*4.5.3 Bio-fertilizers*

*Slope Engineering*

transplanted in the field [10].

*4.4.7 Crop scheduling*

*4.4.8 Crop geometry*

generally coincides with peak rate of runoff. The splash erosion loss in fallow land is 44.2 Mg/ha while it is 26.3 Mg/ha in Green gram and Black gram plots. In a study at Gujarat in Western India it was found that *Bidi* Tobacco, being a clean cultivated crop, allows higher runoff and soil loss and these losses can be reduced by introducing cover cum green manure crops during the early monsoon before Tobacco is

Sowing date and optimum seed rate are pillars for good stand and crop cover. The sowing date must be so adjusted that by the time intensive rainfall take place, there is enough of vegetation cover on the land. This can be done by advancing the date of sowing or even dry sowing in rainfed areas is always recommended. A study conducted at Dehradun in Northern India reported that sowing of Maize at the start of last week of June month produced higher and dense canopy at peak rainfall period, which in turn reduced the splash erosion considerably as compared to crop sown on first week of July. Similarly, the canopy coverage and crop yields were higher under early sowing in Maize + Cowpea intercropping system [28].

Optimum plant population and crop geometry are equally important to have good crop cover on the land. Narrow intra-spacing (within rows) across the slope offers tolerance to runoff and ultimately reduces the soil erosion. Narrow spacing is always better for soil and water conservation, but it may cause severe competition for nutrient, water, light and space resulting in in lower yield of crops. A study carried out Chandigarh in Northern India reported that growing of Maize at 60 cm × 22.5 cm with minimum tillage reduced the runoff from 281 to 253 mm, soil

In order to meet the nutrient requirements of the crops in ravines, the soil fertility loss due to extreme erosion needs to be compensated accordingly as per specific site. The steep decline in soil fertility in the absence of proper measures to check erosion will cause reduction in the crop yields. This can be achieved in the following manner.

The soil fertility in ravine land varies from gully head to gully bed, therefore fertilizer recommendation for crops and cropping system should be site specific based on soil test. The recommended dose of fertilizers, method of application and proper scheduling is required to achieve sustainable yield from ravine lands. The nitrogen fertilizers should be applied in splits basal dose at the time of sowing and as top dressing during crop growth to the crops. The phosphate and potash fertilizers are given only as basal doses. Spraying of liquid Urea and micronutrients should be done on the standing crop, as and when deficiencies are noticed in the crop. The selection of appropriate fertilizers and their accurate combinations are necessary

Organic manures such as FYM (Farm Yard Manure), composts and green manures improve the physical condition, micro-flora of the soil and have a

loss from 5.7 to 4.4 Mg/ha as compared to conventional crop geometry [29].

**4.5 Soil management measures for ravines**

for maintaining the soil fertility in ravines.

*4.5.1 Judicious use of fertilizers*

*4.5.2 Organic manures*

**190**

Bio-fertilizers in the context of present day organic farming can play a key role in sustainable agriculture because of their potential to restore soil health. They are derived from the living organisms and include nitrogen fixing microorganisms i.e. *Rhizobium* spp., *Azospirillum* spp., *Bradyrhizobium* spp., *Azotobactor* spp., *Frankia* spp., Phospho-microorganisms, i.e., phosphate solubilizing bacteria, *Glonus* spp., phosphate solubilizing fungi compost inoculant i.e., *Cellolotic* or *Lignolytic* fungi etc., bio-fertilizers provide better crop yields and are ecofriendly. Bio-fertilizers can be applied through seedling treatments; tuber set treatment or oil treatment. For 10 kg of medium size seeds 483 g of culture is required for one hectare of land. In case of seedlings 1–2 kg of bio-fertilizers may be dissolved in 10 liters of water in a bucket and a suspension/slurry can be prepared for application in soil. The roots of the seedlings are dipped for 15 minutes in the slurry and then transplanted in the field. For treatment of tubers or sets slurry of 2–4 kg bio-fertilizers is prepared in 40–80 liters of water. Before sowing, tubers or sets are dipped in the slurry for 15 minutes. Soil treatment with the bio-fertilizers can also be done in the standing crop at critical stages [29].

## *4.5.4 Vermicomposting*

Vermicomposting is technique of using different species of earthworms to convert the decomposable farm, urban and domestic waste into nutrient rich compost. It is eco-friendly, sustainable, cheaper and easy technique to obtain compost of high quality using biologically decomposable organic waste and crop residue generated from the farmers field.

## *4.5.5 Integrated nutrient management*

The chemical fertilizers are nowadays becoming costly and may not be timely available to the farmers in remote areas. Though chemical fertilizers increase yields quickly, yet their effects on soil is visible for a short period of time and requires frequent application to maintain the soil fertility. These chemical fertilizers have a toxic and residual effect in soil, water and plants system. In order to overcome these constraints, a conjunctive use of organic and inorganic sources to maintain soil fertility has been suggested. This is generally referred to as Integrated Plant Nutrient Management (IPNM). Under this scheme, the some portions of crop nutrient requirement are met by organic manures and the remaining need is fulfilled by the chemical fertilizers. In one of the studies, 20 kg N ha−1 by *Azolla* (a fern) + 20 kg N by ammonium sulfate applied to rice registered a grain yield of 4435 kg ha−1 in comparison to 40 kg N ha−1 with ammonium sulfate giving a yield of 4132 kg ha−1 which explains the role and efficacy of nitrogen fixation in the soil and its use by rice crop. *Rhyzobium* inoculation of the seeds of legumes is being promoted for building up soil nitrogen through nitrogen fixation by increasing the efficiency of legume crop. At the farm level, domestic farm and agro-industrial wastes arising out of the food grain, crop residue and fruit processing can be diverted into the soil. This will add to soil fertility as well as biological waste management [29].
