Based on our findings, it can be concluded that application of Zn in transplanted rice is essential to harvest profitable yield under acidic soils of NEH region of India. Combined application (soil and foliar) was more effective instead of soil or foliar application alone. Successive yield increment of rice was noticed up to the application of Zn 7.5 kg/ha + foliar spray of Zn @0.5% at panicle initiation and booting stages. Thereafter productivity of rice slightly declined with increases of Zn doses in acidic soils. The application Zn @7.5 kg/ha + foliar spray of Zn @0.5% significantly improved yield attributing parameters of rice over control. Among the Zn nutrition treatments, application of Zn @7.5 kg/ha + foliar spray of Zn @0.5% registered 4.5% higher grain yield over its soil application. With regards to the soil biological properties successive increase of Zn doses improved the soil biological properties up to the application of Zn @10 kg/ha + foliar spray of Zn @0.5%. However, it remains statistically at par with Zn @7.5 kg/ha + foliar spray of Zn @0.5% at most of the growth stages of rice. Hence, application of Zn @7.5 kg/ha + foliar spray of Zn @0.5% at panicle initiation and booting stages is a profitable option for sustainable rice production in NEH, India besides sustaining the soil biological properties.

Boron plays an important role in crop nutrition. Cauliflower expresses its sensitivity towards boron application which ultimately decides the potential of crop yield and the quality of curds. In this study, we presented the assessment of the critical level of soil boron concentration by graphical and statistical procedures using cauliflower as a test crop. Thirty (30) soil samples collected from three rice growing sub-division of Imphal-west district were used for conducting the pot experiment. The experiment was laid out in a Completely Randomized Design with six treatments replicated thrice. The treatments setting were as follows: T0= Control, T1= 0.5 mg B kg-1 soil, T2= 1 mg B kg-1 soil, T3= 1.5 mg B kg-1 soil, T4= 2 mg B kg-1 soil and T5= 2.5 mg B kg-1 soil. The plants were harvested at curd formation stage and used for estimation of the critical limits of boron. The critical level of boron concentration in soil and plant was found to be 0.46 and 24.50 mg kg-1, respectively, by graphical procedure, whereas by statistical procedure it was found to be 0.45 and 24.59 mg kg-1 in soil and plant, respectively. It was evident that critical limits worked out by both the procedures, i.e., graphically and statistically, were closely related. These values may be used to predict the response of cauliflower to the applied boron. The range between the deficiency and toxicity for boron in plants is little, therefore utmost care in management should be taken.

An incubation study was conducted in the laboratory of College of Agriculture, Central Agricultural University, Manipur, India, to know the transformation of applied Boron (B) in soils at field capacity. Soil samples was collected periodically at 0, 30, 60 and 90 days after incubation (DAI) and analyzed for different fractions of B. The experiment was carried out under completely randomized block design (CRD). Altogether there were 6 treatment replicated thrice namely, T0= Control, T1= 0.5 mg B kg-1 soil, T2= 1 mg B kg-1 soil, T3= 1.5 mg B kg-1 soil, T4= 2 mg B kg-1 soil and T5= 2.5 mg B kg-1 soil. From the incubation experiment, it was inferred that with applied B, the organically bound B fraction was higher next to residual form when compared to other forms of B. At 30 days of incubation, different fractions of B showed an increasing trend for added levels of B compared to control due to recently applied B into the soil solution. However, at 60 and 90 days different fractions of B in the soil started decreasing due the fact that boron entered into tightly bound state within the soil. In general, B fertilization increased the availability of B content in soil and hence increased its availability to the crop. The sequence of the content of different fractions of B in an acid soils of Imphal-West district was readily soluble-B>organically bound-B>oxide bound-B> specifically adsorbed-B> residual-B.

A pot experiment was conducted with thirty soils of varying characteristics for selecting the most suitable chemical extractant for available sulphur. Rice variety CAU-R1(Tamphaphou) was grown in pots treated with and without sulphur for eight weeks. At harvest dry matter of rice was recorded. The average dry matter yield increased significantly @30 kg ha-1 levels of S application. Sulphur in the soils was extracted with four different extractants. The extractable S of the soils varied considerably with the soils and the extractant used. In term of the efficiency of extraction,the extractants were in the order : 500 ppm Ca(H2PO4)2.H2O > 0.5M NaHCO3 > 0.5M NH4OAc > 0.15% CaCl2. Available sulphur extracted by 0.5M NH4OAc showed the highest correlation with Dry Matter Yield (0.510882**) , Total Plant Uptake (0.548974**), Bray’s % Yield (0.514887**), Bray’s % Uptake (0.70565**).Therefore,0.5M NH4OAc extractant was rated as most promising extractant for assessing S availability for rice in acid soils of Manipur. pH (-0.12481, -0.04153837, 0.15850443, -0.02106*), EC (-0.2696*,-0.08246, -0.21701*,-0.28734*),CEC (-0.27441*, -0.24183*, -0.18531, -0.28287*), sand (-0.00152, -0.0166 , -0.10168, 0.121165), silt (-0.00858 , -0.15039, -0.10699, 0.030722), Ca2+ (-0.1528, -0.1056 , 0.007184 , -0.09847) and Mg2+ (-0.27248*, -0.16614, -0.07896, -0.24056*) had negative correlations with all extractants of S. The positive relationships of almost all extractants of sulphur with clay texture (0.040966, 0.20296*, 0.306651**,-0.0879), organic carbon(0.096396, 0.32224**, 0.201351*, -0.09377), nitrogen (0.036851, 0.203472*, 0.24579*, -0.06179), phosphorus (0.301882**, 0.268273719*, 0.322386047**, 0.209681*) and potassium (0.023932, -0.00667852, -0.04825616 , 0.079524) were observed.