EASY: A review of the nature, causes and possible soluti...

EASY: A review of the nature, causes and possible soluti...: Compact soil is one of the major problems facing modern agriculture. Overuse of machinery, intensive cropping, short crop rotations, ...

EASY: Understanding of crop competition in intercropping...

EASY: Understanding of crop competition in intercropping...: Intercropping is receiving increasing attention because it offers potential advantages for resource utilization, decreased inputs a...

Understanding of crop competition in intercropping system

Intercropping is receiving increasing attention because it offers potential advantages for resource utilization, decreased inputs and increased sustainability in crop production, but our understanding of the interactions among intercropped species is still very limited. Endersen et. al.(2007) conducted an experiment growing of pea Pisum sativum, barley Hordeum vulgare and rape Brassica napus as sole crops and intercrops under field conditions using a replacement design. They collected total dry matter data from sequential harvests and fitted the data to a logistic growth model. At each harvest we estimated the relative Competitive Strength (CS) of the three crops by fitting the data to a simple interspecific competition model.

The pea monocrop produced the largest amount of biomass from the middle to the end of the growth period, but pea was not dominant in intercrops. Fitting data to a logistic growth model emphasizes the importance of initial size differences for interactions among intercrops. Barley was the dominant component of the intercrops largely because of its initial size advantage. The competitive effect of barley on its companion crops, measured as CS, increased throughout most of the growing season.

The performance of each crop species was very different when it grew with a second species rather than in monoculture, but addition of a third crop species had only minor effects on behaviour of the individual crops.

A review of the nature, causes and possible solutions of soil compaction in cropping systems.

Compact soil is one of the major problems facing modern agriculture. Overuse of machinery, intensive cropping, short crop rotations, intensive grazing and inappropriate soil management leads to compaction. Soil compaction occurs in a wide range of soils and climates. It is exacerbated by low soil organic matter content and use of tillage or grazing at high soil moisture content. Soil compaction increases soil strength and decreases soil physical fertility through decreasing storage and supply of water and nutrients, which leads to additional fertilizer requirement and increasing production cost. A detrimental sequence then occurs of reduced plant growth leading to lower inputs of fresh organic matter to the soil, reduced nutrient recycling and mineralization, reduced activities of micro-organisms, and increased wear and tear on cultivation machinery. A review was conducted by Hamza & Enderson, 2005 related to soil compaction, concentrating on research that has been published in the last 15 years. They explain the nature and causes of soil compaction and the possible solutions suggested in the literature. Several approaches have been suggested to address the soil compaction problem, which should be applied according to the soil, environment and farming system.
The following practical techniques have emerged on how to avoid, delay or prevent soil compaction: (a) reducing pressure on soil either by decreasing axle load and/or increasing the contact area of wheels with the soil; (b) working soil and allowing grazing at optimal soil moisture; (c) reducing the number of passes by farm machinery and the intensity and frequency of grazing; (d) confining traffic to certain areas of the field (controlled traffic); (e) increasing soil organic matter through retention of crop and pasture residues; (f) removing soil compaction by deep ripping in the presence of an aggregating agent; (g) crop rotations that include plants with deep, strong taproots; (h) maintenance of an appropriate base saturation ratio and complete nutrition to meet crop requirements to help the soil/crop system to resist harmful external stresses.