NITROGEN,PHOSPHORUS, AND POTASSIUM NUTRIENT EFFECTS ON GRAIN FILLING AND YIELD OF HIGH-YIELDING SUMMER CORN

A three-site-year field experiment was conducted to determine nitrogen (N), phosphorus (P), and potassium (K) fertilizer effects on grain filling dynamics and yield formation of high-yielding summer corn (Zea mays L.) in a wheat (Triticum aestivum L.)-corn double crop cropping system. Application of combined NPK fertilizers resulted in the greatest grain yield, largest grain number and grain weight when compared with the treatments receiving N, NP, or NK. Grain filling rate and duration, grain volume, and grain yield increased with NPK rates; however, doubling the rate of 180 kg N ha^?1, 40 kg P ha^?1, and 75 kg K ha^?1 fertilizer only led to minimal increases in grain filling rate (0.8%), grain filling duration (1.6%), grain volume (1.3%) and grain yield (0.4%). Our results suggested that for the high-yielding summer corn, a combined NPK fertilization is required to enhance grain filling and yield, and that under well-fertilized circumstances, limited increases in both grain filling and sink capacity might be the main factor restricting further yield improvement.     

不同追施氮肥处理对冬小麦产量和品质的影响

以不同品质类型的2个小麦品种为试验材料,采用2因素随机区组设计,研究了不同品种和氮肥追施处理对产量和品质的影响.结果表明,在底肥量和追肥总量相同的条件下,适当增加开花期追施氮肥的比例有利于提高产量,处理间差异显著,品种间产量差异不显著;不同追肥处理对总蛋白含量影响不显著,但对清蛋白、醇溶蛋白和谷蛋白含量影响显著;追肥处...     

EFFECTS OF pH ON GROWTH AND NODULATION OF TWO FORAGE LEGUMES

A study was conducted to compare the responses to acid pH of Medicago sativa and Lotus glaber, two forage legumes with different environmental requirements, either supplied with inorganic nitrogen (N) or inoculated with different strains of their nodule bacteria. Medicago sativa showed, in both treatments, a significant reduction in total dry weight at pH below 6.0. In contrast, Lotus glaber grew equally well at all the pHs assayed in the presence of adequate N. Under inoculated conditions, in the absence of N supply, plant growth was dependent on the bacterial strain used. When the ability of each strain to multiply in culture medium was examined, it was observed that Sinorhizobium meliloti strains showed a pH-sensitive response that inhibited growth at pH 4.0, whereas Mesorhizobium loti strains showed normal growth at this pH. These results suggest that for the effectiveness of Mesorhizobium loti–Lotus glaber symbiosis in acid soils the major factor to be considered is the tolerance of the bacterial strain to acid conditions, while the limiting factors for the Sinorhizobium meliloti–Medicago sativa symbiosis are the sensitivity to low pH of both the plant and its bacteria.     

EFFECTS OF PHOSPHORUS SUPPLY ON GROWTH,YIELD, AND YIELD COMPONENTS OF SAFFLOWER AND SUNFLOWER

This study comparatively evaluates the phosphorus (P) requirement of safflower (Carthamus tinctorius L.) and sunflower (Helianthus annuus L.) in view of identifying low input oil crops. Both species responded strongly to increasing P supply with respect to plant growth and yield. Yield component analysis revealed that oil yield in safflower was affected by P deficiency mainly via the number of capitula per plant followed, in consecutive order, by the number of achenes per capitulum and the single achene mass (SAM). The major yield component influencing oil yield of sunflower was the number of achenes per plant, followed by the SAM. Contribution of the seed oil concentration to overall yield variation was insignificant for both species. Path coefficient analyses indicate that in sunflower total nitrogen (N) accumulated was found to be most important, while in safflower this holds true for both the total P and N accumulated. It was concluded that safflower cannot be considered a low-input oil crop in terms of its P requirement.     

几种除草剂对小麦籽粒产量及生理特性的影响

为评价除草剂的负效应,研究了大田条件下苯磺隆、使它隆、异丙隆、骠马和绿麦隆5种除草剂春季施用对强筋小麦烟农19和弱筋小麦扬麦13的籽粒产量及相关生理特性的影响。结果表明,5种除草剂处理后对小麦株高均有一定的抑制作用,表现为高剂量抑制作用强,低剂量抑制作用较弱,其中抑制作用最强的为异丙隆2倍量处理,其抑制率达对照的9.6...     

NITROGEN,PHOSPHORUS, AND POTASSIUM EFFECTS ON GRAIN SORGHUM PRODUCTION AND STALK ROT FOLLOWING ALFALFA AND BIRDSFOOT TREFOIL

Grain sorghum [Sorghum bicolor (L.)], grown on the often infertile claypan soils of the eastern Great Plains, requires attention to soil fertility. Experimental objectives were to determine the effects of phosphorus (P) and potassium (K) fertility levels, N application, and legume residual on grain sorghum production and stalk rot. Following alfalfa and birdsfoot trefoil, first-year sorghum yield was 7 Mg ha^?1 and not affected by N fertilizer. In subsequent years, yield increases due to N were less than 20%. Sorghum yield increased at low P and K rates, especially with nitrogen (N) fertilization and was greater following birdsfoot trefoil than following alfalfa. In 1995 when fertilized with N, lodging and stalk rot severity were increased by P and reduced by K. In 1996, stalk rot severity was reduced by K fertilization. Grain sorghum, grown after legume crops, required minimal levels of P and K, especially when N fertilizer was added.     

VARIABILITY OF GRAIN AND OIL YIELD IN SPRING SAFFLOWER AS AFFECTED BY NITROGEN APPLICATION

This research was carried out to determine the effects of rate and time of nitrogen (N) application on safflower in a calcareous soil. The nitrogen rates were 50, 75, 100, 125, and 150 kg ha^?1 and three split application methods were used. Experimental treatments were conducted as a factorial in a randomized complete block design (RCBD) with three replications. Duncan's Multiple Range Test (DMRT) indicated that the three split application of 100 kg ha^?1 of nitrogen in stages of sowing date, early stem elongation, and early flowering had higher grain yield (2627 kg ha^?1) than other treatments. This result was forecasted by results of increases in number of heads per square meter (heads m^?2), number of grains per head (grains/head), and thousand grain weight (TGW). The highest oil yield was 755 kg ha^?1 with the 100 kg ha^?1 nitrogen application and was 727 kg ha^?1 in treatment of three split application.     

EFFECTS OF NITROGEN FORMS ON THE GROWTH AND POLYAMINE CONTENTS IN DEVELOPING SEEDS OF VEGETABLE SOYBEAN

A pot culture experiment of nitrogen forms [nitrate (NO^? ₃ ): ammonium (NH ⁺ ₄ )] with four ratios (100:0, 75:25, 50:50, and 25:75) in nutrient solutions was conducted to examine the effect of nitrogen forms on the growth and polyamine contents of developing seeds of vegetable soybean [Glycine max (L.) Merr. cv. ‘Li-xiang 95-1′]. Results showed that the best plant growth vigor was observed in (75%), and then in (50%). However, the fresh and dry weight of biomass decreased when a high concentration of either (100%) or (75%) was the primary nitrogen source in the nutrient solution. The numbers of flowers and pods in (75%) were significantly decreased compared with other ammonium-nitrate ratios in which the numbers of flowers and pods were not influenced by nitrogen forms. During the development of seeds, levels of free Put and Spd decreased, and the decrease extents were more marked in 100:0 and 25:75 (:), but the change of free Spm was opposite. Levels of conjugated and bound polyamines in all nitrogen forms increased, but the increases in 75:25 and 50:50 (:) were not so obvious as in 100:0 and 25:75 (:) treatments. The possible roles of polyamines in the adaptive mechanism of vegetable soybean seeds to different nitrogen forms were discussed.     

NITROGEN NUTRITION ON LEAF CHLOROPHYLL,CANOPY REFLECTANCE,GRAIN PROTEIN AND GRAIN YIELD OF WHEAT VARIETIES WITH CONTRASTING GRAIN PROTEIN CONCENTRATION

Wheat cultivars (‘AC Barrie’, ‘Brook Field’, ‘Hoffman’, and ‘Norwell’) with different protein concentrations were compared under four nitrogen (N) levels (0, 50, 100 and 150 kg ha^?1) in an environment-controlled greenhouse, and the same experiment with an additional N level (200 kg N ha^?1) was repeated in the field in 2007. In the greenhouse experiment, application of 100 kg N ha^?1 resulted in significantly greater grain yield due mainly to higher number of grains per spike and heavier mean grain weight; in the field study, the 150 kg N ha^?1 treatment produced the greatest yield (P<0.01) primarily due to more number of grains per spike. Crude grain protein percentage was increased significantly with each increment of N up to the highest level; however, protein yield (kg ha^?1) increased significantly with fertilizer up to 150 kg N ha^?1. Leaf chlorophyll contents were increased linearly with increment of N levels up to 150 kg ha^?1 both in the greenhouse and field trials while leaf area indices continued to increase up to the highest application rate (200 kg N ha^?1). Canopy reflectance, expressed as normalized difference vegetation index (NDVI), attained maximum value with 150 kg N ha^?1 in the field experiment. Among the varieties tested, “Hoffman” out-yielded other three varieties due to heavier grain weight. Although highest grain and/or plant crude protein content were recorded in ‘AC Barrie’, it was the variety ‘Hoffman’ that produced the highest total protein (kg ha^?1) with largest NDVI and leaf area index (LAI) values.     

气象因子对河南省夏玉米产量与品质的影响

以郑单958、浚单20、登海662三个高产玉米品种为材料,于2007-2008年在河南省4个生态区(豫南、豫中、豫东、豫北)研究了气象因子对河南省夏玉米产量与品质的影响.结果表明:4个生态区的玉米产量表现为豫北＞豫东＞豫中＞豫南,其中豫北玉米2年平均产量为708.5kg/667m2,显著高于其他3个生态区.豫东玉米籽粒...     

富镧稀土对春小麦吸收氮磷素和产量的影响

用盆栽方法进行富镧稀土拌种和叶面喷施春小麦试验。结果表明，富镧稀土对春小麦有促进生长发育的作用，增产幅度在６％～８％。同时促进春小麦对氮、磷素的吸收、利用，并减少土壤中氮素的损失。在施用方法上，叶面喷施比拌种的方法更好。     

EFFECT OF DIFFERENT PHOSPHORUS SOURCES ON THE GROWTH,YIELD, ENERGY CONTENT AND PHOSPHORUS UTILIZATION EFFICIENCY IN MAIZE AT RAWALAKOT AZAD JAMMU AND KASHMIR,PAKISTAN

Effect of poultry manure (PM) and four inorganic phosphorus (P) fertilizers sources, i.e., diammonium phosphate (DAP), single super phosphate (SSP), nitrophos (NP) and triple super phosphate (TSP) on crop production and P utilization efficiency (PUE) of maize was studied. Both inorganic P fertilizers and PM applied alone or combined in 50:50 proportions at equivalent rate of 90 kg P₂O₅ ha^?1. Results indicated that inorganic P sources with PM significantly increased plant height, leaf area and chlorophyll content. Average values showed that combined application of inorganic P with PM increased grain yield by 19 and 41% over inorganic P and PM alone, respectively. Similarly, increase in P-uptake due to the combined application of inorganic P + PM was 17% compared to sole inorganic P. Phosphorus utilization efficiency of inorganic P was increased with PM and the highest PUE was recorded in DAP + PM. Generally, combination of DAP + PM proved superior over the remaining P fertilizers.     

磷素水平对大豆氮素积累及产量的影响

利用砂培方法和15N示踪技术研究了磷素水平对大豆氮素积累、根瘤固氮和产量的影响。结果表明:大豆植株氮素积累、根瘤固氮和产量均随磷素营养水平的提高而呈单峰曲线变化,营养液磷素浓度31mg/L左右时达到峰值,当营养液磷素浓度达11mg/L时,再提高磷素浓度对大豆根瘤固氮率无明显促进作用;而对于大豆植株氮素积累、根瘤固氮量和产量,只有当营养液磷素浓度达到21mg/L时,再提高磷素浓度才无明显促进所用,表明满足根瘤固氮的磷素营养水平较产量形成的水平要求低。     

NITROGEN RATES AND ITS TIME OF APPLICATION INFLUENCE DRY MATTER PARTITIONING AND GRAIN YIELD IN MAIZE PLANTED AT LOW AND HIGH DENSITIES

Best nitrogen (N) management practices are most important for increasing maize (Zea mays L.) productivity and profitability in Northwest Pakistan. Field experiments were performed at the New Developmental Research Farm of NWFP Agricultural University, Peshawar during summer 2002 and 2003. Factorial experimental treatments were two plant densities (D₁ = 60,000 and D₂ = 100,000 plants ha^?1) and three N rates (N₁ = 60, N₂ = 120 and N₃ = 180 kg N ha^?1) as main plots, and six split N applications in different proportions at different growth stages of maize (cv. ‘Azam’) in two equal, three equal, three unequal, four equal, five equal and five unequal splits at sowing and with first, second, third, and fourth irrigation at two week intervals as subplots. Application of the higher N rate (180 kg ha^?1) with 4 to 5 splits significantly increased leaf, stem, ear, and total plant dry weight at silking and physiological maturity as well as grain yield plant^?1 at both low and high plant densities. Variation in dry matter partitioning and grain yield in maize due to fluctuation in the rainfall data of the two years suggests zonal specific effective N management practices for sustainable maize production in different agro-ecological zones of Northwest Pakistan.     

EFFECTS OF CONVENTIONAL AND CONTROLLED RELEASE PHOSPHORUS FERTILIZER ON CROP EMERGENCE AND GROWTH RESPONSE UNDER CONTROLLED ENVIRONMENT CONDITIONS

A series of experiments on the effects of form and rate of seed row placed phosphorus (P) fertilizer were carried out under controlled environment conditions using flats of a P-deficient Brown Chernozemic soil from Saskatchewan, Canada. The experiments were conducted in the laboratory and growth chamber using rates of seed row placed granular P fertilizer up to 100 kg P₂O₅ ha^?1. Two forms of monoammonium phosphate fertilizer were compared: 1) conventional MAP granules and 2) controlled release phosphorus (CRP) fertilizer granules (Agrium Inc, Denver, CO, USA.) made with a polymer coating to slow the release of phosphate to soil solution. Six crops were utilized in the study to provide a range of commonly grown cereal, oilseed, pulse and forage crops in Western Canada: wheat (Triticum aestivum), canola (Brassica napus), mustard (Brassica juncea), flax (Linum usitatissimum), yellow pea (Pisum sativum) and alfalfa (Medicago sativum). Parameters measured were percentage of planted seeds that had emerged after two weeks, plant biomass yield, and plant P uptake after four weeks. Most of the crops tested showed no negative impact on emergence with seed row placed conventional P fertilizer at rates up to ～20 to 30 kg P₂O₅ ha^?1. Pea, flax and mustard tended to be most sensitive to injury from high rates of seed placed MAP while wheat was least sensitive. The controlled release phosphorus fertilizer (CRP) product greatly increased the tolerance of crops to high rates of seed row placed P, with rates of 80 kg P₂O₅ ha^?1 placed in the seed row producing no significant injury for most crops. This effect is attributed to the coating reducing the harmful salt effect that occurs when high rates of fertilizer are placed in the seed row in close proximity to the seed. Generally, a rate of 30 kg P₂O₅ ha^?1 was sufficient to produce maximum early season biomass yield and P uptake for both conventional MAP and CRP fertilizers. Large differences in early P availability were not evident between the conventional P and controlled released P fertilizer products.     

INTERACTIVE EFFECT OF SULFUR AND PHOSPHORUS ON NODULATION,NITROGEN FIXATION,AND NUTRIENT UPTAKE BY CHICKPEA GROWN ON CALCAREOUS SOILS IN PAKISTAN

Field experiments were conducted at two different locations under rainfed conditions of Punjab, Pakistan to assess nodulation, nitrogen fixation and nutrient uptake by chickpea (Cicer arietinum L.) in response to application of three rates [0, 40, and 80 kg phosphorus pentoxide (P₂O₅ ha^?1)] of phosphorus and three rates (0, 15 and 30 kg S ha^?1) of sulfur in different combinations. Effect of phosphorus application was nonsignificant while that of sulfur was significant on percent nitrogen derived from atmosphere. Both phosphorus and sulfur application resulted in increase in nitrogen fixation up to 38% and 33% over control, respectively. Nutrient uptake [nitrogen (N), phosphorus (P), and sulfur (S)] increased significantly with the application of phosphorus and sulfur and correlated positively with nitrogen fixation. There is direct involvement of sulfur in the process of nitrogen fixation whereas effect of phosphorus on nitrogen fixation is indirect mainly through enhanced growth and dry matter production.     

多功能保水剂对黄瓜生长及产量的影响

本文研究新型多功能保水剂对黄瓜生长,产量,品质及水分利用率的影响。试验结果表明,这种新型多功能保水剂可以提高土壤绝对含水量,有效的促进黄瓜营养生长,黄瓜产量、结果数、单果重和水分利用率,分别提高了13.12%、10.34%、2.52%、13.12%,但对品质影响不大。     

土壤水分对小麦产量和品质的影响

本文综述了土壤水分对小麦产量和品质的影响。土壤水分既影响小麦产量,也影响其籽粒品质;土壤水分缺少能够影响器官发育,使叶面积减小,叶绿素含量降低,群体叶片光合性能下降。土壤水分缺少还使开花后的光合产物减少,造成灌浆物质不足,原贮存在营养器官中的物质向籽粒的运转速度加快,贮存物质在粒重中的比例提高,在一定程度上弥补了粒重和产量的降低。同时,土壤水分也影响小麦品质,主要表现在蛋白质和淀粉上。     

DRY BEAN GENOTYPES EVALUATION FOR GROWTH,YIELD COMPONENTS AND PHOSPHORUS USE EFFICIENCY

Dry bean along with rice is a staple food for the population of South America. In this tropical region beans are grown on Oxisols and phosphorus (P) is one of the most yield limiting factors for dry bean production on these soils. A greenhouse experiment was conducted to evaluate P use efficiency in 20 elite dry bean genotypes grown at deficient (25 mg P kg^?1 soil) and sufficient (200 mg P kg^?1) levels of soil P. Grain yields and yield components were significantly increased with P fertilization and, interspecific genotype differences were observed for yield and yield components. The grain yield efficiency index (GYEI) was having highly significant quadratic association with grain yield. Based on GYEI most P use efficient genotypes were CNFP 8000, CNFP 10035, CNFP10104, CNFC 10410, CNFC 9461, CNFC 10467, CNFP 10109 and CNFP 10076 and most inefficient genotypes were CNFC 10438, CNFP 10120, CNFP 10103, and CNFC 10444. Shoot dry weight, number of pods per plant, 100-grain weights and number of seeds per pod was having significant positive association with grain yield. Hence, grain yield of dry bean can be improved with the improvement of these plant traits by adopting appropriate management practices. Soil pH, extractable P and calcium (Ca) saturation were significantly influenced by P treatments. Based on regression equation, optimum pH value in water was 6.6, optimum P in Mehlich 1 extraction solution was 36 mg kg^?1 and optimum Ca saturation value was 37% for dry maximum bean yield.     

EFFECT OF NANOSCALE ZINC OXIDE PARTICLES ON THE GERMINATION,GROWTH AND YIELD OF PEANUT

An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant growth and development. In view of the widespread cultivation of peanut in India and in other parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen as the model system. Peanut seeds were separately treated with different concentrations of nanoscale zinc oxide (ZnO) and chelated bulk zinc sulfate (ZnSO₄) suspensions (a common zinc supplement), respectively and the effect this treatment had on seed germination, seedling vigor, plant growth, flowering, chlorophyll content, pod yield and root growth were studied. Treatment of nanoscale ZnO (25 nm mean particle size) at 1000 ppm concentration promoted both seed germination and seedling vigor and in turn showed early establishment in soil manifested by early flowering and higher leaf chlorophyll content. These particles proved effective in increasing stem and root growth. Pod yield per plant was 34% higher compared to chelated bulk ZnSO₄. Consequently, a field experiment was conducted during Rabi seasons of 2008–2009 and 2009–2010 with the foliar application of nanoscale ZnO particles at 15 times lower dose compared to the chelated ZnSO₄ recommended and we recorded 29.5% and 26.3% higher pod yield, respectively, compared to chelated ZnSO₄. The inhibitory effect with higher nanoparticle concentration (2000 ppm) reveals the need for judicious usage of these particles in such applications. This is the first report on the effect of nanoscale particles on peanut growth and yield.