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1.
Abstract

Field trials were established on a loamy fine sand and a silt loam using snapbeans and soybeans as test crops, respectively. Row fertilizer was placed with the seed (seed‐placed). Treatments were arranged in a 3×3×3 factorial experiment, and N, P, and K were applied in all combinations at three rates (0, 3.4, and 6.8 kg/ha). Ammonium nitrate (AN), monoammonium phosphate (MAP), concentrated superphosphate (CSP) and potassium chloride (KCl) were used as sources of N, P and K. Additional treatments compared MAP with diammonium phosphate (DAP) and KCl with potassium nitrate (KNO3).

The salt index of each treatment was inversely related to emergence, i.e. as the salt index increased, the emergence decreased. Level of N was more important than level of P or K in regards to reduction in emergence. Snapbeans grown on a loamy fine sand were extremely sensitive to damage from seed‐placed fertilizer, even at rates as low as 3.4 kg/ha of N, P or K. Soybeans planted on a silt loam soil were less sensitive than snapbeans planted on a loamy sand. The soybeans were able to tolerate up to 10.2 kg/ha of seed‐placed P plus K or 6.8 kg/ha of seed‐placed N plus P or N plus K without causing a significant delay in emergence.  相似文献   

2.
A glasshouse study was undertaken to investigate the effects of the copper fungicide Kocide 101 and its residues in soil on the growth, nodulation and nitrogen fixation of beans (Phaseolus vulgaris L.). The soil used was a sandy clay loam classified as Typic Rhodustalf. The bean variety SUA 90 was used as test crop. The bean rhizobia strains CIAT 899, PV, and a local isolate were used. Kocide 101 applied at the recommended rate (equivalent to 1.7 mg kg‐1 soil) had no significant negative effects on the growth, nodulation or nitrogen fixation of bean plants. Higher levels of Kocide 101 significantly (P < 0.05) reduced plant growth, nodulation and nitrogen fixation. The bean plants inoculated with the “local isolate”; rhizobia had the highest dry matter weights, nodule numbers and nodule dry weights, and also had more N fixation. They were followed by those inoculated with the PV, strain and, lastly, those inoculated with CIAT 899. The growth and nodulation of bean plants were still curtailed by the Kocide 101 residues four months after the fungicide was first applied to the soil. Therefore, occurrence of high levels of Kocide 101 in soils can have long‐term effects on the performance of the bean‐rhizobia symbiosis.  相似文献   

3.
Two field experiments were carried out over two consecutive years (2010–2011) in the research field of the College of Agriculture, Shiraz University, Fars Province, southern Iran. The study was a factorial experiment based on a randomized complete block design with three replications: the first factor was the ratio of safflower (Carthamus tinctorius L. Pi cv.) to bean (Phaseolus vulgaris L. Saiad cv.) at five levels (safflower and bean sole cropping, and intercropping of safflower and bean at ratios of 1:3, 2:2 and 3:1); and the second factor was weed management at two levels: weed-free (complete weed control) and weedy (no weed control). The results showed that an intercropping system was the most appropriate method for decreasing the adverse effect of weeds on the performance of both crops. Intercropping was more suitable for weedy than weed-free conditions. According to the land equivalent ratio (LER) value, if the main crop was bean, the best intercropping treatment was one row of safflower and six rows of bean (S1B3) under both weedy and weed-free conditions. By contrast, if the main crop was safflower, the best treatment under weedy conditions was S1B3, whereas under weed-free conditions the best treatment was two rows of safflower and four rows of bean (S2B2). Overall, S1B3 can be introduced as the best intercropping method.  相似文献   

4.
The development of stinging nettle (Urtica dioica L.) grown on culture solution containing with either ammonium or nitrate ions, or urea, was investigated under iron deficiency conditions, and with added FeEDTA or FeCto. Both seed‐cultured and vegetatively‐cultured stinging nettle plants produced normally developed green shoots when nitrate and 4 μM FeEDTA or FeCto were supplied. Stinging nettle plants were able to utilize Fe‐citrate, Fe‐ascorbate, and Fe‐malate effectively at the same concentration as well. When K3Fe(CN)6 was supplied, which is impermeable to the plasmalemma, and therefore is used to measure the reductive capacity of the roots, stinging nettle plants became chlorotic because the complex was stable at the pH of the culture solution. Urea did not induce chlorosis but inhibited growth. The plants died when ammonium was supplied as a sole N source. Applying bicarbonate and ammonium together prevented the plants from dying, but the plants became chlorotic. Total exclusion of iron from the culture solution resulted in iron‐deficiency stress reactions as has been described for other dicotyledonous plants (Strategy II).  相似文献   

5.
Pot experiments were conducted in the greenhouse to study the effect of nitrogen (N) nutrition on photosynthesis and water relations of barley plants under salinity conditions. Nitrogen decreased the sodium (Na) content and increased the potassium (K) content in shoots. The net photosynthetic rate of leaves increased significantly with added N increasing from 0 to 100 mg N/kg soil. The activity of ribulose 1,5 bisphosphate carboxylase (RuBPCase) in leaves of high‐salt plants was lower, and in leaves of the low‐salt plants higher than that in control plants. The photosynthetic rate was reduced by sodium chloride (NaCl) and was significantly correlated with total soluble protein per unit leaf area. At each N level, stomatal conductance in leaves was reduced considerably by salt. Proline content of leaves increased with increasing N level. It was higher in leaves of salt‐treated plants than in those of control plants. The osmotic potential of leaves decreased with increasing N applied, and the turgor pressure of high N plants remained higher under salt treatment condition.  相似文献   

6.
Pot experiments were conducted in the greenhouse on a calcareous soil to study the effect of nitrogen on the alleviation of boron toxicity in canola (Brassica napus L.). The treatments consisted of factorial combination of six levels of B (0, 2.5, 5, 10, 20, and 40 mg kg?1 as boric acid), and four levels of nitrogen (N) (0, 75, 150 and 300 mg kg?1 as urea) in a completely randomized design with three replicates. Boron (B) application significantly reduced the yield, whereas N addition alleviated the growth suppression effects caused by B supplements. Boron concentration increased with addition B. However, boron concentration in shoot declined with increasing N levels. Increasing N and B rates increased N concentration. Soil application of B increased proline concentration. However, the supply of N decreased it. Generally, application of B decreased potassium (K):B and calcium (Ca):B ratios, chlorophyll concentration, while N application increased them. It is concluded that N fertilization can be used effectively in controlling B toxicity in canola grown in B-affected soils.  相似文献   

7.
Nitrogen (N) supply increased yield, leaf % N at 10 days after silking (DAS) and at harvesting, the contents of ribulose‐1,5‐bisphosphate carboxylase (RUBISCO) and soluble protein, and the activities of phosphoenolpyruvate carboxylase (PEPC), and ferredoxin‐glutamate synthase (Fd‐GOGAT), but not of glutamine synthetase (GS) for six tropical maize (Zea mays L) cultivars. Compared to plants fertilized with 10 kg N/ha, plants inoculated with a mixture of Azospirillum sp. (strains Sp 82, Sp 242, and Sp Eng‐501) had increased grain % protein, and leaf % N at 10 DAS and at harvest, but not grain yield. Compared to plants fertilized with either 60 or 180 kg N/ha, Azospirillum‐inoculated plants yielded significantly less, and except for GS activity, which was not influenced by N supply, had lower values for leaf % N at 10 DAS and at harvest, for contents of soluble protein and RUBISCO, and for the activities of PEPC and Fd‐GOGAT. Yield was positively correlated to leaf % N both at 10 DAS and at harvest, to the contents of soluble protein and RUBISCO, and to the activities of PEPC and Fd‐GOGAT, but not of GS, when RUBISCO contents and enzyme activities were calculated per g fresh weight/min. However, when enzyme contents and enzyme activities were expressed per mg soluble protein/min, yield was correlated positively to RUBISCO and PEPC, but negatively to GS. These results give support to the hypothesis that RUBISCO, Fd‐GOGAT, and PEPC may be used as biochemical markers for the development of genotypes with enhanced photosynthetic capacity and yield potential.  相似文献   

8.
Reports relating the separate and combined influences of soil aeration, nitrogen and saline stresses on the germination, growth and ion accumulation in sunflowers are lacking in the literature. The sunflowers of this report were grown in sand culture in the greenhouse. Separate and combined treatments of two levels of aeration, three levels of nitrogen and three levels of NaCl were applied to plants which were harvested at 40 and 56 days. Seed germination was excellent in all treatments. Plant height and dry weight decreased with each type of stress. Low oxygen (0.20 μg O2 cm‐2 min‐1) and nitrogen (10 ppm) combined with 70 meq/1 NaCl caused the greatest reduction of plant growth. Leaf number was reduced by low nitrogen and excess salt. Low oxygen reduced the accumulation of K, Ca and Mg and increased the Na and N‐NO3 content of sunflower leaves. Potassium to sodium ratios in plant on sunflower growth could be partially ameliorated with the tissue were decreased by greater EC values of the nutrient solution and low soil ODR. The adverse effects of salt and oxygen stresses addition of nitrogen. Ion accumulation was an earlier indicator of plant stress than plant growth and both parameters provided excellent methods for assessing plant tolerance to soil aeration, nitrogen and saline stresses.  相似文献   

9.
Abstract

A bronzing symptom of trifoliolate leaves of Phaseolus vulgaris is described which has been found to be widespread on the southern slopes of the Meru and Kilimanjaro massifs in northern Tanzania. The symptom occurred on plants growing on freely‐draining soils of moderate pH and has led to complete loss of yield of badly affected plants. Leaves with the bronziug symptom contained large concentrations of iron (>3080 mg/kg) and manganese (>760 mg/kg) considered to be toxic in Phaseolus.  相似文献   

10.
Increased above‐ground dry matter and grain yields were found for two hydroponically grown maize hybrids (Pioneer‐3925 and Pioneer‐3949) when plants were supplied with an NH4 +‐enhanced nutrient solution (31 percent of total N) compared with a control (4 percent of total N as NH4 +). The major difference in yield developed between silking and 2 weeks post‐silking and silking and 4 weeks post‐silking for the P‐3925 and P‐3949 respectively. The reduced nitrogen content of the stover (leaves plus stalk) was consistently higher on the NH4 +‐enhanced nutrient solution. The decreased production of the control treatment may have resulted from a reduced photsynthetic capacity.  相似文献   

11.
Abstract

Six different methods for measuring total sulphur concentrations in plant material were applied to orchardgrass samples derived from three cuts of a field trial with combinations of sulphur and nitrogen fertilizer applications. The results from the methods were grouped into three pairs of high, intermediate and low measured total sulphur concentrations. Highest concentrations were obtained using an oxygen flask and the LECO CNS‐2000 automated dry combustion methods, intermediate concentrations with an alkaline digestion and the Fisher automated dry combustion instrument, and lowest with two perchloric acid digestion methods. The low results with the two perchloric acid methods likely occurred from sulphur volatilization and incomplete organic sulphur compound destruction. The results from the pairs of methods with similar total concentrations did not yield the same significant cut, sulphur and nitrogen main and interaction effects when analysis of variance was applied to the treatment results. The two dry combustion methods agreed reasonably closely regarding the main and interaction effects, but calculated recovery of applied sulphur varied. It is apparent that current methods do not agree precisely in their ability to measure total sulphur in plant material types, and for the same type of plant grown under different climate conditions and fertilizer treatments. It was concluded that values by LECO CNS‐2000 instrument provided the best measurement of total sulphur for fertilizer response trials.  相似文献   

12.
Abstract

A greenhouse experiment was conducted to determine the effect of peat moss‐shrimp wastes compost on barley (Hordeum vulgare L.) grown on a limed loamy sand soil. A control, four rates of compost applied alone and in combination with three rates of nitrogen, phosphorus, and potassium (NPK) chemical fertilizer were evaluated. Applications of compost to limed soil substantially enhanced the growth of barley over the control. When considering all treatments, the main effect of compost rates on straw yield, numbers of tillers, plant height, and number of ears was more important than that of fertilizer. A significant interaction on barley growth parameter values was obtained with compost and fertilizer rates. A combination of moderate application of compost and fertilizer gave in some instances, more yield than compost or fertilizer applied alone. Nutrient content of barley increased with rate of compost applied to soil over the control. A significant relationship was found between soil organic carbon (C) and straw yield, number of tillers, plant height and number of ears whereas grain yield was correlated with soil total N. Results from this study indicate that peat moss‐shrimp wastes compost could represent a potential means of renovating low fertility sand soils.  相似文献   

13.
Abstract

Pansies are one of the most popular annual bedding plants in the United States. Growth and uptake of essential nutrients as influenced by N‐form ratio was evaluated in pansy as well as what role pansy nutrition plays in the protection of pansy against feeding damage by white‐tailed deer provided by selected repellents. Plants were grown under three N‐form ratios: 100:0, 50:50, and 0:100NO3:NH4. Dry weight was highest for pansy treated with 100:0 and lowest for plants treated with 0:100 NO3:NH4 Mean quality ratings were 4.07 for pansies grown with 100:0,1.80 for pansies grown with 50:50, and 0.78 for pansies grown with 0:100. Potassium (K), magnesium (Mg), and manganese (Mn) content was lower in plants treated with 0:100 than in those treated with 100:0. Ammonium may have competed with these cations for uptake. Boron (B), copper (Cu), molybdenum (Mo), and aluminum (Al) content was highest in plants treated with N‐NH4. There was no significant difference shown in nutrient levels caused by repellent treatments. Feeding damage was shown to be affected by N‐form ratio only on Day 3 of the study. Of the three repellent treatments [Deer and Rabbit Repellent (Thiram), Deer Away purrescent egg spray, and no spray], Thiram provided the greatest protection to pansies over the study period.  相似文献   

14.
The response of a salt‐tolerant line ILL 6793 and a salt‐sensitive line ILL 6439 of lentil (Lens culinaris) to N deficiency was studied in a pot experiment under glasshouse conditions. Plants of the two lines were treated with 56, 28, 14 and 7 mg N L?1 in Rorison's nutrient solution. The salt‐tolerant line excelled the salt‐sensitive line in relative biomass production (per cent of control basis) under varying N regimes. Of the various physiological/biochemical variables measured in the present study only chlorophyll b and total soluble sugars proved to be helpful in discriminating the lines. Chlorophyll b was significantly greater in ILL 6793 as compared with ILL 6439 at the two lower N levels. Total soluble sugars increased consistently in both lines with decrease in N level of the growth medium and the salt‐tolerant line ILL 6793 had significantly greater soluble sugars than the salt‐sensitive ILL 6439 at 28 and 14 mg N L?1. Chlorophyll a and free amino acids were uniformly reduced in both lines with decrease in N levels. The salt‐tolerant line showing high efficiency for N utilization could be of great economic value in terms of its use in salt‐affected soils which are usually deficient in N provided it also produces reasonable grain yield.  相似文献   

15.
Abstract

In order to predict release of nitrogen (N) from controlled‐release fertilizers (CRF) from laboratory experiments, new types of lignin‐coated fertilizers were studied. Laboratory methods were 1) release of urea into water and 2) an extraction procedure using an electroultrafiltration technique (EUF). The results of these two methods were compared to the amount of N released in a vegetation experiment in the greenhouse. The results showed a good relationship between the two laboratory methods. The correlation coefficient between the rate constant K determined in the water extract and each of the N‐fractions was highly significant. The total amount of N released in the vegetation experiment was correlated to parameters of the laboratory methods. The N uptake by the plant was significantly correlated with the first order constant and with the fertilizer's EUF‐NII index. The N leached was also correlated with the EUF‐NI and EUF‐N (I+II) indices.  相似文献   

16.
Abstract

In two pot experiments, lettuce plant growth under different soil‐water conditions was examined. In the first experiment, the effect of soil conditioner in combination with slow‐release and water‐soluble fertilizers was considered. In the second experiment, lettuce plant resistance in moisture stress with the use of a soil conditioner was evaluated. The first experiment showed that the use of soil conditioner with slow‐release fertilizers gives greater yield than the use of water‐soluble fertilizers alone. The second experiment showed that there is no difference on the yield and quality of lettuce plants between the trials until the irrigation time of twenty days.  相似文献   

17.
This study investigates the effect of conjoint use of bio-organics (biofertilizers + crop residues + FYM) and chemical fertilizers on yield, physical–chemical and microbial properties of soil in a ‘French bean–cauliflower’-based cropping system of mid hills of the north-western Himalayan Region (NWHR) of India. Conjoint bio-organics at varied levels of NPK chemical fertilizers increased yield of ‘cauliflower’ over corresponding single application. Incorporation of crop residues with 75% of the recommended NPK application resulted in the highest yield (19 t ha?1). Conjoint use of bio-organics produced a yield (15.65 t ha?1), which was statistically on a par with 75% of the recommended NPK application alone. This indicated a saving of 75% NPK chemical fertilizers. In the case of ‘French bean’, the effect was non-significant. The results also showed significant higher soil available N (351.3 kg ha?1) under 75% NPK + biofertilizers, whereas the highest soil available K (268.3 kg ha?1) was recorded under 75% NPK + crop residues. Lowest bulk density (1.03 Mg m?3), highest water holding capacity (36.5%), soil organic matter (10.6 g kg?1), bacterial (4.13 × 107 cfu g?1) and fungal (6.3 × 107 cfu g?1) counts were recorded under sole application of bio-organics. According to our study, we concluded that the combination of NPK fertilizers and bio-organics increased yield except French bean, soil available N, K and saved chemical fertilizers under ‘French bean–cauliflower’-based cropping system.  相似文献   

18.
Abstract

Field trials were established on an irrigated loamy sand using corn as a test crop. Row fertilizer was placed with the seed (seed‐placed) or in the conventional side placement position (side‐placed). The side‐placed treatments consisted of two carriers of UAPP (28–28–0 and 36–18–0), diammonium phosphate (DAP, 18–46–0) plus ammonium nitrate (AN, 33–0–0), and a control treatment. Two rates of application were used for each carrier. Seed‐placed treatments consisted of two carriers of UAPP (28–28–0 and 36–18–0), concentrated superphosphate (CSP, 0–45–0) plus AN, CSP, AN, and a control treatment. Two rates of application were used for each carrier, except AN, which was used at three rates.

High rates of side‐placed UAPP delayed emergence of corn and lowered the final population. Early season N concentration in corn seedlings was not affected by rate or carrier of side‐placed N. Early season P concentration in the corn seedlings was greater for AN + DAP than UAPP treatments at all rates of P, presumably due to toxic accumulation of free NH3 in the UAPP band. High rates of side‐placed UAPP also reduced the yield of corn.

High rates of seed‐placed AN + CSP and UAPP reduced the germination of corn. However, low rates of UAPP also reduced germination, whereas low rates of AN + CSP did not affect germination. Since UAPP has a lower salt index than AN + CSP, the “salt effect”; of low rates of UAPP does not explain its effect on germination and emergence. The deleterious effects of UAPP were due apparently to either NH3 or NO2‐N toxicity.  相似文献   

19.
Abstract

A laboratory experiment evaluated the rate of urea hydrolysis and ammonia volatilization from urea (U) mixed in organo‐mineral (O‐M) fertilizers. These fertilizers were incubated in soil in the presence or absence of N‐(n‐butyl)thiophosphoric triamide (NBPT) as a urease inhibitor. Two organic matrices, leather (L) and peat (P), were used to prepare the O‐M fertilizers. In the absence of NBPT, the highest ammonia losses and the fastest rate of urea hydrolysis were in the soil treated with the fertilizer containing leather (UL50). Significantly lower ammonia losses occurred with peat‐based fertilizers. Although the fertilizer containing peat (UP50) stimulated the rate of urea hydrolysis with respect to the urea alone, no increase in ammonia volatilization was detected. NBPT‐containing fertilizers were stored for different times (0,7, 30, and 60 days) and temperatures (25°C and 40°C), and the NBPT recovery was monitored by extraction and analysis by HPLC. The NBPT recovery decreased by increasing either the storage time or the storage temperature. Differences among the fertilizers occurred after storage at 40°C for 30 or 60 days. With UN, in spite of about 25% extracted amount of NBPT, the ammonia losses did not increase with respect to the non‐stored fertilizer. On the contrary, no inhibitor was recovered from either of the O‐M fertilizers (UNL and UNP). However, in the presence of leather, NBPT reduced the volatilization losses by 35 to 40%, whereas in the presence of peat, a complete loss of NBPT efficiency occurred. In general, either the inhibitor recovery or efficiency were affected by the storage conditions or the type of organic matrix.  相似文献   

20.
A pot experiment evaluated the growth of lettuce (Lactuca sativa L.) and barley (Hordeum vulgar) and accumulation of molybdenum (Mo) in plants and soils following amendments of Mo compost (1.0 g kg?1) to a Truro sandy loam. The treatments consisted of 0 (control), 12.5, 25, and 50% Mo compost by volume. The Mo compost did not affect dry‐matter yield (DMY) up to 25% compost, but DMY decreased at the 50% compost treatment. The 50% compost treatments increased the soil pH an average of 0.5 units and increased the nitric acid (HNO3)–extractable Mo to 150 mg kg?1 and diethylenetriaminepentaacetic acid (DTPA)–extractable Mo to 100 mg kg?1 in the growth medium; the same treatment increased tissue Mo concentration to 569 and 478 mg kg?1 in the lettuce and barley, respectively. Plants grown in the 25% compost produced about 55 mg kg?1 of total Mo in the growth medium; this resulted in tissue Mo concentration of 348 mg kg?1 in lettuce and 274 mg kg?1 in barley without any phytotoxicity. Our results suggested that 55 mg Mo kg?1 soil would be an appropriate limit for Mo loading of soil developed from compost additions, a value which is presently greater than the Canadian Council for Ministers of the Environment (CCME) Guidelines for the use of type B compost in Canada.  相似文献   

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