Abstract:
The Samaru (Lat. 110 11’N; Long. 70 38’E, altitude 686 m asl) long-term DNPK (Dung, Nitrogen, Phosphorus and Potassium) experiments, modelled after the classical Rothamsted Long-term Trials, was laid down in 1949. This was a time when clear signals were being received with respect to the fact that the burgeoning population, coupled with the introduction of more high yielding and nutrient-demanding crop varieties, could no longer allow farmers continue with the practice of shifting cultivation nor adapt intensive cultivation without use of external inputs. The experiment was therefore started in 1950 to compare the effectiveness of inorganic fertilizers with or without Dung (FYM) on soil properties, crop performance and yield under continuous cultivation. A multidisciplinary outlook was given to the experiment and other objectives now include: (i) to monitor weed growth, (ii) insect and pest incidences and (iii) to evaluate the cost and returns associated with all operations. The treatments consist of three levels of D, N, P and K applied annually in all possible combinations. It is a 34 singly replicated randomized complete factorial design, giving a total of 81 plots arranged in 9 blocks. Each treatment combination occupies 1/45th hectare plot, with bunds separating the blocks.