Maize Response to Soil Conditioning and irrigation regimes

Abstract

The contemporary exhaustive agriculture has led to significant turn down in soil potassium status because of constant removal by crops without paying off through K fertilizers. Pakistan totally relies on other countries as all K fertilizers are imported and thus expensive. Therefore substitution of potassium sources have great prospect in developing countries like Pakistan, where potassium fertilizers are imported for crop production. There are some indigenous resources of K-bearing materials which can be exploited as an alternative of the expensive imported K fertilizers. Field experiments were carried out to study the effects of alternative sources of potassium on improving soil fertility and maize productivity. Various organic residues were applied as K sources i.e. animal dung, maize cobs, sugarcane bagasse and sawdust applied in three different forms i.e. residues, biochar and ash were included in the experiment. All the treatments were analysed for nutrients content (N, P and K) and were applied at such rate that 60 kg K ha-1 was obtained from each treatment. K applied from inorganic source i.e. muriate of potassium (KCl) at the rate of 60 kg ha-1 and a control plot with no K fertilizer were also included in the experiment for comparison. The results revealed among different organic material used as source of potassium, sesbania stem delayed tasselling and silking by 4 days and maturity by 6 days as compared to sawdust. Likewise, animal dung produced taller plants with greater leaf area and leaf area index and higher number of ears m-2, grains ear-1 and heavier grains. Animal dung also increased biological yield by 17% and grain yield by 26% as well as harvest index by 10% as compared to sawdust and increased biological yield by 31 and 7% and grain yield by 41 and 20% as compared to control and chemical fertilizer, respectively. Among soil parameters, application of sawdust increased soil organic matter by 19% as compared to animal dung, while soil N, P and K were higher with the application of animal dung. Among various forms of organic materials, biochar delayed maturity by 3 days and increased plant height by 11% as compared to ash form. Similarly, biocharproduced greater leaf area, leaf area index, ears m-2, grains ear-1 and thousand grains weight. Similarly, biochar increased biological yield by 17 and 4%, grain yield by 23 and 11% as compared to ash and residues form, respectively. Similarly biochar increased grain yield by 40 and 17% and biological yield by 29 and 4% as compared to control and chemical fertilizer, respectively. Biochar form increased soil organic matter by 34%, soil N by 23%, soil P by 27% and soil K content by 6% as compared to ash. However, soil pH was increased with the application of ash form of organic materials. It is concluded that animal dung performed better among different types of organic materials, while among different forms of organic material, biochar was found superior. Thus application of animal dung in the form of biochar can substitute chemical K fertilizer and hence recommended for improved soil fertility as well as maize productivity.