Improvement of the soil fertility of a volcanic indurate layer (Tepetate) by applying acid treated biosolids
Volcanic indurate matter produces low soil fertility when rises to the surface, reducing the agricultural potential of the land and distressing marginal zones that live from agriculture. The habilitation of these materials using biosolids has not been explored, although the problem exists in several countries around the world. This work evaluated the impact of the application of biosolids on the fertility of a fragmented volcanic indurate layer (Tepetate). Tepetate’s fertility was measured before and after biosolids application with three biosolids application rates: agronomic rate (AR), as well as 10 and 20xAR. Biosolids were mixed with Tepetate and kept in pots under green house conditions along with a control, during four months. One set of pots with and without vegetative species. Organic matter content increased between 180 and 470% compared to the control. Cation exchange capacity (21.8 to 42.3 Cmol+kg-) resulted adequate for keeping nutrients for plants. pH values were adequate for agricultural activities (5.9-7.2). Dry color of the Tepetate, becomes darker (grayish brown; 10YR 5/2) than the initial yellowish brown (10YR 5/4) because of the addition of stable organic matter from biosolids. Considering edaphologic characteristics it is suitable to habilitate volcanic indurate layer by the application of biosolids.
LAND DEGRADATION IN THE DEVELOPING WORLD: ISSUES AND POLICY OPTIONS FOR 2020
Land degradation takes a number of forms, including depletion of soil nutrients, salinization, agrochemical pollution, soil erosion, vegetative degradation as a result of overgrazing, and the cutting of forests for farmland. All of these types of degradation cause a decline in the productive capacity of the land, reducing potential yields. Farmers may need to use more inputs such as fertilizer or manure in order to maintain yields, or they may temporarily or permanently abandon some plots. Degradation may also induce farmers to convert land to lower-value uses. For example, farmers may plant cassava, which demands few nutrients, instead of maize, or convert cropland to grazing land.
The role of microorganisms in aggregate formation and soil stabilization: Types of aggregation
Abstract Soil biota and the presence of organic matter are the major factors for developing soil structure in sandy soils. Three types of aggregates were observed in sand dunes: (1) microbial aggregates, 1–12 mm in diameter, formed by the action of bacteria, actinomycetes, and fungi, (2) root‐microbial aggregates, formed by microorganisms in conjunction with root exudates and root structural components, and (3) debris‐microbial aggregates, up to 6 mm in diameter, formed during decomposition of macroscopic plant debris. In maritime sand dunes the aggregates contributed up to 0.4% of total bulk soil weight. The VAM fungal hyphae participated in aggregate formation, and the presence of cyanobacteria in aggregates indicated their contribution to nitrogen cycling. Inocculation of dune sand with fungi and bacteria in addition to soluble organic matter improved soil structure and plant growth. The results indicated that soil microflora could be used as a tool for improving soil structure with a subsequently impr...