Accumulation of zinc,phosphorus, and magnesium by navy bean seed

Considerable variation is found in zinc (Zn Concentration in navy bean (Phaseolus vulgaris L.) seed, an important food source of Zn and magnesium (Mg). The influence that phosphorus (P) and Zn fertilizers, and source of nitrogen (N) (inoculation with Rhizobium phaseoli versus 150 mg/kg NH₄NO₃‐N) had on growth and nutrient uptake of ‘Upland’ navy bean was studied under greenhouse conditions on a Glyndon loamy fine sand, a Calciaquoll low in available N, P, and Zn. Yields of stems (+ pod walls), blades, and seed were increased by N, P, and Zn fertilizers. Zinc concentration at maturity varied between 13 and 37 mg/kg for seed, 15 and 39 mg/kg for blades, and 5 and 30 mg/kg for stems. Zinc fertilizer was the chief factor responsible for this variability. Phosphorus concentration at maturity varied between 4.0 and 6.2 g/kg for seed, 1.9 and 11.8 g/kg for blades, and 1.0 to 2.7 g/kg for stems. Added P fertilizer increased P concentration in the three tissues, but the effect was most pronounced for blades of plants without added Zn. Magnesium concentration at maturity was mainly affected by N fertilizer.and ranged from 1.6 to 1.9 g/kg for seed, 4.0 and 9.7 g/kg for blades, and 4.0 to 7.1 g/kg for stems. Soil management can greatly affect Zn concentration in navy bean seed.     

Fertilizer placement studies on calcareous and non‐calcareous chernozemic soils: Growth,P‐UP‐take,oil content and yield of Canadian rape

Abstract

Field experiments were conducted on calcareous and non‐calcareous Orthic Black Chemozemic soils over a five year period to study the effect of rates and placements of P‐fertilizer on Canadian rape (Brassica napus L. cv Tower) production. Six rates of P as mono‐ammonium phosphate (MAP) were applied at seeding using four placement methods: i) broadcast and cultivated 10 cm into the soil (BC); ii) banded in the seed row with the seed (PWS); iii) banded 2.5 below and 2.5 cm to the side of the seed (PSS); iv) banded 2.5 cm directly below the seed (PBS). Soil type had no significant effect on rape growth, seed yield and P‐uptake. Rape responded best to P‐fertilizer banded with (PWS) or near (PSS, PBS) the seed. But, placing 15 kg/ha P or greater with the seed reduced seedling emergence; with 25 kg P/ha insufficient plants emerged to justify harvesting. The reduced seedling emergence resulted in reduced seed yield and P‐uptake. Maximum yields were obtained when the fertilizer was banded 2.5 cm away from the seed (PSS, PBS). The BC method produced the least growth, yield and P‐uptake responses of the four methods. Only when broadcast rates of P were in excess of 10 kg/ha did rape dry matter, seed and P‐uptake increase. Banding 10 kg/ha with or near to the seed was equivalent to broadcasting 25 kg/ha in terms of seed yield and P‐uptake. Application of P fertilizer also increased seed protein and oil concentrations.     

Nitrogen efficiency of grain sorghum grown on flat and raised seedbeds on poorly drained soil

Grain sorghum (Sorghum bicolor L. Moench) production commonly occurs on poorly drained clayey soils of the Mississippi River delta region inArkansas. Raised, wide seedbeds may improve grain yield and fertilizer N efficiency for narrow‐row sorghum production on these soils. The influence of individual row positions on raised, wide seedbeds was compared to conventional flat seedbed for grain yield, yield components, dry weight, and N uptake. A 193‐cm wide and 15 cm high crowned seedbed (CB) was compared to the flat seedbed (FB) in 1987 and 1988 on a Sharkey silty clay (very fine, mont‐morillonitic, nonacid, thermic, Vertic Haplaquepts) at Keiser, AR. Three rows were planted on each seedbed treatment; one in the middle of the bed and one row 48 cm to each side of the row in the middle. Nitrogen rates of 0, 56, 112, and 168 kg/ha were applied at planting. In addition, two split applications at the 168 kg/ha N rate (56 kg N/ha at planting and 112 kg N/ha at either four‐leaf or eight‐leaf growth stage) were evaluated. Each row position was evaluated for grain yield, yield components, plant dry weight, and N uptake. Whole plant samples were collected at the anthesis and physiological maturity growth stages. The field average grain yield was higher on the CB each year regardless of N rate applied at planting. This yield increase on the CB was related to the row on the top of the CB yielding more than the equivalent row on the FB. The responses of plant dry weight at each growth stage, N uptake at each growth stage, and N content of the seed was similar to grain yield responses. The split N application at planting and the eight‐leaf growth stage was as effective or better than any other treatment for increasing grain yield, N uptake, and seed N content.     

氮锌互作对水稻产量及籽粒氮、锌含量的影响

为探明氮锌互作对水稻产量及氮、锌含量的影响,以镇稻11号为供试材料,在大田条件下研究了2个氮肥用量（N 200、300 kg/hm2）下6个施锌水平（ZnSO47H2O 0、10、25、50、100、150 kg/hm2） 对水稻产量及成熟期植株氮、锌浓度及累积量的影响。试验结果表明: 在本试验条件下,锌肥的施用对水稻产量的增加不显著,但施锌能显著提高水稻各部位的锌浓度和籽粒锌累积量,并能提高水稻籽粒的氮浓度和粗蛋白含量,且表现出随施锌量的增加籽粒的氮浓度和粗蛋白含量增加的趋势; 高施氮量有利于水稻的增产及对锌的吸收与累积。因此,氮锌配施具有增加籽粒锌富集和提高蛋白质含量的双重效益。     

Field evaluation of N2 fixation and N partitioning in climbing bean (Phaseolus vulgaris L.) using 15N

Summary The common bean (Phaseolus vulgaris L.) is generally regarded as a poor N₂ fixer. This study assessed the sources of N (fertilizer, soil, and fixed N), N partitioning and mobilization, and soil N balance under field conditions in an indeterminate-type climbing bean (P. vulgaris L. cv. Cipro) at the vegetative, early pod-filling, and physiological maturity stages, using the A-value approach. This involved the application of 10 and 100 kg N ha^-1 of ¹⁵N-labelled ammonium sulphate to the climbing bean and a reference crop, maize (Zea mays L.). At the late pod-filling stage (75 days after planting) the climbing bean had accumulated 119 kg N ha^-1, 84% being derived from fixation, 16% from soil, and only 0.2% from the ¹⁵N fertilizer. N₂ fixation was generally high at all stages of plant growth, but the maximum fixation (74% of the total N₂ fixed) occurred during the interval between early (55 days after planting) and late podfilling. The N₂ fixed between 55 and 75 days after planting bas a major source (88%) of the N demand of the developing pod, and only about 11% was contributed from the soil. There was essentially no mobilization of N from the shoots or roots for pod development. The cultivation of common bean cultivars that maintain a high N₂-fixing capacity especially during pod filling, satisfying almost all the N needs of the developing pod and thus requiring little or no mobilization of N from the shoots for pod development, may lead to a net positive soil N balance.     

Effects of residual and applied κ on soybean nodulation,root growth,pod formation and K and N composition

Abstract

Inoculated soybeans (Glycine max L. Merr. cv. Eragg) were grown in an intensively managed cabbage (Brassica oleracea L. Capitata group)‐ sweetcorn (Zea mays L.) multiple‐cropping sequence on a tile‐drained Arenic Haplaquod having variable residual K levels. The study was conducted to assess the effect of residual and applied K on soybean K and N composition, nodulation, root growth, and pod formation. Sidedress treatments of 0 and 100 kg K/ha were applied at bloom to plots that received either 0 or 300 kg K/ha/acre that had been applied previously to other crops in the sequence. Treatments were arranged in a randomized complete block design witn six replications. Although leaf N conc, was uniform at bloom (R2), leaf N at pod‐fill (R6) ranged from 2.8 to 4.3% and wasquadratically related to leaf K (r² = 0.92). Without residual K fertilizer from cabbage and sweet corn applications sidedress application of K increased leaf and nodule K and N. Root K conc. was correlated with root dry wt. (r = 0.35) at bloom stage, and with root 10 dry wt. (r = 0.54), pod number (r = 0.43), and pod dry wt. (r = 0.39) at pod‐fill stage. Root K conc. was negatively correlated with nodule number (r = ‐0.34) and nodule dry wt. (r = ‐0.41). Sidedress‐applied K did not increase root growth and pod number whereas residual fertilizer K did. A curvilinear relationship between leaf K and N conc. and a linear relationship between leaf N and soybean yield indicated that K deficiency limited the capacity of the soybean plant to supply N to the developing grain during pod‐fill, and that this response was not due to inadequate nodulation.     

Influence of P,Zn and Fe fertilization upon yield and protein quality of Sanilac Navy bean seed

Abstract

Treatments of P, Zn and Fe fertilizers were added to a Zn deficient Wisner silty clay loam soil. Sanilac bean plants were grown as the Zn responsive test crop and tissue samples were taken 5 weeks after planting for early growth and Zn uptake responses. At maturity, yield data were obtained and composite samples of beans were taken for determination of protein quality as evaluated by percentage of N, percentage of crude protein and relative contents of essential amino acids. A growth and Zn uptake response was obtained to ZnSO₄, ZnNTA and FeNTA fertilization at both P levels, while a yield response to the same treatments was obtained only at high soil P (448 kg/ha) levels. The percentage N, percentage crude protein and relative contents of essential amino acids did not change as a result of P, Zn or Fe fertilization even when yields were tripled due to Zn fertilization.     

Dry bean production with various tillage and residue management systems

Limited information is available on the influence of high surface residue tillag systems and the interaction of weed control methods, cultivar maturity, and phosphorus fertilizer placement on yield parameters of dry bean (Phaseolus vulgaris L.) A 3-year field study was conducted on a Fargo clay (fine, frigid, montmorillonitic Vertic Haplaquoll) to evaluate the influence of surface or deep band placed phosphorus fertilizer, tillage systems (PLOW, SWEEP, STRIP, NOTILL) and weed control methods on harvest plant populations, seed yield and seed weight of ‘Upland’ (early maturity) and ‘C-20’ (late maturity) dry bean cultivars. Yield variables were influenced by cultivar planted and climatic conditions. Zinc deficient plants and decreased yield were observed with the ‘C-20’ cultivar when grown on PLOW system plots where phosphorus fertilizer was surface applied. Zinc deficient plants were not present when the phosphorus fertilizer was deep banded or none was applied. No zinc deficient plants were observed on NOTILL, STRIP and SWEEP system plots. Both cultivars matured 7 to 10 days earlier with NOTILL, STRIP and SWEEP systems when compared with the PLOW system. Dry bean yields were reduced 180 to 310 kg ha⁻¹ by cultivation for weed control. Little difference in yields occurred among tillage systems when climatic conditions were normal. During a cool wet season, seed yields on PLOW system plots were 150 to 400 kg ha⁻¹ higher than on plots of systems with surface residue. Seed weight, although lower on the late maturity cultivar, was not greatly changed by tillage or weed control method. Results from this study indicate that dry beans can be successfully grown with small grain surface residue systems in northern climatic areas where growing degree days exceed 1200 and growing season precipitation does not exceed 400 mm. Further, deep band placement of phosphorus fertilizer is essential in dry bean rotations to eliminate potential zinc deficiency on soils low in zinc. Switching to a high residue management system may require a special cultivator design to eliminate yield loss due to pruning of shallow roots present with high surface residue.     

Use of velvet bean to improve soil fertility and weed control in corn production in northern belize

Abstract

The objective of this research was to mesasure the effect of intercropping corn (Zea mays L.) with velvet bean (Mucuna pruriens) oil corn yields, soil fertility, and weed control in northern Belize. Two soils were used which are widespread in the area. These soils are high in clay (simectitc) and are well supplied with bases. One soil, the Louisville, has a black surface horizon overlying light gray to white calcareous weathered coral. The other soil was Xaibe which consists of a reddish‐brown clay over hard limestone “cap rock”; at 30–40 cm. Both soils had a relatively high organic carbon (C) and total nitrogen (N) content. We classified the Louisville as Calciustert and the Xaibe as a Ustropept. The treatments used (carried out annually in 1990, 1991, and 1992) were residue burn (B), bum plus fertilizer (BF), a velvet bean intercrop (G), and a velvet bean intercrop plus fertilizer (GF). Velvet bean intercropping did not have a positive effect on corn yields on these soils. For adequate yields to be maintained, it appears that fertilization with N, phosphorus (P), potassium (K) and certain micronutrients are required. We did obtain some indication that velvet bean intercropping will reduce weed population, including a serious infestation of cogongrass (Jmperata cylindrica). Velvet bean did not maintain the soil N content Corn yields decreased on the Louisville soil at San Victor from a range of 2,804 kg/ha to 3,181 kg/ha in 1990 to 1,783 kg/ha to 2,065 kg/ha in 1992. There were no significant treatment effects in any year. With the Xaibe soil, no yields were obtained in 1990 because of weed competition. In 1991, yields ranged from 555 kg/ha to 1,146 kg/ha (no significant treatment effects). In 1992, the fertilized plots, BF and GF, had corn yields of 1,391 kg/ha and 1,592 kg/ha, respectively. The unfertilized plots, B and G, had corn yields of 751 kg/ha and 699 kg/ha, respectively. We did obtain sufficient information valuable for persons making fertilizer recommendations on similar types of soil. The Mehlich 3 and the ammonium bicarbonate‐DTPA extractant (the latter extractant similar to that used in Belize) did not give good correlations between P and K leaf levels and corn yields. Where soil test P and K were often adequate, corn ear leaf levels were deficient (and presumably yields were reduced because of this metabolic deficiency). We concluded from both soil tests and leaf analyses that the micronutrients copper (Cu), manganese (Mn), and molybdenum (Mo) are seldom, if ever, limiting plant growth and grain yield, although there appears to be seasonal differences. With both soils, soil tests were not good indicators of zinc (Zn) concentrations in the leaf. In 1992, soil tests indicated adequacy of this element, although leaf Zn was deficient in all plots on the Louisville soil in 1990, most plots in 1992, and several plots on the Xaibe soil in both years.     

Availability of previous and current applications of zinc fertilizer using single superphosphate for the grain production of wheat on soils of south Western Australia

Thirty field experiments on a range of soils in different rainfall zones of South Western Australia were used to examine the effectiveness, relative to freshly applied zinc (Zn) fertilizer of previously applied Zn fertilizer for grain yield of wheat. The soils had been fertilized with Zn at 0.2 to 1.2 kg Zn ha^‐1, 9 to 24 years previous. The effect of applied nitrogen (N) fertilizer on grain yield and Zn concentrations in the youngest emerged blade (YEB) was also examined. At all sites, the current application of Zn fertilizer to soils previously treated with Zn did not increase grain yield. The highest level of N fertilizer did not reduce grain yield where Zn had been applied previously or induce Zn deficiency in wheat plants. The lowest level of Zn (0.2 kg Zn ha^‐1, Experiment 17) applied 15 years earlier was still fully effective for maximum grain production. The application of currently applied Zn increased the Zn concentration in the YEB for 23 experiments. Application of N decreased Zn concentration in YEB in the 19 experiments, had no effect on the Zn concentration in 11 experiments, and increased Zn concentrations in two experiments. This was so for recent and previously applied Zn. In experiments where N decreased the Zn concentration in YEB, the concentration declined to 10 mg kg^‐1 in seven experiments. Zn concentration in the grain was increased by the current application of Zn in 25 experiments. It had no effect in five experiments (Experiments 11–13, 21–22). The application of N fertilizer decreased the Zn concentration of the grain for both previously and currently applied Zn in 20 experiments. Nitrogen decreased the concentration of Zn in the grain to 10 mg Zn kg^‐1 in seven experiments. Zinc extracted from the soil by DTPA was correlated with the amount of previously applied Zn fertilizer. DTPA‐extractable Zn for the experimental sites were 0.3 mg kg^‐1, except for 2 experiments which were 0.2 mg/kg. The results show that where Zn fertilizer had been applied previously, applications of high levels of N fertilizer to cereal crops did not require further applications of Zn if superphosphate (400–600 mg Zn kg^‐1) was used in the cropping and pasture phase. This is because of contaminates of Zn in rock phosphate used to make superphosphate. However, the requirements for Zn for wheat grain need to be reconsidered if diammonium phosphate (DAP) is used for cropping and if superphosphate applications are less than 150 kg ha^‐1 during the legume crop or pasture species in rotation with the cereal.     

Response of burley tobacco to banded fertilizer and in‐row subsoiling

Abstract

Field experiments were conducted during 4 years at two locations in Kentucky to study the response of burley tobacco to phosphorus (P) and potassium (K) fertilizer rate and placement, and to in‐row subsoiling. In one experiment on Pope soil (mesic Fluventic Dystrochrepts), dry matter and P and K uptake 40 days after transplanting, and cured leaf yield and value/ha were increased as application of a 5–13–36 (%N‐P₂O₅‐K₂O) grade fertilizer increased from 310 to 930 kg/ha. Generally, fertilizer placed in 40‐cm wide bands directly under and parallel to the row was more effective than broadcasting and in‐row subsoiling was more effective than not subsoiling. Significant 2‐way and 3‐way interactions suggested that plant responses to band applications over broadcasting were greater in the presence than absence of subsoiling. In another experiment conducted on two silt loam soils, Pope and Maury (typic Paleudalfs), fertilizer applied in a 40‐cm band with in‐row subsoiling was more effective than broadcasting without subsoiling or placement in 10‐cm wide bands applied 0.6‐m apart and perpendicular to the row without subsoiling. Growth and yields increased up to the 620 kg/ha rate and 40 days after transplanting, soil pH decreased and soil electrical conductivity and plant manganese (Mn) increased with increased rate of fertilizer.     

Nitrogen requirements associated with improved conservation tillage for corn production

Abstract

Excessive soil erosion and use of nitrogen fertilizer are costly to the Atlantic Coastal Plain corn (zea mays L., ’Funks G 4507') producer and both may serve to create environmental hazards. An in‐row chisel (36 cm deep) tillage method was compared with the standard 5 cm fluted coulter method for planting corn in premature wheat (Triticim aestivum L.) residues grown on an Orangeburg sandy loam (Typic Paleudult). Five orthogonal N levels ranging up to 440 kg of N/ha were used to determine an economic N optimum for each tillage method.

The in‐row chisel tillage method provides a possible yield advantage in the Atlantic Coastal Plain because of observed restricting soil layers within the normal corn rooting zone. The estimated profit‐maximizing quantities of N fertilizer were 262 and 295 kg of N/ha (234 and 263 1b of N/acre) for the fluted coulter and in‐row tillage procedures, respectively. Corn grain yields associated with these inputs were 9.6 × 10³ and 12.6 × 10³ kg/ha (153 and 200 bu/acre), respectively. The yield increase associated with in‐row chiseling through a 2.5 metric ton mulched surface is attributed to potentially improved rooting and more efficient water storage and use.     

Phytoextraction of Zinc by Indian Mustard and Tall Fescue

Abstract

This experiment evaluated the capacity of two species, Indian mustard (Brassica juncea Czern.) and tall fescue (Festuca arundinacea Schreb.) to extract zinc (Zn) from soils. Also, this experiment focused on using nitrogen (N) fertilizers to increase the phytoextraction of Zn. Two soils of the Hadley series (Typic Udifluvents) were studied. A treatment array of Zn concentrations in soils was supplied as zinc sulfate. Nitrogen was supplied at 200 mg N/kg of soil as calcium nitrate, urea, or compost. Two successive plantings of Indian mustard in the same media were grown until flowering and harvested. Fescue was grown from seeding to a height of 15 cm, harvested, grown again in the same media to a height of 15 cm, and harvested again. After the second harvests of Indian mustard and fescue, soil samples were taken for analysis of extracts with water and with Morgan's solution. Indian mustard was grown with Zn additions ranging from 0 to 100 mg/kg soil. The shoot mass of Indian mustard in both harvests increased to a soil‐Zn level of 25 mg/kg and then decreased. Although growth decreased as the soil‐Zn levels increased beyond 25 mg/kg, Zn concentration and total accumulation increased linearly as the soil‐Zn levels increased. Zinc concentration and accumulation in Indian mustard were highest in soils amended with urea and were lowest in soils with no fertilizer. Fescue was grown with Zn additions ranging from 0 to 1000 mg/kg soil. The shoot mass of fescue increased to a soil‐Zn level of 125 mg/kg (harvest 1) or 250 mg/kg (harvest 2) and then decreased as the soil‐Zn levels increased. Concentration and accumulation of Zn in fescue increased linearly as the soil‐Zn levels increased. Zinc concentration and accumulation were highest in fescue grown in soils amended with urea and lowest in soils with no fertilizer. The highest accumulation of Zn in fescue (3800 mg/pot) occurred at 1000 mg Zn/kg soil. Highest concentrations of soil Zn were extracted with Morgan's solution or water from soils amended with urea, regardless of the species grown in the soils. Lowest concentrations of Zn were extracted from soils with no fertilizer added, regardless of extract or species. In general, if fertilizers (calcium nitrate, urea, or compost) were added to the soils, the pH decreased. Fescue was easy to grow, tolerated much higher soil‐Zn levels than Indian mustard in this research, and could be a species useful for phytoextraction of Zn.     

Effect of starter fertilizer in seed-row on emergence,biomass and nutrient uptake by six pulse crops grown under controlled environment conditions

Abstract

Legumes have a unique ability to obtain a significant portion of atmospheric nitrogen (N₂) through a symbiotic relationship with Rhizobia spp of bacteria but it takes time, thus, an early supply of N to the plant may positively influence growth and development. However, too much fertilizer in close proximity to the seed can damage the seedling. Therefore, this study was conducted to determine the maximum safe rates for starter seed-row fertilizer application under low seedbed utilization conditions (15%). Emergence, biomass yield and nitrogen (N), phosphorus (P) and sulfur (S) uptake responses to starter fertilizer products and blends applied at 0, 10, 20 and 30?kg?N?ha^?1 in the seed-row were investigated for six different pulse crops: soybean, pea, faba bean, black bean, lentil and chickpea. The general sensitivity (injury potential) for starter N, P, S fertilizer was lentil?≥?pea?≥?chickpea?>?soybean?≥?black bean?>?faba bean. Lentil, pea and chickpea could generally only tolerate the 10?kg?N?ha^?1 rates while soybean and black bean could tolerate 10–20?kg?N?ha^?1. Faba bean emergence appeared relatively unaffected by all three rates of N and showed least sensitivity to seed row placed fertilizer. In terms of 30-day biomass response, soybean and black bean were most responsive to fertilization, while pea, faba bean, lentil and chickpea were least responsive to the starter fertilizer applications, with no benefit increasing above the 10?kg?N?ha^?1 rate.     

菜-稻轮作对菜田氮、磷利用特性和富集状况的影响

菜田氮、磷污染治理的最佳途径是提高化肥利用率.本研究开展了四季豆(Phaseolus vulgaris)-瓢瓜(Lagenaria sicerariae)-早稻轮作中不同氮、磷肥用量的3年定位田间试验.结果表明,经济施肥量为四季豆N 155kg/hm2和P2O579 kg/hm2、瓢瓜N 247 kg/hm2和P2O5 130 kg,/hm2,早稻不施肥.取得最佳经济效益的施肥处理,净增收比其他氮、磷水平提高1.6％～46.8％,氮肥利用率从四季豆和瓢瓜连作的45.1％提高到四季豆-瓢瓜-早稻轮作的65.6％,磷肥利用率则从17.9％提高到26.5％.四季豆-瓢瓜-早稻轮作的土壤硝态氮和有效磷含量分别为四季豆和瓢瓜连作的27.5％和87.0％,为基础土壤硝态氮和有效磷含量的63.7％和93.9％.养分吸收特性分析表明,四季豆的氮、磷最大吸收速率分别是早稻的25.1倍和2.5倍,瓢瓜则分别是早稻的18.4倍和1.2倍;四季豆的氮、磷最大吸收量分别是早稻的1.7倍和2.2倍,瓢瓜则分别是早稻的2.5倍和1.9倍.因此,菜-稻轮作体系利用了蔬菜和水稻在氮、磷吸收强度上的差异,较蔬菜连作促进了氮、磷高效利用,从而削减菜田过高的氮、磷富集,降低了土壤氮、磷流失潜力.     

Yield response of barley and rapeseed to K fertilizer: Influence of soil test K level and method of placement

Abstract

Field experiments were conducted in central Alberta to determine the yield response of barley and rapeseed to KCl on soils varying in soil test K levels and to evaluate three methods of K placement for effectiveness. The soil test K extractant was 1M ammonium acetate solution. Placement methods were incorporation, banding with the seed and banding beside the seed row. The percentage of sites that responded to K fertilizer significantly and yield increase of barley from K fertilizer decreased with increasing soil test K in the soil. Rapeseed responded less often to K than barley and K placement was more critical for barley than for rapeseed. Barley yields were greatest when the K fertilizer was banded in the seed row and least when incorporated into the soil. Rapeseed yields on K‐responsive sites were same when the K fertilizer was incorporated or banded beside the seed row, but tended to be greater when banded with the seed.     

Estimating nitrogen requirements for irrigated malting barley

Abstract

The production of marketable malting barley requires careful N management to meet the quality standards set by the malting industry. Nine field trials were conducted over an eight‐year period at four locations to develop N fertilization guidelines for irrigated malting barley. Residual soil NO₃‐N (0 to 60 cm) ranged from 15 to 103 kg N/ha. Nitrogen fertilizer was applied preplant as either urea or NH₄NO₃ at rates ranging from 0 to 269 kg N/ha. Maximum yields were obtained when the sum of residual plus applied N (available N) was above 110 kg N/ha. However, the percentage of plump kernels generally fell below acceptable levels (85%) when available N exceeded 135 kg N/ha. Grain protein exceeded acceptable levels (12%) when available N was above 210 kg N/ha. Stem NO₃‐N sufficiency levels were determined from high‐yielding barley with acceptable quality parameters. At the three‐leaf stage, the barley stem NO₃‐N sufficiency level was approximately 6,000 μg/g and decreased to about 1,000 μg/g at the eight‐leaf stage.     

RESPONSES OF COOL-SEASON GRAIN LEGUMES AND WHEAT TO SOIL-APPLIED ZINC

The yield and zinc (Zn) content response of faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), lentil (Lens culinaris Medik.) and wheat (Triticum aestivum L.) to applications of Zn fertilizer was compared in a glasshouse experiment using two alkaline soils from southwestern Australia. Comparative Zn requirements were determined from yields of 46-day-old dried shoots when no Zn fertilizer was applied, the amount of Zn required to produce the same percentage of the maximum (relative) yield of dried shoots, and the Zn content of dried shoots (Zn concentration multiplied by yield of dried shoots). The concentration of Zn in youngest tissue and in dried shoots was used to determine critical concentrations for Zn in tissue. Faba bean used indigenous soil Zn more effectively than chickpea, followed by wheat and then lentil. The Zn requirement was lowest for faba bean, and increased in the order faba bean < chickpea < wheat < lentil. Zinc concentration in dried youngest tissue and in dried shoots increased with an increase in the amount of added Zn. The critical Zn concentration in the youngest tissue, associated with 90% of the relative yield, was (mg Zn kg^?1): 25 for lentil, 18 for faba bean, 17 for chickpea and 12 for wheat; corresponding values for dried whole tops (mg Zn kg^?1) were: 30 for lentil, 19 for faba bean, 17 for chickpea, and 20 for wheat. Information on comparative responses of the grain legumes to Zn additions relative to wheat, and critical tissue test values, will aid in the fertilizer management of Zn in cool-season grain legumes in the southwestern Australian farming systems.     

Phosphorus and zinc fertilization effects on dry matter yield and phosphorus and zinc uptake by Crambe

Crambe (Crambe abyssinica Hochist.) is an oilseed crop high in euricic acid with industrial applications in production of nylon, plasticizers, and lubricants. Little information is available on crambe response to phosphorus (P) and zinc (Zn) fertilization. This glasshouse study was conducted to evaluate the response of crambe to four rates of P and five rates of Zn fertilizer application to a soil with 10 mg/kg NaHCO₃‐extractable P and 0.6 mg/kg DTPA‐extractable Zn. Phosphorus fertilizer, but not Zn fertilizer, increased the dry matter yield of plant tops. Phosphorus response was consistent in both 35‐ and 62‐day‐old plants. Zinc response was most consistent in 35 day‐old plants. Significant interactions were observed between P and Zn for dry matter weight, P:Zn ratio, and Zn uptake at 35 days. No significant interactions were observed at 62 days. Analysis of the data showed a negative correlation coefficient between P or Zn treatment and tissue concentration or uptake for the opposite element.     

不同氮肥用量及其生育期分配比例对四川丘陵区带状种植小麦氮素利用的影响

【目的】带状种植是四川小麦的典型种植方式,主要分布在丘陵旱地,与玉米构成小麦/玉米复合种植系统。本文通过两年大田试验研究了不同氮肥用量和生育期分配比例对四川丘陵旱地带状种植小麦氮素吸收累积、 分配与转运的影响,以及氮素利用效率和土壤氮残留问题,筛选适合于该地区带状种植小麦的适宜氮肥用量和分配比例,为生产应用提供理论和技术依据。【方法】试验在四川省仁寿县进行,试验材料为四川主推品种川麦42,带状种植(即2 m为一带,种5行小麦,行距20 cm,小麦幅宽80 cm,预留行1.2 m),2BSF-4-5A型谷物播种机播种,密度150104 plant/hm2。试验采用二因素裂区设计,施氮量为主区,设N 90(N1)、 135(N2)、 180(N3)、 225(N4) kg/hm2 4个水平;生育期分配比例为裂区,设基肥一次性施入(R1)、 底肥:苗肥=7:3(R2)、 底肥:拔节肥=7:3(R3)和底肥:苗肥:拔节肥:孕穗肥=5:1:2:2(R4)4个水平,并以不施肥(CK)为对照。【结果】 1)施用氮肥后收获期地上部植株总吸氮量显著提高,开花期植株各营养器官氮素积累量、 成熟期叶和茎鞘中氮素残留量以及转运氮的贡献率均随施氮量的增加而增加,而花后氮素同化量及其对籽粒氮的贡献率随施氮量增加呈先增后降的趋势,在施氮量为N 135 kg/hm2时达最大。底肥:拔节肥=7:3的施氮方式有利于提高花后氮素同化量及其对籽粒氮贡献率,而底肥:苗肥:拔节肥:孕穗肥=5:1:2:2的施氮方式有效地促进了花前贮存氮素向籽粒转移,同时也增加了成熟期氮素在营养器官中的残留,降低了氮素在籽粒中的分配比例;2)氮利用效率和植株氮生产力均随施氮量的增加而降低,土壤中残留的全氮、 NO-3-N及NH+4-N含量则随施氮量的增加而增加;在施氮量较高(N 180～225 kg/hm2)的条件下,底肥一次施极大地增加了土壤中氮的残留,且随施氮量增加,拔节期一次性追肥土壤中氮残留也增加,氮肥分次追施和加大分配比例能够有效降低土壤中的氮素残留; 3)在四川丘陵旱地套作条件下,施氮量和籽粒产量的关系可用二次曲线方程来拟合,平均每生产100 kg籽粒需N 3.6 kg;施氮量为180 kg/hm2、 分配比例为底肥:拔节肥=7:3时籽粒产量最高,可达4800 kg/hm2(第二年4706 kg/hm2),较CK增产27.6%(第二年增产25.6%)。【结论】综合考虑小麦籽粒产量、 氮吸收利用特性以及土壤中残留氮量,在保证获得较高小麦产量(4650 kg/hm2以上)的前提下,应适当减少氮肥用量,采取氮肥后移及分次施用的方式。本试验条件下带状种植小麦推荐的氮肥用量为N 135～180 kg/hm2,分配比例为底肥:拔节肥=7:3。