Mussoorrie rock phosphate-pyrite mixture as phosphate fertilizer

Mussoorrie rock phosphate (MRP), MRP + pyrite (25% by weight), diammonium phosphate (DAP), ammonium polyphosphate (APP) and nitrophosphate (NP) were compared in a field experiment as fertilizers for wheat. At 20 kg P ha^–1, MRP was only 6 per cent as effective as DAP. However, when it was mixed with pyrite, the efficiency of MRP increased to 64 per cent at 20 kg P ha^–1 compared with 97 per cent at 40 kg P ha^–1. The P requirement for a targeted yield for 4.5 t ha^–1 decreased from 39.4 kg P ha^–1 as MRP to 23.7 kg P ha^–1 as MRP + pyrite. Of the other P fertilizers studied, NP was as effective as DAP, whereas APP was 9 to 37 per cent more effective than DAP. However, the P requirement as DAP, NP and APP for a targeted yield of 4.5 t ha^–1 was similar (11 ± 0.5 kg P ha^–1).     

高产小麦磷钾效应和适宜氮磷钾配比研究

黄泛冲积石灰性土壤在适宜施氮水平下磷钾不同用量及配比对小麦生长的影响表现为:(1)磷肥以中量施用水平(每公顷施用P2O5120kg)增产效果最好,分别比未施磷、低量施用水平(每公顷用P2O548kg)增产30.82%、20.27%,高量施用水平(每公顷施用P2O5192kg),虽然比中量施用水平表现出增产,但增产幅度很小,只有2.85%;(2)钾肥对小麦的增产效应小于磷肥,只有在施用磷肥的基础上配施钾肥,才能使钾的效应得到充分发挥;(3)小麦全生育期氮磷钾施用比例1∶0.5∶0.5为最佳,每公顷施用N240kg、P2O5120kg、K2O120kg效益最高。     

Integrated fertilizer requirements of groundnut-wheat cropping system

Investigations were carried out in a long term field experiment from 1976 to 1982, on a loamy sand soil to find out the fertilizer requirements of groundnut and wheat grown in fixed rotation. Application of 26 kgP/ha to wheat alone was found to be sufficient for both wheat and succeeding groundnut. Application of phosphorus to both wheat and groundnut did not result in extra beneficial effect over P application to wheat alone. However, application of 26 kg P/ha to groundnut alone was not sufficient for succeeding wheat. There was no response from K application (25 kg K/ha) in either of these two crops. Increasing the dose of N from 50–150 kg/ha to wheat significantly increased the grain yield of wheat but the pod yield of succeeding groundnut were markedly lowered. Response of wheat to 150 kg N/ha was more marked when P was also applied to wheat and response was less when P was applied to preceding groundnut alone. Zinc application at 6.25 kg/ha to wheat alone resulted in significant increase in grain yield of wheat and pod yield of succeeding groundnut.     

麦田草害及其化学防除

麦田杂草不仅种类多而且适应性广，抗逆性强，严重威胁着大，小麦生产。麦田化学除草，首先要正确选用对口除草剂品种，提高整地和施药质量。     

Phosphate sorption approach for determining phosphorus requirements of wheat in calcareous soils

Five field experiments involving P application rates from 0 to 66 kg P ha^–1 were conducted on irrigated wheat at Tandojam, Pakistan. The soils belonged to two great soil groups, Torrifluvent and Camborthid. All soils were calcareous. Olsen-P contents ranged from 3.5 to 6.3 mg P kg^–1. Phosphate sorption curves were developed for soils from control (no P) plots at each site. Concentrations of P in solution established by fertilization in the field as estimated from the sorption curves ranged from 0.008 to 0.16mg P L^–1. Actual grain yields were converted to relative grain yields and plotted against corresponding concentrations of P in solution. Yield response to P application was obtained in each experiment. Control plot yields ranged from 57 to 89% of maximum yield of respective experiments. Phosphorus requirements of wheat were 0.032 mg L^–1 for 95% yield as determined from a composite yield response curve. Predicted quantities of P required to attain 0.032 mg P L^–1 ranged from 18 to 29 kg P ha^–1. The results of the study suggest that the P sorption approach can be used as a rational basis for making P fertilizer recommendations for various soil-crop combinations.     

Use of a sex attractant and an inhibitor for monitoring winter moth and bruce spanworm populations

A single sex pherormone component was isolated from abdominal tip extracts of female Bruce spanworm.Operophtera bruceata (Hulst). This was identified as (Z,Z,Z)-1,3,6,9-nonadecatetraene by capillary gas chromatography (GC), electroantennography, and mass spectrometry. In addition, hexane extracts of female abdominal tips from Bruce spanworm and the winter moth.O. brumata L., were analyzed by GC coupled to an electroantennographic detector (GC-EAD). The extracts ofO. bruceata andO. brumata females elicited only a single response, at the same retention time, from antennae of their conspecific and reciprocal males. In field tests conducted in Saskatchewan, traps baited with the synthetic tetraene captured Bruce spanworm males. In tests carried out on Vancouver Island, British Columbia, where the two species coexist, both Bruce spanworm and winter moth males were captured. The attractancy of lures containing the synthetic pheromone alone and in combination with several structurally related analogs was field tested at both locations. One of these, an isomer of the natural pheromone, (E,Z,Z)-1,3,6,9-nonadecatetraene, inhibited the capture of Bruce spanworm males but had no effect upon the number of winter moth males which were taken. Thus, populations of these two very similar species can be distinguished by employing traps baited with pheromone ± the inhibitor. Coneorifice Hara traps were found useful for field trapping males of both species.Issued as NRCC No. 26107     

The role of manganese and nitrogen nutrition in the susceptibility of wheat plants to take-all in Western Australia

Five field experiments are described which measured the effect of take-all on grain yield of wheat when 5 levels of manganese fertilizer were applied in a factorial combination with 5 different types of nitrogen fertilizer.Ammonium nitrogen fertilizer, either as ammonium sulphate or ammonium chloride, lowered the severity of take-all. By contrast, sodium nitrate had no effect on the incidence and severity of take-all. Ammonium chloride and ammonium sulphate were equally effective at controlling take-all, suggesting that the chloride or sulphate ion had little or no effect on the disease.Manganese sulphate decreased take-all severity at two trial sites. Where manganese was deficient, an application of manganese lowered the severity of take-all, had no effect on the incidence and increased the dry matter and grain yields of the wheat plants. There were no beneficial effects of applied manganese if the wheat plants were adequately supplied with soil manganese.The results suggest that take-all is more severe where plants are deficient in either manganese or nitrogen. The work also suggests that manganese deficiency is not necessarily the reason why the wheat plants grown on the acid soils of south-west Western Australia are prone to take-all.     

夏热冬冷地区热环境下城市设计策略初探

从夏热冬冷地区热环境出发,引入熵的概念,对城市空间类型进行新的划分,研究不同空间类型下城市设计的设计要点,从热平衡角度出发,改善城市热环境,探讨适合夏热冬冷地区热环境下的城市设计策略。     

夏热冬冷地区住宅建筑节能改造技术研究

为解决夏热冬冷地区既有住宅建筑能耗较大问题,对本地区气候特征、现有围护结构热工性能进行了测试分析和研究,提供了夏热冬冷地区既有住宅建筑节能改造技术措施,为解决夏热冬冷地区住宅节能改造技术提供了重要依据.     

Cr3+、Pb2+单一及复合胁迫对小麦种子萌发及幼苗脯氨酸含量的影响

研究在污染条件下小麦对重金属胁迫的反应,为农业生产中早期诊断重金属污染提供一些依据。用Cr3+、Pb2+及Cr3+、Pb2+混合溶液的各种浓度溶液处理小麦,研究Cr3+、Pb2+及Cr3+、Pb2+混合溶液对小麦萌发和脯氨酸含量的影响。结果表明:在Pb2+的培养环境中,各个浓度下的发芽率相差不多;在Cr3+的培养环境中,小麦的发芽率随着浓度的增加呈下降趋势,浓度越大对小麦发芽率的抑制作用越明显;在Cr3+、Pb2+混合的培养环境中,各个浓度下的发芽率随浓度的增加而呈降低的趋势,并且各个浓度下发芽率基本都相对低于相同浓度下的单一Cr3+、Pb2+的发芽率。在低浓度的重金属离子中,游离脯氨酸的含量与重金属离子浓度呈正相关。