The Inceptisol of Karangploso has low soil pH, low organic matter (OM), medium total soil N, very low C/N ratio, and low available sulphurthat cause low soil productivity. The application of bokashi preserves strongly productivity and organic matter in the soil. This research aimed to determine the effect of bokashi application in improving soil chemical properties and N, P, Savailable in an Inceptisol of Karangploso. The experiment was conducted in greenhouse of Facultyof Agriculture, Brawijaya University using a completely randomized design with 7 treatments and 3 replications. The treatments consisted of O1 = dose of 5 t ha -1 + ½ A, O2 = dose of 10 t ha -1 + ½ A, O3 = dose of 15 t ha -1 + ½ A, O4 = dose of 20 t ha -1 + ½ A, O5 = dose of 25 t ha -1 + ½ A, and O6 = dose of 30 t ha -1 + ½ A. The results showed that the increasing dose of bokashi significantly increased soil pH (from 5.1 to 5.4), C/N ratio (from 9.64 to 9.93), P-available (from 141 to 142.6 ppm P) at 60 DAI (days after incubation), total N (from 0.21 to 0.24% at 30 DAI and 0.18% to 0.24% at 60 DAI ) and NO3 -(from 24.96 to 65.47 ppm at 30 DAI and 14.91 ppm to 39.20 ppm at 60 DAI) compared to the control, but it had no significantly effect on organic carbon, OM, SO4 2-in soil. The correlation test showed that there was a strong and positive correlation between pH and NO3 -(r=0,77*), organic carbon and NO3 -(r=0,63), organic carbon and P-available (r=0,78*), OM to NO3 -(r=0,70*), and OM to P-available (r=0,86*).

Farmer’s interest in planting cassava is relatively high because cassava is one of tolerant commodities toward drought, and low soil fertility. With minimum input, cassava still grow and produce. However, cassava absorb greater nutrients, especially potassium (K), leading to the depletion of essential nutrient availability. This research was carried out in Pati, Central Java, aimed to determine K nutrients status in the soil at the various durations of cassava land use. The research consisted of two factors, i.e 1) duration under cassava (five years, 10 yr, and 15 yr), and 2) slope (8 to 15% and 15 to 40%), each repeated four times. Soil and plant samples were taken at each location to determine K nutrients in the soil and plant (at harvest). Exchangeable K varies from low to moderate content, i.e. 0.44 to 0.50 cmol/kg (slope 1) and 0.22 cmol/kg (slope 2). Cassava land use showed an imbalance between input (fertilizer) and output (crop harvest) with negative results in the range of 114.59 to 524.78 kg K/ha. Exchangeable K content in the soils decreased with increasing K imbalance, meaning the longer period under cassava could lead to impoverishment of nutrients. Nutrient input should be increased to reduce the nutrient imbalance on the cassava farming system.

Changes in natural land use for monoculture cropping systems may affect the soil properties over a certain period of time. In an attempt to evaluate soil chemical properties in the cassava cropping system, the research was conducted in Pati Regency, Central Java. Four land use systems were compared, i.e. monoculture cassava (cultivated for 5, 10, and 15 years) and agroforestry systems in two different slopes (i.e., 8-15% and 16-40%), with four replications. Soil samples from each location were taken at a depth of 0-20 and 21-40 cm for soil chemical analysis (pH, cation exchange capacity, organic C, total N, available P, exchangeable K, Ca, and Mg). Soils in agroforestry systems had higher pH, CEC, the content of organic C, total N, exchangeable K, Ca and Mg than in cassava cropping systems, especially on the slope of 8-15%. The soil under 15 years cassava and on the slope of 16-40% had the most degraded soil chemical properties, as reflected by the lowest content of organic C, total N, exchangeable K, and slightly lower CEC and the content of exchangeable Ca and Mg. Soil chemical properties on the slopes of 8-15% were significantly better than on the slopes of 16-40%, especially in CEC and the content of organic C, total N, exchangeable K and Mg. However, there was an unclear pattern of the available P content, which was possibly due to the application of P fertilizer in cassava cropping systems.

Climate change greatly impacts on agricultural cultivation, including in rainfed rice fields. Improving rice crop performance and productivity in rainfed fields could be done by adaptation in dealing with climate change. This study aims were to determine the effect of providing P, Zn and Crop Residue Return (CRR) on direct seeded rice. This study was conducted at the Jakenan Experimental Station, Pati, Central Java, Indonesia from September 2012 to January 2013. A randomized block design was used, and these treatments consisted of various doses of P fertilizer (0P, ½P, P), providing Zn, and incorporation of crop residue. The observed parameters were plant height, maximum tillers per hill, productive tillers per hill, filled grain per panicle, grain yield, weight of dry straw, P-uptake. The results of this study indicated that providing P, Zn, and CRR have positive effects to plants growth and rice yield component. The treatment of ½P+ CRR + Zn took the best effect on plant growth and rice yield component. Applying of CRR and Zn could be a adaptation techniques and sustainable tools in the field that has beneficial impact for plant growth and rice yield component.