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1.
氮钾肥配合施用对桑叶产量品质及蚕茧质量的影响   总被引：3，自引：0，他引：3  
通过连续4年田间施肥试验和一季养蚕试验,研究了氮肥和钾肥配合施用对桑叶产量、品质及相应桑叶喂饲家蚕对蚕生长及蚕茧品质的影响。结果表明,桑园施用氮钾肥显著提高桑叶产量,在氮钾肥各养分配比中,以高氮高钾处理(N450K300)的产量最高,比N0K0处理年均增产35.2%,与其他各处理产量差异显著。桑叶品质分析结果表明,桑叶中必需氨基酸、氨基酸总量、粗蛋白、油脂含量随氮肥用量增加而提高,但单施氮肥会对蛋氨酸和油脂含量产生负面影响;施钾导致糖分含量下降,其他品质参数值随钾肥施用而提高,氮钾肥配合施用具有提高桑叶品质的作用。养蚕结果表明,桑园增施氮钾肥生产出的桑叶,有助于降低蚕茧的死笼率、具有提高全茧量和茧层率及提高蚕茧产量的作用。蚕茧上茧率、茧丝长、解舒率和茧丝净度随着钾肥用量的增加而提高,在施钾基础上增加氮肥用量有提高蚕茧品质的作用,但不施钾只施氮肥对上茧率有负面影响,说明氮钾肥配合施用能促进蚕茧质量的提高。  相似文献   

2.
钾肥用量和品种对桑叶生产及蚕茧质量的影响   总被引：3，自引：0，他引：3  
通过为期 4年的田间施肥试验和 1季养蚕试验 ,研究了钾肥用量和钾肥品种对桑叶产量、品质、养分吸收和蚕茧质量的影响。结果表明 ,施K2 O 1 5 0、30 0、375kghm-2 a-1 处理分别比不施K肥年均增产桑叶 2 3.9%、31 .7%、36 .0 %;等量钾肥时 ,KCl对桑叶增产效果基本等同于K2 SO4;施钾增产效果有逐年增加趋势 ,同时钾肥施用表现后效。施钾明显提高桑叶中N、K和S(K2 SO4为钾源时 )含量 ,而降低Ca、Mg和Zn含量 ,对P含量影响不大。结果显示 ,钾肥施用大幅度促进了桑树对各种养分的吸收 ,从而提高了肥料利用率。施钾明显促进桑叶品质的改善 ,随着钾肥用量增加 ,桑叶中必需氨基酸、氨基酸总量、蛋白质、糖分和油脂含量均呈增加趋势。KCl施用也能提高桑叶品质 ,但效果比K2 SO4差。蚕茧质量测试结果表明 ,桑树施钾后对喂养的蚕茧品质产生正面影响 ,蚕重、全茧量、上茧率、茧丝长、解舒率、茧丝净度等指标均因施钾而提高 ,高量钾比低量钾效果好 ,在等量钾用量时K2 SO4对蚕茧质量的促进作用明显好于KCl。  相似文献   

3.
Response of sugar beet ( Beta vulgaris var. altissima ) to potassium fertilization—a 20‐year field experiment A long‐term fertilizer experiment was performed to develop a K fertilization strategy to achieve highest extractable sugar yields (BZE). Sugar beet was grown in a crop rotation with wheat and barley on an alluvial soil (clayic silt) in Lower Saxony with annual recycling of straw and beet tops, respectively. Since 1983, the treatments were as follows: 1) K fertilization with 0, 29, 58, 87,174, and 524 kg K ha–1 a–1 corresponding to 0, 0.5, 1, 1.5, 3, and 9 times the average annual K removal by the marketable products of the crop rotation—since 1995, the two highest treatments (3 and 9 times the removal) received only 174 kg ha–1 every third year; 2) K fertilization according to the average K removal, given each year (58 kg K ha–1) or every third year (174 kg ha–1) to sugar beet; 3) annual K fertilization of 87 kg K ha–1 (1.5 times the removal) applied in autumn or spring, respectively; 4) annual K fertilization, applied as mineral fertilizer or as organic material (recycling of grain and straw or root and leaves); 5) application of 29 kg NaCl ha–1 to sugar beet supplemental to a yearly application of 58 kg K ha–1. Both root yield and soil concentration of lactate‐soluble K increased with K fertilization up to the highest K treatment. The extractable sugar content reached a maximum at a yearly application of 174 kg K ha–1. Averaged over years, the extractable sugar yield (BZE) increased up to the highest K application. The time of K application (autumn or spring) and the source of K (mineral fertilizer or organic material) had no effect on BZE. An additional fertilization with NaCl increased BZE only slightly in single years. Low‐grade muriate of potash containing 33% K and 3% Na can thus be used. The economically optimal K‐fertilization rate was 174 kg K ha–1 given once in the crop rotation to sugar beet. A soil K concentration of about 110 mg (kg soil)–1 (lactate‐extractable K) is sufficient in this soil to achieve a high BZE.  相似文献   

4.
The present study is based on the hypothesis that different methods of supplying boron (B) may have different effects on the yield and quality performance of tobacco crop. A field experiment was conducted to study the effect of different methods of B fertilization on the yield, quality, and leaf composition of flue-cured Virginia tobacco (cv. K-399) in 2007 at the Pakistan Tobacco Research Station, Mansehra. Three different methods (i.e., foliar spray, soil application, and root dipping at the rates of 0.25 kg ha–1, 1 kg ha–1, and 0.5 mg B L–1, respectively) in the form of boric acid along with a control (where no B was applied) were used in a randomized complete block design and replicated four times. Results revealed that different methods of B application significantly affected tobacco yield, quality, and nutrient uptake compared to the control. Maximum leaf area of 707 cm2, green leaf yield of 18553 kg ha–1, cured leaf yield of 2314 kg ha–1, grade index of 79%, nicotine content of 2.54%, and sugar content of 18.35% were noted in the treatment plot where B was applied as a foliar spray; however, in a few cases, there was no significant difference found among different methods of B application. Chloride and potassium contents were not significantly affected by any method of B fertilization. The B fertilization increased the concentration of this element in tobacco leaf, and a maximum concentration of B 48.55 mg kg–1 was noted in the foliar spray treatment. Moreover, fertilizer-use efficiency for different methods of B application revealed that foliar spray is more efficient as compared to soil application and root-dipping methods. Nutrient ratios to B such as potassium (K) / B and chloride (Cl) / B considerably decreased in tobacco leaf with increases in the concentration of B in leaves. These ratios provided some indication of the interrelationship of B with these nutrients in tobacco plants. Results also revealed that K/B and Cl/B ratios closely correlated with the grade index of tobacco leaf, and good grades of tobacco were found to be at a K/B ratio of 682 and a Cl/B ratio of 148 under the experimental conditions. The overall results indicated that the B foliar spray at the rate of 0.25 kg ha–1 significantly increased the yield, quality, and the nutrient uptake by the tobacco crop under the prevailing conditions and was more effective than other methods of B application.  相似文献   

5.
Phosphorus (P)‐solubilizing bacteria and fungi can increase soil‐P availability, potentially enhancing crop yield when P is limiting. We studied the effectiveness of Bacillus FS‐3 and Aspergillus FS9 in enhancing strawberry (Fragaria × ananasa cv. Fern) yield and mineral content of leaves and fruits on a P‐deficient calcareous Aridisol in Eastern Anatolia, Turkey. The 120 d pot experiment was conducted in three replicates with three treatments (Bacillus FS‐3, Aspergillus FS9, control) and five increasing rates of P addition (0, 50, 100, 150, and 200 kg P ha–1). Fruit yield and nutrient content of fruits and leaves and soil P pools were determined at the end of the experiment. Phosphorus‐fertilizer addition increased all soil P fractions. Strawberry yield increased with P addition (quadratic function) reaching a maximum of 94 g pot–1 at 200 kg P ha–1 in the absence of P‐solubilizing microorganisms. At this yield level, Bacillus FS‐3 and Aspergillus FS9 inoculation resulted in P‐fertilizer savings of 149 kg P ha–1 and 102 kg P ha–1, respectively. Both microorganisms increased yields beyond the maximum achievable yield with sole P‐fertilizer addition. Microorganism inoculation increased fruit and leaf nutrient concentrations (N, P, K, Ca, and Fe) with the largest increases upon addition of Bacillus FS‐3. We conclude that Bacillus FS‐3 and Aspergillus FS9 show great promise as yield‐enhancing soil amendments in P‐deficient calcareous soils of Turkey. However, moderate additions of P fertilizer (50–100 kg ha–1) are required for highest yield.  相似文献   

6.
Abstract

Plant nutrition and disease suppression are among the most important management tools for producers of hard red winter wheat (Triticum aestivum L.) in the central and southern Great Plains. This study was conducted to examine the effects of phosphorus (P) (0, 15, and 30 kg ha?1) and potassium (K) (0, 37, and 74 kg ha?1) fertilization, foliar fungicide application, and cultivar disease tolerance on wheat yield, yield components, and severity of leaf rust (Puccinia triticina Eriks.). Compared with no P, fertilizing with P increased yield by as much as 60% (>1.3 Mg ha?1 increase). Yield of cultivars susceptible to leaf rust was nearly 0.6 Mg ha?1 less without K than with K fertilization. Fungicide application resulted in mean yields of 4.8 Mg ha?1 for both resistant and susceptible cultivars, however, yield of susceptible cultivars was suppressed more than yield of resistant ones without fungicide. Although P fertilization had a moderately suppressive effect on leaf rust, the increased yield was primarily due to production of about 50% more heads m?2 apparently from more prolific tillering. Similarly, K fertilization appeared to reduce leaf rust severity and improve yield by increasing kernel weight, but this response may have been related partially to chloride (Cl) in the KCl fertilizer. Correlations suggested that improving dry matter production and N, P, and K uptakes at the boot stage by P and K fertilization can reduce leaf rust severity later in the growing season and increase wheat grain yield. These results indicate that especially P fertilization, but also K fertilization and fungicide application, are important management tools for reducing disease and increasing winter wheat yield.  相似文献   

7.
Insufficient potassium (K) nutrition produces detrimental effects on cotton (Gossypium hirsutum L.) lint yield and fiber quality. To further understand the deleterious effects caused by K deficiency, a 2‐yr (1991 and 1992) field study was conducted to determine how dry matter partitioning and nutrient concentrations of various plant tissues for the cotton genotypes, ‘DES 119’ and ‘MD 51 ne’, were altered by varying the application rate of fertilizer K and nitrogen (N). All plots received a preplant application of 112 kg N ha‐1, and half of the plots were later sidedressed with an additional 38 kg N ha‐1. Within each N treatment, half the plots received 112 kg K ha‐1, preplant incorporated, with the remaining plots not receiving any fertilizer K. Dry matter harvests were taken three times in 1991 and two times in 1992. At cutout (slowing of vegetative growth and flowering), plants that received K fertilization had a 14% more leaf area index (LAI), a 3% increase in the number of main stem nodes, and a 2% increase in plant height. However, those plants had a 12% lower specific leaf weight (SLW) than plants receiving no K fertilization. By the end of season, the of K fertilization had resulted in more stem (21%), bur (13%), seed (19%), and lint weight (20%), but harvest index was not affected. Varying the level of N fertilization did not affect any of these dry matter parameters at any harvest. In general, the larger plants produced under K fertilization had reduced concentrations of N, phosphorus (P), magnesium (Mg), and sodium (Na) in the various plant parts. While N uptake efficiency was not affected by K fertility, plants that received K fertilization had increased efficiency of fertilizer N use and of N utilization within the plant. The smaller LAI of the K deficient plants probably reduced the photosynthetic capacity per plant. A reduced assimilation capacity could explain the inefficiency of N use, lint yield reductions, and poorer fiber quality often associated with K deficiencies.  相似文献   

8.
A potato field experiment was conducted for 2 consecutive years to determine the effects of nitrogen (N) and potassium (K) fertilization rates on the yield and quality of potato cv. Spunta cultivated on soil low in N and K. A 3?×?4 complete factorial experiment was used with three rates of nitrogen (330, 495, and 660 kg N ha–1) and four rates of potassium (112, 225, 450, and 675 kg K2Ο ha–1). An additional treatment without fertilization was used as the control. On soils low in N and K, potatoes showed low yield response to K fertilizer. The greatest tuber yields for both years were achieved at 495 kg N ha–1 and 112 kg K2O ha–1 (29.81 t ha–1) and 225 kg ha–1 (27.13 t ha–1), respectively. Differences in mean fresh weight due to treatment application were not significant. Application of 495 kg N ha–1 significantly reduced harvest index (the ratio of tuber dry weight to the total dry weight at harvest) compared to 330 kg N ha–1, but at 660 kg N ha–1 harvest index achieved the greatest significant value. Potassium fertilization had no significant influence on harvest index. Nitrogen rates positively influenced the number of tubers. The addition of 450 kg K2O ha–1 significantly enhanced the number of tubers compared to the lower K rates, and the number was significantly decreased by the application of 675 kg K2O ha–1. Tuber dry-matter concentration was significantly promoted by N fertilization in both cultivation years, but it was negatively affected by K fertilization in the first year of cultivation. There was no change in tuber N with N application, but N application strongly increased nitrate (NO3) concentration, which fluctuated between 360 and 1382 mg kg–1 wet mass. Tuber NO3 was negatively correlated with tuber yield, indicating that high levels of NO3 in tubers can adversely affect yield. Tuber response to K fertilization was not in accordance with the rate of applied nutrient.  相似文献   

9.
Abstract

A field trial was conducted during the short‐day period of 2004–2005 at Ona, Fl., to study the factorial effect of nitrogen (67, 90, and 134 kg N ha?1) and phosphorus (0, 5, 10, 20, and 40 kg P ha?1) rates on forage dry‐matter yield, quality, nutrient uptake, and leaf pigment concentration of limpograss (Hemarthria altissima). The N and P fertilizers were applied 45 days before each of two harvests. There was no interaction between N and P rates on any of the measured variables. Cool‐season forage yield increased curvilinearly from 137 to 350 kg ha?1 in winter and 237 to 1389 kg ha?1 in early spring, whereas crude protein (CP) concentration increased from 145 to 158 g kg?1, as P was increased from 0 to 40 kg ha?1, but yield and CP were not affected by N rate. There was a decreasing linear relationship between leaf concentration of anthocyanins and P rate of application such that forage obtained with 0 kg P ha?1 had 61% more leaf anthocyanins and purple pigmentation than with 40 kg P ha?1. There was no effect of N on anthocyanins content. It was concluded that increased level of leaf anthocyanins was due to the cumulative stress from cool weather and lower plant‐tissue P levels, which resulted in reduced growth and yield of limpograss. In cool weather, P played a critical role in controlling leaf purple pigmentation and forage yield.  相似文献   

10.
The great achievement of the development of intensive in agriculture in China can be partly attributed to substantial increases in mineral‐nutrient application. However, whereas farmers tend to apply high levels of nitrogen (N) and phosphorus (P) application of potassium (K) has been neglected. A greater understanding of the relationship between maize (Zea mays L.) grain yield and K‐application rate is thus required to provide an improved rationale for K fertilization for farmers in the various agro‐ecological regions of China. In this study, a total of 2765 farmers' survey data and 3124 on‐farm experiments across major maize agro‐ecological regions in China were collected and evaluated for farmers' K‐management status and to determine grain‐yield response to K application. Nationally, the average K‐application rate on farms was 26 kg K ha–1 and varied from 0 to 158 kg K ha–1, with a coefficient of variation of 107%, but the applied K‐fertilizer rates were not related to grain yield. Maize grain yields at recommended K rates increased by 14.0%, 14.7%, 19.4%, and 4.3% in Northeast China, North China Plain, Southwest China, and Northwest China, respectively, compared to zero K fertilization (K0). Increased yield due to K fertilization (IYmax, difference between maximum yield across all treatments and K0‐treatment yield for each experiment) averaged 1.4 t ha–1 but varied widely in different agro‐ecological regions. Soil extractable K (NH4OAc‐K) and intercounty variation resulted in large variation in IYmax in agro‐ecological regions, as did other factors, such as use of particular maize hybrids, soil types, or years in different regions.  相似文献   

11.
ABSTRACT

Long-term fertilization tests evaluated rice (Oryza sativa) productivity in relation to application of nitrogen (N)-phosphorus (P)-potassium (K) (120-34.9-66.7 kg ha? 1, respectively) during 1967–1972 and N-P-K (150-43.7-83.3 kg ha? 1, respectively) during 1973–2000. The comparison treatments (NP, PK, and NK) and the control (not fertilized) were selected for calculating nutrient efficiency. Rice grain yield increased at a 17.78 kg ha? 1 yr? 1 in the control, mainly due to development of improved cultivars. Phosphorus management was found to be important for indigenous fertility and rice productivity in this paddy soil. Yield increased significantly with P fertilization. Without N fertilization (PK), rice productivity increased 56.85 kg ha? 1 yr? 1 from 62% of NPK at the initial stage to 74% after passing 34 years, which might be affected by increasing biological N fixation with P accumulation in soil. In NK treatment, rice yield increased at a relatively low rate (37.82 kg hr? 1 yr? 1) from the same rice productivity with that of NPK in 1967 to 91% after 34 years. In comparison, yield increased at a high rate (62.82 kg hr? 1 yr? 1) without K fertilization (NP) from ca. 90% of NPK and might exceed the yield of NPK after 64 years of long-term fertilization. Therefore, K fertilization level might be readjusted after long-term fertilizing in paddy soil.  相似文献   

12.
陕西建立陡坡蚕桑水保经济的前景与效益分析   总被引：2，自引：0，他引：2  
丝织品销售量在国内外市场呈上升趋势，我国近年蚕丝出口创汇３０亿美元，占世界贸易的４０％。陕西丘陵山区以陡坡灌桑聋槽栽培新法在２５°以上退耕坡地植桑，每ｈｍ＾２产桑叶９００－１８０００ｋｇ；每ｈｍ＾２养蚕１５－３０张，产茧４５０－９００ｋｇ，每ｈｍ＾２桑年获得利３０００－６０００元以上；水土保持效益６０００－１２０００。陕西省有我国《水土保持法》规定２５°以上陡坡应退耕坡耕地９．２２×１０＾５ｈｍ＾  相似文献   

13.
Abstract

Nutrient resorption from senescing leaves is a pivotal component of nutrient conservation strategy in a plant. Thus understanding the response of nutrient resorption to fertilization is of great help to minimize fertilizer use and further optimize fertilization management. However, little is known about how nutrient resorption responds to fertilization in N2-fixing species. Nitrogen (N) and phosphorus (P) fertilizers were applied at different rates to alfalfa stands in the Loess Plateau. N fertilization hardly affected leaf N and K resorptions, but tended to increase P resorption. P fertilization increased N and K resorptions but affected P resorption in various ways. However, effect of N or P fertilization was significantly interplayed by P or N rate. At N100P60, alfalfa had the maximum biomass accumulation and less leaf resorption. Therefore, alfalfa could be performed well with 100?kg N ha?1 and 60?kg P2O5 ha?1 in this region.  相似文献   

14.
不同施肥处理对桑叶产量及其品质的影响   总被引：3，自引：1，他引：2  
利用现代肥料二次回归3414试验设计,研究了氮、磷、钾不同施肥处理对桑叶产量及其构成因素、桑叶品质的影响。结果表明:氮、磷、钾主要是通过影响桑树春季新稍长和秋季条长及其米条产叶量,进而影响桑叶产量。随着单因素施肥量的增加,桑叶产量也随之增加,在X1-2X2-2X3-2达到最大（其中X1、X2、X3分别为N、P、K肥料因子）,为30780.1 kg/hm2。通过建立桑叶产量的肥料效应函数,获得该地区最佳推荐施肥量为N 736.47 kg/hm2、P2O5 215.29 kg/hm2、K2O 267.74 kg/hm2,桑叶最佳产量为30709.5 kg/hm2。随着施肥量的增加,桑叶中粗蛋白、可溶性糖、氨基酸和脂肪含量也随之显著增加,在2水平时达到最大,分别为22.63%、18.62%、17.76%、9.19%;所以适量氮、磷、钾施肥量及其配比能显著提高桑叶的产量和品质。本文可为四川丘陵蚕区高产优质桑园建设提供科学依据和参考。  相似文献   

15.
A 3-year field study was conducted in central Greece to determine the productivity of two stevia [(Stevia rebaudiana (Bertoni) Bertoni] varieties (‘Morita’ and ‘Candy-stevia’) under normal and reduced irrigation (100% and 75% of the evapotranspiration) and fertilization [1:0.8:1.1 or 1:0.4:0.8 N:P:K ratio in the first year and only N fertilization (100% or 74% of the recommended rate) in the second and third years] inputs. Averaged across years, stevia cv. Morita achieved greater dry leaf yield (3.48 t ha?1) than the cv. Candy-stevia (2.85 t ha?1). Irrigation and fertilization inputs did not significantly affect stevia cv. Morita dry leaf and steviol glycosides (stevioside plus rebaudioside-A) yields; however, decreasing irrigation and fertilization caused slight reduction of cv. Candy-stevia yields. In cv. Morita leaves, the concentrations of stevioside and rebaudioside-A ranged from 5.97% to 7.78% and 3.73% to 4.79%, respectively, while the corresponding concentrations in cv. Candy-stevia leaves were 8.21–9.36% and 3.89–6.33%. Conclusively, both stevia varieties could achieve satisfactory dry leaf biomass and steviol glycosides yield, even when grown under reduced irrigation (at 75% of evapotranspiration) and reduced N fertilization (74% of the recommended rate). Thus, stevia could represent an alternative crop to tobacco in the Mediterranean conditions.  相似文献   

16.
Cocoon samples were collected from fifty-two mulberry gardens with high, intermediate, and low silkworm cocoon productivities in the lower-middle reaches of the Yangtze River in the six China’s provinces of Jiangsu, Jiangxi, Anhui, Fujian, Hunan, and Hubei to determine the transformation efficiency of S from mulberry leaves to silkworm cocoons, and to evaluate the sulfur cycle (uptake and output) in the mulberry leaf-silkworm cocoon system with typical mulberry gardens in the lower-middle reaches of the Yangtze River in China. The transformation efficiency of sulfur (TES) from mulberry leaves into silkworm cocoons in the high-productivity mulberry gardens was significantly lower (P < 0.05) than that in the low-productivity gardens. For the high-productivity mulberry gardens the TES from mulberry leaves into the cocoon shell was significantly higher (P < 0.05) than that for low-yield mulberry gardens. Producing 1 kg dry cocoon in mulberry gardens required uptake of about 20 g S, however 1 kg of dry cocoon only removed about 4 g S. Therefore, recycling of these organic wastes with silkworm cultivation was important for sulfur balances.  相似文献   

17.
The diameter at breast height (dbh) growth of black walnut (Juglans nigra L.) trees in an 18‐year‐old plantation was measured over 4 years to determine the effect of nitrogen (N) and potassium (K) fertilization separately, in combination, and with and without phosphorus (P), broadcast annually at two rates. Trees in treatments containing N had significantly better dbh growth than trees in other treatments. However, doubling the application rate of 310 kg ha‐1 of N and P and 490 kg ha‐1 of K had no significant effect on dbh growth. There was a positive significant correlation for leaf N and dbh growth. The significant negative correlation between leaf P and dbh growth suggests that soil P concentrations may be less than the amount needed for accelerated dbh growth.  相似文献   

18.
The quality of mulberry leaf supports good growth and development of silkworm larvae. Mulberry leaves are hampered by the various detrimental diseases and pests. The mealy bug is one of the important insect pests of mulberry; its sap sucking nature may alter nutritive levels. An attempt was made to evaluate the macro and micro nutritive elemental levels in the infested leaves. There was a large variation of nitrogen, phosphorus, potassium, magnesium, manganese and molybdenum in almost all the varieties. There was a small difference in calcium, sulphur, iron, copper, boron and chloride. However, there was no change in zinc content in all the varieties of infested leaves. Disparity shown in majority of the macro nutrients in almost all the mulberry cultivars leads to variation in their quality. This feature of the leaves may hinder the good growth and development of silkworm, in turns producing low quality and poor yield of silk.  相似文献   

19.
This study aims to examine the effects of long‐term fertilization and cropping on some chemical and microbiological properties of the soil in a 32 y old long‐term fertility experiment at Almora (Himalayan region, India) under rainfed soybean‐wheat rotation. Continuous annual application of recommended doses of chemical fertilizer and 10 Mg ha–1 FYM on fresh‐weight basis (NPK + FYM) to soybean (Glycine max L.) sustained not only higher productivity of soybean and residual wheat (Triticum aestivum L.) crop, but also resulted in build‐up of total soil organic C (SOC), total soil N, P, and K. Concentration of SOC increased by 40% and 70% in the NPK + FYM–treated plots as compared to NPK (43.1 Mg C ha–1) and unfertilized control plots (35.5 Mg C ha–1), respectively. Average annual contribution of C input from soybean was 29% and that from wheat was 24% of the harvestable aboveground biomass yield. Annual gross C input and annual rate of total SOC enrichment from initial soil in the 0–15 cm layer were 4362 and 333 kg C ha–1, respectively, for the plots under NPK + FYM. It was observed that the soils under the unfertilized control, NK and N + FYM treatments, suffered a net annual loss of 5.1, 5.2, and 15.8 kg P ha–1, respectively, whereas the soils under NP, NPK, and NPK + FYM had net annual gains of 25.3, 18.8, and 16.4 kg P ha–1, respectively. There was net negative K balance in all the treatments ranging from 6.9 kg ha–1 y–1 in NK to 82.4 kg ha–1 y–1 in N + FYM–treated plots. The application of NPK + FYM also recorded the highest levels of soil microbial‐biomass C, soil microbial‐biomass N, populations of viable and culturable soil microbes.  相似文献   

20.
Two popular concepts of soil fertilization, basic cation saturation ratio (BCSR) and sufficiency level of available nutrients (SLAN), were tested on a calcareous soil (Aeric haplaquept) during 1995–1996 at the Bangladesh Rice Research Institute (BRRI) Regional Station Rajshahi using wheat as a test crop. According to BCSR concept the soil was deficient in potassium (K) and according to SLAN concept it was deficient in phosphorus (P), respectively. Potassium dose of 120 kg ha‐1 [to attain 2% saturation of total cation exchange capacity (CEC) according to BCSR] along with other two doses (0 and 60 kg K ha‐1) and P dose of 50 kg ha‐1 (to attain available P at sufficiency level) along with other two doses (0 and 100 kg P ha‐1) were compared in a randomized complete block design. The application of 50 kg P ha‐1 significantly increased plant height, spikes m2, grains per spike, grain and straw yields of wheat over 0 kg P ha‐1 with or without K but increasing P dose from 50 to 100 kg P ha1 did not give additional yields. The agronomic parameters and yields were not affected significantly by K application. Similar results were also observed in nutrient content and nutrient uptake. Thus, SLAN concept appeared as an effective tool for fertilizer recommendation for the calcareous soil while BCSR gave no apparent result there.  相似文献   

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