Determinants of Inorganic Fertilizer Use Intensity on Cereal Crop among Smallholder Farmers: The Case of Toke Kutaye District, West Shewa Zone, Oromia National Regional State, Ethiopia

The study was aimed to analysis determinants of inorganic fertilizer use intensity on cereal crops among small holders in Toke Kutaye District, West Shewa Zone, Ethiopia. Correctional data were collected from 156 respondents using two stage random sampling methods. Data analyses were carried out using descriptive statistics and Double hurdle model. Result of the first hurdle reveals that out of twelve explanatory variables Sex ,Education, Off/non-farm income, Land size and Improved seed were determine positively whereas Age and Distance from nearest market determine small holders use of inorganic fertilizer negatively. The result of second stage of double hurdle model indicate that, out of twelve explanatory variables Sex, family size and Land size were positively affect extent (intensity) of inorganic fertilizer use whereas Age and Distance of household from nearest market determine use intensity negatively. Therefore, these results implied that there is a room to increase inorganic fertilizer use intensity on cereal crop productions. Hence, Farmers capacity to purchase this input beginning from lower income farmers to model farmers should be acknowledged; and should be designed the means to address those who have no ability to use inorganic fertilizer in their own farm through diverse development interventions.


Background of the Study
In Ethiopia, agriculture accounts about 42 percent of the GDP, employs about 85 percent of the labor force and contributes around 90 percent of the total export earnings of the country (FAO, 2016). About 15 million smallholders producing 95 percent of the national agricultural production which shows that the overall economy of the country and the food security of the majority of the population depend on small holder agriculture. For this reason, the growth of agricultural sector is taken as an engine and the last resort to take-off the national economy (CSA, 2018). Cereal yields in Sub-Saharan Africa are the lowest in the world, having stagnated at around 1 ton/ha for the past 50 years compared to 4 tons/ha in developing countries (Heffer and Homme, 2018).
Low rate of usage of inorganic fertilizer is due to a number of reasons including a thin network of agrodealers; lack of technical knowledge on appropriate fertilizers; lack of access to finance all along the value chain which prohibits the purchases of sufficient quantities to capture economies of scale; and high transport costs due to inadequate ports, rail and road networks (IFDC, 2015); Tamene (2017). These factors result in high costs, putting fertilizer beyond the reach of most farmers Jayne et al., (2018);Abate et al., (2014;Debrauw et al., (2014), (FAO, 2013).
As it is specified in the above elucidation, agricultural technology use is unquestionable for agricultural production to be enhanced the nation. Smallholder farmers should as well use it properly to feed their household sufficiently and become surplus producers for commercial product as input of industry (Mellor, 2014); Abdulkadir et al., (2017). The productivity of Ethiopian agriculture has been low and a number of According to Oromia Agriculture and Natural Resource Bureau (OANRB, 2019) repot shows the use of inorganic fertilizer for major cereal crops in 2019 production, inorganic fertilizer use intensity is 82 kg/ha, Farmers in Toke Kutaye use 98 kg/ha of inorganic fertilizer for their cereal crops which is below the blanket recommendation rate 200kg/ha (100DAP/NPS and 100UREA) (TKANRO, 2019) due to low input use, they suffered from low productivity of cereal productions.
Policy makers of the African nations and development specialists in agricultural sector in this day are giving evidence why productivity increment is quite below the population growth and the radical divergence of income inequalities among farmers of Africa compared with other side of developing nations. The problem is mainly connected with knowledge for input technologies supported by essential policy intervention. For instance, African farmers consume extremely low inorganic fertilizer in the world especially when compared to Asian farmers. Therefore, the specific target put in Abuja declaration in the summit of African Union members' countries through their agriculture ministers further conferred about to increase inorganic fertilizer use intensity by six fold in 2015 in SSA (ADB, 2007).
Inorganic fertilizer use intensity is still at low levels, and the efficiency of fertilizer use in raising output per unit of land is significantly lower in Sub-Saharan Africa than in Asia(Mellor, 2014); Abdulkadir et al., (2017). Several arguments are brought forward in the economics literature about possible reasons for the low fertilizer use in developing countries like Ethiopia. There is poor access to modern farming inputs which emanates from both supply and demand side constraints. Weak infrastructure and non-conducive policy environment together with institutional problems lead to relatively high input costs and the absence or late arrival of supplies legesse (2019). Cereal yields in Africa are lower than half the world average (FAO, 2010).
According to Agbahey et al., (2015) and Holden (2018) fertilizer use in Ethiopia, as in most SSA countries, is very low due to several constraints, these constraints pointing to two groups. The first group is the market-based constraints, which suggest that farmers do not use inorganic fertilizer because of a relatively high fertilizer to crop price ratio. The second group, the non-market-based constraints, emphasizes farmer's lack of knowledge about inorganic fertilizer use as well as land degradation, which lowers the returns to fertilizer application.
Cereal crop production has been lifted well above long-term levels. Although area expansion has been considerable, yield growth has accelerated more than area expansion particularly in the last few years.
However, the recent large yield increases do not seem to be explained by a sudden large increase in use of modern inputs and improved farm management. Similar stories can be told of other modern inputs: use of improved inputs did not expand in such an overwhelming rate, as the yield growth did Abegaz (2011).
Relatively low productivity of cereals, the national average grain yield of cereals in Ethiopia is relatively low amounting to about 1.7 tone per hecktar for teff, 2.1 tone per hecktar for barley,2.7 tone per hecktar for wheat, 3.8 tone per hecktar for maize and 2.5 tone per hecktar for sorghum in 2016 (CSA, 2017). This, amongst others, is due to the widespread use of low yielding varieties coupled with unimproved traditional practices that ultimately contribute to the low national average yield of major cereal in the country. Ethiopia's cereal crop yield levels are lower than the average yield in least developed countries Yiu and Pratt (2014).
National level inorganic fertilizer use and use intensity is still lower than the recommended rate of 200 kg per ha (100 kg of DAP and 100 kg of Urea) Demeke et al.(1998), Fufa and Hassen (2005), Alem et al.(2008, Endale in (2011). According to Toke Kutaye Agriculture and Natural Resource Office annual report shows, the average of inorganic fertilizer use intensity on cereal crops of small holder in the district is 98 kg/ha which is below the recommendation rate whereas the recommended inorganic fertilizer use in the district is 200 kg/ha(TKANRO,2019). Smallholder agricultural production remains low; particularly for cereal crops and major contributory factors include inorganic fertilizer price, inadequate supply and knowledge of using. Therefore this problem shows that, there is the research gap in the district and it needs to examine determinants of inorganic fertilizer use and its intensity use of households on cereal crop which is not carried out yet and needs to recommend possible solutions in the study area.

Description of the Study Area
Toke Kutaye district is located in West Shewa Zone, Oromia National Regional State, Ethiopia, which found at a distance of 126 km west of Addis Ababa and 12 km from Ambo town. It is bordered by Ambo district in East and North, Dire Inchini district in South and Liban Jawi in West. It lies between 8 0 50'0"N 37 0 30'0"E latitude and 9 0 5'0"N 37 0 55'0"E longitude with elevation between 1580 and 3144 meters above sea level, the optimum temperature is 10 0 C to 30 0 C and annual rainfall ranged from 800-1200mm. The district comprises in to three agro ecologies; namely, the lowland (27.6%) the midland (51.4%) and the highland (20.9%). There are also three types of soils in the district, these are vertisoils which is (27.3%) having black color and clay texture; the latosoils covers (47.7%) and other soils comprise of (25%) of the total land found in the district. The natural vegetation's in the district comprised of woods, bushes and remnant forests which were previously dense forest. The availability of mineral deposit sites has also confirmed. The extraction of sand stones from the aforementioned largest rivers including Indris River; gypsum and lime stone and coal are among the deposits found in the district (TKEDCO, 2019).
The district is known in surplus agricultural production relative to other districts of the Zone. This is due to relative favorable climatic condition even in the regional level. The proximity to Addis Ababa can also contribute to produce for the national market. It's irrigation potential and utilization is much better than other district of the zone since it has ten modern irrigation schemes and more than eighteen traditional schemes. Holota and Ambo agricultural research centers are the other good contributor for the surplus production because the district farmers used as best experience sharing for different crop varieties. The district is also known in fattening cattle and supply for Addis Ababa and nearby market (TKFLDO, 2019).

Types and Sources of Data
The study was accomplished using primary and secondary data sources, which is qualitative and quantitative in nature and the study have used and examined household demographic characteristics, socio-economic conditions of the sample household heads and other inorganic fertilizer use and use intensity determinants as a whole.

Methods of Data Collections
Data collection methods were done through structured questioner prepared for farm households. The questioner was designed and pre-tested in the field and refined in the office before the implementation of the actual survey for its validity and content, and to make overall improvement of the same and in line with the objectives of the study.

Sampling Techniques and Sample Size
Two stage sampling procedure were used to select three kebele representative out of the 23 rural kebeles in Toke Kutaye District that was used for sampling techniques for this study. In the first stage, kebeles were stratified ecologically into three: Accordingly, Seven kebeles into lowland, nine kebles into midaltitude and seven kebeles into highland since farmers in different agro-ecological zone are usually used inorganic fertilizer intensity for cereal crop production and exposed for soil fertility problem differently.
In the second stage, simple random samplings were used to select three kebeles randomly since the study was focused on the inorganic fertilizer use intensity on cereal crops at district level. One Keble from low land (Melka Nega Dembi) one kebele from medium altitude, (Emala Dawe Ajo) and one kebele from highland (Dada Gelan) were selected as representative of sample kebeles randomly using probability proportional to sample size (PPS). Moreover, out of the total these three Kebles, 2,514 total population and 156 sample household heads were represented as sample size.
For this study, the total sample size for sample household farmers was determined based on the sampling formula provided by Yamane (1967) with precision error at 8 % of (since the small holders have homogeneity characteristics).
Where, = sample size, = Total house hold head of three kebele, = level of precision considered. Source: Own sampling design(2020)

Method of Data Analysis
Both qualitative and quantative method of data analysis were used and key informants interview and secondary document analysis were done. In relation to the quantitative data analysis, coding and feeding the collected primary data into the computer, management and analysis of data were done by using statistical packaging for social science (SPSS) version 20.0 and STATA version14. Analyses of results were presented using tables and figures. Both descriptive statistics and econometric model of the data analysis were used to analyze the data collected from target respondents.

Double Hurdle Model
The model was introduced by Cragg (1971) and assumes that a household head makes two independent and regarding sequential decisions. In order to justify the use of the double hurdle model, a restriction test was carried out where the log likelihood values were obtained from a separate estimation of Tobit, Probit and Truncated regression models. The test statistic has a chi-square distribution with degrees of freedom equal to the number of independent variables (including the intercept). The double hurdle model was used for the analysis with the assumption that the determinants of inorganic fertilizer use and its intensity were independently determined. The individual's determinants of inorganic fertilizer use are dichotomous, involving two mutually exclusive alternatives. The framework for such analysis has its root in the threshold theory of decision making in which a reaction occurs only after the strength of a stimulus increases beyond the individual's reaction threshold (Miller and Hay 1981). This  (2006). Empirical studies have also indicated that a variable appearing in both equations may have opposite effects in the two equations. The double-hurdle model, developed by Cragg (1971), has been extensively applied in several empirical studies such as Newman et al. (2001).
As already noted, in this study a double hurdle model is used to identify factors determine use and use intensity of inorganic fertilizer. The double-hurdle model is a parametric generalization of the probit model in which two separate stochastic processes determine the decision to use inorganic fertilizer or not.
Probit model predicts the probability of determinants of whether an individual household use inorganic fertilizer or not. The probit model is specified as: Where: is a binary variable (1 if user is exist; and zero otherwise), representing the individual's participation decision on inorganic fertilizer use. To be specific, it takes 1 if a household uses inorganic fertilizer and is positive; and it is zero otherwise, C is a vector of independent variables (explanatory)variables that affect use of small holders inorganic fertilizer on cereal crops, D is objective to be estimated (parameters to be estimated) is house hold to use inorganic fertilizer, ɛi is an error term is normally distributed with mean (0) Where is the inorganic fertilizer use intensity which depends on the latent variable * being greater than zero and conditional to the decision to use fertilizer, is the vector of explanatory variables hypothesized to determine inorganic fertilizer use intensity, is the threshold of inorganic fertilizer use intensity in the study area.

RESULT AND DISCUSSION
This chapter present result and discussion in two main sections such as descriptive results and econometrics result.

Households characteristics by descriptive and inferential statistics in the study area.
The result of the survey indicates that out of 156 sample respondents, 133(85.25%) households are inorganic fertilizer user and 23(14.74%) households are non-user of inorganic fertilizer used by household in 2019 production year. Group comparison of user and non-user was computed by using t-test for continuous and chi-square for dummy variables indicated in Table 2 below.

Socio-economics of house hold characteristics
The mean livestock holding of small holder is 16.6 in the study area, where as mean number of livestock owned by user and non-user were 19.1 and 2.52 in TLU respectively. The mean difference of livestock owned among users and non-users is at 1% significance level with t-value (t= -3.7) and (p=0.0001).
Livestock is kept both for generating income and traction power in the study area. In order to make comparison easy, depend on Strock et al (1991) the livestock population of sampled house hold converted in to TLU (Table appendix 2). Livestock has a significant influence on generating income and power of tractors; in addition livestock used for threshing, transporting and farmers who had more livestock holding doesn't have difficulties to purchase inorganic fertilizers, in communities where agriculture is the main source of economic activity.
As survey result indicated in this study, out of total sample house hold, off-farm income users and nonusers were 62.8% and 37% respectively. The result showed that in terms of off-farm income there is statistically significant difference between inorganic fertilizer users and non-users at 1% significance level (chi=39.4) (P=0.000). This implied that off-farm income gained trade, labor sale, remittance, salary and renting of animals serves as a means of surviving of life when the income from the on farm couldn't be as expected. On the other hand, off-farm-income of household's increase, risk taking behavior may lead to a higher probability of using inorganic fertilizer. According to survey data result in (Table 2) fertilizer price for users and non-user is 1.4 and 1.2 respectively. It shows there is no significant relationship between fertilizer price perceptions and dependent variable with t-test (t=-1.62) and value of (p=0.05). Fertilizer price sometimes hinders smallholder farmers to purchase the required amount of inorganic fertilizer for their cereal crop productions. According to result in (Table 2) extension contact has 1.43 and 1.6 mean of users and non-users which is not significant and has no relation as respondents response in this study with t-test(t=1.04) and value of (p=0.85).
The result in (Table 3) indicated that sampled house hold credit accessible for users and non-users were44.3%and55% respectively with(chi2=0.9763) (pr=0.323) this modify that, there is no significant relation between credit accessible and non-accessible in the study area. According to result in (Table 2) distance from nearest market has a mean of 1.45 and 1.65 for users and non-users respectively. As a survey year result indicated that, there is no significant relation for t-test (t=1.21) and value of (p=0.88) in this study. Distance from nearest market should decide for smallholders to purchase inorganic fertilizer on time. The mean land size of sampled house hold was 1.79; whereas the mean of landholder users and non-users is 1.96 and 0.83 respectively. According to result in (Table 2) the mean difference in size of land owned among users and non-users is at 1% significance level with t-test (t= -4.49) and value of (p=0.0000). Farmers use their land for multiple agricultural activities especially for crop production and animal rearing. According to the result of the study area, large cultivated land size holder use huge inorganic fertilizer because land resource had enabled them to gained high income from his/her land asset.
Survey result in (Table 3) shows, the improved seed used by household user and non-user were 53.2% and 46.7% respectively. The chi-square result indicated improved seed used by house hold between user and non-user were at 1% significance level (chi=25.8) with value (p=0.000). Improved seed give high production potential for small holder farmers, thus they used improved seed to get more productions. This modify that using improved seed could enables farmers to use huge amount of inorganic fertilizer to get high production and income. Promoting high improved seed uses indirectly enhance inorganic fertilizer use intensity relatively.  (2020) Note, *** at 1% significant level and NS, not significant  (2020) Note, *** at 1% significant level and NS, not significant

Inorganic fertilizer use of major cereal crops in the study area.
Teff land fertility matters teff production because of low inorganic fertilizer use adds fewer amounts of productions. Teff cultivation covers large area of production in the study area because of small holder's family consume at home and supply large scale of production to the market due to it has lions share in the study area. For this reason farmers cultivate large area of teff in hectares and apply inorganic fertilizer of minimum 54kg/ha and with maximum 141kg/ha. Wheat is the second largest share of cereal crops produced by sampled household in the study area and cultivated next to teff. They produce mostly to supply to market as well as for home consumption. Farmers apply inorganic fertilizer to the wheat, minimum 65kg/ha, and maximum 147kg/ha. Maize is the third largest share of cereal crop productions in the study area, small holders produce maize majorly for family consumption at home. According to maize production in 2019, the use of inorganic fertilizer for maize production is 52kg/ha with a minimum and maximum of 139 kg/ha. Despite the fact that, the application rate and coverage gradually increased, intensity use of inorganic fertilizer is still at a low level. In the study area, there are farmers who have never been using inorganic fertilizer on their farm for maize productions.
Barely is one of the most highland cereal crop production cultivated in the study area. Small holders cultivate crop proportionally for home consumption and commercials purpose. But they use fewer amounts of inorganic fertilizers in relation to other cereal crop productions in the area. According to 2019 production year of small holders opinion at survey time, they used 49kg/ha minimum and 137kg/ha maximum averagely, this result shows small holders use less amount of inorganic fertilizer in the study area, due to this productivity decrease yearly.
Farmers are producing sorghum without inorganic fertilizer application mostly because culturally they believe sorghum never need inorganic fertilizer application but they use little inorganic fertilizer which is 23kg and 51kg/ha minimum and maximum respectively. Cereal crops constitute the largest share of household's production and consumption in the study area. Major cereals crops (Teff, wheat, maize, barely, and sorghum) account for about 70 percent of area cultivation and still small holders in the study area are using low inorganic fertilizer and harvest low production and productivity.
Source: Own sketch from survey result (2020) Figure 1: Major cereal crops inorganic fertilizer use

Factors determining smallholders' inorganic fertilizer use on cereal crops.
A result from first stage of double hurdle model has been estimated by the maximum likelihood method.
The overall model significant at 1% significance levels (Pro>chi2=0.0000) as indicated by Log pseudo likelihood value of -24.35 and this implies the significance of explanatory variables included in the models. Result from first stage of double hurdle model indicated that the statistically significant factor determine use of small holders inorganic fertilizer on cereal crops were Age of house hold head, Sex, Education, Off/non-farm income, Land size, Improved seed, and Distance from nearest market.
According to the results in (Table 4) age of household significantly and negatively determine inorganic fertilizer use at 5% significance level. As age of the sample house hold head increases by one year, their inorganic fertilizer use decreased by 0.3%. This analysis shows increase in age make farmers fear of risk taking to use inorganic fertilizer. This entails when the age of the house hold increases the probability of taking risk to use improved agricultural inputs would decrease. This result is in line with findings of Kubayo (2009), andFufa andRashid (2006) asserted that older farmers were more conservative and this negatively impacts on inorganic fertilizer user while young farmers tend to be more innovative.
As the result depicted in ( According to result in (Table 4) education of house hold head affect farm households' inorganic fertilizer use positively at 10% significance level. As an individual education increase by one year, he/she is empowered with the best skills and knowledge that can effectively use farming activities as well as it enables an individual to make independent choices and to act on the basis of the decision, and increase the tendency to co-operate with other people and use in group activities than uneducated farmers. Because According to result in (Table 4)  According to result in (Table 4) improved seed used by house hold is positive at 5% significance level.
Using improved seed by house hold enable them to get enough production, it increase their income through selling high value cereal crop productions. Result in marginal effect shows, one quintals increase in improved seed, and increase probability of inorganic fertilizers use by 13.8% remaining other variables constant. This result is in line with findings of Nambiro and Okoth,(2013) farmers that used improved maize seed had a high probability of inorganic fertilizer use compared to those who did not use improved maize seeds. This is attributed to the responsiveness of the improved maize seed inputs, thus becomes an important catalyst for using inorganic fertilizer Heisey et al.(1998). Use of improved varieties also influenced farmer's decision to use inorganic fertilizer Zegeye et al.(2001).
According to result in (Table 4) distance from nearest market affect inorganic fertilizer use negatively and significantly at 5% significance levels. Distance from input market is one of the major limiting factors for smallholder farmers to purchase inorganic fertilizer by going long distance to transport from cooperative center to their residence and lack transporting agent and cost. Oppositely, the nearer household residence to the market, the higher the probability of inorganic fertilizer use, due to the fact that, the time house hold spent is short and, need lower transportation cost and have better to agricultural input centers due to their proximity. The result indicated that, one hour increase distance of house hold from nearest market, it decrease 4.3% probability to use inorganic fertilizer remaining other variables constant. Inorganic fertilizer use decreases with an increase distance to the nearest market. This study is in line with findings of Gebresilassie (2015) result shows distance from market affects inorganic fertilizer use by small holders' farmers negatively.

Factors determining inorganic fertilizer use intensity on cereal crops.
According to the second stage of the double hurdle model in ( According to result in (Table 5) age of household negatively and significantly associated with inorganic fertilizer use intensity at 5% significance level. An increase age of small holders by one year, it decrease inorganic fertilizer use intensity by 0.95 kg/ha. The assumption that small holders who are elders not consistently follow agricultural experts' advice and doesn't accept agricultural technology and change to practice soon. This is in line with findings of Anago et al. (2020) older farmers were more risk averse and assessed the attributes of inorganic fertilizer use intensity than younger farmers.
According to the results in ( Note , ** and * represents significance at 5%, and 10% probability level Source: Computed from survey result (2020) differences based on the presumption that male and female headed households are subjected to different binding constraints with females presumably worse off in this regards emphasizing access to information, land tenure security and understanding of inorganic fertilizer use intensity.
Result in (Table 5) shows that family size has positive and significant relation with inorganic fertilizer use intensity at 10% significance level. The model result indicated that, as family size increase in numbers, increase inorganic fertilizer use intensity by 3.97kg/ha. This result indicated that having large family sizes were better for using inorganic fertilizer intensity. This is because those household who had more family, had more labor force, in terms of paying for external labors, household purchase inorganic fertilizer and use intensively. This is in line with findings of Bamire et al.(2002) explained house hold sizes provide farm labor especially in field application and intensity use of inorganic fertilizer.
According to result in (Table 5) land size indicated that, it has positive and highly significant relation with inorganic fertilizer use intensity at 1% significance level. Thus, the use intensity of inorganic fertilizer by household is basically and highly influenced by their land holding size. According to survey results, as increase in landholding size, increases the intensity use of inorganic fertilizer by 124 kg/ha. This implies that a household who have large land size is more likely to apply inorganic fertilizer intensity to increase their production and productivity than a household who have small land size. This result is consistent with findings of Negera and Bashargo (2014) land holding had a positive relationship with the intensity use of inorganic fertilizer.
According to result in (Table 5) indicated that, distance of small holders from the nearest market is negatively and significantly affect inorganic fertilizer use intensity at 10% significance level. Farmers found over distance especially elders and female headed house hold couldn't went more distance to purchase inorganic fertilizer because of lack of transportations facility, cost and energy. Computed data result indicated that, one hour increase distance of house hold head from nearest market, inorganic fertilizer use intensity decrease by 12.8 kg/ha. It is consistent with findings of Okemute et al.(2006) distance from market center, negatively influenced inorganic fertilizer use intensity. Log pseudo likelihood=-729.22 Note ,***, ** and * at 1%, 5%, and 10% significance probability level Source: Computed from survey result (2020)

Summary and conclusion
This study was conducted on examining the determinants of inorganic fertilizer use intensity on cereal crops among small holder farmers in Toke Kutaye District Oromia Regional National State, Ethiopia.
The double hurdle model was used to compute determinants of inorganic fertilizer use intensity on cereal crops among stakeholders in the study area. In the first stage double hurdle probit model was used to examine factors determine house hold inorganic fertilizer use, and result from primary stage indicated that, out of twelve explanatory variables Sex, Education, Off/non-farm income, Land size and Improved seed used by house hold were determining positively and statistically significant whereas, Age of house hold head and Distance from nearest market determine small holders inorganic fertilizer use negatively and statistically, that as Age of house hold and Distance from nearest market increase, inorganic fertilizer use decrease in the study area. Second truncated regression model was used to analyze factor determine inorganic fertilizer use intensity on cereal crops among small holders. Out of twelve explanatory variables Sex of the household head, Number of family size and Land size were positively determine extent (intensity)use of inorganic fertilizer and statistically significant whereas Age of house hold and Distance of household from nearest market determine negatively and significantly indicated that decrease inorganic fertilizer use intensity. Based on analysis done, Toke kutaye district has great potential for cereal crop production and however; inorganic fertilizer use intensity is still below the recommendation rate. So, government and non-government organization should have to give special attention to increase inorganic fertilizer use intensity on cereal crop to increase product and productivity.