Influence of pH on Productivity,Nutrient Use Efficiency by Dry Bean,and Soil Phosphorus Availability in a No‐Tillage System

Abstract

Low pH is one of the most yield‐limiting factors for crop production in Cerrado soils. The objective of this study was to determine influence of soil pH on grain yield and its components, and use of nutrients by dry bean in a no‐tillage system in an Oxisol (Typic Haplorthox) of the Cerrado region of Brazil. Five field experiments were conducted for three consecutive years. The pH levels were low (5.3), medium (6.4), and high (6.8), created by applying lime at the rates of 0, 12, and 24 Mg ha^?1. Grain yield and its components were significantly influenced by soil pH. Adequate pH for grain yield and its components was 6.4. Maximum variation in grain yield was measured by shoot dry weight, and minimum variation was due to 100‐grain weight. Nutrient utilization efficiency was in the order of magnesium (Mg) > phosphorus (P) > calcium (Ca) > potassium (K) > nitrogen (N) > copper (Cu) > manganese (Mn) > zinc (Zn) > iron (Fe). Soil extractable P increased linearly with increasing pH in the range of 5.3 to 7.3. These results show that adequate soil pH is an important soil acidity index in improving bean yield in Brazilian Oxisols.     

Sewage Sludge Usage in Agriculture: a Case Study of Its Destination in the Curitiba Metropolitan Region,Paraná, Brazil

The agricultural destination of sewage sludge promotes the return of organic matter and nutrients to the soil, prevents contamination and degradation of hydric resources, and contributes to food and fiber production. In Brazil, the Resolution of the National Environment Council (Conama 375/06) and in the State of Paraná the Resolution of the State Environment Cabinet (Sema 021/09) established criteria and procedures for agricultural use of sewage sludge seeking to avoid risk to public health and the environment. This case study attempts to present the results of the destination of the sludge generated in the Sludge Management Units (SMU) in Curitiba Metropolitan Region (CMR), State of Paraná, Brazil from 2007 to 2010. Data analysis of agronomic parameters and inorganic substances (metals) of 99 batches of sewage sludge destined for agricultural use, based on 239 agronomic projects, was performed. The comparison of the characteristics of the batches generated in anaerobic and aerobic SMUs of CMR was also conducted. During the study, 88,166 t of sludge (33,404 dry tons) were destined for 2,288 ha of agricultural areas. The sludge provided 88 % of the lime, 74 % of N, 73 % of P₂O₅, and 35 % of K₂O for fertilizing the corn, soybean, bean, oat, wheat, green manure, and in the implementation and postharvest of stone fruit trees. The 80 benefited farmers reduced expenses with fertilizers and limestone, saving an average of US$813.45 per ha.     

Study on the distribution patterns of sulfate-reducing bacteria in a paddy-field soil by Iδ-index

An attempt was made to elucidate the distribution patterns of sulfate-reducing bacteria in a paddy-field soil quantitatively by the use of Morishita's Iδ-index. It was shown from the Iδ-quadrat size relations and Iδ(s)/Iδ(2s) curves that the bacterial distribution was not uniform nor random, but contagious, forming a small clump or clumps of several sizes, which were estimated to be 8 to 32 mm².     

Evaluation of Soil Fertility Quality Variation During Past 30 Years in a Major Grain-producing Region of the North China Plain——A Case Study of Yucheng County

土壤肥力质量的时空演变分析有助于了解区域土壤肥力变化情况和变化规律,对制定相应的农业管理措施,进一步提升土壤生产力,稳定粮食产量具有重要意义.本文以华北平原典型区禹城市为例,进行了土壤肥力质量时空演变分析.结果表明:自1980年以来,经过近30年的耕作和中低产田改造,禹城市土壤肥力质量显著提高,尤其在土壤肥力质量较差的区域,土壤质量捉升更显著;土壤肥力质量空间变异性减弱,土壤肥力水平趋于一致,且空间变异受自然因素的影响降低,更多的受到人为管理因素的影响.