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Chapter Fallow Effects on Soil

Debasish Borah Our experiments in the last many years have shown that organic manure was effective in increasing yields of corn, sweetpotato, and vegetables when combined with chemical fertilizers especially in low fertility soils. Fallowing consistently improved the organic carbon status of the soil.

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Article Influence of Different Organic Fertilizers on Growth and Yie...

When monoculture is practiced continually the effect is to reduce the yield potential. This is the function of nutrient depletion and biological attack from pathogens insects and weeds which develop under the monoculture fallow system.

Crop rotation and cover cropping can be employed to greatly reduce these issues.

In addition when organic materials are added they can have a positive effect on soil condition and be related to the increased ability to biologically control root pathogens and stimulate plant responses to stresses.

When a simple monoculture of maize or soybean is changed to rotation the yield of both crops are stimulated by about 20%.

Organic manures and composts provide both nutrients but also improves the soil water capture and use by adding organic matter which transforms the physical nature of the soil. In addition the organic material feeds largely beneficial soil biology which stimulates a natural biological control and stimulate plant reaction by bioregulator activity which stimulates the plant stress responses.

Use of crop rotation, cover crops, and organic amendments allow for high productivity agricultural systems which improve the soil and even the environment and can help address the issues with excess atmospheric

greenhouse gases as improved soil organic matter contents are derived from transformed GHG into plant material and then soil humus or organic matter.

In general fallow from a scientific viewpoint is less effective in address productivity issues that the other practices which are mentioned.

not necessary , thats why we often question , when should we give holiday to crop for organic manure.. may be after application of how many years??

Pathogens are usually present in manure and can survive for several months or years after being deposited on the soil. In addition, the application of these manures without composting them can contaminate the soil and crops with pathogens. Studies have shown that pathogenic bacteria such as E. coli, Salmonella, Listeria and Campylobacter can survive for more months in stored manure. After the manure was applied to the soil, these bacteria survived in the soil for up to a month after application.

In addition, successive application of manure to the soil can cause soil salinization.

Agree with K Dahdah that the utility of compost is greater than use of raw manure directly.

Composting accelerates to reduction of pathogenic bacteria and promotes a positive microflora for crop production.

In addition the stabilized carbon and nitrogen causes more long term ability to improve soils and counteract greenhouse gases.

Composting can reduce the mass while increasing the ability to manage the bulky manure. Mobilizing and transporting organic materials is an important consideration and on farm development and use can avoid much of those issues.

When soil organic matter is elevated the need to fallow soils is greatly lessened.

Cover cropping rotation and organic amendment especially are highly effective in this effort.

in Majority of cases, it increases crop yield and promote postive soil flora. However, manure should be use with caution, it can promote soil borne pathogenic diseases, and heavy metal accumulation. In some cases where SOC levels are too high it only sustain SOC and does not enhance yield. However, in soils with low organic matter, and poor water/nutrient holding capacity it definately promotes yield levels, and over the years increase in crop yield and SOC levels become much shlow with continious application of manure.

Consistent with the answer by Muhammad Ahmed Waqas It is important to keep in mind the issues such as heavy metal accumulation and pathogenic diseases while applying organic manure. The quality and quantity of OM are the most important deciding factors to enhance SOC and hence soil physicochemical properties. Moreover, soil type and soil saturation deficit further determine the response of soil to applying manure. However, all the aforementioned factors and other factors collectively contribute to enhance crop yield.

Agreed Bawa G's Muhammad Mohsin Abrar Muhammad Ahmed Waqas

Additon of organic matter will definitely influence crop growth and yield, following the principles of time, methods, quantity and quality of organic matter used.

Fallow always helps in conservation of all the essential principles for crop production.

Application of Organic manures definitely will improves physico-chemical properties, water holding capacity, regulating temperature, and maintaining long term soil productivity and fertility. Partially decomposed FYM @10 tonnes/ha has to be applied 3–4 weeks before sowing, while well-decomposed FYM should be applied 10-15 days before sowing for maintaining soil fertility.

Fallow have positive effect on improving organic carbon status of soil and soil stability but not much effective in address productivity constraints. In fallow period germinate lot of weeds and these weeds removed nutrients from soil and play major role as a host for insects, pests and diseases for survival and completion of their life cycle.

To get a strong evidence for improving soil quality due to application of organic manure, one should study the soil microbiological and biochemical properties of manure fertilized soil. Most organic manure added to soil contain polymeric compounds and their breakdown to simple low M.wt compound is necessary before their take up by microbial cells. The decomposition depends upon the production of extracellular enzymes. Application of organic manure brings changes in microbial communities and so is the effect on soil properties. Prolonged application of organic manure may not have positive effect on soil microbiological properties. Avoid using fresh manure due to presence of weed seeds and pathogens.

The effect of organic manure on crop productivity may also depend on how mature the manure is. Well managed and matured manure usually has more effect on soil fertility thereby enhancing crop productivity because of the stimulated activity of micro-organisms.....

The effective use of FYM and vermicompost, not only supply macronutrients but also meet the requirements of micronutrients, besides improving soil health. The use of organics plays a major role in maintaining soil health due to buildup of soil organic matter, beneficial microbes. To sustain the soil fertility and crop productivity the role of organic manures and fermented organic nutrients are very important. The organic fertilizers in addition to nutrients contain microbial load and growth promoting substances which helps in improving the plant growth, metabolic activity and resistance to pest and diseases. Boosting yield, reducing production cost and improving soil health are three inter -linked components of the sustainable triangle. s. In India, there is sufficient availability of organic manures like animal dung manure (791.6 mt), crop residues (603.5 mt), green manure (4.50 m ha), rural compost (148.3 mt), city compost (12.2 mt) and biofertilizer (0.41 mt) and these may become a good substitute of chemical fertilizers to maintain the soil physico-chemical and biological properties. The incorporation of organic manures improves the nutrient content and uptake. Although organic manures contain plant nutrients in small quantities as compared to the fertilizer, the presence of growth promoting principles like enzyme and hormones besides plant material.

Soil organic matter improves soil health and this is the base for sustainable agricultural production.

Yes, perhaps, it is effective if the irrigation rate and irrigation regime are observed

we cannot say properly that which one is better option without knowing the soil microbiological and biochemical properties, manure characteristics, irrigation rate, and regime and so on.