Nitrogen

Deficiency symptom- Nitrogen deficiency can be distinguished by the light red cast seen on veins and petioles. The older mature leaves gradually change from their normal characteristic green appearance to a much paler green. As the deficiency progresses these older leaves become uniformly yellow (chlorotic).

            Fig: Nitrogen deficiemcy symptoms

Management 

Green Manure Cultivation

Green Manure crop of Sesbania aculeata and Crotalaria juncea can be taken. The 60-day-old crop can contribute approximately 100 kg N/ha, 25-30 kg P/ha and 75 kg K/ha and these can meet the requirement of organic rice crop.

                                                                            Fig: Green manure crop

Seed rate for Green Manure: A seed rate of 25-30 kg/ha of Sesbania and Crotalaria should be used for raising green manure. Generally broadcasting of green manure seeds is practiced. However, better green manure crop can be raised if line sowing is adopted at 45 cm row spacing. One pre-sowing irrigation should be applied with 1-2 irrigations in between green manure crop depending on summer rains, are sufficient for growth of green manure crop.

Time of sowing: Last week of April to first fortnight of May.

Time of incorporation: The green     manure crop to be turned down around 55-60 days after sowing. The Trichoderma (10 g/l) should be sprayed on turned Sesbania/Crotalaria crop in the field before puddling and transplanting rice crop.

                                                                    Fig: Incorporation of green manure crop

FYM: If available, well decomposed FYM should be applied @15-20 t/ha, which can supply about 75-100kgN/ha, 35-40 kg P₂O₅/ha and 75-100 kg K₂O/ha. FYM should be decomposed by adding Trichoderma powder.

                                                                                      

                                                                          Fig: Trichoderma powder addition in FYM

Enriched compost: Various methods of composting for nutrients enrichment through rock phosphate, pyrite and micro-organism have better quality with respect to N, P, K and S content.

Azolla: Inoculation of Azolla bio-fertilizer at 7 days after transplanting of rice crop @ 2 t/ha in standing water and its growth during the rice crop adds organic matter and nitrogen to the soil. The Azolla incorporation at the time of puddling of rice soil @ 6t/ha can also provide about 25-30 kg N/ha to the rice crop in organic farming system. For Azolla incorporation we need to produce required amount of biomass in multiplication tanks/ponds.                                                               

            Fig: Azolla biofertilizer

Vermicompost:  Application of Vermicompost @ of 5 tonnes /ha can meet out the nutrient requirement of organic rice partially. For the preparation of vermicompost, culture of Pseudomonas fluorescens may be added (@ 200g/100kg).

                                                        

               Fig; Improvement of soil health through biological activities