The use of compost for horticultural crops production in Nigeria is beginning to gain some attention, since it has been reported to improve plant growth and yield. Some cereals and legumes crops residues with potentials of being used as compost materials such as Sorghum Stovers, Rice Straws, Maize Stovers, Millet Stovers, Groundnut Haulms, Cowpea Stems and Cotton Stalks grown at the Kano University of Science and Technology Research farm were selected and analyzed for nutrient content. Data obtained were subjected to analysis of variance (ANOVA) using F-test. Results obtained indicated that Nitrogen (0.98gkg -1 ) and Phosphorous (0.31kg -1 ) were highly significant (p<0.05) in rice straws compared to other residues of cereals. Also Groundnut haulms was found to be highest in N(1.10kg -1 ) and P(0.0597) than other legumes residues. Other essential nutrients like calcium, magnesium and potassium were also determined. Generally, crop residues and their ashes are valuable materials that can be used in making compost fertilizer as they contain high amount of nutrients. However, intensive cultivation and crop residues removal tend to break the natural cycle and prevent the return of nutrient taken up by the crop to the soil.

Nitrogen is the most limiting major nutrient required by all living plants. Nitrogen fertilizer is costly and too much application of nitrogen causes detrimental effects to our ecosystem. Alternatively, the use of commercial microbial inoculants will be an alternative to chemical fertilizer for the small holder farmers in northern Nigeria. Groundnut (pea nut) was selected as a test crop for the inoculation. The experiment was conducted at Sudan savannah in Kano State and Guinea savannah in Bauchi state of Nigeria during the 2016 cropping season. The design of the experiment was RCBD with seven treatments and four replications in each site. Two rhizobia inoculants were tested on groundnut in two agroecological zones of northern Nigeria to monitor their performance and their ability to establish symbiotic and nodulate the crops. The treatments combinations were; histic, biofix, nitrogen, cattle manure, histic + cattle manure, biofix + cattle manure and control. In the groundnut field, Biofix produced higher nitrogen fixed than all treatments in the Sudan savanna, while in the Guinea savanna no significant differences (P = 0.67) were observed between the treatments and the control. However, inoculated plots had higher nitrogen fixation than the control.

For sustainable agriculture nitrogen must be adequately supplied because it is the most limiting major nutrient required by all living plants. This experiment was conducted at the two ecological zones, Sudan savannah in Kano State and Guinea savannah in Bauchi state of Nigeria during the 2016 cropping season. The design of the experiment was Randomized Complete Block Design (RCBD) with seven treatments and four replications in each site. The treatments were; legume fix, alosca, 50 kg N ha-1, cattle manure, legume fix + cattle manure, alosca + cattle manure and control. The result showed that Legume fix had the highest grain N uptake (90.51 kg N ha-1) which differed significantly (P≤0.001) from the rest of the treatments. At Guinea savannah legume fix gave the highest N uptake value (95.53 kg N ha-1) which was significantly different from all treatments except legume fix + cattle manure. However, 50 kg N ha-1 gave the least (48.64 kg N ha-1) even lower than the control and differs significantly with the rest of treatments (P≤0.001). Legume fix gave the highest P uptake value (9.66 kg P ha-1) which significantly differed from all other treatments. At Sudan savannah, significant differences (P ≤ 0.001) occurred between some of the treatments. Alosca + cattle manure recorded the highest K uptake (49.99 kg K ha-1). Result for the fixed N in the Sudan and Guinea savannahs soybean field revealed a significant difference between the treatments and the control.

In this research, laboratory studies were conducted to evaluate the effects of furfural urea as a slow release N fertilizer in an alfisol of Nigeria Savanna in the year 2009/2010 season. Incubation studies revealed that released N through mineralizatoin and microbial activities had confirmed that the compound may stay longer in the soil than urea. The method used for the research is completely randomised design with three repetitions, which consists four nitrogen levels each of urea and furfural urea and an absolute control. Attention is being directed towards slow release compounds. The controlled or slow availability supplies N continuously over an extended period , thus, avoiding the need for repeated application of conventional water soluble fertilizers. The mineralization of both fertilizers differ, the first, and the third to the fourth week should be synchronized with demand in further studies.

A study was conducted on the distribution of potassium in the surface soil of Kano University of Science and Technology teaching, research and commercial farm, Gaya during 2018/2019 session. The contents of different forms of potassium were observed. Water soluble, exchangeable, non-exchangeable, mineral and total potassium were determined in surface soil (0–15cm) in KUST teaching, research and commercial farm, Gaya. The results showed that the average values for water soluble K, exchangeable K, non-exchangeable K, mineral K and total K were: 0.14, 0.18, 0.35, 1.36 and 3.92 Cmol/Kg soil respectively. The values for K saturation percentage (KSP) ranged between 0.12–019 and exchangeable K between 0.13–0.20 Cmol/Kg clay. There was a wide variation in the values of various forms of K and among indices associated with mineral composition in different soils. The results show that the values of K form in most of the studied soils are quite low. Consequently, the supplying power of potassium in these soils is low and the need for potassium fertilizer is recommended.