we conducted an on‐farm field experiment in the Khon Kaen province of Northeastern Thailand to assess the effects of different application rates of eucalyptus biochar in combination with mineral fertilizers to upland rice and a succeeding crop of sugarcane on a sandy soil. The field experiment consisted of three treatments: (1) no biochar; (2) 3.1 Mg ha?1 biochar (10.4 kg N ha?1, 3.1 kg P ha?1, 11.0 kg K ha?1, and 17.7 kg Ca ha?1); (3) 6.2 Mg ha?1 biochar (20.8 kg N ha?1, 6.2 kg P ha?1, 22.0 kg K ha?1, and 35.4 kg Ca ha?1). All treatments received the same recommended fertilizer rate (32 kg N ha?1, 14 kg P ha?1, and 16 kg K ha?1 for upland rice; 119 kg N ha?1, 21 kg P ha?1, and 39 kg K ha?1 for sugarcane). At crop harvests, yield and nutrient contents and nitrogen (N) use efficiency were determined, and soil chemical properties and pH0 monitored. The eucalyptus biochar material increased soil Ca availability (117 ± 28 and 116 ± 7 mg kg?1 with 3.1 and 6.2 Mg ha?1 biochar application, respectively) compared to 71 ± 13 mg kg?1 without biochar application, thus promoting Ca uptake and total plant biomass in upland rice. Moreover, the higher rate of eucalyptus biochar improved CEC, organic matter, available P, and exchangeable K at succeeding sugarcane harvest. Additionally, 6.2 Mg ha?1 biochar significantly increased sugarcane yield (41%) and N uptake (70%), thus enhancing N use efficiency (118%) by higher P (96%) and K (128%) uptake, although the sugar content was not increased. Hence, the application rate of 6.2 Mg ha?1 eucalyptus biochar could become a potential practice to enhance not only the nutrient status of crops and soils, but also crop productivity within an upland rice–sugarcane rotation system established on tropical low fertility sandy soils.  相似文献   

8.
A long-term study was conducted to study the impact of integrated nutrient management on soil quality in post-monsoon sorghum (Sorghum bicolor) at Solapur in Maharashtra State in Western India under All India Coordinated Research Project for Dryland Agriculture. The experiment was laid out with ten Integrated Nutrient Management Treatments in a randomized block design with three replications. The results of the study indicated that among all the integrated nutrient management treatments practiced, the application of 25 kg nitrogen (N) ha?1 through crop residue (CR) + 25 kg N ha?1 (urea) showed the highest soil quality index of 2.36, which was at par with other treatments receiving farmyard manure (FYM) and crop residues along with urea. The relative order of performance of the integrated nutrient management treatments in influencing soil quality was: T6: 25 kg N ha?1 (CR) + 25 kg N ha?1 (urea) (2.36) >T5: 25 kg N ha?1 (FYM) (2.31) > T7: 25 kg N ha?1 (FYM) +25 kg N ha?1 (urea) (2.30) = T8: 25 kg N ha?1 (CR) +25 kg N ha?1 (Leucaena loppings) (2.30) > T10: 25 kg N ha?1 (Leucaena loppings) +25 kg N ha?1 (urea) (2.17) > T4: 25 kg N ha?1 (CR:crop residues) (2.16) > T9: 25 kg N ha?1 (Leucaena loppings) (2.15) > T3: 50 kg N ha?1 (urea) (2.10) > T2: 25 kg N ha?1 (urea) (1.99) > T1: 0 kg N ha?1 (control) (1.77). The results of the study also indicated that average percent contribution of each soil key indicator towards soil quality indices was: pH (3.97%), EC (1.94%), organic carbon (18.6%), available P (2.80%), available K (6.57%), exchangeable Ca (7.02%), available S (3.45%), Available Zn (17.9%), dehydrogenase (DHA) (16.2%), microbial biomass carbon (MBC) (18.5%) and mean weight diameter (MWD) (3.14%). Thus, the results of the present study will be highly useful to the land managers in planning effective management of soil quality.  相似文献   

9.
Long-term effects of the different combinations of nutrient-management treatments were studied on crop yields of sorghum + cowpea in rotation with cotton + black gram. The effects of rainfall, soil temperature, and evaporation on the status of soil fertility and productivity of crops were also modeled and evaluated using a multivariate regression technique. The study was conducted on a permanent experimental site of rain-fed semi-arid Vertisol at the All-India Coordinated Research Project on Dryland Agriculture, Kovilpatti Centre, India, during 1995 to 2007 using 13 combinations of nutrient-management treatments. Application of 20 kg nitrogen (N) (urea) + 20 kg N [farmyard manure (FYM)] + 20 kg phosphorus (P) ha?1 gave the greatest mean grain yield (2146 kg ha?1) of sorghum and the fourth greatest mean yield (76 kg ha?1) of cowpea under sorghum + cowpea system. The same treatment maintained the greatest mean yield of cotton (546 kg ha?1) and black gram (236 kg ha?1) under a cotton + cowpea system. When soil fertility was monitored, this treatment maintained the greatest mean soil organic carbon (4.4 g kg?1), available soil P (10.9 kg ha?1), and available soil potassium (K) (411 kg ha?1), and the second greatest level of mean available soil N (135 kg ha?1) after the 13-year study. The treatments differed significantly from each other in influencing soil organic carbon (C); available soil N, P, and K; and yield of crops attained under sorghum + cowpea and cotton + black gram rotations. Soil temperature at different soil depths at 07:20 h and rainfall had a significant influence on the status of soil organic C. Based on the prediction models developed between long-term yield and soil fertility variables, 20 kg N (urea) + 20 kg N (FYM) + 20 kg P ha?1 could be prescribed for sorghum + cowpea, and 20 kg N (urea) + 20 kg N (FYM) could be prescribed for cotton + black gram. These combinations of treatments would provide a sustainable yield in the range of 1681 to 2146 kg ha?1 of sorghum, 74 to 76 kg ha?1 of cowpea, 486 to 546 kg ha?1 of cotton, and 180 to 236 kg ha?1 of black gram over the years. Beside assuring greater yields, these soil and nutrient management options would also help in maintaining maximum soil organic C of 3.8 to 4.4 g kg?1 soil, available N of 126 to 135 kg ha?1, available soil P of 8.9 to 10.9 kg ha?1, and available soil K of 392 to 411 kg ha?1 over the years. These prediction models for crop yields and fertility status can help us to understand the quantitative relationships between crop yields and nutrients status in soil. Because black gram is unsustainable, as an alternative, sorghum + cowpea could be rotated with cotton for attaining maximum productivity, assuring sustainability, and maintaining soil fertility on rain-fed semi-arid Vertisol soils.  相似文献   

10.
Acetylene blockage was evaluated as a method for measuring losses of N2O + N2 from two Denchworth series clay soils. The denitrification potential in anaerobic, dark incubations at 20°C with nitrate (equivalent to 100 kg N ha?1 0–20 cm depth), maximum water holding capacity, and acetylene (1%), was equivalent to 32 ± 11 and 39 ± 6 kg N ha?1 per day for the two 0–20 cm soils and was positively correlated with carbon content (r= 0.98). After 4 days N2O was reduced to N2 in the presence of C2H2. In April 1980 following irrigation (24 mm) and applications of ammonium nitrate (70 kg N ha?1) and acetylene, the mean nitrous oxide flux from soil under permanent grass was 0.05 ± 0.01 kg N2O-N ha?1 per day for 8 days. In June 1980, the losses of nitrogen from cultivated soils under winter wheat after irrigation (36 mm) and acetylene treatment were 0.006 ± 0.002 and 0.04–0.07 ± 0.01 kg N ha?1 per day respectively before and after fertilizer application (70 kg N ha?1). The nitrous oxide flux in the presence of acetylene decreased briefly, indicating that nitrification was rate determining in drying soil.  相似文献   

11.
Abstract

The experiment was conducted at Kulumsa, South East Ethiopia, using four levels of nitrogen (N) (0, 50,100 and 150?kg N ha?1) and four levels of phosphorus (P) (0, 35, 70 and 105?kg P2O5 ha?1) fertilizers arranged in 4?×?4 factorial arrangements in randomized complete block design with three replications. The available P was increased after harvest due to the application of N and P fertilizer at the rates of 100 or 150?kg N ha?1 and 70 or 105?kg P2O5 ha?1. More specifically, nutrients concentration and nutrient uptake were significantly (p?<?.01) varied among treatment combinations and nutrient use efficiency was declined by increasing N and P after optimum rates. The higher physiological efficiency of N (53.47?kg kg?1) and P (580.41?kg kg?1) and the highest apparent recovery of N (19.62%) and P (2.47%) was recorded from application of 50?kg N ha?1 and P at 70?kg P2O5 ha?1 and the highest agronomic efficiency of N (10.78?kg kg?1) and P (15.25?kg kg?1) was recorded from N at the rate of 50?kg N ha?1 and P at 35?kg P2O5 ha?1, respectively. The combination of N at 100?kg N ha?1 and P at 70?kg P2O5 ha?1 was promising combination that generated highest net benefit 488,878.5 ETB (Ethiopian birr) ha?1 with the highest marginal rate of return (36638%) and gave the highest seed yield (1858.82?kg ha?1) with yield increment of about 57.72% over the control.  相似文献   

12.
ABSTRACT

Reducing nitrogen (N) leaching from croplands is important to protect environmental quality and improve recovery of applied N. To contribute to this broader goal of nutrient management, a simple pot experiment evaluated the potential differences among urea (250 kg N ha?1), urea+compost (125 kg N ha?1 from urea + 125 kg N from 8 Mg ha?1 of compost), compost (250 kg N from 16 Mg ha?1 of compost) and a zero control (Ctrl), in terms of their effects on apparent N recovery (ANR), mineral N (Nmin) leaching and soil retention of applied N. Cabbage (Brassica oleraceae L.) and corn (Zea mays L.) were grown in rotation where compost application was not repeated in the 2nd year. Nmin leaching was monitored by adding 83 mm and 62 mm of water fortnightly to cabbage and corn crops, respectively for a total of 28 times in a two-year period. Combined (urea+compost) and independent (compost) treatment application retained 1.5 to 2 times higher N, and lowered 2.1 to 4.6 times Nmin leaching, relative to independent (urea) application. We conclude that farmers’ practice of fertilization that has an inherent problem of N leaching for high rainfall areas in Taiwan could be improved by proper compost and urea combinations within agronomically recommended rates of N application.  相似文献   

13.
Farmers are looking for better management practices to utilize animal manure as an alternative to chemical fertilizers. A 2-year field experiment was conducted to study the effects of nitrogen (N) fertilizer source and application methods to Nicholson silt loam soil in central Kentucky, USA for no-till corn (Zea mays) production. The region has a temperate climate with a mean temperature of 14.5°C and rainfall of 1300 mm year?1. Treatments included a control, 179 kg N ha?1 urea ammonium nitrate (UAN) applied as preplant and sidedress, and swine effluent that was applied by three methods: broadcast, injection, and Aerway. Injection method produced the greatest corn grain yield (11.88 Mg ha?1) and biomass yield (18.9 Mg ha?1) in 2007. Results demonstrated that the effluent application methods and the timing of UAN application may not be agronomically important for corn production in this region. Hence, more studies are needed on different soils in this region.  相似文献   

14.
Seedrow-placed urea minimizes soil disturbance in reduced tillage systems, but it generally decreases seedling emergence (or stand density) at nitrogen (N) rates adequate for optimum crop yield. Two three-year field experiments were conducted on canola (Brassica napus L.) and spring wheat (Triticum turgidum L.) at Melfort Research Farm, Saskatchewan, Canada, to determine the influence of N rate (40, 80 and 120 kg N ha?1), N source [untreated urea (urea), polymer-coated urea (ESN), and urea treated with Dicyandiamide (DCD) and N-(n-butyl) thiophosphoric triamide (NBPT or AgrotainTM) (SuperU) in 2007, or NBPT only (AgrotainU) in 2008 and 2009], and placement (side-banded N and seedrow-placed N, using knives to create 2 cm wide band), plus a zero-N control, on seedling emergence, seed and straw yield, protein concentration (PC) in seed, and N uptake in seed and straw. For both crops, side-banded N had no detrimental effect on seedling emergence compared to the zero-N control for all rates and sources. Seedrow-placed ESN had little or no effect on seedling emergence of wheat or canola. Conversely, seedrow-placed urea, SuperU or AgrotainU reduced seedling emergence for wheat at the 80 and 120 kg N ha?1 rates and reduced canola seedling emergence substantially at all rates, but particularly at the 80 and 120 kg N ha?1. Seed yield and N uptake were generally greater with ESN than urea and also SuperU or AgrotainU, when the fertilizers were seedrow-placed at high N rates. The findings suggest the effectiveness of ESN in providing greater seedrow-placed N application options for producers.  相似文献   

15.
To study the effects of organic and inorganic nitrogen (N) on yield and nodulation of chickpea (Cicer arietinum L.) cv. ILC 482, a spilt-plot experiment based on randomized complete block design with four replications was conducted in 2008 at the experimental farm of the Agriculture Faculty, University of Mohaghegh, Ardabili. Experimental factors were inorganic N fertilizer at four levels (0, 50, 75, and 100 kg ha?1) in the main plots that applied in the urea form, and two levels of inoculation with Rhizobium bacteria (with and without inoculation) as subplots. Nitrogen application and Rh. inoculation continued to have positive effects on yield and its attributes. The greatest plant height, number of primary and secondary branches, number of pods per plant, number of filled and unfilled pods per plant, number of grains per plant, grain yield, and biological yield were obtained from the greatest level of N fertilizer (100 kg urea ha?1) and Rh. inoculation. Application of 75 and 100 kg ha?1 urea showed no significant difference in these traits. Furthermore, the greatest rate of N usage (100 kg urea ha?1) adversely inhibited nodulation of chickpea. Number and dry weight of nodules per plant decreased significantly with increasing N application rate. The lowest values of these traits recorded in application of 100 kg ha?1 urea. Results indicated that application of suitable amounts of N fertilizer (i.e., between 50 and 75 kg urea ha?1) as starter can be beneficial to improve nodulation, growth, and final yield of inoculated chickpea plants.  相似文献   

16.
A field study was conducted in the sub-humid tropical region of India to examine the effect of different nitrogen (N) management strategies on nitrate leaching, nitrous oxide (N2O) emission and N use efficiency in aerobic rice. Treatments were: control (no N), 120 kg N ha?1 applied as prilled urea (PU) in conventional method, 120 kg N ha?1 applied as neem coated urea (NCU) in conventional method, N applied as PU on the basis of leaf colour chart (LCC) reading, N applied as NCU on the basis of LCC reading, and 120 kg N ha?1 applied as PU and farm yard manure (FYM) in 1:1 ratio. Results showed that 3.4–16.1 kg NO3-N ha?1 was leached below 45 cm depth and 0.61–1.12 kg N2O-N ha?1 was emitted from aerobic rice during the growing season. NCU when applied conventionally reduced nitrate-nitrogen (NO3-N) leaching and N2O emission by 18.6% and 21.4%, respectively However when applied on the basis of LCC reading NCU reduced NO3-N leaching by 39.8% as compared to PU applied in conventional method. NCU when applied on the basis of LCC reading synchronized N supply with demand and reduced N loss, which resulted in higher yield and N use efficiency.  相似文献   

17.
Soil, crop, and fertilizer management practices may affect quality of organic carbon (C) and nitrogen (N) in soil. A long-term field experiment (growing barley, wheat, or canola)was conducted on a Black Chernozem (Albic Argicryoll) loam at Ellerslie, Alberta, Canada, to determine the influence of 19 years (1980 to 1998) of tillage [zero tillage (ZT) and conventional tillage (CT)], straw management [straw removed (SRem) and straw retained (SRet)], and N fertilizer rate (0, 50, and 100 kg N ha?1 in SRet and 0 kg N ha?1 in SRem plots) on macro-organic matter C (MOM-C) and N (MOM-N), microbial biomass C (MB-C), and mineralizable C (Cmin) and N (Nmin) in the 0- to 7.5-cm and 7.5- to 15-cm soil layers. Treatments with N fertilizer and SRet generally had a greater mass of MOM-C (by 201 kg C ha?1 with 100 kg N ha?1 rate and by 254 kg C ha?1 with SRet), MOM-N (by 12.4 kg N ha?1 with 100 kg N ha?1 rate and by 8.0 kg N ha?1 with SRet), Cmin(by 146 kg C ha?1 with 100 kg N ha?1 rate and by 44 kg C ha?1 with SRet), and Nmin(by 7.9 kg N ha?1 with 100 kg N ha?1 rate and by 9.0 kg N ha?1 with SRet)in soil than the corresponding zero-N and SRem treatments. Tillage, straw, and N fertilizer had no consistent effect on MB-C in soil. Correlations between these dynamic soil organic C or N fractions were strong and significant in most cases, except for MB-C, which had no significant correlation with MOM-C and MOM-N. Linear regressions between crop residue C input and mass of MOM-C, MOM-N, Cmin, and Nmin in soil were significant, but it was not significant for MB-C. The effects of management practices on dynamic soil organic C and N fractions were more pronounced in the 0- to 7.5-cm surface soil layer than in the 7.5- to 15-cm subsoil layer. In conclusion, the findings suggest that application of N fertilizer and retention of straw would improve soil quality by increasing macro-organic matter and N-supplying power of soil.  相似文献   

18.
Increased use of nitrogenous fertilizers in agriculture has led to the increased pollution of ground water and atmosphere. Certain plant products can be used as coating materials onto urea to reduce the N losses. We evaluated the effectiveness of citronella and palmarosa grass oils as nitrification inhibitors in a soil incubation study. The treatments (14) were combinations of 4 N sources (neem, citronella and palmarosa oil coated prilled ureas, and uncoated prilled urea), 2 coating thicknesses of oils (500 and 1000 mg kg?1) and 2 N levels (75 and 150 kg N ha?1), replicated thrice in a randomized block design. N levels at 75 and 150 kg ha?1 were equivalent to 34 and 68 mg N kg?1 soil, respectively. Results showed that N sources citronella (CCPU1000) and neem oil (NCPU1000) coated prilled ureas at 1000 mg kg?1 coating thickness with 75 kg ha?1 released similar amount of ammonical-N to uncoated prilled urea at 150 kg N ha?1, suggesting the beneficial effect of coated ureas. The highest nitrification inhibition (%) was recorded with NCPU1000, the reference nitrification inhibitor, which was significantly greater to all the other N sources at 7 days after incubation (DAI), and at par to CCPU1000 at 14 and 21 DAI.  相似文献   

19.
ABSTRACT

Nutrient uptake and grain and straw yield of Egyptian winter wheat (Triticum aestivum L. Merr.) were evaluated for two site-years after the seed inoculation with two biofertilizer products, Phosphorien, containing the phosphorus (P)-solubilizing bacteria Bacillus megatherium, and Nitrobien, containing a combination of nitrogen (N)-fixing bacteria Azotobacter chroococcum and Azospirillum liposerum. Ammonium nitrate and polymer-coated urea fertilizers were applied to plots alone and together with the biofertilizers at rates of either 83 kg N ha?1 or 186 kg N ha?1 for comparison. The highest grain yield (5.76–6.74 Mg ha?1) and straw yield (11.49–13.32 Mg ha?1) occurred at the highest fertilizer rates with N fertilizer. There was a slight additional increase in grain and straw yields when a biofertilizer was applied along with N fertilizer. A slightly higher grain and straw yield was measured with the polymer-coated urea treatment than with the ammonium nitrate treatment. The biofertilizer materials were not as effective as N fertilizers in producing grain (4.02–4.09 Mg ha?1) or straw (7.71–8.11 Mg ha?1) for either year, although the Nitrobien + Phosphorien combination increased these parameters over the N-fertilizer control. The effect of the Nitrobien biofertilizer in increasing grain yields was equivalent to a urea application rate of about 13 kg N ha?1. Biofertilizer inoculations increased iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) concentrations in wheat tissue (at boot stage), but these higher levels did not influence grain or straw yield.  相似文献   

20.
In 2012, a greenhouse experiment was conducted to investigate the effects of field soil (C0), residual composted municipal waste (CMW), and residual composted sheep manure (SM) on the growth of triticale in pots previously growing oilseed rape in 2011. To each soil group, one of three levels of urea nitrogen (N) fertilizer was added. Results demonstrated that triticale grown in pots previously containing oilseed rape plants containing SM or CMW with 150 kg urea N ha?1 had the highest N content. Plants grown in SM with 150 kg N ha?1 had the greatest seed yield, but yield was not significantly different from plants grown in CMW receiving 150 kg N ha?1. Triticale plants enriched by either SM or CMW had a higher amount of N, copper, zinc, and manganese compared to the field soil control.  相似文献   

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