Evaluation of micronutrient status of sandy clay loam as influenced by sulphur fertilization on blackgram

Secondary nutrient deficiency especially sulphur (S) in blackgram has imparted poor grain setting percentage and yield as well. Interest on S availability in soils has increased due to acute shortage production of quality blackgram. Therefore, an attempt was made to assess the three SO4-2- S sources (Gypsum, Ammonium sulphate and Potassium sulphate) and two S levels (10 and 20 kg S ha-1) under irrigated condition. This experimental trial was replicated three times along with randomized block design at farmer field of Thenamallur village, T. Kallikudi block, Madurai district. S treatments were also evaluated by two methods of fertilizer amendment such as, soil application (as basal dose) and foliar spray (0.5 % K2SO4) on 30th and 45th days after sowing and its combinations. Soil analysis is good method to assess the S nutritional status of soil under tropical areas. The results revealed that the S and micronutrient content was low in single soil application or foliar spray and irrespective of source and level. Foliar spray treatment plants recovered limited S concentration. We could found that the better higher S concentration among the combination treatments. Soil application of K2SO4 @ 20 kg ha-1 + foliar spray was increased the soil available S and DTPA - extractable Micronutrient (Zn, Fe, Mn and Cu) status. Our study explains that the treatment combinations had synergistic effect and it may be concluded that the combinations (soil + foliar spray) are increased soil available S and micronutrient status. Further, future studies are required to confirm the results of S fertilizers in alkaline soil

Effect of long term fertilization on phosphorus dynamics in root zone environment under finger millet - Maize cropping sequence

In an agro-ecosystem, phosphorus (P) is found in organic and an inorganic form which includes soluble P, sorbed P and mineral bounded P. In soil, added P sources undergo various soil processes like mineralization, immobilization, precipitation, weathering, dissolution, sorption and desorption. For understanding the P dynamics in clay loam (Vertic Ustropept) soil, the present study was undertaken in P dynamics under rhizosphere and non-rhizosphere environment of maize in Long Term Fertilizer Experiment at Tamil Nadu Agricultural University, Coimbatore. The results revealed that the fractions of various pools of inorganic NaOH extractable Fe - P, H2SO4 extractable Ca- P, NH4F extractable Al- P, NH4Cl extractable Saloid P and Na citrate - Dithionate extractable Reductant soluble P were dominant in the non-rhizospheric soil than rhizospheric environment. The order of inorganic P fractions in the non-rhizospheric and rhizospheric region of the soil was found as Ca-P > Fe-P > Al-P > Reductant soluble-P > Saloid P and the knee-high stage of the non - rhizosphere soil recorded the highest inorganic as well organic P fractions. Irrespective of P fractions, Ca – P was recorded high (192.5 &  186.7 mg kg-1 ) followed by Fe - P (40.8& 34.9 mg kg-1) at a knee-high stage in non-rhizosphere and rhizosphere, respectively. Practising various nutrient management systems, application of 100% recommended dose of fertilizer along with FYM @ 10 t ha-1 (T8) recorded significant changes in all inorganic (Ca-P, Fe-P, Al-P, Reductant soluble-P, Saloid P), organic fractions and also Total P followed by 150% NPK (T3) in sandy clay loam soil. Nowadays, increasing demand for P fertilizer in India, judicious use of P fertilizer is important. Despite that, intensively cultivated soils have a lot of P reserves like organic and inorganic P pools and effective way of P transformation management could reduce the quantum of P fertilization in soil

Long Term Impact of Fertilization and Intensive Cropping on Maize Yield and Soil Nutrient Availability under Sandy Clay Loam Soil (Inceptisol)

A field experiment was conducted to evaluate the impact of crop productivity and soil nutrient availability under continuous cropping and fertilization. A single nutrient application or omission of nutrient or mineral fertilizer alone can deteriorate the soil nutrient availability and yield in long run. The result revealed that soil pH and EC have not changed substantially even after the repeated application of fertilizers over five decades. The use of balanced fertilizers either alone or integrated with organic manure (FYM) has significantly increased the grain and straw yield of maize. The yield increment of maize was observed 13.9 percent higher than 100% NPK and 18.3 percent higher than without the addition of S (S free). Balanced fertilization can improve the soil nutrients (N, P, K & S) and soil organic carbon instead addition of FYM @ 10 t ha-1 could increase the SOC and soil nutrients in long run in a sustainable manner. Concerning nitrogen, single nutrient (N alone) plots received low available nutrients and yield also it’s deteriorated the soil nutrients over long period. A build-up of available soil P and S was observed due to its continuous addition through fertilizer but soil K has reduced because of intensive cropping and high-yielding cultivars. Hence, for sustainable  roduction, application of a recommended dose of mineral fertilization (100% NPK) along with FYM @ 10 t ha-1 may be used to achieve a higher yield, stable nutrient balance and soil quality over decades