DETERMINING SOIL LIMITING FACTORS FOR CABBAGE IN THE MAIN VEGETABLE PRODUCTION AREA IN LAO CAI PROVINCE

MINISTRY OF EDUCATION MINISTRY OF AGRICULTURE AND TRAINING AND RURAL DEVELOPMENT VIETNAM ACADEMY OF AGRICULTURAL SCIENCES TRẦN THỊ MINH THU DETERMINING SOIL LIMITING FACTORS FOR CABBAGE IN THE MAIN VEGETABLE PRODUCTION AREA IN LAO CAI PROVINCE Major: Soil science Code : 962 01 03 SUMMARY OF DOCTORAL THESIS IN AGRICULTURE HA NOI, 2022 The study was completed at: VIET NAM ACADEMY OF AGRICULTURAL SCIENCES Scientific instructors: Associated Prof Dr Nguyen Van Bo Associated Prof Dr Tran Minh Tien Reviewer 1: Associated Prof Dr Le Van Thien Reviewer 2: Associated Prof Dr Pham Quang Ha Reviewer 3: Associated Prof Dr Ho Quang Duc The thesis will be defended at the Institue’s Thesis Evaluation Council at the Vietnam Academy of Agricutural Sciences: Time : , date : / ./2022 The thesis can be found at the: Vietnam National Library The Library of Vietnam Academy of Agricultural Sciences The Library of Soils and Fertilizer Research Institute INTRODUCTION Rationale of the research Cabbage (Brassica oleracea var Capitata) plays a significant role in vegetable production in cold winter of Northern Vietnam regions Advantages of cabbage are easy to grow, easy to store, easy to transport Especially it brings high productivity and has a large consumption market Lao Cai has the advantage of terrain, cool climate all year round, so it is considered an advantageous locality for vegetable production In particular, Sa Pa town and Bac Ha district, Lao Cai province are the areas with the most favorable conditions, which can grow many kinds of vegetables Due to the influence of altitude, this region has a climate that allows cabbage to be grown all year round with good yield and quality However, cabbage productivity in Sa Pa and Bac Ha is not high compared to the potential, the annual output is still low compared to local consumption demand, not to mention export In addition to the causes due to the negative impacts of pests and diseases, natural disasters such as rain, frost, etc., the soil and nutrient management in the soil are extremely important factors directly related to the growth and development of crops in general and cabbage in particular Due to the change in fertilization and farming regimes, on the other hand, the cultivated land in Sa Pa and Bac Ha is mainly distributed on sloping terrain, with heavy rain with high intensity leading to erosion and washing away of the topsoil decrease in cation exchange capacity and base satiety, increase in acidity, increase in phosphorus fixation ability these are the causes leading to deficiency/excess, formation of limiting factors in soil, reducing plant yield planting, and reducing production efficiency In order to make Lao Cai become one of the major producers of branded cabbage in the market, it is necessary to expand cabbage production in households However, to boost cabbage production, it is necessary to have appropriate technical solutions to improve production efficiency First, it is necessary to determine the limiting factors in the soil, from which to determine the appropriate farming techniques, to use fertilizers reasonably according to the requirements of the crop, in accordance with the cultivation conditions of the locality method, not only increase crop productivity and, production efficiency but also improving soil fertility towards building an efficient and sustainable vegetable farming system Therefore, it is urgent to conduct "Determination soil limiting factors for cabbage and vegetable crops in the main vegetable production area in Lao Cai province" Research purpose 2.1 Purposes Improve productivity and efficiency of cabbage production in the main vegetable production area in Lao Cai province 2.2 Requirements - Assessing the current situation of cabbage production and soil characteristics of cabbage cultivation in the main vegetable production area of Lao Cai province - Determining the limiting factors of soil and soil nutrients for cabbage productivity in the main vegetable production area of Lao Cai province - Proposing solutions to overcome the limiting factors of soil and soil nutrients for cabbage, improving productivity and efficiency of cabbage cultivation in Lao Cai province - Build tests to verify the scientific conclusions that have been determined Research scope and object 3.1 Research scope Spatial scope: - The study was conducted in the main vegetable production areas in Sa Pa town and Bac Ha district, Lao Cai province - Experiments on nutritional balance and building experimental models to verify scientific conclusions in the study were carried out on a household scale Time: - Primary data: Collected during 2014-2015 - Secondary data: Collected during the period from 2014-2020 - Experiment and model: Implemented from 2016-2021 3.2 Research subjects - Vegetables: Cabbage varieties Grand KK Cross and New star cross - Soil: Soil properties pH, OC, TBC, CEC, BS and some macronutrients, intermediate nutrients and micronutrients in the soil Scientific and practical significance of the research 4.1 Scientific significance - Provide scientific data on limiting factors in soil, soil nutrients for cabbage productivity in Lao Cai and some remedial measures, as a premise for further research - Provide scientific data for further studies on cabbage in Vietnam 4.2 Practical significance - The results of the study are the scientific basis for building a reasonable fertilizer application process for cabbage plants in Sa Pa town and Bac Ha district, Lao Cai provinc,e and other localities with similar conditions, contributing to change production practices, shift towards commodity agriculture, improve profitability and sustainability in vegetable production of farmer households, farms and cooperatives producing vegetables and cabbage, contributing to hunger eradication, poverty reduction for ethnic minorities in the province's highlands - Contributing to improving soil fertility, protecting soil resources, protecting the environment and building a sustainable vegetable farming system New contributions of the thesis - A comprehensive study on the limiting factor in soil and nutrient management for cabbage in Sa Pa town and Bac Ha district, Lao Cai province in particular and the northern mountainous region of Vietnam in general - Identified the trace element Bo (B) as an organic medicine for cabbage in the study area and determined the appropriate amount of lime, nitrogen and phosphorus for cabbage in the study area - Initially, using cabbage leaf analysis to determine the deficiency or excess of 12 nutritional elements N, P, K, Ca, Mg, S, B, Mn, Fe, Cu, Zn and Mo for cabbage plants in Lao Cai, not only as a basis for the adjustment of suitable fertilizers, but also provide a data set to analyze the macronutrients, intermediate nutrients and micronutrients in cabbage leaves grown in the mountainous areas in northern Vietnam, as a basis for other studies on cabbage Thesis layout The thesis consists of 135 pages (excluding references), divided into parts: Introduction pages; chapter I: Review of research papers, 42 pages; chapter II: Materials, contents and research methods, 19 pages; chapter III: Research results and discussion, 67 pages; Conclusion and recommendations, pages ; published works related to the thesis, page; documents and references, 18 pages with 149 references in Vietnamese, English and online newspapers The thesis has 25 tables, 16 figures and charts Chapter LITERATURE REVIEW 1.1 Cabbage production Asia leads the world in cabbage area and production, especially China In Vietnam, cabbage is also grown on a large scale for commodity production and is grown mainly in the northern midland and mountainous provinces, the Red River Delta and the Central Highlands Sa Pa town and Bac Ha district in Lao Cai province have suitable climate and soil conditions for growing vegetables, especially cabbage Lao Cai cabbage has a reputation for quality such as tastier, crisper, stronger flavor than cabbage in other localities Although the quality is good, the productivity of Lao Cai cabbage is not high compared to the potential and the annual output has not yet met the consumption demand 1.2 Research results on the limited factors of soil properties and plant nutrients in soils for cabbage production The causes of reducing cabbage yield due to farming techniques are lack of irrigation, excessive fertilization, imbalanced fertilization There are many methods to identify the limiting factor in soil and soil nutrients The most common way to identify the limiting factor is the FAO traditional land evaluation methods, Conduct field defect experiments; Diagnose nutrient deficiency/excess of crops through: (i) visible deficiency symptoms; (ii) crop analysis; (iii) soil analysis and (iv) determination of the nutrient balance of crops Although vegetable production in Vietnam in general and in Lao Cai province in particular plays an important role, there are few studies on the soil limiting factors for vegetable and cabbage cultivation Therefore, it is necessary to study the limiting factors of soil and soil nutrients for cabbage in Vietnam 1.3 Research results on the solutions of mitigating limited factors of soil properties and plant nutrients in soils for cabbage production In addition to the study to determine the appropriate dosage and ratio of macronutrients (N, P, K), some solutions to overcome the limiting factors on soil and soil nutrients for cabbage plants have also been mentioned such as: Applying lime helps reduce acidity, limit diseases from soil and create favorable conditions for plants to absorb nutrients; Add trace elements such as molybdenum, spray 125 g of sodium- or ammonium molybdate in 500 liters of water per hectare when there are signs of deficiency; foliar spraying of iron sulfate (1%) to overcome iron deficiency on alkaline and lime soils; foliar spray kg of manganese sulfate or 2-3 kg of manganese oxide/ha when there are symptoms of plant deficiency; used at a dose of kg Solubor/ha in areas with boron deficiency Chapter MATERIALS, CONTENTS AND METHODS 2.1 Materials 2.1.1 Experimental cabbage variety Grand KK Cross and New Star Cross, this is a popular cabbage variety in the area during the study period 2.1.2 Fertilizers and soil amendments Nitrogen urea (46% N), superphosphate (17% P2O5), potassium chloride (60% K2O); boric acid (H3BO3); copper(II) chloride dihydrate (CuCl2.2H2O); zinc sulfate heptahydrate (ZnSO4.7H2O) and ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24.4H2O); Lam Thao NPK 5:10:3, farmyard manure (with analysis of N, P, K); lime powder Ca(OH)2 or limestone powder CaCO3 2.2 Content research - Evaluation of the current situation of vegetable production and soil characteristics of cabbage and vegetables in the main vegetable production area of Lao Cai province - Determination of limiting factors on soil and soil nutrients for cabbage in the main vegetable production area of Lao Cai province - Researching solutions to overcome some limiting factors and improve the efficiency of cabbage cultivation in the main vegetable production areas of Lao Cai province - Build tests to verify the scientific conclusions that have been determined 2.3 Methods - Data collection: Participatory rural appraisal (PRA) - Soil samples were taken according to TCVN 7538-2:2005 Soil samples were analyzed according to Vietnamese standards (TCVN) The organic health hazards in soil with cabbage were determined according to the guidelines of FAO (1976) - Cabbage leaves were taken at the end of vegetative growth period, leaf samples were analyzed for parameters by plasma mass spectrometry method, N and S criteria were analyzed by combustible gas analyzer The threshold for nutrient deficiency/excess in leaves was compared with published data in cabbage leaves (Reuter & Robinson, 1997; Bryson & Mills, 2014) - Nutrient balance at household scale is determined based on the partial nutrient balance calculation method (Achim Dobermann, 2007) - The experiment on lime in pots and jars included treatments (0; 0.25; 0.5; 1.0; 2.0; 3.0 and 4.0 tons of lime/ha) and replicates - Field experiments were arranged in a completely randomized block design Lime experiment has treatments (0; 0.25; 0.5; 1.0; 2.0 and 4.0 tons of lime/ha) with replicates on the background with and without micronutrients The nitrogen experiment had treatments (30; 90; 150; 210 and 270 kg N/ha) with replicates The experiment on phosphorus had treatments (0; 30; 60; 90, 120 and 150 kg P2O5/ha) with reminders on fertilized and unlimed substrates The microbiological experiment consisted of formulas: Control (no fertilization); Zn (0.2%); B (0.2%); Mo (0.1%); Cu (0.2%) and fully applied Zn + B + Mo + Cu with replicates - The experimental model was arranged according to the "Onfarm Research" method on the fields of farmers, including 02 formulas: Farmer (farmer-based farming) and Experimental (lime supplement, N-P-K balance and micronutrient supplements) Chapter RESULTS AND DISCUSSIONS 3.1 The situation of cabbage production in the study area 3.1.1 Characteristics of the study area Sa Pa and Bac Ha have a temperate climate, favorable for the development of many crops, suitable for building concentrated vegetable production areas, especially temperate vegetables such as cabbage, kohlrabi, and cauliflower 3.1.2 Status of vegetable production and methods of cultivating cabbage in the study area Some limitations for vegetable production in the study area: - High mountainous terrain, strongly dissected, affecting farming, transportation and production expansion - Soil is sloping, easily eroded, washed away, arable land is often poor in nutrients, acidic and not porous - Low production level of farmers greatly affects the efficiency of vegetable production - Unbalanced fertilizer use (only focusing on N, P) and unevenly across regions In Sa Pa town (the Kinh farmers) the amount of macronutrient fertilizer (NPK) is more than recommended, while in other regions (ethnic farmers) often applY very little, much lower than the recommended amount - Lime is rarely used for soil improvement - Many plant diseases, especially cabbage root swelling disease - Most of the area for growing vegetables and producing vegetables is still spontaneous by the people - Cabbage yield is much lower than potential 3.2 Soil limiting factors and soil nutrients for cabbage 3.2.1 Determination of organic health of soil through assessment of suitability of soil characteristics for cabbage The results of analysis of 96 soil samples in cabbage gardens of 96 surveyed households (57 samples in Sa Pa and 39 samples in Bac Ha) are shown in Table 3.6 Table 3.6 Statistical analysis results of soil samples for cabbage cultivation Criteria Min Max Mean SE SD Range pHH2O pHKCl OM, % Nts, % P2O5ts, % K2Ots, % P2O5dt, K2Odt, CECmeq/ 100g soil, TBCmeq/ 100g soil, BS% 4,00 3,50 1,06 0,06 0,09 0,13 0,86 4,32 7,48 7,05 7,37 0,36 0,67 2,89 96,13 67,00 5,41 4,48 3,32 0,16 0,22 1,27 15,00 19,47 0,07 0,07 0,12 0,01 0,01 0,06 1,77 1,21 0,65 0,72 1,19 0,05 0,12 0,62 17,38 11,89 4,76 - 6,06 3,76 - 5,20 2,12 - 4,51 0,11 - 0,21 0,11 - 0,34 0,65 - 1,89 2,38 - 32,38 7,57 - 31,36 5,08 20,64 11,17 0,31 3,02 8,15 - 14,19 0,85 6,23 3,05 0,11 1,12 1,93 - 4,18 8,57 66,53 28,26 1,10 10,80 17,47 - 39,06 Compared with the requirements for soil properties of cabbage (FAO, 1976), the land for cabbage cultivation in Sa Pa and Bac Ha towns is evaluated as follows: - Non-restrictive factors: Soil organic content (OC), phosphorus content (P2O5) in soil - Factors at medium limit: nitrogen content (N%) in soil, potassium content (K2O) in soil, total alkaline cation exchange in soil (TBC), cation exchange capacity in soil (CEC) soil) and basic saturation (BS) in the soil - Factors that are severely limiting: Soil acidity (pH) 3.2.2 Determination of limiting factors on soil and soil nutrients through analysis of cabbage leaves The content of macro- and intermediate nutrients in leaves (N, P, K, S and Ca) varied greatly (Table 3.8), possibly caused by the difference in the amount of fertilizer used by each household For the remaining elements, the difference in nutrient content in leaves was relatively small, except for Fe in Sa Pa (110–420 mg/kg) 11 for cabbage while Cu deficiency has not yet been clearly demonstrated Table 3.10 Effect of micro-spray treatments on nutritional content of cabbage leaves in Sa Pa and Bac Ha Treat ment CT1 CT2 CT3 CT4 CT5 CT6 Nutrients Micronutrient supplement treatment No supplement B Cu Mo Zn Zn+B+Mo+Cu Micronutrient content in cabbage leaves (mg/kg) B Cu Zn Mo B Cu Zn Mo Sa Pa Bac Ha 5,8 2,7 22 0,9 3,3 3,5 27 0,13 24 3,5 6,0 4,3 23 21 23 21 23 18 1,2 0,7 13 0,6 7,2 23 3,3 3,4 2,9 21 24 26 26 27 25 0,16 0,15 4,1 0,12 3,9 2,7 2,8 2,7 2,8 2,3 3,3 3,4 3,5 3,7 3,2 3.2.3 Determination of limiting factors on soil and soil nutrients for cabbage vegetables through determination of nutrient balance at household scale There is a significant difference in fertilizer use by households in Sa Pa and Bac Ha (Figures 3.3 and 3.4) The average amount of fertilizer applied by households in Sa Pa tend to be higher than in Bac Ha, especially phosphate fertilizer Yield and N, P2O5 and K2O contents of cabbage grown in Sa Pa were higher than in Bac Ha Despite the high productivity, households in Sa Pa have low fertilizer efficiency, due to the significant excess of fertilizer over demand and the loss of crops For farmers in Bac Ha, household number 07 has the lowest amount of fertilizer, however, the total yield of fresh biomass is quite high and the efficiency of fertilizer use is the highest In contrast, for household number 02 in Sa Pa, although the number of nutrients applied to the plants was the highest, the fresh yield and the efficiency of fertilizer use were the lowest (table 3.12) Among the three types of macronutrients, the use of K2O fertilizers is the most effective, especially in Bac Ha, all three households have a K 2O utilization coefficient in the range of 74.59-78.63% 12 Figure 3.3 Efficiency of using nutrients for cabbage of some households in Sa Pa Figure 3.4 Efficiency of using nutrients for cabbage of some households in Bac Ha The use of macronutrients, especially N, P2O5 and for cabbage plants both in the main and off-season is not effective, the amount of fertilizer exceeds the needs of the crop and the efficiency of fertilizer use is low The inappropriate use of fertilizers, especially nitrogen fertilizers, not only increases production costs, reduces plant disease resistance, attracts many pests, but also affects product quality and reduces storage and transport of products and adverse effects on the environment All of these problems lead to the reduction of economic efficiency and unsustainability of the production system and this is also one of the limitations in vegetable cultivation in the study area 13 Table 3.12: Total biomass, harvest index, nutrient removal in the harvest, fertilizer input and fertilizer use efficiency of cabbage Total No biomass -1 (ton ) Rate of nutrient Harvest removal (kg/ha) Fertilizer input (kg/ha) Fertilizer use efficiency (%) rate (%) N P2O5 K2O N P2O5 K2O N P2O5 K2O Sa Pa Household 01 Household 02 Household 03 Household 04 83,80 67,96 202,09 21,45 143,01 424,00 264,07 240,38 47,66 8,12 59,50 60,94 68,18 152,50 16,62 116,75 468,17 256,02 258,71 32,57 6,49 45,13 96,04 70,12 211,26 29,88 204,00 457,67 171,99 269,06 6,16 7,37 75,82 62,64 74,82 148,24 23,42 129,30 384,69 41,44 411,40 8,54 6,51 31,43 81,90 59,16 178,01 20,67 181,07 474,66 117,71 242,75 7,50 7,56 74,59 87,03 65,21 178,03 25,18 143,30 388,94 67,27 188,56 5,77 37,43 76,00 80,19 64,38 162,20 22,03 145,06 291,80 64,69 184,48 55,59 4,06 78,63 Bac Ha Household 05 Household 06 Household 07 3.3 Solutions to overcome some limiting factors on soil and soil nutrients for cabbage crops in Sa Pa and Bac Ha districts 3.3.1 Determine the appropriate amount of lime for cabbage The results of laboratory experiments on the effect of lime application on soil pH showed that: The pH of the soil reached a value close to neutral with the equivalent amount of Ca(OH)2 applied at 1.02.0 tons/ for soil samples in Sa Pa and from 0.5-1.0 tons for soil samples in Bac Ha 14 a) (b) Figure 3.5 Effect of lime levels on soil pHKCl after days (a) and after 15 days (b) The experiment of liming in the field (Figures 3.6 and 3.7) shows that: To improve the acidity of cabbage soil, raise the pH of the soil from acidic to neutral, the amount of lime Ca(OH)2 needs to be applied from 0.5 -2.0 tons/ha depending on soil properties and growing season Yields in the liming treatments were not higher or insignificantly higher than those in the non-lime treatments (a) (b) Ghi chú: BF pH đất trước thí nghiệm Figure 3.6: Effect of lime application levels on soil pH value of summer cabbage in Sa Pa (a) and Bac Ha (b) 15 (a) (b) Figure 3.7: Effect of liming levels on soil pH value of winter cabbage Experiment results of lime application combined with microspray Zn (0.2%) + B (0.2%) + Mo (0.1%) + Cu (0.2%) + Urea (0.5%) showed that: The yield of cabbage did not have a significant difference between the liming treatments compared with the nonliming formula, between different lime levels, there was no difference in cabbage yield and the difference between the two treatments other (if any) did not show a statistically significant difference (table 3.16) Table 3.16 Effects of liming levels on the substrate with added micronutrients on cabbage yield in the winter crop in Bac Ha Biomass yield (ton/ha) Head yield (ton/ha) T1 Lime application rate (ton Ca(OH)2/ha) 50,60 30,34 CT2 0,25 52,84 31,19 CT3 0,50 46,20 26,45 CT4 1,00 50,52 29,81 CT5 2,00 49,43 28,06 CT6 4,00 51,48 29,81 CV% 10,3 14,7 LSD05 7,79 6,49 CT 16 3.3.2 Determine the appropriate amount of nitrogen fertilizer for cabbage The results of the experiment to determine the amount of nitrogen fertilizer for cabbage (table 3.18) showed that: Table 3.18 Effect of nitrogen fertilizer on cabbage Nitrogen Biomass application yield rate (kg (ton/ha) N/ha) 30 25,73 90 63,00 150 68,50 210 87,78 270 78,80 15,7 16,1 CT CT1 CT2 CT3 CT4 CT5 CV% LSD05 Nitrogen Agronomic Head yield efficiency efficiency (tonn/ha) (%) (kg/kg N) 16,30 40,23 43,30 59,13 43,90 21,2 13,4 265,56 180,00 203,81 102,22 146,63 7,71 36,49 (25,72) 100 100 80 80 -1 Marketable Yield (t ) -1 Total Biomass Yield (t ) Total biomass and cabbage yield both increased with increasing nitrogen fertilizer from 30 Kg N/ha to higher levels (90, 150, 210 and 270 kg N/ha) However, it reached the highest level at 210-240 kg N/ha (Figure 3.9) and decreased when the amount of nitrogen fertilizer increased to 270 kg N/ha This result shows that the appropriate level of nitrogen fertilizer for cabbage in this crop is 210240 kg N/ha with the agronomic efficiency of the fertilizer reaching 203.81 kg of cabbage per kg of N applied Yield peaked at 210 kg N/ha and was significantly different from the rest of the fertilizers 60 40 60 40 20 20 0 30 60 90 120 150 180 -1 N Rate (kg ) 210 240 270 300 30 60 90 120 150 180 210 240 270 300 N Rate (kg ha-1) Figure 3.9 Effect of nitrogen fertilization on total biomass (left) and yield (right) of cabbage 17 3.3.3 Determine the appropriate amount of phosphorus fertilizer for cabbage Experimental results (table 3.19) showed that on the background without lime, the phosphate content also had a very clear effect on the corn yield The highest yield was at 150 kg P2O5/ha with 24.20 tons/ha, but the agronomic effect was low Furthermore, the correlation between the amount of phosphate and the yield of cabbage also showed a downward trend starting at the level of application of 150 kg P2O5/ha (Figure 3.12) Therefore, in this experiment, the application of 120 P2O5/ha was suitable and effective for cabbage in the study area Table 3.19 Effect of phosphate fertilizer on cabbage yield on non-lime substrates Application Biomass Head Agronomic Phosphate Treatment rate (kg yield yield efficiency efficiency P2O5/ha) (ton/ha) (tonn/ha) (kg/kg N) (%) CT1 29,95 10,51 CT2 30 34,96 15,32 160,33 45,77 CT3 60 40,96 18,68 136,17 21,93 CT4 90 42,78 20,39 109,78 9,15 CT5 120 44,52 22,03 96,00 8,04 CT6 150 46,25 24,20 91,27 9,85 CV (%) 11,2 17,9 LSD0,05 6,75 5,01 - Figure 3.12 Effect of phosphorus on the unlimed substrate on total biomass (left) and yield (right) of cabbage 18 On the liming substrate, the effect of phosphate fertilizer application was similar to that of no liming (Table 3.20), the highest corn yield was at 120 kg P2O5/ha with a yield of 22.03 tons/ha with a yield of 22.03 tons/ha, agronomic efficiency was 96 kg/kg P2O5 and started to trend sideways (Figure 3.12), the yield was lower at 150 kgP2O5/ha Thus, on the liming background, the level of phosphorus suitable for corn is 120 kg P2O5/ha This is also the level of fertilizer with the highest agronomic efficiency Table 3.20 Effect of phosphate fertilizer on cabbage yield on liming substrate CT CT1 CT2 CT3 CT4 CT5 CT6 Application rate (kg P2O5/ha) 30 60 90 120 150 CV (%) LSD0,05 Biomass Agronomic Head yield yield efficiency (tonn/ha) (ton/ha) (kg/kg N) 29,94 11,08 33,43 12,84 58,67 36,94 14,99 65,17 37,77 15,53 49,44 42,32 19,35 68,92 40,84 16,77 37,93 13,31 30,05 7,40 7,05 Phosphate efficiency (%) 15,88 16,74 3,60 24,60 (13,33) Figure 3.14 Effect of phosphorus on liming substrate on total biomass (left) and yield (right) of cabbage ... 75,82 62, 64 74, 82 148 , 24 23 ,42 129,30 3 84, 69 41 ,44 41 1 ,40 8, 54 6,51 31 ,43 81,90 59,16 178,01 20,67 181,07 47 4,66 117,71 242 ,75 7,50 7,56 74, 59 87,03 65,21 178,03 25,18 143 ,30 388, 94 67,27 188,56... Household 04 83,80 67,96 202,09 21 ,45 143 ,01 42 4,00 2 64, 07 240 ,38 47 ,66 8,12 59,50 60, 94 68,18 152,50 16,62 116,75 46 8,17 256,02 258,71 32,57 6 ,49 45 ,13 96, 04 70,12 211,26 29,88 2 04, 00 45 7,67 171,99... 25,93 40 , 74 100,00 18,52 74, 07 18,52 within the appropriate threshold Excess Amount Ratio (%) Amount 12 27 27 20 16 22 24 27 20 44 ,44 100,00 100,00 3,70 74, 07 59,26 81 ,48 88,89 25,93 100,00 74, 07