Soil Nutrient Status and Leaf Nutrient Norms in Oil Palm (Elaeis guineensis Jacq.) Plantations Grown on Southern Plateau of India
Oil palm is a heavy feeder of nutrients and requires balanced and adequate supply of nutrients for optimum growth and yield. Information regarding soil nutrient status and leaf nutrient concentration is very much required for proper fertilizer application. Therefore, a survey was conducted for assessment of soil nutrient status and leaf nutrient concentration in 42 oil palm (Elaeis guineensis Jacq) plantations in the state of Karnataka, situated in southern plateau of India. In surface soil layers, soil acidity (pH), electrical conductivity (EC) and organic carbon (OC) content ranged from 4.91 to 8.74, 0.10 to 2.54 dS m−1 and 1.17 to 28.9 g kg−1 respectively. The values of available potassium (K) (NH4OAc–K), phosphorus (P) (Olsen-P) and exchangeable calcium (Ca) (Exch. Ca) varied from 31.2 to 386 mg kg−1, 7.69 to 242 mg kg−1 and 156 to 1273 mg kg−1 respectively. The concentration of exchangeable magnesium (Mg) (Exch. Mg), available sulphur (S) (CaCl2-S) and hot water soluble boron (B) (HWB) ranged from 52.8 to 307 mg kg−1, 2.25 to 73.5 mg kg−1 and 2.29 to 16.0 mg kg−1 respectively. Diagnosis and recommendation integrated system (DRIS) norms were established for different nutrient expressions and it was used to compute DRIS indices. As per DRIS indices, the order of requirement of nutrients in the region was found to be K > P > nitrogen (N) > B > Mg. Optimum leaf nutrient ranges varied from 2.24 to 2.97 %, 0.08 to 0.14 % and 0.78 to 0.91 % for N, P and K respectively, from 0.74 to 1.53 %, 0.25 to 0.98 % and 0.72 to 1.09 % for Ca, Mg and S respectively and from 5.71 to 31.0 mg kg−1, 7.42 to 12.9 mg kg−1, 33.6 to 58.6 mg kg−1, 82.5 to 681 mg kg−1 and 82.8 to 936 mg kg−1 for B, copper (Cu), zinc (Zn), manganese (Mn) and iron (Fe) respectively. On the basis of DRIS derived sufficiency ranges, 57, 24, 62, 3, 3, 9, 7, 5, and 26 % leaf samples were having less than optimum concentration of N, P, K. Ca, Mg, S, B, Cu and Mn respectively. The optimum ranges developed can be used as a guide for routine diagnostic and advisory purpose for balanced utilization of fertilizers.
Leaf and soil nutrient norms in mango (Mangifera indica L.) grown in tribal belt of southern Gujarat
Tribal area of southern Gujarat (taluk Vansda in Navsari district) was surveyed to assess the nutrient status of mango (cultivar Rajapuri) orchards in relation to their productivity. To achieve a yield of 2.0 to 7.5 t ha−1, the optimum leaf N may range from 0.89 to 1.93 g per 100 g dry matter (dm), P from 60 to 110 mg per 100 g dm and K from 1.02 to 2.01 g per 100 g dm. Secondary nutrient namely S (107 to 169 mg per 100 g dm) and micronutrient namely Zn (11 to 16 μg g−1) status were also worked out along with soil parameters for the targeted yield using Diagnosis and Recommendation Integrated System. Study indicated low N, Mg, Mn and Zn in large number of orchards. Although many orchards were low in nutrients, the status was expressed neither in leaf nutrient content nor in the form of deficiency symptoms due to “hidden hunger”. Continuous exhaustion may lead to decline in growth, productivity and quality of mango, unless integrated nutrient management is taken up and practised. In soils, 0.40 to 0.80% organic carbon, 42 to 180 μg g−1 available N, 6 to 10 μg g−1 available P, 100 to 730 μg g−1 available K, 250 to 1600 μg g−1 available Mg, 10 to 16 μg g−1 available S and 1.0 to 2.0 μg g−1 available Zn and 25 to 100 μg g−1 available Mn would provide optimum yield of mango fruits under the situations of the project area. In the case study, taking large number of orchards under investigation, the nutrient norms developed were refined. Nutrient recommendations were made considering nutrient need, plant nutrient status as assured by leaf analysis and soil fertility evaluation. Study indicated that 53% orchards were giving very low to low yields and are not economically sustainable.
Organelle transformation.
The source of genetic information in a plant cell is contained in nucleus, plastids, and mitochondria. Organelle transformation is getting a lot of attention nowadays because of its superior performance over the conventional and most commonly used nuclear transformation for obtaining transgenic lines. Absence of gene silencing, strong predictable transgene expression, and its application in molecular pharming, both in pharmaceutical and nutraceuticals, are some of many advantages. Other important benefits of utilizing this technology include the absence of transgene flow, as organelles are maternally inherited. This may increase the acceptability of organelle transformation technology in the development of transgenic crops in a wider scale all over the globe. As the need for crop productivity and therapeutic compounds increases, organelle transformation may be able to bridge the gap, thereby having a definite promise for the future.