RELATIVE RESPONSE OF FORAGE AND SEED YIELD OF ALFALFA TO SULFUR,PHOSPHORUS, AND POTASSIUM FERTILIZATION

A field experiment was conducted from 2000 to 2007 on three-year old alfalfa stand near Star City in northeastern Saskatchewan to determine the influence of balanced application of sulfur (S), phosphorus (P), or potassium (K) fertilizers on forage dry matter yield (DMY) and seed yield, protein concentration (PC) in forage, concentration and uptake of total nitrogen (N), P, K, S, and boron (B) in forage and seed, and residual soil extractable P, exchangeable K and sulfate-S. Appropriate application of S, P, or K fertilizer nutrients was required to obtain optimum yield, PC, and nutrient concentration and uptake, especially when alfalfa was grown for hay production. Yield response to fertilization was much more frequent and much higher when alfalfa was managed as hay compared to when managed for seed production. The results suggest the importance of proper fertilization in increasing longevity of alfalfa stands. Under both hay and seed plots, there was only a small increase in residual sulfate-S from S fertilization, but significant accumulation of extractable P mainly in the 0–15 soil layer from P application. There was relatively higher concentration of exchangeable K in soil in the seed plots than in hay plots. In hay plots, concentrations of residual exchangeable K in soil were negatively related to DMY, especially in 2007. The findings suggest that when a soil is testing low (or deficient) in a nutrient and alfalfa growth is reduced, then alfalfa producers should consider applying fertilizers to supply adequate amounts of nutrients that are lacking in the soil, especially for optimum forage production. However, it is still difficult to predict accurately if a profitable alfalfa seed yield response to fertilization would occur, particularly when soils are testing marginal in some nutrient levels and yields are negatively affected by abnormal weather conditions (drought soil moisture conditions reducing plant growth, wet, cloudy and cool weather conditions decreasing pollination activity and late summer and/or early autumn frost damage to seed formation) that often occur in the growing season in this region.     

IMPROVING YIELD IN ALFALFA SEED STANDS WITH BALANCED FERTILIZATION

Field experiments were conducted from 2000 to 2007 on three-year or older alfalfa stands grown for seed production at various sites in northeastern Saskatchewan to determine the influence of balanced application of phosphorus (P), sulfur (S), or potassium (K) fertilizers on seed yield and longevity of alfalfa stands. Survey trials were also conducted to determine the possible reasons for low seed yields on some alfalfa seed fields by comparing “bad” (i.e., low alfalfa seed-yielding) and “good” (i.e., high alfalfa seed-yielding) areas within alfalfa seed stands. The results of alfalfa seed field survey trials suggest that poor seed yields in “bad” areas compared to “good” areas in most alfalfa stands were due to nutrient deficiencies and/or a soil fertility imbalance, as evidenced by soil tests for available nutrients. The findings of field research experiments indicated that application of P, K, or S fertilizer nutrients was essential to obtain optimum seed yield in most cases under normal soil moisture conditions. This also suggests the importance of balanced fertilization in increasing longevity of alfalfa seed stands over a number of years. In summary, the findings suggest that when a soil is testing low (or deficient) in a nutrient and alfalfa growth is reduced, then alfalfa seed producers should consider application of fertilizers to supply adequate amounts of nutrients lacking in the soil. However, it is still difficult to predict accurately if a profitable alfalfa seed yield response to fertilization would occur, particularly when the soils are testing marginal in some nutrient levels and alfalfa seed yields are often reduced by dry weather conditions and/or frost damage.     

SEED YIELD AND YIELD COMPONENTS RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZER APPLICATION IN NORTHWEST PAKISTAN

Improper sulfur (S) and potassium (K) fertilizer management, particularly with continued soil nutrient mining, is one of the major factors contributing to low seed yield of canola in northwestern Pakistan. A field experiment was conducted in 2007?2008 on a S and K deficient clay loam soil at the Research Farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine seed yield and yield components response of Brassica oilseed rape versus mustard to S and K application. Twenty treatments in a randomized complete block design were consisted of two oilseed rape (B. napus canola) and mustard (B. juncea canola) genotypes at three rates each of S (15, 30, and 45 kg S ha^?1) and K (30, 60, and 90 kg K ha^?1) fertilizers plus one control (no S and K applied). Seed yield and yield components increased significantly with K and S fertilization as compared to the zero-S/zero-K control. Both genotypes responded positively for seed yield and yield components to K and S fertilization, but the magnitude of response varied with levels of S and K, as well as combined K + S applications. It is concluded that a combination of 60 kg K + 30 kg S ha^?1 would improve seed yield and yield components of rape and mustard in the study area and contribute significantly to increased production. Growing B. napus was better than B. juncea in the study area, because B. napus produced significantly higher seed yield and yield components than B. juncea, indicating that yield components are the most important criteria for selection of Brassica genotypes for higher seed yield.     

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.     

不同生育期温光条件对直播稻产量的影响

在江苏苏南太湖稻区的常熟市(N 31.4°)、苏中里下河稻区的姜堰市((N 32.3°)及苏北淮北稻区的东海县(N 34.5°),分别以不同类型粳稻品种为材料,通过分期播种试验,比较研究不同生育期温光条件对江苏上述不同生态区直播稻产量的影响。结果表明,在本研究设置的播期范围内,随着播期的推迟,各生态区不同熟期类型品种水稻的产量均呈极显著下降趋势,但变化程度略有不同,表现为晚熟品种大于早熟品种,过迟播种导致各生态区部分类型品种不能安全成熟。产量构成因素随播期的推迟按变化程度的大小分为两类,变化较小的一类为千粒重和穗数,变化较大的一类为结实率和每穗颖花数,后者是导致产量极显著下降的主要原因。总颖花量、结实率和产量与抽穗前以及全生育期的积温和光照时数呈显著或极显著相关,各生育期温光条件对千粒重的影响不显著。     

栗钙土中磷肥转化及效应的研究

采用石灰性土壤无机磷的分级方法,研究了磷肥在栗钙土中的转化以及包被物对土壤中磷肥转化的影响和莜麦的磷肥效应。研究结果表明,在不种作物的情况下,磷肥施入土壤后很快转化为Ca2-P、Ca8-P、Al-P、Fe-P等形态,随施肥时间的延长,Ca2-P呈减少趋势,其它形态的无机磷则逐渐增加;在种植莜麦的情况下,莜麦对磷肥的吸收利用率为31.1％,土壤残留为68.9％,残留磷中各形态无机磷占施入磷的比率:28.9％为Ca2-P,11.0％为Ca8-P,10.3％为Al-P,5.5％为Fe-P,9.5％为O-P,3.7％为Ca10-P;包被磷肥较未包被磷肥减少了土壤中Ca2-P向Ca8-P转化,增加了施入磷向Al-P的转化而减少了向Fe-P、O-P的转化,磷肥的利用率提高2.9个百分点。施用磷肥莜麦增产178％。     

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.     

CHICKPEA RESPONSE TO TILLAGE SYSTEM AND PHOSPHORUS MANAGEMENT UNDER DRYLAND CONDITIONS

A field study was conducted at the Research Farm of NWFP, Agricultural University, Pakistan. Chickpea (Cicer aeritinum L.) cultivar, ‘Hassan-2000’, was sown as a winter crop under conventional tillage (CT) or no-tillage (NT) dryland systems in a randomized complete block design with split plot arrangement using four replications. Three levels of phosphorus (P; 0, 80 and 120 kg P₂O₅ ha^?1) were broadcast applied at the time of last plowing and were thoroughly mixed in subplot size of 1.8 × 5 m. About 20% less weed biomass and 2% higher grain yield was recorded under CT than in NT. Plots supplied with P₂O₅ had higher value of the all the parameters under study except number of plant m^?2 when compared with control (no P applied). However, the grain yield response to P beyond 80 kg ha^?1 was not positive. CT + 80 kg P₂O₅ ha^?1 was identified as the optimum level for maximum chickpea production under the existing dryland condition where application of herbicides in NT is not possible. Further experiments to study the optimization of P in chickpea production under dryland conditions are required.     

YIELD AND YIELD COMPONENTS OF HYBRID RICE AS INFLUENCED BY NITROGEN FERTILIZATION AT DIFFERENT ECO-SITES

Hybrid rice (Oryza sativa L.) cultivars play an important role in rice production due to its high yield potential. Optimum nitrogen (N) rate is necessary to achieve the maximum yield of hybrid. The main objective of this study was to reveal the responses of yield and yield component of hybrid rice ‘Eryou 107’ to different N rates in Nanjing and Taoyuan, a special eco-site. Leaf area index (LAI), dry matter accumulation was also compared. Rice yield showed a quadratic response to N rates at both sites with maximum yields approximately 10 t ha^?1 at the 195 kg ha^?1 N rate in Nanjing and maximum yield above 18 t ha^?1 at the 375 kg ha^?1 N rate in Taoyuan. Panicle per m² was positively linear related to N rate at both sites in both years, while spikelets per panicle showed a quadratic relation. Larger sink size was the primary contributor to higher yields in Taoyuan compared with Nanjing, and panicle per m² was the main cause. With the increasing N rate, LAI increased linearly and the dry matter accumulation first increased than declined at both sites. Greater effects of N rates on yield and yield components, LAI, and biomass was observed in Taoyuan than Nanjing. Higher LAI, biomass, and larger sink size resulted in the higher yields and more N rate for maximum yields in Taoyuan, compared with Nanjing.     

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.     

津郊潮土磷素组成及其演变规律的定位研究

本文从１９７９－１９９３年研究了长期定位施肥对津郊潮土磷素组成及其演变规律的影响。结果表明潮土磷手组成以无机磷为主，其中又以磷酸钙盐最多，其次是闭蓄态磷酸盐，而磷酸铝盐与铁盐所占比例很少。长期定位施肥对潮土速磷影响显著，变幅也最大，并以化肥的影响高于有机肥。     

NUTRIENT UPTAKE,SOIL AND PLANT NUTRIENT CONTENTS,AND YIELD COMPONENTS OF WHEAT PLANTS UNDER DIFFERENT PLANTING SYSTEMS AND VARIOUS IRRIGATION FREQUENCIES

The effects of seed bed shaping on nutrient variation in soil and plant under two different irrigation intervals were investigated on wheat (Triticum asetivum L.) plants with a split plot design in a field plot in Zahak Agricultural Research Station in Sistan province in 2005. Irrigations after 80 and 160 mm evaporation from class A evaporation pan were used as main plots. Flat surface irrigation, single, triple, and 6-row beds with four replications were subplots. Total soil nitrogen (N), available phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sodium (Na) were measured in a 30 cm depth top layer at five sampling times. Shoot samples were analyzed for N, P, K, Ca, Mg and Na. Results showed that the 3-row and the 6-row beds with more frequent irrigation (shorter irrigation interval) increased soil solution sodium content in beds resulting in increased plant sodium absorption. With the 3-row and the 6-row beds, increased solution sodium concentration in soil increased solution ionic strength, dissolution of lime and hence soluble Ca and Mg. With the more frequent irrigation (shorter irrigation interval), only grain nitrogen and sodium contents were increased with no change in the absorption of other nutrients. The shoot N, P, and K uptake with more frequent irrigation (shorter irrigation interval) was greater, however the grain P and K uptakes were similar with the less frequent irrigation (longer irrigation interval), suggesting a lack of transfer from other tissues to grain. The transfer of nitrogen and all other major elements from other tissues to grain was greatest with single row bed with both irrigation intervals, suggesting grain yield might not have been affected by a greater N, P and K fertilizer application. A key to grain yield increase with a more frequent irrigation (shorter irrigation interval) might be using a limiting micronutrient, effective in major nutrients transfer to grain from the other plant tissues or a bed shaping method enhancing its uptake.     

砂土供磷特性及磷肥效应研究

砂土供磷特性及磷肥效应的研究结果表明，砂土磷素形态以无机磷为主，有机磷甚少，仅占全磷含量的８．８４％。无机磷占９１．１５％，无机磷形态组成以磷酸钙为主，Ｃａ－Ｐ平均为无机磷总量的８６．１％，Ｏ－Ｐ占９．６％，Ａｌ－Ｐ占３％，Ｆｅ－Ｐ占１．３％。各种形态无机磷与速效磷的关系为：ｙ（速效磷）＝４９．３０ｘ１（ＡＬ－Ｐ）＋２１．８５４７ｘ４（Ｃａ－Ｐ）－３．４２０９，表明Ａｌ－Ｐ、Ｃａ－Ｐ对砂土速效磷的     

水和磷互作对红壤丘岗地区旱作水稻生物量和产量的影响

通过盆栽和大田试验研究了水和磷互作对旱作水稻生物量和产量的影响。研究表明:土壤含水量和施磷量对旱作水稻生物量和产量有极显著的影响,且二者的交互作用十分明显,影响程度以籽粒> 茎>根。上壤含水量为饱和持水量的60%时对旱作水稻生物量和产量影响较大,而80%和100%时几乎没有影响。旱作水稻生物量和产量均随施磷量的增加而增加。这说明控制土壤水分为饱和持水量的80%时就能完全满足旱作水稻的生长,但要求获得较高的产量时必须注意磷肥的投入,或者采取一些凋控措施提高土壤磷的利用率。     

METABOLIC CHANGE,TILLERING AND ROOT SYSTEM OF BRACHIARIA BRIZANTHA IN RESPONSE TO PHOSPHORUS AND ZINC NUTRITION

Phosphorus (P) and zinc (Zn) availabilities are important to the nutrition of tropical forage grasses. In this manner, this study aimed to identify and quantify changes in metabolism, tillering, and root system of Brachiaria brizantha cv. ‘Marandu’ related to P and Zn availabilities. Plants of B. brizantha cv. ‘Marandu’ were grown in nutrient solution under five rates of P (0.1, 0.6, 1.1, 1.6, and 2.1 mmol L^?1) and five rates of Zn (0.00, 0.75, 1.5, 2.25, and 3.00 μmol L^?1), in a fractionated factorial. The interaction P x Zn rates and the Zn supply were not significant for the activity of acid phosphatase enzyme, P-use index, number of tillers, and root parameters. P-use index and enzyme activity decreased as P availability increased. The high efficiency in P use was a result of high acid phosphatase activity and P supply was essential to the development of ‘Marandu’ palisadegrass root system.     

有机-无机肥配施的增产效应及对土壤肥力影响的定位研究

本文根据１３年的研究资料，较系统的阐述了不同量有机肥与氮、磷化肥配合施用，及关中灌区两熟制粮食产量、土壤肥力和养分平衡的影响。     

RESPONSE OF FRIJOLILLO RHYNCHOSIA MINIMA (L) DC. TO SUPPLEMENTARY PHOSPHORUS WITH THREE SOIL MOISTURE CONDITIONS: I. GROWTH AND DEVELOPMENT

This study was undertaken with the objective of evaluating the response of frijolillo, grown with three levels of soil moisture and supplemented with phosphorous (P). The experiment was carried out under greenhouse conditions without climate control. Plants were tested during the period from germination to vegetative growth stage. Three soil moisture levels (100, 50, and 25% of field capacity) combined with four levels of P (0, 50, 100, and 150 mg kg^?1) were tested in a factorial arrangement with four replications. This species showed tolerance to drought stress since its leaf area, dry mass of stems and root mass did not decrease with 50% of constant moisture. Furthermore, with the highest concentrations of phosphorous (100 and 150 mg kg^?1) there was more aerial mass accumulation. Finally, with maximum drought stress (25% moisture) growth of main stem decreased. However, root growth had a maximum length under the lowest moisture conditions.     

RESPONSE OF FRIJOLILLO RHYNCHOSIA MINIMA (L) DC. TO SUPPLEMENTARY PHOSPHORUS WITH THREE SOIL MOISTURE CONDITIONS: II. SOLUTE ACCUMULATION

The objective of this study was to evaluate the effects of induced drought conditions and phosphorous (P) application on osmotic adjustment as reflected in the accumulation of organic solutes in the leaves of frijolillo. The experiment took place under greenhouse conditions without climate control. Plastic containers were used measuring 20 cm high × 15 cm in diameter. In each container, five plants were evaluated from emergence to vegetative growth phase. Three soil moisture regimes were evaluated (25%, 50%, and 100% of field capacity) combined with four concentrations of phosphorous (0, 50,100 and 150 mg kg^?1 of soil). A completely randomized block design with a factorial arrangement of 3×4 with four replications was used. The cellular osmotic adjustment as a response to drought stress in frijolillo was associated with the accumulation of sugars, amino acids and proline in that higher concentrations than the control were measured with moisture at 25%. Concentrations of chlorophyll and carotene increased as soil moisture levels decreased.     

基本苗数和底追肥比例对冬小麦籽粒产量和蛋白质组分的影响

以中任1号小麦为试验材料,采用二因素随机区组设计,研究了基本苗和氮肥施用策略对小麦植株性状、产量和蛋白质组分的影响。结果表明,不同基本苗数和氮肥底/追比例的处理间株高、穗长、产量、千粒重、容重均有显著差异。穗长与穗粒数呈极显著正相关(r=0.931**)。随基本苗增加,穗长、穗粒数和千粒重逐渐减少,处理间差异显著。容重有随基本苗增加而升高的趋势。对产量而言,基本苗以450万/hm2时较高,但与300万/hm2和375万/hm2基本苗处理间的产量差异不显著,因此,生产中在偏晚的播期内,可以根据实际播种时间和地力条件,在300~450万/hm2基本苗范围内进行调整。不同蛋白组分对基本苗处理的反应有别,在基本苗较少时清蛋白和球蛋白含量较低,而谷蛋白和总蛋白含量较高。清蛋白、球蛋白、醇溶蛋白在各追肥比例处理间差异不显著,谷蛋白和总蛋白含量处理间差异显著,且均以底追比例3∶7的处理含量最高。总蛋白含量有随追肥比例增加而提高的趋势。