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1.
Abstract

Chinese cabbage (Brassica rapa L. Chinensis group) production is expanding in the U. S., and guidelines regarding its production under Western cultural practices are needed. The objectives of this study were to investigate the effects of N source and rate on Chinese cabbage yield, marketability, and wrapper leaf nutrient concentrations, and to estimate the critical wrapper leaf‐N concentration associated with maximum yield and marketability. Chinese cabbage was grown in five sequential plantings using raised‐bed, polyethylene mulch culture with subsurface irrigation on a sandy soil. Nitrogen fertilizer was applied at rates of 0, 67,112, and 157 kg/ha using the following sources: 1) ammonium nitrate. 2) calcium nitrate, 3) urea‐ammonium nitrate solution (Uram, 32% N), 4) urea, and 5) a urea‐calcium solution (18% N). Mature Chinese cabbage wrapper leaf concentrations of P, Ca, and Mg increased with increasing N rate, while leaf‐K concentration decreased. Leaf‐N concentration increased in response to N rate, but was not affected by N source or harvest date. Leaf‐P, K, Mg, and B concentrations were sufficient or high according to established standards, but leaf‐Ca was low. Leaf‐Ca and Mg concentrations were lowest with N sources containing only urea, and highest where at least part of the N was applied as NO3 ‐. Chinese cabbage head weight and percentage marketable heads increased as N rate increased. Yield and quality were highest with N sources which contained NO3 ‐, and were smallest where N was applied entirely as urea, which may have been due to plant sensitivity to NH4 +. The critical value of mature cabbage wrapper leaf‐N concentration above which yield or marketability was not limited was estimated to be 36 to 41 mg/g, which agrees well with established standards.  相似文献   

2.
Li  Yuan  Cui  Song  Chang  Scott X.  Zhang  Qingping 《Journal of Soils and Sediments》2019,19(3):1393-1406
Purpose

The aim of this meta-analysis was to investigate the interactive effects of environmental and managerial factors on soil pH and crop yield related to liming across different cropping systems on a global scale.

Materials and methods

This study examined the effects of liming rate, lime application method, and liming material type on various soil chemical properties and crop yield based on data collected from 175 published studies worldwide since 1980.

Results and discussion

The most important variables that drive changes in soil pH and crop yield were liming rate and crop species, respectively. Soil conditions, such as initial soil organic matter and soil pH, were more important for increasing soil pH in field-based experiments, while lime material type and application method were more important for improving crop yield. To effectively neutralize soil acidity, the optimum liming duration, rate, and material type were?<?3 years, 3–6 Mg ha?1, and Ca (OH)2, respectively. Averaged across different crop species, the application of CaO, CaCO3, Ca (OH)2, and CaMg (CO3)2 increased yield by 13.2, 34.3, 29.2, and 66.5%, respectively.

Conclusions

This meta-analysis will help design liming management strategies to ameliorate soil acidity and thus improve crop yield in agroecosystems.

  相似文献   

3.
The structural stability of soil is a physical characteristic that affects soil degradation processes. Calcium‐based amendments, such as calcium carbonate, calcium sulfate, and calcium oxide/hydroxide, have been shown to improve the stability of soil aggregates. This study seeks to determine which calcium‐based soil amendments, and at what concentration, are the most efficient in improving aggregate stability of sandy topsoils derived from granitic and metamorphic parent materials, and to analyze the mechanisms involved. In the pot experiment, soils amended with CaCO3, CaCl2, and CaSO4 did not present significant differences in aggregate stability compared to the control or among each other. In contrast, Ca(OH)2 soil amendment brought the greatest stability to the soil aggregates. A dose of 1% Ca(OH)2 significantly increased the stability of soil aggregates. This effect is due to the reaction of Ca(OH)2 with atmospheric CO2 which leads to the formation of CaCO3, a delayed reaction not showed by the other soil amendments tested. Likewise, the greater solubility of Ca(OH)2 compared to CaCO3 exerts a greater aggregation effect on soil. Thus, the mechanism of action of Ca(OH)2 is related to cementation, rather than flocculation. Future studies should be carried out to demonstrate the effectiveness of Ca(OH)2 under field conditions.  相似文献   

4.
Abstract

Allophanic Andosols are widely used as a major material in commercial nursery media for fruit vegetables in Japan because of their remarkable physical properties, such as a high water-holding capacity. In the present study, our objectives were: (1) to examine the effect of phosphogypsum (PG) on the chemical properties of Andosols, (2) to investigate the effect of PG on the growth and Ca uptake of melon seedlings. The effect of PG on chemical properties of Andosols was studied using five Andosols with different inorganic and organic colloidal components. The change in soil pH (H2O) was dependent on the soil samples; an increase was observed in the case of Kawatabi 3Bw soil; a sharp decrease in Kawatabi A2 soil; and almost no change or a slight decrease in Kameoka A1, A2 and Bw soils. The water-soluble Ca content was examined as an index of Ca availability in Andosols treated with PG. The increment in water-soluble Ca by PG application was depressed by allophane. The effect of PG application to the nursery media prepared from Andosols on growth and Ca uptake of melon (Cucumis melo L.) was examined in 2002. Three different varieties, Amusu, Earl's and Midorishima, were used in this experiment. The pH value of nursery media was stable at 6.4 ± 0.1 regardless of PG application rate. In contrast, electrical conductivity was clearly increased by PG application, and was reached at 1.2 dS m?1 in 4.0 g L?1 application. The application of PG increased water soluble Ca of nursery media from 1.7 to 5.2 cmolc L?1. Both top and root growth of melon seedlings were enhanced regardless of varieties, dry matter weights were maximized at 4 g L?1 PG application. The Ca uptake of melon seedlings was promoted by PG application in all the varieties. It was suggested that the relative root growth rate of melon seedlings was closely related to the Ca uptake of melon seedlings.  相似文献   

5.
Abstract

Three hypotheses that involved manipulation of soil calcium (Ca), potassium (K), and pH in relation to the occurrence of leaf tipburn of cabbage in eastern North Carolina (NC) were formulated and tested: 1) adding K to soil will increase (induce) leaf tipburn; 2) adding Ca and K together to soil will block K‐related tipburn induction, and 3) raising soil pH to levels of 6.0 to 6.5 will decrease leaf tipburn. Six experiments were conducted in commercial cabbage production fields in eastern NC in 1996 and 1997 to test these hypotheses. Hypothesis 1 was accepted since higher rates of K significantly (p<0.05) increased leaf K concentration, soil K content and leaf tipburn incidence compared with the control. Total cabbage yield increased as K rates increased, however, significant differences were only observed between the control and the highest rate (365 kg K ha‐1) in 1996. Hypothesis 2 was accepted since adding increased amounts of Ca and K. did not significantly increase leaf tipburn incidence. Hypothesis 3 was rejected since a range of soil pH from 5.3 to 6.6 did not increase or decrease leaf tipburn incidence, nutrient uptake or total yield. These data suggest that leaf tipburn of cabbage can be increased (induced) with excessive K fertilization and that this practice may be associated with the disorder observed in NC. Also, the addition of Ca with K may potentially reduce the risk associated with K‐related leaf tipburn of cabbage.  相似文献   

6.
Cadmium is both readily available and highly toxic to plants and animals. Our objectives were to evaluate the effect of oyster shell as a liming material on reducing plant cadmium (Cd) uptake and to compare oyster shell and Ca(OH)2, a common liming material in Korea. Ground oyster shell and Ca(OH)2 were applied at 0, 2, 4, and 8 Mg Ca per hectare to an upland soil contaminated manually with CdSO4 (total Cd 8.96 mg kg?1). Radish (Raphanus sativa L.) was sown on the contaminated soil. Oyster shell was less effective at increasing soil pH and net negative charge than Ca(OH)2, but more effective at suppressing radish Cd uptake in both roots and shoots. The portion of Cd that is strongly bound to soil (fraction 5) increased more with oyster shell than with Ca(OH)2. Radish plant Cd concentration was positively correlated with 0.1 N HCl-extractable Cd and negatively correlated with the residual Cd fraction (F5), indicating that an increase in the strongly bound Cd fraction played an important role in reducing radish Cd uptake in soil to which oyster shell was applied. The greater potential of oyster shell to decrease Cd extractability in soil and plant Cd uptake compared to Ca(OH)2 might be attributed to the layered morphology of oyster shells. Based on these results, oyster shell could be a very good alternative liming material to reduce Cd phytoavailability in Cd-contaminated soil.  相似文献   

7.
Organic white cabbage response to the application of a source-separated municipal organic-waste compost, lime, and Gafsa phosphate was investigated throughout a randomized block pot experiment under greenhouse conditions. Cabbage yield and nitrogen (N) uptake increased with all fertilizes; however, lime and phosphate effects on cabbage yield were enhanced when the compost was not applied. Phosphate application partially replaced the need for lime, showing that liming has to be estimated based on soil acidity but also on soil P availability and phosphate recommendation. Partitioning of N, phosphorus (P), potassium (K), and calcium (Ca) between leaves and roots was held for the benefit of the leaves, but to a lesser extent for P and Ca, compared to for N and K. This study shows the importance of P availability to improve cabbage growth and recommends source-separated organic waste compost to increase soil N availability for organic cabbage.  相似文献   

8.
One pot experiment was conducted to study the effects of a new polymeric slow release fertilizer (PRF) on Chinese cabbage growth and soil nutrients. The experiment comprised three kinds of fertilizer (common compound fertilizer, 21% and 45% solubility of PRF in 25°C water, all fertilizers with N:P2O5:K2O = 10:5.7:20) and three fertilizer levels (0, 21.6 and 43.2 g m?2). Results showed that the high water-soluble PRFs (PRFHH and PRFHL) fit nutrient requirements of Chinese cabbage, and the high fertilization level significantly increased yield and improved quality of Chinese cabbage. Although the PRFHL treatment at 21.6 g fertilizer m?2 had one-half less supplied nutrient than that of common compound fertilizer treatment (43.2 g fertilizer m?2), the yield of Chinese cabbage with PRFHH and PRFHL was 8.0% more. The soluble sugar, vitamin C and leaf chlorophyll contents of Chinese cabbage can be effectively improved with PRFHH (43.2 g m?2), PRFHL (21.6 g m?2) and PRFLH (low water-soluble PRF, 43.2 g m?2). The PRF treatment reduced the nitrate content and improved soil capacity of supplying nutrient effectively, and there were no changes in values of pH and electrical conductivity of soil.  相似文献   

9.
The steel-making slag (SMS), a by-product of steel manufacturing process with an alkaline pH (11–12) and high amount of iron (Fe) and calcium (Ca) oxides, was used to reduce arsenic (As) phytoextractability. The by-product was selected as an alternative to commercial Fe oxides, which can decrease plant uptake, but they are expensive if used as amendments of contaminated arable soils. SMS was applied at rates 0, 2, 4, and 8 Mg ha−1 to an As (1 N HCl-extractable As 25 mg kg−1) contaminated soil prepared by mixing non-contaminated soil and mine tailings and cropped to radish (Raphanus sativa L.) seeding. Calcium hydroxide (Ca(OH)2), a common liming material in Korea, was applied at the same rates for comparison. Steel-making slag more effectively suppressed radish As uptake and increased yield than Ca(OH)2 due to stronger As immobilization because it significantly increased extractable Fe concentration and decreased extractable As. The SMS-treated soil showed an apparent increase in As chemisorbed by Fe and Al oxides and hydroxides of surface soil, As associated at the Fe and Al oxides and hydroxides of internal surfaces of soil aggregates, and Ca-associated As. The steel-making slag can be a good soil amendment to suppress As phytoextractability and improve nutrient balance in As-contaminated soil.  相似文献   

10.
Cultivation of a teak crop in acid soils needs adequate agronomic management of these characteristics of high acidity and low nutrient supply to obtain high yields in wood. This work evaluated the effect of liming and application of boron in teak plants during early stage of growth in acid soils from Córdoba, Colombia. The experiments were conducted in the greenhouse and soils laboratory of the Faculty of Agricultural Sciences by using acid soil limed with calcium hydroxide (Ca(OH)2) and fertilized with boron. The treatments were chosen according to the Box Bernard augmented matrix 3, with dosages of Ca(OH)2 from 300 to 5700 kg ha?1 and boron from 0.3 to 5.225 kg ha?1, using three repetitions per treatment. Data obtained on boron in the soils (Bs) and in the plant (Bp), foliar area (AF), leaf dry mass (MSH), and roots (MSR) were analyzed through means tests and regressions from response surfaces (p ≤ 0.05). The results indicated increased pH and in the soil’s exchangeable calcium (Ca). To reach the maximal AF, the dosages of 2.26 kg ha?1 of boron (B) and 4522.6 kg ha?1 of Ca(OH)2 were estimated; for MSH, stem, and roots boron, dosages ranged between 2.02 and 5.225, with the dosage of 5700 kg ha?1 of Ca(OH)2 in all the variables evaluated. Application of calcium hydroxide also showed positive effect in leaf, stem, and MSR gain of teak seedlings during early growth stages. Fertilization with boron (B) did not show significant effect upon growth of dry masses of the parts evaluated.  相似文献   

11.
低钾配施纳米氢氧化镁对白菜的营养效应研究   总被引：4，自引：2，他引：2  
【目的】 探讨低量施钾条件下配施纳米氢氧化镁对白菜营养效应的影响和提高钾素利用效率的作用。【方法】 采用酸性紫色土在西南大学进行了大白菜盆栽试验。在所有处理均施N 200 mg/kg和P2O5 100 mg/kg的基础上,试验设不施钾,低钾量（K2O 75 mg/kg土）,适量钾（K2O 105 mg/kg土）,低量钾配施纳米氢氧化镁1.13、1.88 mg/kg土,共5个处理。在大白菜生长68天后收获,测定了白菜产量、叶绿素含量、抗氧化能力、养分吸收量及钾素利用效率、营养品质等指标。【结果】 低量钾配施纳米氢氧化镁对白菜增产作用极显著,配施氮磷钾肥总量的0.3%（1.13mg/kg土）时白菜产量增加21.5%;配施纳米氢氧化镁使白菜叶绿素a含量、叶绿素b含量、叶绿素总量和叶绿素a/b值分别提高5.3%~10.3%、4.0%~6.1%、4.8%~8.9%和4.3%~8.7%。提高白菜抗氧化能力,使白菜胡萝卜素、总酚和类黄酮等非酶类抗氧化物质含量分别提高7.6%、6.2%和6.8%~20.0%,超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）等酶类抗氧化物质含量分别提高9.8%~18.8%、10.7%~11.2%和7.4%~9.9%。配施纳米氢氧化镁促进白菜养分吸收,白菜磷、镁含量分别提高3.8%~16.9%、11.1%~24.9%,氮、磷、钾和镁吸收量分别提高9.1%~10.2%、13.2%~32.3%、8.4%~14.4%、26.6%~39.7%,钾素偏生产力、钾素农学效率、钾素生理效率和钾素利用率分别提高20.6%~23.7%、74.5%~77.6%、27.4%~36.5%和14.6%~25.0%。低钾与纳米氢氧化镁配施的效果以配施氮磷钾肥总量的0.3%好于配施0.5%（1.88 mg/kg土）。配施纳米氢氧化镁对白菜可溶性糖含量影响不大,对氨基酸含量有一定的降低作用,但显著降低硝酸盐含量11.5%~12.9%,有利于改善白菜卫生品质。【结论】 综合白菜产量、叶绿素含量、抗氧化能力、养分含量和吸收量、钾素利用效率和营养品质,以配施氮磷钾肥总量0.3%的纳米氢氧化镁处理综合效应最佳。  相似文献   

12.
This study evaluated soil chemical attributes, leaf nutrient concentrations and grain yield of corn (Zea mays), barley (Hordeum vulgare), common bean (Phaseolus vulgaris) and wheat (Triticum aestivum) as affected by phosphogypsum (PG) rates and split application to a Typic Hapludox under no-till from Southern Brazil. A Randomized complete block design was used, with factorial treatment structure (5 x 2) consisting of increasing PG rates (0, 3, 6, 9 and 12 Mg ha?1) either in single or split (half dose, two consecutive years) application. PG rates have reduced concentrations of Al3+, increasing Ca2+, SO42- and pH values in soil layers up to 0.8 m. Leaf concentrations of Ca (between 28 and 42%) and S (between 6% and to 50%) increased in all crops, while leaf levels of Mg decreased on corn (?16%), bean (?22%) and wheat (?14%) by PG rates. Compared to the control, PG rates between 4.0 and 6.1 Mg ha?1 promoted increases of 11%, 10% and 10% on corn, barley and wheat yields, respectively. There was no effect of PG on common bean’s yield. Phosphogypsum was effective for improving soil fertility, plant nutrition and crop yields. Applying the PG annually at one-half rate gave best overall results.  相似文献   

13.
It has been suggested that liming can improve soil structure and thereby decrease losses of particles and associated nutrients. In this study, two types of structure lime, slaked lime (Ca(OH)2) and a mixed product of calcium carbonate (CaCO3) and slaked lime (Ca(OH)2), were applied at three different rates in field trials on clayey soils (23%–40% clay). A combination of primary tillage and structure liming was also studied, in a split-plot trial on a clayey soil (25% clay). Aggregate (2–5?mm) stability, measured as reduction in turbidity (which is strongly correlated with losses of particulate phosphorus), was significantly increased with the highest application rates of both structure lime products. Aggregate size distribution was also improved with structure lime, creating a finer tilth in the seedbed. Yield response to structure lime was not consistent, with both negative and positive responses over the four-year study period. Positive yield responses can possibly be attributed to the finer tilth preventing evaporation in two dry growing seasons. Negative yield responses were probably an effect of impaired phosphorus availability associated with limited precipitation in May-July in 2011 and 2013. Two years after liming, soil pH levels were significantly elevated in plots with the highest application rate of structure lime, whereas no significant increases were found three years after liming. However, a lingering effect of liming was still detectable, as manganese concentration in barley grain was significantly lower in plots with the highest application rates of both structure lime products in the fourth study year. These results indicate that structure liming can be used as a measure to mitigate phosphorus losses from clayey soils, thereby preventing eutrophication of nearby waters. However, the yield response was varying and unpredictable and thus further investigations are needed to determine the circumstances in which field liming can act efficiently not only to prevent phosphorus losses, but also to ensure consistent yield increases.  相似文献   

14.
When evaluating phosphate rock (PR) dissolution, previous to the extraction with sodium hydroxide (NaOH), dry soil samples with PR were extracted with three solutions to remove exchangeable and solution calcium (Ca) [sodium chloride (NaCl) 1 M, buffered NaCl with ethylenediaminetetraacetic acid (EDTA) (NaCl–EDTA), and NaCl buffered at pH 7 with triethanolamine (TEA) (NaCl–TEA)] for comparison with the extraction of soil samples without any prewash. In acidic soils, up to 51% of applied P was recovered during the NaCl extraction because of the high exchangeable acidity released during the extraction. In soils with exchangeable Ca>2 cmol(+)kg?1, high EDTA quantities also promoted PR dissolution. The NaCl–TEA solution efficiently removed Ca, avoiding PR dissolution and P retention by calcium hydroxide [Ca(OH)2] during the NaOH extraction. Thus, when evaluating PR dissolution we recommend the use of NaCl–TEA to remove Ca. We also recommend the same procedure when applying the Chang and Jackson fractionation to calcareous soils and soils submitted to PR application.  相似文献   

15.
Soybean is one of the most important legume crops in the world. Two greenhouse experiments were conducted to determine the influence of liming and gypsum application on yield and yield components of soybean and changes in soil chemical properties of an Oxisol. Lime rates used were 0, 0.71, 1.42, 2.14, 2.85, and 4.28 g kg?1 soil. Gypsum rates applied were 0, 0.28, 0.57, 1.14, 1.71, and 2.28 g kg?1 soil. Lime as well as gypsum significantly increased grain yield in a quadratic fashion. Maximum grain yield was achieved with the application of 1.57 g lime per kg soil, whereas the gypsum requirement for maximum grain yield was 1.43 g per kg of soil. Lime significantly improved soil pH, exchangeable soil calcium (Ca) and magnesium (Mg) contents, base saturation, and effective cation exchange capacity (ECEC). However, lime application significantly decreased total acidity [hydrogen (H) + aluminum (Al)], zinc (Zn), and iron (Fe) contents of the soil. The decrease in these soil properties was associated with increase in soil pH. Gypsum application significantly increased exchangeable soil Ca, base saturation, and ECEC. However, gypsum did not change pH and total acidity (H + Al) significantly. Adequate soil acidity indices established for maximum grain yield with the application of lime were pH 5.5, Ca 1.8 cmolc kg?1, Mg 0.66 cmolc kg?1, base saturation 53%, Ca saturation 35%, and Mg saturation 13%. Soybean plants tolerated acidity (H + Al) up to 2.26 cmolc kg?1 soil. In the case of gypsum, maximum grain yield was obtained at exchangeable Ca content of 2.12 cmolc kg?1, base saturation of 56%, and Ca saturation of 41%.  相似文献   

16.
京郊大白菜的氮素吸收特点及氮肥推荐   总被引：6，自引：0，他引：6  
在京郊露地生产条件下,研究不同供N处理对秋季大白菜的生长、N吸收和土壤N矿化及损失的影响,并根据土壤-作物系统中N的借贷平衡原理确定大白菜N供应的合理目标值。结果表明,大白菜的产量和N吸收随施N水平的增加呈线性-平台的增长趋势。在作物的目标产量(120t/hm2)和N吸收数量(N200kg/hm2)的情况下,适宜的N素供应水平,即目标值为N350kg/hm2。大白菜的N吸收量随生育期逐渐增加,包心前期平均每周的N吸收量为N8.5kg/hm2,而在包心后期达到N220kg/hm2。在作物的整个生育期间土壤N的净矿化数量为N37kg/hm2,平均每周的土壤表观N损失为N7.8kg/hm2。这些参数有助于利用简单的N借贷平衡指导京郊秋季大白菜的推荐施肥。  相似文献   

17.
A local variety of tomato (Lycopersicon esculentum, Ife plum cv. 51691) was grown in soil culture for 5 months and treated with B at concentrations of 0, 1, 2, 4, 8, and 16 ppm as H3BO3, and Ca at 0, 40, 80, and 160 ppm as Ca(OH)2. A significantly positive correlation was established between organic matter and water ‐ soluble B (r = 0.970), while the relationship between pH and B was negative (r = ‐0.490). Application of B at 2 ppm improved all growth parameters studied. Boron application higher than 2 ppm, induced leaf chlorosis and later necrosis of nodes and roots. Fruit yield correlated positively with soil ‐ B, stem diameter and floral number (r = 0.597, r = 0.650 and r = 0.812, respectively). Soil‐ and plant‐B were positively correlated (r = 0.790). Calcium when applied singly at higher levels increased total chlorophyll content of the leaf. Tomato fruit yield was optimum at B:Ca treatment concentration of 2 ppm B (4.48 kg/ha B) and 160 ppm Ca (358.4 kg/ha Ca), corresponding to a B:Ca fertilizer ratio of 1.80.  相似文献   

18.
为探究不同新型肥料对贵州省酸性黄壤小白菜产量、品质、光合特性及肥料利用的影响,同时筛选出适合贵州黄壤施用的新型肥料产品,以贵州酸性黄壤为基础,通过盆栽试验设置对照(CK,不施氮肥)、西洋复合肥(常规施肥)、保水型功能性肥和稳定性缓释肥4个处理,研究了新型肥料对小白菜产量、品质、光合特性以及养分吸收利用的影响。结果表明:施用保水型功能性肥和稳定性缓释肥可显著增加小白菜播种后34 d的生物量,较常规施肥处理相比鲜重分别增加4.16%和22.28%,干重分别增加41.55%和62.35%;施用新型肥料还可以改善小白菜的营养品质,与常规施肥处理相比,保水型功能性肥可显著降低硝酸盐含量18.61%,而还原性糖、V_c和游离氨基酸含量分别增加25.74%、130.95%和16.91%;而稳定性缓释肥则使硝酸盐、还原糖和Vc含量分别提高26.68%、15.35%和50.00%,但是游离氨基酸含量则较常规施肥相比降低14.43%;而且新型肥料还增强了小白菜叶片的光合能力(净光合速率Pn、气孔导度gs、胞间CO_2浓度Ci以及蒸腾速率Tr),其中以稳定性缓释肥处理的小白菜光合能力最佳,且气孔因素是导致净光合速率增加的主要原因。施用新型肥料小白菜对氮素的吸收显著增加,氮肥利用效率显著提高,新型肥料处理的氮肥农学效率(AEN)、偏生产力(PFPN)、生理利用率(PE_N)和表观利用率(REN)平均分别为48.30 kg·kg~(-1)、59.85 kg·kg~(-1)、95.46 kg·kg~(-1)和52.79%,以稳定性缓释肥处理的氮肥利用效率最佳,尤其是氮肥表观利用率达66.66%。此外,相关性分析结果显示,小白菜产量与叶片净光合速率P_n、气孔导度g_s以及蒸腾速率T_r均呈显著正相关关系,说明提高小白菜叶片的气体交换参数P_n、g_s和T_r可以增加小白菜产量;同时小白菜叶片氮含量与氮肥生理利用率和氮肥表观利用率存在极显著相关性,r值分别为-0.937和0.978,表明增加小白菜叶片氮含量可以提高小白菜对氮肥的利用效率。综上所述,新型肥料对贵州酸性黄壤上小白菜的生物增产效应以及光合特性提高等效果显著,可为将来在贵州农业生产中推广应用提供参考和理论依据。  相似文献   

19.
Abstract

Adequate availability of calcium (Ca) in the upper 7–10 cm of soil is extremely important for pod development and therefore for production of quality peanut (Arachis hypogaea L.). Supplemental Ca is usually applied as gypsum, however, availability of Ca may depend on the type of gypsum. The objective of a laboratory study was to evaluate recovery of Ca in Mehlich I, 0.01 M NaNO3 and deionized water extractants from seven gypsum materials which varied physically from fine and coarse powders to crystals, granules and pellets. Overall, recovery of Ca was much greater in Mehlich I (89.5–99.6% of total Ca) than in either 0.01 M NaNO3 (81.0–98.4%) or deionized water (78.7–97.5%). However, for 3 sources, recovery of Ca was very similar in NaNO3 solution and deionized water.

Field experiments were conducted on Lakeland sand (Mehlich I Ca = 127 kg/ha, 0–15 cm) and Tifton loamy sand (Mehlich I Ca = 665 kg/ha) soils to study the effects of the gypsum materials on Florunner peanut grade and yield. Effects of gypsum treatments on Mehlich I‐ and 0.01 M NaNO3‐extractable soil Ca were also evaluated during peanut pod development. On the Lakeland soil, Mehlich I Ca increased from 127 to a range of 420–737 kg/ha following application of gypsum depending on the type of gypsum material. Percent sound mature kernels were significantly greater where gypsum was applied than in the control treatment, regardless of source. Total sound mature kernel yield and gross return were greatest for the more soluble sources. The yield vs. soil test Ca relationship 90 d after planting revealed that yield response was very minimal if soil Ca was greater than 290 and 85 kg/ha of Mehlich I and 0,01 M NaNO3‐extractable Ca, respectively. Application of gypsum to the Tifton soil, regardless of type of material, had no significant effect on yield, grade or gross return because Mehlich I extractable Ca in the control treatment was well over 560 kg/ha; the critical soil test Ca for runner peanut according to the current Georgia soil test recommendation.  相似文献   

20.
Following 13‐year treatments of soil pH and nitrogen (N) source in a peach orchard of North Carolina, the concentration of calcium (Ca), magnesium (Mg), N, phosphorus (P), and potassium (K) in leaves, shoots, trunks and roots, as well as soil pH, soil exchangeable Ca, Mg, and K content, were determined. Through liming, higher soil pH treatment enhanced soil Ca and tissue Ca level. Among six N sources examined, the highest values of soil pH and soil Ca, Mg, and K were detected following poultry manure application. Compared to ammonium sulfate [(NH4)2SO4], calcium nitrate [Ca(NO3)2] increased soil pH and soil Ca and K content, but reduced soil Mg. For most of macronutrients examined in peach tissues, the highest levels were found in manure treatment. Mineral N sources containing Ca(NO3)2 resulted in high tissue Ca and low tissue N. In the above‐ground tissues, Mg concentration was relatively low following application of mineral N materials containing Ca, K, or sodium (Na). Acid‐ forming N, especially (NH4)2SO4, reduced tissue Ca and P. The magnitude of impact of liming and N source on macronutrients was tissue‐type dependent, with leaves and other new growth the most sensitive ones while trunks seldom responded to the treatments.  相似文献   

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