STUDIES ON DIFFERENTIAL RESPONSE OF SPRING CANOLA CULTIVARS TO BORON TOXICITY

Although many states recommend boron (B) fertilizer for many field crops, information about B toxicity of canola is lacking. This experiment was carried out at Central Anatolia, Turkey from 2002 to 2003, to determine genotypic range in B efficiency of eight spring canola cultivars, to identify the B-inefficient cultivars and to identify specific responses. The cultivars were grown under B moderate deficiency (extractable B 0.56 mg kg^?1) and toxic B applied (15 kg B ha^?1) conditions. According to the results, seed yield varied significantly among the cultivars and B application decreased the seed yield by 31% on average. Also, toxic B application reduced protein and oil contents similar to seed yield, and increased leaf B concentration in all varieties. This study has shown that leaf B concentration has increased considerably when B is applied to Pactol and Star cultivars, but seed yield of +B and ?B has not shown significantly a change. It is possible to say that Star and Pactol—which have not been affected by the toxic B application—are genotypes that are tolerant to B toxicity and may be cultivated at B toxic lands.     

RESPONSE OF SOYBEAN TO SOIL APPLIED SULFUR AND BORON IN A CALCAREOUS SOIL

A greenhouse experiment with soybean grown on sulfur (S) and boron (B) deficient calcareous soil was conducted for two years in northwest India to study the influence of increasing sulfur and boron levels on yield and its attributing characters at different growth stages (55 days, maturity). The treatments included four levels each of soil applied sulfur viz. 0, 6.5, 13.4, 20.1 mg S kg^?1 and boron viz. 0, 0.22, 0.44, 0.88 mg B kg^?1 at the time of sowing. The highest dry matter yield at 55 days after sowing, DAS (19.3 g pot^?1) and maturity (straw yield ?25.2 g pot^?1 and grain yield ?7.3 g pot^?1) was recorded with B_0.44 S_13.4 treatment combination. The combined applications of sulfur and boron yielded highest oil content with B_0.44S_13.4 (21.7%) treatment level. Chlorophyll ‘a’ and ‘b’ increased significantly with successive levels of sulfur and boron addition at 55 DAS. The mean sulfur and boron uptake in straw and grains increased significantly with increasing levels of sulfur and boron up to 13.4 mg kg^?1 and 0.44 mg kg^?1 and decreased non-significantly thereafter. At both the growth stages, a synergistic interactive effect of combined application of sulfur and boron was observed with B_0.44 S_13.4 treatment level for sulfur and boron uptake in straw and grains.     

ROLE OF BORON IN LEAF ELONGATION AND TILLERING DYNAMICS IN FINE-GRAIN AROMATIC RICE

This study was conducted to explore the role of boron (B) in seedling emergence, leaf elongation, and tillering dynamics. Boron was applied as seed priming. For priming seeds of two rice cultivars (Super Basmati and Shaheen Basmati) were soaked in B solutions having 0.001, 0.01, 0.1 and 0.5% concentrations. Substantial improvement in seedling emergence was observed from hydropriming and seed priming in 0.001 and 0.01% solutions; beyond this B concentration, emergence potential was suppressed. Seeds primed in 0.5% B solution even did not emerge. A linear increase in plant height was recorded up to 30 days from seeds primed in 0.001% solution. Similarly rate of leaf emergence and elongation and rate of tiller appearance were substantially improved in seedlings raised from seeds primed in 0.001% B solution. Overall B plays a significant role in leaf appearance, elongation and tillering dynamics of rice when used in very low concentration.     

BORON NUTRITION OF PEANUT GROWN IN BORON-DEFICIENT CALCAREOUS SOILS: GENOTYPIC VARIATION AND PROPOSED DIAGNOSTIC CRITERIA

Field studies were conducted to assess boron (B) requirement, critical concentrations in diagnostic parts based on yield response curves and genotypic variation by growing three peanut (Arachis hypogaea L.) cultivars (‘Golden’, ‘BARD-479’, ‘BARI-2000’) on two B-deficient calcareous soils. Boron application significantly increased pod yield of all the cultivars over control. Maximum pod yield increases were: ‘Golden’, 16?23%; ‘BARD-479’, 21?27%; and ‘BARI-2000’, 25?31%. The cultivars varied in B efficiency and cv. ‘Golden’ was the most B efficient (81?86%) while cv. ‘BARI-2000’ was the least efficient (76?80%). Boron requirements for near-maximum (95%) dry pod yield were 0.65 kg ha^?1 for ‘Golden’, 0.75 kg ha^?1 for BARD-479 and 0.80 kg ha^?1 for BARI-2000. Critical B concentrations in shoots and seeds were: ‘Golden’, 33 mg kg^?1 and 26 mg kg^?1; ‘BARD-479’, 38 mg kg^?1 and 31 mg kg^?1; and ‘BARI-2000’, 42 mg kg^?1 and 33 mg kg^?1.     

OXIDATIVE STRESS AND ANTIOXIDANTS IN COWPEA PLANTS SUBJECTED TO BORON AND HIGH IRRADIANCE STRESSES

The effects of boron (B) and high irradiance (HI) on the growth and activities of antioxidant enzymes have been investigated in cowpea plants (Vigna unguiculata L. Walp. ‘P152’). A significant decrease in root and shoot lengths were observed in B-deficient (0 ppm) and B-excess (50 ppm) plants compared to B-sufficient (0.5 ppm) plants. Under B and B + HI stress, significant increase in membrane permeability (EC), lipid peroxidation (MDA) and hydrogen peroxide (H₂O₂) were observed in B-deficient and B-excess leaves. Under B and B + HI stress, the superoxide dismutase (SOD) activity was found to be significantly high whereas the peroxidase (POX), polyphenol oxidase (PPO) activities and the non-enzymatic antioxidants, ascorbic acid and proline accumulation were found to be significantly decreased in B-deficient and B-excess leaves which showed the B inefficiency and susceptible nature of the cowpea plants to B and B + HI stress.     

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.     

矮壮素对马铃薯磷素营养动态变化和产量的影响

通过对生育前期的马铃薯品种"中薯3号"喷施浓度为0、1.5、2.0和2.5g/L矮壮素(chlorocholine chloride,CCC)后,应用32P示踪技术研究其对磷素营养及其平均每穴产量的影响。结果表明:在各出苗后天数,CCC增加了植株对磷素的吸收,植株中的磷素主要分配到地上茎和叶中,按其相对含磷量依次为地上茎>叶>根>地下茎;植株吸磷量随其生长而增加,但在生育后期总株的吸磷量减少;在各出苗后天数,2.0g/L处理对中薯3号的总株吸磷量增加最大;1.5、2.0、2.5g/LCCC处理使中薯3号平均每穴产量分别增加6.83%、10.10%和3.08%,各处理平均每穴产量与其出苗后36d的叶片含磷量成极显著性正相关。     

A NEW STRATEGY TO ENRICH CALCIUM NUTRITION OF FRUIT: SYNERGISTIC EFFECTS OF POSTHARVEST FOLIAR CALCIUM AND BORON SPRAYS

The objective of the study is to investigate the role of calcium (Ca) and boron (B) synergy in higher maintenance of Ca in fruit buds during senescence. To study the hypothesis, an experiment was conducted for two years in two ‘Starking Delicious’ apple (Malus domastica Borkh.) orchards established on seedling rootstocks in Banaz, Usak, Turkey. Treatments composed of postharvest foliar sprays of Ca at rate of 15.13 kg h^?1, B at rate of 2.47 kg h^?1 and their combination (Ca+B) compared with control trees sprayed with water. Fruiting spurs, flower ovaries, young and mature fruits were sampled and analyzed for their Ca, B, potassium (K) and magnesium (Mg) contents. Fruit were stored for six months and quality attributes were studied. Results put forth that Ca+B treatments significantly increase fruit Ca and B concentrations and firmness. The results displayed that postharvest B spray improves Ca nutrition of fruits through synergism of Ca+B on Ca translocation.     

ARBUSCULAR MYCORRHIZAL COLONIZATION DOES NOT ALLEVIATE SODIUM CHLORIDE-SALINITY STRESS IN VINCA [CATHARANTHUS ROSEUS (L.) G. DON]

We conducted a study to determine if inoculation with arbuscular mycorrhizal fungi (AMF) would enhance the tolerance of vinca [Catharanthus roseus (L.) G. Don] plants to sodium chloride (NaCl)-induced salinity in irrigation water. Vinca tolerated salinity levels up to 40 mM. Chlorophyll concentration, proline synthesis, and total antioxidant activity were increased with saline irrigation, while leaf potassium (K), calcium (Ca), magnesium (Mg), iron (Fe), and boron (B) content decreased, suggesting a detrimental salinity effect. Despite the limited effect of increasing salinity on N content, NaCl-stressed vinca plants showed a marked decrease in nitrate reductase activity, which was associated with decreased leaf K and Fe total content. Mycorrhizal inoculation resulted in reduced growth when compared to non-AMF plants, regardless of salinity level. The K/sodium (Na) ratio decreased dramatically with increasing salinity regardless of AMF treatment. Suggesting, that the AMF isolate was not able to selectively uptake K and Ca, and avoid uptake of Na.     

MODULATION OF PHYSIOLOGICAL AND BIOCHEMICAL METABOLITES IN SALT STRESSED RICE BY FOLIAR APPLICATION OF ZINC

An experiment was conducted to evaluate the effect of zinc (Zn) application on five rice cultivars grown under salt stress conditions. Two salinity levels of 0 and 10 dS m^?1 were created with sodium chloride (NaCl) and foliar spray of Zn (0.05%; Chelated-Zn) was applied. A decrease in growth and yield related parameters were observed under salt stress, which was ameliorated in plants that received Zn foliar spray. Similar effects of salinity and Zn foliar spray were noted on photosynthetic rate, transpiration rate, stomatal conductance, water use efficiency, and water relations of plants. Salt induced increase in sodium (Na) content and decrease in other macro- and micronutrients contents were also reversed by Zn. Other salt tolerance indicating parameters likSe total free amino acids and total soluble sugars increased under Zn spray, clearing its role in improving salt tolerance.     

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.     

利用叶片生化性状预测不同基因型甘蔗产量和品质的研究

分别在伸长后期和工艺成熟前期取样分析了9个甘蔗基因型叶片中的10个生化性状,发现多种酶活性,蛋白质和光合色素含量等与甘蔗的经济性状有一定的联系,但只用某个生化性状预测经济性状具有较大的局限性.以10个叶片生化性状作为自变量,分别以甘蔗产量和品质性状作为依变量进行多元回归分析,能建立多个达到显著水平的多元回归模型,表明利用多个叶外生化性状对不同基因型甘蔗产量和品质进行预测是可能的.     

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.     

RESPONSE OF ALFALFA SEED YIELD AND YIELD COMPONENTS TO PHOSPHORUS FERTILIZING SYSTEMS AND SEEDING RATE AT SEMI-SALINE SOIL CONDITIONS

To study the effects of phosphorus (P) fertilizer (cow manure, phosphorus solublizing bacteria) and sowing density on seed production of alfalfa, an experiment was laid out in a three-replicated split-split plot design with four phosphorus fertilizer rates (0, 30, 60 and 90 kg ha^?1) in main plots, three phosphorus-solublizing bacteria (9, 41strains, and no bacteria) in sub-plots and three sowing densities (2, 6 and 10 kg ha^?1) in sub-sub plots. The highest seed yield resulted from 60 and 90 kg P ha^?1. Application of bacteria strain 41 was more efficient than bacteria strain 9 in seed yield and 1000-seed weight. Seed yield at 6 seed kg ha^?1 treatment was higher than 10 kg ha^?1, although there was no significant difference between them. Based on the results of this experiment the triple application of P60, B41 and SD6 could be recommended as the best treatment for seed production of alfalfa (Cultivar ‘Nikshahri’) under the semi-saline condition.     

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。     

冷处理对中国水仙鳞茎及其不定芽分化过程中生理生化代谢的影响

以2-3年生中国水仙鳞茎为材料,研究了冷处理对水仙鳞茎生理状态的影响以及不定芽分化过程生理生化代谢的变化。冷处理降低了中国水仙鳞茎的总糖、蔗糖以及淀粉含量,还原糖和可溶性蛋白含量以及POD、CAT等活性也显著升高,这些生理变化与冷处理后鳞茎盘分化所需时间缩短及分化能力增强有关;处于不同分化时期鳞茎盘的抗氧化酶活性及可溶性蛋白含量随培养时间的延长,均表现为先升高后降低的变化趋势,在接种后4-10d达到峰值,可以初步确定抗氧化酶活性和可溶性蛋白含量的规律性变化与鳞茎盘的分化相关。     

INTERACTIVE EFFECT OF SULFUR AND NITROGEN ON GROWTH AND YIELD ATTRIBUTES OF OILSEED CROPS (BRASSICA CAMPESTRIS L. AND ERUCA SATIVA MILL.) DIFFERING IN YIELD POTENTIAL

Field experiments were conducted to determine the interactive effect of sulfur (S) and nitrogen (N) on growth and yield attributes of oilseed crops [Brassica campestris L. (V₁) and Eruca sativa Mill. (V₂)] differing in yield potential. Two combinations of S and N (in kg ha^?1): 0S + 100N (?S+N;T₁) and 40S + 100N (+S+N;T₂) were used. Biomass accumulation, leaf area index (LAI), leaf area duration (LAD), and photosynthetic rate in the leaves were determined at various phenological stages. The results showed that the combined application of S and N (+S+N) significantly (P<0.05) improved the growth and yield attributes of both the genotypes compared with N applied alone (?S+N). Genetic variability was observed between the two genotypes in response to combined application of S and N (T₂). Genotype V₁ had higher biomass accumulation, photosynthetic rate, seed yield, oil yield, biological yield, and harvest index when compared with genotype V₂. Treatment T₂ resulted in 142, 95, 56, and 349% enhancement in biomass accumulation, leaf-area index (LAI), leaf-area duration (LAD) and photosynthetic rate, respectively in comparison with treatment T₁ in genotype V₁. Seed yield, oil yield, biological yield, and harvest index were improved by 141, 171, 85, and 30%, respectively, by treatment T₂ in comparison with T₁. In the case of genotype V₂, increase in biomass accumulation, LAI, LAD, and photosynthetic rate due to application of treatment T₂ were 156, 137, 125 and 467%, respectively, over the results of T₁. Seed yield, oil yield, biological yield and harvest index improved by 193, 251, 98, and 48%, respectively, with this treatment. On the basis of results obtained in this study, it can be concluded that sulfur must be included in the nutrient management package for optimum growth and yield attributes of oilseed crops. Furthermore, the yield potential of oilseed crops with low seed and oil yield can be improved using this treatment as achieved in our study in case of taramira (Eruca sativa Mill.), a genotype with low seed and oil yield.     

GROWTH,YIELD, AND ION RELATIONS OF STRAWBERRY IN RESPONSE TO IRRIGATION WITH CHLORIDE-DOMINATED WATERS

Strawberry is listed as the most salt sensitive fruit crop in comprehensive salt tolerance data bases. Recently, concerns have arisen regarding declining quality of irrigation waters available to coastal strawberry growers in southern and central California. Over time, the waters have become more saline, with increasing sodium (Na⁺) and chloride (Cl^?). Due to the apparent extreme Cl^? sensitivity of strawberry, the rising Cl^? levels in the irrigation waters are of particular importance. In order to establish the specific ion causing yield reduction in strawberry, cultivars ‘Ventana’ and ‘Camarosa’ were grown in twenty-four outdoor sand tanks at the ARS-USDA U. S. Salinity Laboratory in Riverside, CA and irrigated with waters containing a complete nutrient solution plus Cl^? salts of calcium (Ca²⁺), magnesium (Mg²⁺), Na⁺, and potassium (K⁺). Six salinity treatments were imposed with electric conductivities (EC) = 0.835, 1.05, 1.28, 1.48, 1.71, and 2.24 dS m^?1, and were replicated four times. Fresh and dry weights of ‘Camarosa’ shoots and roots were significantly higher than those of ‘Ventana’ at all salinity levels. Marketable yield of ‘Camarosa’ fruit decreased from 770 to 360 g/plant as salinity increased and was lower at all salinity levels than the yield from the less vigorous ‘Ventana’ plants. ‘Ventana’ berry yield decreased from 925 to 705 g/plant as salinity increased from 0.835 to 2.24 dS m^?1. Relative yield of ‘Camarosa’ decreased 43% for each unit increase in salinity once irrigation water salinity exceeded 0.80 dS m^?1. Relative ‘Ventana’ yield was unaffected by irrigation water salinity up to 1.71 dS m^?1, and thereafter, for each additional unit increase in salinity, yield was reduced 61%. Both cultivars appeared to possess an exclusion mechanism whereby Na⁺ was sequestered in the roots, and Na⁺ transport to blade, petiole and fruit tissues was limited. Chloride content of the plant organs increased as salinity increased to 2.24 dS m^?1 and substrate Cl increased from 0.1 to13 mmol_cL^?1. Chloride was highest in the roots, followed by the leaves, petioles and fruit. Based on plant ion relations and relative fruit yield, we determined that, over the range of salinity levels studied, specific ion toxicity exists with respect to Cl^?, rather than to Na⁺ ions, and, further, that the salt tolerance threshold is lower for ‘Camarosa’ than for ‘Ventana’.     

PHENOLOGY AND SEED QUALITY RESPONSE OF RAPE (B. NAPUS) VERSUS MUSTARD (B. JUNCEA) TO SULFUR AND POTASSIUM FERTILIZATION IN NORTHWEST PAKISTAN

Inappropriate sulfur and potassium fertilization, particularly with continued soil nutrient mining and yearly fluctuations in rainfall, are major factors contributing to slow growth and low seed quality of canola in northwestern Pakistan. A field experiment was conducted in 2007–2008 on a sulfur (S) and potassium (K) deficient clay loam soil under irrigation at the research farm of NWFP (Northwest Frontier Province) Agricultural University, Peshawar, Pakistan, with an objective to determine response of phenology and seed quality of Brassica oilseed rape versus mustard to S and K fertilizer application. Twenty treatments in a randomized complete block design were consisted of two oilseed genotypes [rape (B. napus canola) and mustard (B. juncea canola)], at three rates each of S (15, 30, and 45 kg S ha^?1) and K (30, 60, and 90 kg K ha^?1), plus control (no K and S applied). Days to flowering, pod formation, seed filling duration and maturity were enhanced with K and S fertilization compared to control plots. The species B. napus took more time to flowering, pod formation, seed filling duration and maturity compared to B. juncea. Both genotypes responded positively for seed quality (oil and protein content) to K and S fertilization, but the magnitude of response varied with level and combination of K and S fertilization. Delay in the phenological stages showed negative relationship with oil and protein content in seed of both genotypes. It is concluded that a combination of 60 kg K ha^?1 + 30 kg S ha^?1 would accelerate phenological development and improve seed quality of rape and mustard in the study area.     

不同施肥模式对水稻生理特性、产量及其N肥农学利用率的影响

以水稻品种金优207为材料,对不施氮肥(T1)、试验区当地农民习惯氮肥用量(T2:尿素,纯N187.5 kg/hm2)和在农民习惯施氮量基础上减量配施氮肥(T3:氮减少20%,30%农民习惯用化肥+20%习惯用量的有机肥+30%习惯用量的缓释肥,纯N 150kg/hm2)3种施肥模式下水稻不同生育期的生理特性、产量及其...