Soil Conservation through Agronomic Measures
UncategorizedIntroduction
Soil is natural dynamic body which supports many organisms, acts as a reservoir of carbon and supply nutrients for food production which supports the human as well as livestock lives on earth. In recent years, this natural entity is facing problems of erosion and deterioration due to indiscriminate exploitation by human. Soil erosion removes topsoil layer containing organic matter, nutrients and microorganisms required for plant growth. This emphasis on the need of soil conservation.
Definition of soil conservation: Soil conservation is the prevention of loss of the top most layer of the soil from erosion or prevention of reduced fertility caused by over usage, Acidification, salinization or other chemical soil contamination. According to WOCAT (World Overview of Conservation Approaches and Technologies) soil conservation are the activities at the local level which maintain or enhance the productive capacity of the land in areas affected by or prone to degradation.
Importance of soil conservation:
• Boosts earth quality and productivity.
• Promotes water infiltration and increases its storage.
• Aids air and water purification.
• Gives food and shelter for wildlife.
Soil conservation strategies rely on three basic steps:
1. Obtaining proper knowledge of the land resource use.
2. Monitoring fields and detecting critical zones.
3. Controlling and estimating the efficiency of applied soil conservation technique
AGRONOMIC MEASURES OF SOIL CONSERVAION
These measures are suited for areas withfor areas with less than 2 % slopes.
A. CONTOUR CULTIVATION:
1. Line joining the places of equal elevation is known as contour.
2. All the cultural practices such as ploughing, sowing, intercultivation etc. carried out along the contour and across the slope.
3. The major idea behind this kind of activity is to reduce the loss of soil and water by erosion.
MECHANISM
1. By ploughing and sowing across the slope, each ridge of plough furrow and each row of crop act as obstruction to runoff.
2. It provides more time for the water to penetrate the soil leading to reduced soil and water loss.
BENEFITS:
1. Contour cropping can reduce soil erosion as much as 50%.
2. By reducing sediments and runoff and increasing water infiltration it promotes better water availability.
IMPORTANCE/USES
1. It has been practiced over centuries in areas where irrigation farming is important.
2. Contour farming has been proved to reduce fertilizer loss, power and time consumption and wear on machines as well as to increase crop yield and reduce erosion.
3. Contour cropping is most effective when used in conjunction with strip cropping, bench
B. STRIP CROPPING
Strip cropping is a practice of growing field crops in narrow strips either at right angles to the direction of the prevailing wind, or following the natural contours of the terrain to prevent wind and water erosion of the soil.
2. Cultivation of crops in alternative strips to prevent soil erosion.
PURPOSE
1. Basically, strip cropping agriculture is used either to improve soil health, support primary crop growth and reduce soil erosion.
2. It is basically a practice of growing erosion permitting and erosion resting crops in alternate strips.
TYPES
1. Contour strip cropping
a. Crop bands are aligned according to the relief contour.
b. The practice is particularly efficient on slopes.
c. It protects soil from rill formation and sedimentation by slowing runoffs down.
2. Field Strip Cropping
a. Crop bands are arranged in parallel lines across the field without following the contours.
b. This method is suitable for both flat & gentle slopes, and also used if soil is not too prone to erosion.
3. Buffer Strip Farming
a. Buffer planting is implemented on steep hilly slopes where typical contouring is complicated.
b. Buffers (e.g., bushes, grasses, or legumes) grow between contour bands alternatively and can be either permanent (often native vegetation) or temporary.
c. The practice is particularly winning on erosion prone terrains when buffer vegetation holds the soil in place.
4. Wind Strip Cropping
a. In this case, protecting plants perpendicularly face the prevailing winds, so their position does not depend on the slope contour.
b. They serve as a shield and mitigate the wind damage on yields and soils.
C. Conservation tillage
a. This is an umbrella term that includes reduced tillage, minimum tillage, no-till, direct drill, mulch tillage, stubble-mulch farming, trash farming, strip tillage, plough-plant.
b. Conservation tillage is any tillage practice that builds up crop residues on the soil surface to minimize the impact of water and wind erosion.
c. The 30% residue is the benchmark for water erosion and 1000 pounds per acre or 454 kg per acre benchmark for wind erosion are minimum requirements.
Advantages:
a. Conservation tillage will reduce the soil erosion.
b. Soil health will be improved.
c. Water conservation will increase.
d. Improvement in the Air quality.
e. Wildlife Habitat will be safeguarded to some extent
f. Production costs will be lowered.
g. Improved crop yields & Revenue opportunities
Disadvantages:
a. There are some disadvantages which hinder the application of conservation tillage in semi-arid conditions like;
b. Dense plant covers may be incompatible with the well-tested strategy of using low plant populations to suit low moisture availability.
c. Crop residues may be of value as feed for livestock.
d. Planting through surface mulches is not easy for ox-drawn planters although there may be no problem with hand job planters.
e. And farmers acceptance to new technology will be the main problem
D. Mulching
a. Surface mulches are used to prevent soil from blowing and being washed away, to reduce evaporation, to increase infiltration, to keep down, to improve soil structure and eventually to increase crop yields.
b. Inter-culture kills weeds and produces five or seven cm thick soil mulch which helps to reduce evaporation from the top soil.
c. It also breaks the surface crust which forms after each downpour.
d. Mulches will be available in various types like Plastic, Stubble, Pebble, Dust, Straw and various vegetative mulches.
Advantages of Mulching
a. Mulching will reduce the direct impact intensity of Rain and Wind on the soil.
b. It will reduce the water evaporation
c. Decrease the weed invasion and weed population in the field
d. Maintains the soil structure, porosity and overall soil physical properties were stabilized.
e. Improves the soil biota, so organic matter will increase.
E. Growing of cover crops
a. Cultivated legumes, in general, furnish a better cover and hence better protection to cultivated land against erosion than ordinary cultivated crops.
b. The crops and the cropping systems will naturally vary from region to region, depending on the soil and climatic conditions.
c. The mostly preferred cover crops are green gram, black gram, cowpea, groundnut etc.
Advantages of cover crops
a. Cover crops decreases the barren land area as row spaces of main crop will also used for cultivation. b. It increases the infiltration rate of the soil.
c. Slows the direct impact velocity of rain water on the soil.
d. Supply nutrients and supress weeds.
e. Breaks the pest cycles and decrease the pest incidence.
f. Improves soil physical and biological properties
F. Mixed cropping
a. Mixed cropping is the growing of 2 or more crops simultaneously in the same field without any definite row pattern. This is done by mixing their seeds.
b. Important objectives of mixed cropping are a better and continuous cover of the land, good protection against the beating action of the rain, almost a complete protection against soil erosion and the assurance of one or more crops to the farmer.
Advantages of Mixed cropping:
a. Exposure of soil to water and wind will be minimized
b. The risk of total crop failure is reduced
c. Farmers tend to harvest a variety of produce such as cereal, pulses or vegetables or fodder to meet the various requirements of family or of an agricultural farm.
d. Due to complementary effect of component crops, yield of both crops is increased. e.g., wheat and gram.
e. Fertility of the soil is improved by growing two crops simultaneously.
f. Chances of pest infestation are greatly reduced.
G. Conservation farming
a. It includes any farming practice which improves yield, or reliability, or decreases the inputs of labour or fertilizer, or anything else leading towards improved land husbandry, which we have defined as the foundation of good soil conservation.
b. It includes strip cropping, crop rotations, alternate cropping, mixed cropping and interplanting, surface and mulching, organic mulches, deep planting of varieties, dry seeding etc.
Conservation tillage
In this practice at least 30% of soil surface should remain covered with crop residue before and after planting the next crop to reduce soil erosion and runoff, as well as other benefits such as C sequestration. This term includes reduced tillage, minimum tillage, no-till, direct drill, mulch tillage, stubble-mulch farming, trash farming, strip tillage, etc. The concept of conservation tillage is widely accepted in large scale mechanized crop production systems to reduce the erosive impact of raindrops and to conserve the soil moisture with the maintenance of soil organic carbon. Conservation tillage improves the infiltration rate and reduces runoff and evaporation losses. It also improves soil health, organic matter, soil structure, productivity, soil fertility, and nutrient cycling and reduces soil compaction.
Organic farming
Organic farming is an agricultural production system that devoid the use of synthetic fertilizers or pesticides and includes organic sources for plant nutrient supply viz. FYM, compost, vermicompost, green manure, residue mulching, crop rotation, etc. to maintain a healthy and diverse ecosystem for improving soil properties and ensuring a sustained crop production. It is an environmentally friendly agricultural crop production system.
The maintenance of high organic matter content and continuous soil surface cover with cover crops, green manure, and residue mulch reduce the soil erosion in organic farming. It leads to the addition of a large quantity of organic manures which enhances water infiltration through improved bio-physico-chemical properties of soil, and eventually reduces soil erodibility. Organic materials improve soil structure through the development of soil binding agents (e.g., polysaccharides) and stabilizing and strengthening aggregates which reduce the disintegration of soil particles and thus reduced soil erosion. Soil erosion rates from soils under organic farming can be 30–140% lower than those from conventional farming.
Land configuration techniques
Adoption of appropriate land configuration and planting techniques according to crops, cropping systems, soil type, topography, rainfall, etc. help in better crop establishment, intercultural operations, reduce runoff, soil and nutrient loss, conserve water, efficient utilization of resources and result in higher productivity and profitability. Ridge and furrow, raised bed and furrow, broad bed and furrow, and ridging the land between the rows are important land configuration techniques.
Ridge and furrow system: Raising rainy season crops on ridges and rabi season crops in furrows reduces the soil crusting and ensures good crop stand over sowing on flat beds. Moreover, inter-row rainwater can be drain out properly during the monsoon period and collected in farm ponds, for life-saving irrigations and profile recharging for the establishment of rabi crops. It leads to the increased moisture content in soil profile which reduces moisture stress on plants during the drought period. This method is most suitable for wide-spaced crops viz. cotton, maize, vegetables, etc.
Broad bed and furrow system: This system has been developed by the ICRISAT in India. It is primarily advocated for high rainfall areas (>750 mm) having black cotton soils (Vertisols). Beds of 90–120 cm width are formed, separated by sunken furrows of about 50–60 cm wide and 15 cm depth. The preferred slope along the furrow is between 0.4 and 0.8% on Vertisols. Two to four rows of the crop can be grown on the bed, and the width and crop geometry can be adjusted to suit the cultivation and planting equipment.
Advantages
Increase in-situ soil moisture conservation
Safely dispose of excess runoff without causing erosion
Improved soil aeration for plant growth and development
Easier for weeding and mechanical harvesting
It can accommodate a wide range of crop geometry.
Agroforestry measures
Agroforestry is a sustainable land management system which includes the cultivation of trees or shrubs with agricultural crops and livestock production simultaneously on the same piece of land. It is an emerging technology for effective soil and water conservation and comprises a wide range of practices for controlling soil erosion, developing sustainable agricultural production systems, mitigating environmental pollution, and increasing farm economy. The leaf litter addition act as a protective layer against soil erosion improves soil health and moisture retention capacity of the soil and increases crop productivity. It has been reported that different agroforestry practices can reduce up to 10% of soil erosion. Agroforestry not only controls soil erosion but also produce tree-based several marketable products.
Types of agroforestry systems
Agri-Silviculture: It is the growing of agricultural crops as a primary component with the secondary component of multipurpose trees (MPTs) on the same managed land unit. The tree species bind soil particles in the root zone and increase water infiltration, and reduce runoff.
Agri-Horticulture: Growing of agricultural crops and fruit trees on the same managed land unit is known as agri-horticulture. Fruit tree species like lemon (Citrus limon), mango (Mangiferaindica), ber (Ziziphusmauritiana), and aonla (Phyllanthusemblica) can be successfully planted in agricultural fields and on degraded and low fertile lands with some restoration measures.
Alley Cropping: Growing of agricultural crops in the alley formed between the hedge rows of leguminous nitrogen-fixing tree species. This system is one of the effective measures for soil and water conservation in hilly areas.
Silvi-pasture System: Raising grasses or livestock with MPTs on the same managed land unit is known as silvi-pasture system. This system has the potential to reclaim eroded and degraded lands. Mechanical measures combined with grass species cultivation are more effective for controlling soil erosion processes. The grass species such as Cenchrusciliaris (buffel grass), Cenchrussetigerus (birdwood grass), Dichanthiumannulatum (marvel grass), Panicumantidotale (blue panicgrass), Panicum maximum (Guinea grass), Brachiariamutica (para grass) and Pennisetum purpureum (elephant grass) are important in ravine restoration.
Benefits of Conservation agriculture
- Environmental benefits that protect the soil and make agriculture more sustainable:
a. Reduction in soil erosion, and thus of road, dam and hydroelectric power plant maintenance cost
b. Improvement of water quality.
c. Improvement of air quality.
d. Biodiversity increase.
e. Carbon sequestration.
Economic benefitsthat improve production efficiency.
Three major economic benefits can result from CA adoption:
a. Time saving and thus reduction in labour requirement.
b. Reduction of costs, e.g., fuel, machinery operating costs and maintenance, as well as a reduced labour cost.
c. Higher efficiency in the sense of more output for a lower input.
Agronomic benefits that improve soil productivity.
a. Adopting conservation agriculture leads to improvement of soil productivity.
b. Organic matter increase.
c. In-soil water conservation.
d. Improvement of soil structure, and thus rooting zone.
Mr. Sharandeep Singh Cheema
Assistant Professor,
School of Agricultural Studies, Geeta University, Panipat, Haryana
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