Most of the soils of Nepal had a higher potassium (K, expressed as K2O) level inherently. Later in 1976, the Government of Nepal has recommended K fertilizer rate at 30 kg K2O ha-1 in rice-wheat cropping systems. However, those crops began showing K deficiency symptoms in recent decades, which could be due to a large portion of soils with depleted K level or the insufficient input of K fertilizer for crop production. This study explored a limitation of K nutrient in the crops by establishing field trials from 2009–2014 at three agro-ecozones i.e., inner-Terai (2009–2010), high-Hills (2011–2012), and Terai (2012–2014) in Nepal. Seven rates of K fertilizer at 0, 15, 30, 45, 60, 75, and 90 kg K2O ha-1 were replicated four times in a randomized complete block design, where crop yields and yield-attributing parameters of rice-wheat cropping system were recorded. Results revealed that an increase in K rates from 45 to 75 kg K2O ha-1 under inner-Terai and Terai conditions and 45 to 60 kg ha-1 under high-Hills conditions produced significantly higher grain yields compared to the recommended K dose. Economically, the optimum rate of K fertilizer should not exceed 68 kg K2O ha-1 for rice in all agro-ecozones, or 73 kg K2O ha-1 for wheat in inner-Terai and 60 kg K2O ha-1 for wheat in high-Hills and Terai. Our findings suggest to increase potassium application in between 1.5 to 2.5 times of the current K fertilizer rate in rice-wheat cropping system of Nepal that need to be tested further in different locations and crop varieties.

Relay cropping of maize with fingermillet (maize/fingermillet) is the predominant cropping system for sustaining food security situation in the hilly regions of Nepal. In this region weed pressure severely reduces crop yields. Basic information on weed species composition, biomass production and their effect on crop yields and economics are lacking for this region. This information will be necessary to develop effective weed management strategies for the future. In light of this an empirical study was carried out in two representatives mid hill districts of Parbat and Baglung during summer season of 2010/2011 in Nepal. A total of 10 major weed species with densities of 172 in Parbat and 311 per 0.25m2 area in Baglung were observed. The highest percentage of both relative and absolute densities were recorded for Ageratum conyzoides in Parbat and Polygonum chinensis in Baglung. Weed infestation under farmers practice of crop management reduced the grain yield of maize by 1.985 Mt ha-1 (117%) in Baglung and 1.760 Mt ha-1 (108%) in Parbat. Similarly, in finger millet it was 0.489 Mt ha-1 (63%) in Baglung and 0.403 Mt ha-1 in Parbat. Similarly, the combined yield of both the crops was also significantly reduced by 79.3% and 61.7% in Baglung and Parbat respectively. Hence, weeds are directly affecting the crop performance in the region. Therefore, there is an urgent need to develop an alternative crop production system in the hills. DOI: http://dx.doi.org/10.3126/ijasbt.v2i3.10790Int J Appl Sci Biotechnol, Vol. 2(3): 275-278

Under rainfed rice-wheat cropping system, experiments were conducted on wheat variety Annapurna-2 from 1998 to 2002 to study the effect of continuous application of inorganic and organic fertilizers in longer run on wheat production and soil properties in alluvial soil of Khumaltar, Lalitpur at 1365 msal. Eleven different fertilizers combinations comprised of inorganic  and organic fertilizers were used. The results of the five-year experiment  indicate that the applications of optimal level of inorganic fertilizers could  supply the plant nutrients to wheat crop to produce sustainable yield. On the other hand, organic fertilizers could help to increase the crop yield and maintain soil fertility at the same time. Residual effect of available  phosphorus applied in previous rice crop had significant response on wheat yield. For maintaining soil fertility, application of FYM and incorporation of  crop residue into soil are worth practicable.Nepal Agric. Res. J. Vol. 9, 2009, pp. 40-48DOI: http://dx.doi.org/10.3126/narj.v9i0.11640

The response of two pipeline potato clones to various levels of major nutrients (N: P2O5 and K2O) was studied during 2010/11 to 2011/12 at Hattiban Potato Research Farm, Khumaltar, Lalitpur. An experiment was laid out in a split plot design with three replications considering combinations of six different fertilizer levels as the main plot and three potato clones as sub-plot. The use of different doses of chemical fertilizers and 20 mt/ha farm yard manure (FYM) did not bring any improvements on soil properties. However, soil pH was slightly improved. The effect of different doses of chemical fertilizers was non-significant on plant emergence (at 30 DAP), ground cover and plant uniformity at 55 DAP. However, increased dose of N and K fertilizer gave taller plants and increased number of main stems per plant. Variety Kufri Jyoti performed better than both of the tested clones in the parameters such as plant emergence, ground cover and number of main stems per plant. Interaction effect was highly significant on number of stems per plant. Highest number of under and seed sized tubers were produced in the treatment with 100:100:60 N: P2O5: K2O kg/ha with 20 mt/ha, whereas highest number of over sized potato tubers were produced in the treatment 150:100:60 N: P2O5:K2O kg/ha and 20 mt/ha FYM. Total number of tubers and total weight (kg) was obtained highest in the treatment of 100:100:60 N: P2O5:K2O kg /ha with 20 mt/ha FYM. Variety Kufri Jyoti is still better yielding if there is no late blight disease in growing season. Though numbers of undersize and seed size tubers were produced highest from clone L 235-4, variety. Kufri Jyoti potato variety still is doing better in hill conditions of Nepal if the environment is not conducive to Phytophthora pathogens. Variety Kufri Jyoti has been able to produce highest yielded (30.9 t ha-1) in the application of 150:100:60 N: P2O5:K2O kg/ha and 200:100:60 N: P2O5:K2O kg/ha with 20 mt/ha FYM, whereas clone L 235-4 gave the highest yield (29.4 t ha-1) and clone CIP 389746.2 yielded highest (25.5 t ha-1). DOI: http://dx.doi.org/10.3126/njst.v14i2.10410 Nepal Journal of Science and Technology Vol. 14, No. 2 (2013) 9-16

An experiment was conducted to evaluate the effect of organic and conventional nutrient management on post harvest status of Broad Leaf Mustard (Brassica juncea var. rugosa) in field at Dakshinkali Municipality-2, Kathmandu, Nepal during the year 2016-2018. The experiment was laid out in a Randomized Complete Block Design. There were 13 treatments viz. T 1 (24 t ha-1. farm yard manure (FYM), T 2 (6 t ha-1. vermicompost), T 3 (4 t ha-1. poultry manure), T 4 (12 t ha-1 compost), T 5 (½ N: P 2 O 5 : K 2 O + 3 t ha-1 vermicompost), T 6 (¾ NPK + 1.5 t ha-1 vermicompost), T 7 (½ NPK+12 t ha-1 FYM), T 8 (¾ NPK +6 t ha-1 FYM), T 9 (½ N: P 2 O 5 : K 2 O + 2 t ha-1. poultry manure), T 10 (¾ N: P 2 O 5 : K 2 O +1 t ha-1 poultry manure), T11 (½ N: P 2 O 5 : K 2 O + 6 t ha-1 compost), T 12 (¾ N: P 2 O 5 : K 2 O + 3 t ha-1. compost) and T 13 (control) with three replications. In the study, maximum shelf life (8.67 days) was recorded in T6 (¾ N: P 2 O 5 : K 2 O + 1.5 t ha-1. vermicompost) and maximum organolaptic test score out of ten (7.72 Score) was detected in T 2 (6 t ha-1. vermicompost) while the maximum vitamin C (75.00 mg/100gm) and vitamin A (13.57 mg/g) were detected in T 5 (½ N: P 2 O 5 : K 2 O + 3 t ha-1 vermicompost)in green leaf of Broad Leaf Mustard.