Influence of indigenous inputs on the properties of old alluvial soil in a mustard cropping system

Field experiments were conducted at the Crop Research and Seed Multiplication Farm of Burdwan University, Burdwan, West Bengal, India, to evaluate the influence of integrated nutrient management on soil physicochemical properties in a mustard (Brassica campestris cv. ‘B9’) cropping system. The experiment was conducted during the winter seasons of 2011–2012 and 2012–2013 in old alluvial soil (pH 6–7). Seven different doses of biofertilizers (Azotobacter and phosphate solubilizing bacteria (PSB)), vermicomposts, organic (cow dung), and chemical fertilizers were applied on mustard in both the experimental seasons. The results indicated an improvement in soil quality by increasing soil porosity and water holding capacity significantly, as well as gradual build-up of the soil micronutrient status after harvesting of the crop. Dual applications of biofertilizers and vermicomposts have contributed significantly to higher soil organic matter, available nitrogen (N), phosphorus (P), and potassium (K) contents as well as micronutrient availability of iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu) and subsequently increased the soil health.     

Evaluating the effectiveness of biofertilizer on salt tolerance of cotton (Gossypium hirsutum L.)

In the present study, the effectiveness of biofertilizer containing plant growth promoting rhizobacteria was evaluated on growth and physiology of cotton under saline conditions. Cotton plants were exposed to different levels of NPK (50%, 75%, and 100% of recommended levels) along with coating with biofertilizer under saline (15 dS m^?1) and non-saline conditions. It was observed that the biofertilizer seed coating improved growth, physiological (relative water content and chlorophyll content index), and ionic (K⁺/Na⁺) characteristics under saline and non-saline conditions. However, shoot growth (shoot fresh and dry weight) and leaf gas exchange characteristics (CO₂ assimilation rate, A; intercellular CO₂ concentration, C_i; transpiration rate, E; stomatal conductance, g_s) were decreased by biofertilizer coating under saline condition. Increasing levels of NPK fertilizer increased shoot growth, whereas root growth was maximum at 75% NPK level under saline conditions. The results of the study indicate that the biofertilizer application was very effective for cotton plant in non-saline conditions but not very effective in saline conditions.     

Performance of wheat (Triticum aestivum) to incorporation of organic manure and bioinoculants

A field experiment was conducted to evaluate the effect of integrated use of farmyard manure and bio-inoculants on wheat productivity for two years in succession. Increasing levels of farmyard manure (FYM) up to 15 t ha^?1 significantly (p ≤ 0.05) improved the dry matter accumulation, effective tillers per m row length, and grain weight per spike in both the years. Application of 15 t ha^?1 FYM caused significant increase in spikelets per spike and grains per spike over control and 5 t ha^?1 during two consecutive years. Inoculation with MSX-9 strain of Azotobacter chroococcum produced significantly higher dry matter accumulation to 25.63, 13.33, 7.78 and 23.66, 8.35, 5.50% over uninoculation, Azospirillum brasilense (SP-7) and Azospirillum lipoferum (A-5) at harvest during 1999–2000 and 2000–2001, respectively. Incorporation of 15 t ha^?1 FYM significantly (p ≤ 0.05) enhanced grain and straw yield to 62.45 and 38.05%; 56.66 and 36.28%; 59.42 and 37.52% over control in 1999–2000, 2000–2001 and pooled analysis, respectively. The grain and straw yield of wheat significantly (p ≤ 0.05) enhanced to 26.51, 10.10, 7.54 and 14.45, 5.77, 3.16% through A. chroococcum (MSX-9), A. brasilense (SP-7) and A. lipoferum (A-5) over uninoculation.     

Harnessing Plant Growth Promoting Rhizobacteria Beyond Nature: A Review

Root-associated plant growth promoting rhizobacteria (PGPR) interact with the plant roots and influence plant health and soil fertility. Plant growth promoting rhizobacteria play an important role in plant growth by exerting various mechanisms such as biological nitrogen fixation, growth hormone production, phosphate solubilization, siderophore production, hydrolytic enzyme production, antagonistic activity against fungal pathogens etc. Hence, these are employed as inoculants for biofertilizer and biocontrol activities. This review summarizes various mechanisms of PGPR and their potential for use as inoculants. It shows that their use is a worthwhile approach for exploring disease management in conjunction with other strategies.     

PGPR菌肥对燕麦根系性状影响的研究

利用从牧草根际筛选的优良促生菌株制作溶磷,固氮及复合PGPR菌肥,并在燕麦上进行PGPR菌肥对燕麦根系影响的测定。结果表明,不同PGPR菌肥及其与化肥组合处理水平对燕麦根系性状的影响不同。其中PGPR菌肥+半量化肥处理下,不同生育期燕麦主根长,根体积和根系干重均明显高出对照(CK0),且在拔节期和抽穗期效果更为显著,与单独使用PGPR菌肥差异显著。     

解淀粉芽孢杆菌菌剂对雪菜生长和土壤氧化亚氮排放的影响

由于化肥的过度使用对环境的不利影响,微生物肥料的研究得到了广泛关注。实验利用甘薯淀粉废水培养解淀粉芽孢杆菌并将其作为微生物肥料用于雪菜种植。通过盆栽实验考察了尿素(CN)、解淀粉芽孢杆菌菌液(BF)、解淀粉芽孢杆菌灭活菌液(BI)、甘薯淀粉废水(SW)、尿素结合微生物肥料(BC)对蔬菜产量、NO3-、NO2-含量,以及土壤性状,N2O排放的影响。实验表明:BC和CN在蔬菜产量方面比CK提高了5倍。BF和SW对蔬菜产量影响不显著。半量氮肥配合菌肥处理(BCL)表现出与CN相近的增产效果,而蔬菜NO3-含量同CN处理相比下降了16.4%~73.6%,土壤NO3-含量降低了22%~29%,降低了土壤中氮淋溶风险;土壤N2O平均排放通量(FLUX30)较CN处理降低了58.3%~73.1%。综上,利用淀粉废水培养解淀粉芽孢杆菌不仅可以资源化利用废水,并且其产物可作为一种绿色肥料应用于蔬菜种植,为淀粉废水资源化利用和农田温室气体减排提供了一个新思路。     

生物肥料研究和应用中存在的问题和对策

我国生物肥料研究和应用中存在着基础研究落后于生产实践、菌种退化现象严重等主要问题,生物肥料的发展应在研究适合我国不同地域条件的系列菌种筛选和基础科研方面下大力气,为生物肥料推广应用提供理论依据。     

PGPR菌肥制作及其对燕麦生长和品质影响的研究

利用从牧草根际筛选的优良促生菌株制作PGPR菌肥,并进行田间完全区组随机试验,研究其对燕麦生长和品质的影响。结果表明,本试验研制的PGPR菌肥最好在4个月内使用,液态复合菌肥肥效不如固态复合菌肥。单施PGPR菌肥或PGPR菌肥 半量化肥处理下,燕麦株高、地上植物量、地下植物量、粗蛋白、粗脂肪含量均显著高于CK0,NDF和ADF含量则明显低于CK0。施用固氮(或溶磷)菌肥 半量化肥,各生育期燕麦株高、地上植物量及地下植物量与各全量化肥处理相比无显著差异。单施固氮菌肥或施用固氮(或溶磷)菌肥 半量化肥,能显著提高各生育期燕麦粗蛋白含量。溶磷(或复合)菌肥 半量化肥处理下,燕麦粗脂肪含量显著提高。PGPR菌肥 半量化肥处理,能显著降低燕麦NDF和ADF含量。     

城市生活污泥生物肥的肥效初试

通过污泥生物肥在番茄、大白菜及黄瓜上试验应用，结果表明，适量施用污泥生物肥使番茄增产 12.37％；大白菜增产 12.58％；黄瓜苗期的生长势、株高等都明显优于对照，苗高增加 9.96％，干、鲜重分别增加 23.85％， 29.31％。证明污泥生物肥对促进作物生长和增产效果明显。     

化肥减量配施菌草固氮菌肥对巨菌草生长、营养品质及土壤养分的影响

生物肥料替代部分化肥在植物种植中发挥了重要作用。利用从巨菌草根部筛选的优良内生固氮菌株制作菌草固氮菌肥,并进行田间随机完全区组试验,设不施肥（空白对照,CK₀）,灭菌的菌草固氮菌肥（基质对照,CK₁）,全量化肥（FHF）,菌草固氮菌肥（T₁）,菌草固氮菌肥+75%化肥（T₂）共5个处理,研究其对巨菌草生长、产量、营养品质及土壤理化性质的影响。结果表明：与不施肥相比,只施菌草固氮菌肥和菌草固氮菌肥+75%化肥处理均能显著促进巨菌草生长,提高其产量,改善巨菌草品质和土壤理化性质;与只施化肥相比,只施菌草固氮菌肥处理在不同程度上降低了巨菌草产量、粗纤维、木质素、粗灰分含量和土壤碱解氮、速效磷、速效钾、有机质含量;而菌草固氮菌肥+75%化肥处理下,巨菌草叶片数、分蘖数、粗蛋白、粗纤维、酸性洗涤纤维、木质素、粗灰分含量均显著高于只施化肥处理,巨菌草产量、株高、粗脂肪含量和土壤碱解氮、速效磷、速效钾、有机质含量比只施化肥高但差异不显著,中性洗涤纤维含量则低于只施化肥处理。因此,适当减施化肥配施菌草固氮菌肥（化肥菌草固氮菌肥+75%化肥）在稳定巨菌草产量的同时,也能够在一定程度上促进其生长,改善其营养品质和土壤理化性质。