Course Content
Learn soil fertility, fertilizers and integrated nutrient management with Braimy- B.SC Agriculture
About Lesson
  1. Indigenous supply

a. Soil nutrient pool:

  • Continuous and intensive cultivation without residue or organic management can lead
  • to a poor soil nutrient pool.
  • The soils of Nepal are generally low in organic matter; total nitrogen and medium in available phosphorus but have adequate level of potassium.
  • Soil nutrient pool can be improved by reducing nutrient losses, ameliorating problem soil to increase nutrient availability and selecting legume based cropping system.


b. In situ green manuring:

  • By growing different green manuring crops like sesbania canabina, S. rostrata, Mungbean in the field before rice and turning and incorporating in the same field after 45 to 60 days is called in-situ green manuring.
  • This can supplement about 30-60 kg N ha-1. Azolla, a water fern, can also be used as green manuring where water management is good.


  1. Exogenous supply

a. Inorganic-fertilizers:

Efficiency of applied fertilizer can be increased by:

  • Making recommendation “system level” instead of a “single crop in the system” considering all sources of plant nutrient as discussed in IPNS module.
  • Minimizing pre (during transportation) and post application (in the field) losses. Losses in the field can be reduced by applying fertilizer on appropriate time and method.
  • Taking care of all other production factors like seed health, cultural practices, plant protection, pre and post-harvest losses, storage etc. and eliminating nutrient limiting including secondary and micronutrients.
  • Selecting appropriate kind of fertilizer depending on soil condition.


b. Organic-manure:

  • Organic sources of plant nutrient are usually by products of farming and related industries from plant animal sources and are also called organic fertilizer.
  • Integrated nutrient management package should include alternative sources to address above problems like planting forage crops and trees to substitute feed for cattle and fuel for household use and increase nutrient content to reduce transportation problem.
  • Different experimental results had shown comparable response of 5 t ha-1 poultry manure, 20 t ha-1 FYM/compost to 100:40:30 kg ha-1 NPK


c. Microbial fertilizers

  • Different bacteria like Rhizobium, Azotobacter and fungal like Mycorrhizal associations contribute nitrogen and phosphorus, respectively.


  1. Management of cropping system

a. Inclusion of Legumes

  • Legumes contribute to soil fertility directly through their unique ability, in association with Rhizobia, to fix atmospheric nitrogen and also by incorporation of organic matter.
  • Fixed nitrogen can be available to the legume crop and also to the subsequent crop by decomposition of nodules and by using legumes as green manure, it is estimated that legume residue can provide about 20-40 kg N ha-1 to succeeding crops.


b. Agro-forestry:

  • Agro forestry can be a major source of agricultural compost, animal fodder, fuel wood and biomass for bedding material.
  • This does not only reduce pressure on the Nepalese forest but also reduce pressure on the use of crops residue as animal fodder and cattle manure as fuel wood, which can be diverted to recycle in farming system additionally, growing nitrogen fixing tree like Acacia sp., Leucenea sp., Gliricidia sp. can supply nitrogen rich foliage for quality compost in addition to insitu improvement of soil N from atmospheric nitrogen.
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